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Nathan Goodyear

Circulating 2-hydroxy and 16-α hydroxy estrone levels and risk of breast canc... - 1 views

www.ncbi.nlm.nih.gov/...PMC2562592

estrogen metabolism menopause post-menopause post menopause estrogen metabolite 2-OH-estrone 16-alpha-OH-estrone 2:16alpha-OH estrone breast cancer risk hormone hormones

shared by Nathan Goodyear on 21 Aug 14 - No Cached
  • 2-OH estrogens bind to the estrogen receptor (ER) with affinity equivalent to or greater than estradiol
  • previous prospective studies have not observed any significant associations with either 2-OH or 16α-OH estrone or the ratio of the two metabolites and breast cancer risk overall.
    • Nathan Goodyear
      Nathan Goodyear on 08 Oct 15
       
      whether that risk is increased or decreased
  • it has been hypothesized that metabolism favoring the 2-OH over the 16α-OH pathway may be inversely associated with breast cancer risk (28).
  • ...24 more annotations...
  • they may act as only weak mitogens (14, 15), or as inhibitors of proliferation
  • While 16α-OH estrone binds to the ER with lower affinity than estradiol, it binds covalently (18-20) and once bound, fails to down-regulate the receptor (21). Thus, 16α-OH estrone stimulates cell proliferation in a manner comparable to estradiol in ER+ breast cancer cell lines
  • No significant associations have been observed between 2-OH estrone and breast cancer risk
  • In this large prospective study of 2-OH and 16α-OH estrone metabolites and breast cancer risk, we did not observe any significant associations overall with either individual metabolite or with the ratio of the two metabolites
  • our results do not support the hypothesis that metabolism favoring the 2-OH estrone pathway is more beneficial to breast cancer risk than that favoring the 16α-OH estrone pathway
  • To date, several epidemiologic studies have examined the association between the 2-OH and 16α-OH estrogen metabolites and breast cancer risk with inconclusive results.
  • circulating estrogen levels have been associated more strongly with ER+/PR+ tumors than with ER-/PR- tumors
  • we observed positive associations with 2-OH estrone and the 2:16α-OH estrone ratio among women with lower BMI and women with ER-/PR-tumors,
  • we observed significant positive associations of both 2-OH estrone and the 2:16α-OH estrone ratio with ER-/PR-tumors
  • Three (30, 32, 33) of four (30-33) studies observed RRs above 1 for the association between 16α-OH estrone and breast cancer risk (range of RRs=1.23-2.47); none of the point estimates was statistically significant though one trend was suggestive
  • we observed a suggestive inverse association with 16α-OH estrone and a significant positive association with the 2:16α-OH estrone ratio among lean women, suggesting possible associations in a low estrogen environment.
  • No significant associations have been observed between 2-OH estrone, 16α-OH estrone, or the 2:16α-OH estrone ratio and breast cancer risk and the direction of the estimates is not consistent across studies.
    • Nathan Goodyear
      Nathan Goodyear on 08 Oct 15
       
      better worded is no consistent, significant associations.   There are some studies that point to the 16 catecholestrogen and increased cancer risk; limited studies show negative effects of 2 catecholestrogens on cancer risk and prospective studies available pretty much dispel the idea that the 2:16 ratio has an risk predictability.
  • based on animal studies, 2-OH estrone and the 2:16α-OH estrone ratio have been hypothesized to be inversely associated with breast cancer risk
  • 16α-OH estrone increases unscheduled DNA synthesis in mouse mammary cells (27) and hence also may be genotoxic
  • Although 2-OH estrogens are capable of redox cycling, the semiquinones and quinones (i.e., the oxidized forms) form stable DNA adducts that are reversible without DNA destruction
  • In our population of PMH nonusers, we observed no associations with ER+/PR+ tumors, but significant positive associations with 2-OH estrone and the 2:16α-OH estrone ratio among women with ER-/PR- tumors
    • Nathan Goodyear
      Nathan Goodyear on 08 Oct 15
       
      one of the few studies to find this association between 2 catecholestrogens and the 2:16 ratio and ER-/PR-tumors
  • Animal and in vitro studies have shown that hydroxy estrogens can induce DNA damage either directly, through the formation of quinones and DNA adducts, or indirectly, through redox cycling and the generation of reactive oxygen species
    • Nathan Goodyear
      Nathan Goodyear on 08 Oct 15
       
      genotoxic via directe DNA adducts and indirectly via ROS; this is in addition to the proliferative effect
  • we observed a significant positive association between the 2:16α-OH estrone ratio and breast cancer risk among lean women
  • No significant associations have been observed with the 2:16α-OH estrone ratio
  • In the Danish study, no associations were observed with either ER+ or ER- tumors among PMH nonusers
  • significant positive associations with 2-OH estrone and the 2:16α-OH estrone ratio were observed among PMH users with ER+, but not ER-, tumors
  • it is possible that the genotoxicity of 2-OH estrone plays a role in hormone receptor negative tumors
  • 4-OH estrogens have a greater estrogenic potential than 2-OH estrogens, given the lower dissociation rate from estrogen receptors compared with estradiol (61), and are potentially more genotoxic since the quinones form unstable adducts, leading to depurination and mutation in vitro and in vivo
  • the balance between the catechol (i.e., 2-OH and 4-OH) and methoxy (i.e., 2-Me and 4-Me) estrogens may impact risk
  • Nathan Goodyear on 21 Aug 14
     
    The risks of estrogen metabolism are not clear cut.  Likely never will be due to the complexity of individual metabolism.  This study found no correlation between 2OH-Estrone and 2OH:16alpha-Estrone and breast cancer risk in ER+/PR+ breast cancer.  Translated: no benefit in breast cancer risk in 2OH-Estrone metabolism or increased 2OH:16alpha estrone metabolism.  There was a positive association between 2OH-Estrone and 2:16alpha-Estrone in women with ER-/PR- tumors and low BMI.
  • anonymous on 28 Oct 15
     
    pakistani sexy girls escort in dubai // russian sexy girsl escort in dubai // sexy girls in dubai // sexy girls escort in dubai //
Nathan Goodyear

Unintended effects of statins from observational studies in the general population: sys... - 0 views

www.ncbi.nlm.nih.gov/...PMC3998050

statin therapy statins myopathy cholesterol side effects diabetes liver liver enzymes

shared by Nathan Goodyear on 19 Mar 15 - No Cached
  • A markedly increased risk of myopathy was observed
  • One cohort study (Women’s Health Initiative) of higher quality and larger sample size found stronger evidence of an increased risk of self-reported T2DM (OR=1.47; 95% CI 1.32 to 1.64) for the groups of women who reported statin use at baseline and three years later
  • Hippisley-Cox et al. found an increased risk of liver enzyme changes
  • ...5 more annotations...
  • weak evidence of an increased risk of type 2 diabetes mellitus (T2DM) was observed
  • Smeeth et al. found an increased risk of incident liver disease in the first year after the index date
  • The cumulative incidence of T2DM after three years of statin treatment was 6.25%, corresponding to an excess risk of 2.25%
  • We found no increased risk of peripheral neuropathy, depression, common eye diseases, renal disorders or arthritis associated with taking statins. Studies of higher quality did not show previously reported protective effects of statins on fractures, venous thrombo-embolism or pneumonia
  • There was evidence of an increase in myopathy, raised liver enzymes and diabetes.
  • Nathan Goodyear on 19 Mar 15
     
    Statin use associated with increased myopathy, liver dysfunction, and type II Diabetes.  The authors conclude that the absolute risk is very low, yet OR was 1.47 for type II Diabetes (translated 47% increased odds of developing Diabetes as a result of statins) and OR of 2.63 in risk of myopathy (translated 163% increased odds of developing myopathy as a result of statins).  Seems the authors "low risk" statement is just applies to those without symptoms/side effects.  Physicians need to do a better job of understanding risks and customizing therapies.
Nathan Goodyear

Urinary estrogen metabolites in women at high risk for breast cancer - 0 views

carcin.oxfordjournals.org/...1532.full

breast cancer CA estrogen metabolism 2:16 OHE 2-OH-estrone 16-alpha-OH-estrone

shared by Nathan Goodyear on 10 May 12 - No Cached
  • obesity has also been linked to preferential estrogen metabolism via the 16-alpha-hydroxylation pathway; thus, a prediction of the mechanism by which obesity could increase breast cancer risk would be through a lowering of the 2:16 ratio in favor of the 16 pathway
  • increased BMI was associated with a lower 2:16 OHE ratio
  • Our data show a significant association between alcohol use, defined as at least one drink per day or an average of seven per week, and 2:16 OHE ratio
  • ...10 more annotations...
  • An alcohol-induced rise in estrogens as a consequence of alcohol catabolism in the liver has been reported
  • The only study that looked at the association between alcohol and wine consumption in healthy women did not report a clear association
  • smoking has been reported to increase induction of the 2-hydroxylation metabolic pathway (24). However, the few epidemiological studies conducted on healthy women showed no difference in estrogen metabolites with smoking status (22) or smoking dose (20), in line with our findings.
  • Family history of a first-degree family member with breast cancer confers a 2- to 4-fold risk of developing breast cancer
  • 16% of breast cancers are due to unidentified hereditary factors
  • Estrogen metabolism occurs through enzymes whose activity is determined by the presence of specific genetic polymorphisms, thus can be defined as unique to each individual.
  • the metabolism is also influenced by a number of environmental factors, which change over a lifetime
  • significantly lower 2:16 OHE ratio in women who have known breast cancer risk factors compared with healthy women
  • There was an additional significant association specifically with BMI and alcohol use, which also supports the evidence that these factors affect estrogen metabolism
  • Profiling estrogen metabolites may identify women who are more likely to develop breast cancer within a population of women with known risk factors
  • Nathan Goodyear on 10 May 12
     
    urinary estrogen metabolites shown to provide insight into breast cancer risk.  This study suggested that a low 2:16 OHE ratio increase breast cancer risk.
Nathan Goodyear

JAMA Network | JAMA | Sex Differences of Endogenous Sex Hormones and Risk of Type 2 Dia... - 0 views

jama.jamanetwork.com/article.aspx

SHBG Diabetes type II DM testosterone hormone hormones

shared by Nathan Goodyear on 11 Jun 13 - No Cached
  • lack of reliable data on levels of free hormones
  • endogenous levels of testosterone and SHBG each exhibit sex-dependent relations with risk of type 2 diabetes
  • high testosterone levels were associated with greater type 2 diabetes risk in women but lower risk in men
  • ...1 more annotation...
  • the inverse association of SHBG was stronger in women than in men
  • Nathan Goodyear on 11 Jun 13
     
    No surprise, testosterone in men and women have different effects.  I just wrote a post on this.  Testosterone is positively associated with increased risk of diabetes in women, but inversely with men.  That is increased T in women equals increased Diabetes in women; contrast with increased T associated with decreased Diabetes in men.   But the interesting point is SHBG.  This study found a strong inverse association between SHBG with diabetes in women when compared to men.  Meaning: low SHBG is associated with an increased risk of type II Diabetes.  This is at the same time that testosterone is associated with an increased risk.
Nathan Goodyear

PLOS ONE: Increased Risk of Non-Fatal Myocardial Infarction Following Testosterone Ther... - 0 views

www.plosone.org/...10.1371%2Fjournal.pone.0085805

Testosterone therapy cardiovascular disease men male hormones

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • For all TT prescription subjects combined, the post/pre prescription rate ratio for MI (RR)was 1.36
  • In men aged 65 years and older the RR was 2.19 (1.27, 3.77), while in men under age 65 years the RR was 1.17
  • increasing RR with increasing age.
  • ...20 more annotations...
  • The RRs were 0.95 (0.54, 1.67) under 55 years
  • 1.35 (0.77, 2.38) at 55–59
  • 1.29 (0.71, 2.35) at 60–64,
  • 1.35 (0.44, 4.18) at 65–69, 1.62
  • 3.43 (1.54, 7.66) at 75 years and older
  • The adjusted post/pre RR for PDE5I across all ages was 1.08
  • For TT prescription, in men under age 65 years, the RR was 2.90 (1.49, 5.62) for those with a history of heart disease and 0.90 (0.61, 1.34) for those without
  • In men aged 65 year and older, the RR was 2.16 (0.92, 5.10) for those with a history of heart disease and 2.21 (1.09, 4.45) for those without.
  • Among men aged 65 years and older, we observed a two-fold increase in the risk of MI in the 90 days after filling an initial TT prescription
  • Among younger men with a history of heart disease, we observed a two to three-fold increased risk of MI in the 90 days following an initial TT prescription and no excess risk in younger men without such a history
  • Among older men, the two-fold increased risk was associated with TT prescription regardless of cardiovascular disease history
  • our own findings appear consistent with a higher frequency of thrombotic events following TT prescription among men with more extensive coronary vascular disease.
  • Our findings are consistent with a recent meta-analysis of placebo-controlled randomized trials of testosterone therapy lasting 12 or more weeks among mainly older men, which reported that testosterone therapy increased the risk of adverse cardiovascular-related events (OR = 1.54, 95%CI:1.09, 2.18), as well as serious adverse cardiovascular-related events (OR = 1.61, 95%CI:1.01, 2.56) which included myocardial infarction along with other conditions
  • This association appeared unrelated to average baseline testosterone level (p = 0.70) but varied by source of funding (p = 0.03), with a stronger summary effect in a meta-analysis of studies not funded by the pharmaceutical industry (OR = 2.06, 95%CI:1.34, 3.17) compared with studies funded by the pharmaceutical industry
    • Nathan Goodyear
      Nathan Goodyear on 30 Jan 14
       
      This supports prior analysis that studies done by pharmaceutical corps will be more favorable to their product(s) than those independently funded.  This is called bias.
  • the evidence supports an association between testosterone therapy and risk of serious, adverse cardiovascular-related events–including non-fatal myocardial infarction–in men
  • there is some evidence that low endogenous testosterone levels may also be positively associated with cardiovascular events
  • effects of endogenous and exogenous testosterone may differ. Exogenous testosterone (TT) is associated with physiologic changes that predispose to clotting and thrombotic disorders including increased blood pressure [18], polycythemia [19], reductions in HDL cholesterol [18], [20], and hyperviscosity of the blood and platelet aggregation. [20]–[23]; TT also increases circulating estrogens [24], [25] which may play a role in the observed excess of adverse cardiovascular-related events, given that estrogen therapy has been associated with this excess in both men and women
  • did not include information on the serologic or diagnostic indications for treatment.
  • no association between PDE5I prescriptions and the risk of MI
  • Recently TT has been increasing extraordinarily rapidly, including among younger men and among those without hormone measurement
  • Nathan Goodyear on 30 Jan 14
     
    New cohort study finds increased risk of Testosterone in men > 65 and those : these are based in marketing-based medicine not evidence based medicine.
Nathan Goodyear

Genetic Determinants of Serum Testosterone Concentrations in Men - 0 views

www.ncbi.nlm.nih.gov/...PMC3188559

epigenetics low Testosterone SNPs Testosterone

shared by Nathan Goodyear on 19 Sep 17 - No Cached
  • mean serum testosterone concentrations were found to be lower in men with GG than in those with TT genotype for rs12150660
  • men with the CT genotype for rs6258 had lower serum testosterone concentrations than those with CC genotype.
  • The two autosomal SNPs identified by GWAS had a significant influence on the risk of having low serum testosterone (serum testosterone <300 ng/dl) in both the discovery and the replication cohorts with a combined odds ratio (OR) per minor allele of 0.72 (95% CI, 0.65 – 0.79) and 2.7 (95% CI, 2.1 – 3.5) for rs12150660 and rs6258, respectively
  • ...3 more annotations...
  • The risk of having low serum testosterone concentrations increased by the number of risk alleles with an OR of 1.62 (95% CI, 1.41 – 1.86) for each risk allele (Figure S4). Low serum testosterone concentrations were 6.5-times more prevalent in men with ≥3 risk alleles (30.1% prevalence of low serum testosterone) compared to men without any risk allele (4.6% prevalence of low serum testosterone;
  • SNP rs5934505 was associated with serum testosterone without SHBG-adjustment (combined p-value of 1.7×10−9) and with free testosterone (combined p-value of 6.7×10−15), but not with SHBG
  • The mean serum testosterone and calculated free testosterone but not SHBG concentrations were lower in men with T genotype than in those with C genotype for rs5934505
  • Nathan Goodyear on 19 Sep 17
     
    Genetic SNP rs5934505 associated with lower total Testosterone and lower calculated free Testosterone.  No effects on SHBG.
Nathan Goodyear

Statin use and risk of diabetes mellitus - 0 views

www.ncbi.nlm.nih.gov/...PMC4360430

statin statin therapy diabetes insulin resistance GLUT4 HgbA1c

shared by Nathan Goodyear on 04 Oct 17 - No Cached
  • An increase in new onset diabetes, i.e., 3% in statin arm and 2.4% in placebo arm was reported. This was accompanied by increase in median value of glycated haemoglobin and was one of the earlier studies to report the increase in new onset diabetes in patients on statins
  • Even after adjustment for potential confounders, statin therapy was associated with an increased risk of new-onset diabetes mellitus
  • Authors suggest that statin-induced diabetes mellitus is a medication class effect
  • ...10 more annotations...
  • Another study also reported that as compared to placebo, statin group showed a higher risk of physician reported incident diabetes and it was also observed that risk was higher in women as compared to men
  • Meta-analysis of randomized controlled trials by Sattar et al[25] involving 91140 non-diabetic patients showed that statin therapy was associated with 9% increased risk of incident diabetes
  • A number of studies showed dose dependent association between statin administration and incident diabetes
  • intensive dose of statins was associated with high incidence of new - onset diabetes
  • Treatment with atorvastatin and simvastatin may be associated with an increased risk of new onset diabetes as compared to pravastatin
  • Increased incidence of diabetes was seen with atorvastatin in the Anglo-Scandinavian Cardiac Outcomes Trial
  • Increased insulin resistance secondary to statins was demonstrated in a prospective non randomised study in patients with coronary bypass surgery
  • downregulation of GLUT4
  • Prevention of coronary and stroke events with atorvastatin in hypertensive patients who have average or lower-than-average cholesterol concentrations, in the Anglo-Scandinavian Cardiac Outcomes Trial--Lipid Lowering Arm (ASCOT-LLA): a multicentre randomised controlled trial
  • Prevention of coronary and stroke events with atorvastatin in hypertensive patients who have average or lower-than-average cholesterol concentrations, in the Anglo-Scandinavian Cardiac Outcomes Trial--Lipid Lowering Arm (ASCOT-LLA): a multicentre randomised controlled trial
  • Nathan Goodyear on 04 Oct 17
     
    Great review article of the increased risk of worsening insulin resistance, glycated hemoglobin, and diabetes risk.  Atorvastatin appears to be the worst culprit.  Mechanism partially through a decrease in GLUT4.
Nathan Goodyear

Estrogen Metabolism and Risk of Breast Cancer in Postmenopausal Women - 0 views

www.ncbi.nlm.nih.gov/...PMC3283536

estrogen metabolism estrogen metabolism breast cancer breast cancer

shared by Nathan Goodyear on 14 Oct 13 - No Cached
  • The ratio of the 2-hydroxylation pathway to parent estrogens was associated with a statistically significantly decreased risk of breast cancer
  • In this study, this ratio was more strongly associated with the risk of breast cancer compared with the ratio of 2-hydroxylation pathway to 16-hydroxylation pathway or unconjugated estradiol alone
  • 2-hydroxylation pathway catechols have relatively low affinities for estrogen receptors (4) and are rapidly cleared from circulation
  • ...6 more annotations...
  • In this study, the ratio of the 2-hydroxylation pathway to the 16-hydroxylation pathway was associated with a non-statistically significantly decreased risk of breast cancer
  • In this study, the ratio of catechols to methylated catechols in the 4-hydroxylation pathway was associated with statistically significantly increased risk of breast cancer.
  • This result is consistent with the hypothesis that mutagenic quinones derived from 4-hydroxylation pathway catechols contribute to pathogenesis of postmenopausal breast cancer.
  • Catechols in both the 2- and 4-hydroxylation pathways can be oxidized to form quinones; these reactive electrophiles can then react with DNA to form a variety of adducts
  • Methylation of the catechols prevents their conversion to reactive quinones
  • the most common DNA adducts derived from 4-hydroxylation pathway catechols are depurinating and highly mutagenic (7,40), most of those derived from 2-hydroxylation pathway catechols are stable and can be repaired with little error
  • Nathan Goodyear on 14 Oct 13
     
    Lower 2-OH estrone metabolism associated with lower risk of breast cancer, but 4-OH estrone associated with increased risk of breast cancer.
Nathan Goodyear

Unequal risks for breast cancer associated with di... [Breast Cancer Res Treat. 2008] -... - 0 views

www.ncbi.nlm.nih.gov/...17333341

bioidentical progesterone breast cancer risk

shared by Nathan Goodyear on 30 Mar 11 - No Cached
  • The association of estrogen-progestagen combinations with breast cancer risk varied significantly according to the type of progestagen: the relative risk was 1.00 (0.83-1.22) for estrogen-progesterone, 1.16 (0.94-1.43) for estrogen-dydrogesterone, and 1.69 (1.50-1.91) for estrogen combined with other progestagens.
  • These findings suggest that the choice of the progestagen component in combined HRT is of importance regarding breast cancer risk; it could be preferable to use progesterone
  • Nathan Goodyear on 30 Mar 11
     
    progesterone shows no increased risk of breast cancer; compared to synthetic progestins significantly increased risk
Nathan Goodyear

Testosterone deficiency and cardiovascular mortality Morgentaler A, - Asian J Androl - 0 views

www.ajandrology.com/preprintarticle.asp

testosterone low t low Testosterone CVD cardiovascular mortality therapy

shared by Nathan Goodyear on 01 Dec 14 - No Cached
  • overall mortality and CV mortality were inversely associated with serum T concentrations.
  • men with low serum T, defined as < 8.7 nmol l−1 (250 ng dl−1 ), demonstrated significantly greater all-cause mortality than men with higher serum T (hazard ratio [HR]: 2.24; 95% CI: 1.41-3.57), as well as greater CV mortality
  • lower T levels were significantly associated with the presence of any CV disease
  • ...19 more annotations...
  • more than 30 years of studies suggesting that low levels of T represent an increased risk for CV and overall mortality,
  • lower serum T concentrations also are associated with CV disease, including incident coronary artery disease [17],[18],[19] and atherosclerosis,
  • the actual rate of adverse events was only half as great in the T group (123 events in 1223 men at risk = 10.1%) as in the untreated group (1587 events in 7486 men = 21.2%)
  • The study by Vigen et al. [7] has already undergone two published corrections,
  • 29 medical societies have called for retraction of the article, asserting "gross data mismanagement and contamination," that rendered the study "no longer credible
  • Mortality in T-treated men was reduced by approximately half in treated men compared with untreated men, at 10.3% versus 20.7%, respectively
  • The mortality rate for men who received TTh was 3.4 deaths per 100 person-years, and 5.7 deaths per 100 person-years in untreated men
  • HR of 0.61 (95%CI: 0.42-0.88; P = 0.008), indicating a significant reduction in mortality with TTh
  • men in the highest prognostic MI risk quartile, treatment with TTh was associated with reduced risk
  • tripling in T prescriptions in the US over the last decade
  • a majority of observational studies have found that low endogenous serum T levels are associated with increased mortality.
  • Men who received TTh were able to exercise significantly longer without ischemia compared with men who received placebo
  • In men with congestive heart failure, those who received T demonstrated greater walking distance and other functional endpoints compared with those who received placebo
  • TTh has been shown uniformly and repeatedly to improve several known CV risk factors, including reduced fat mass, body fat percent, and waist circumference, and increased lean mass
  • improved glycemic control
  • reductions in insulin resistance.
  • the evidence strongly points to improved CV status with normal serum T or treatment with TTh in men with TD
  • analysis of health insurance claims data that reported a 36% increased rate of nonfatal MI in the 90d following receipt of a T prescription compared with the 12 prior months.
  • Comparison with men who received a prescription for a phosphodiesterase type 5 inhibitor (PDE5i) revealed no increased rate of MI following the prescription
  • Nathan Goodyear on 01 Dec 14
     
    Great review by Morgentaler of Testosterone and CVD.  He highlights the significant flaws in the JAMA and the NEJM articles of Testosterone therapy risks.  Morgentaler highlights the significant evidence that points to low T and increased risk of CVD. On contention I have, is Morgantaler seems to flip aside the massive uptick of Testosterone use in the US as compared to other countries.  The evidence definitely points to Testosterone therapy as being safe in those with low T, but there is definitely a problem of significant Testosterone doping that is taking place as well.
Nathan Goodyear

Coffee and cancer risk: a summary overview - 0 views

insights.ovid.com/pubmed

coffee cancer

shared by Nathan Goodyear on 20 Apr 18 - No Cached
  • Nathan Goodyear on 20 Apr 18
     
    2017 meta-analysis finds no increase relative risk (RR) of cancer with coffee consumption.  First, this must consider all the "other" junk put in coffee these days.  Second, and most important, this study looked at RR which tells us nothing about risk.  Studies like this don't do much more than confuse the general public, doctors, and judges--recent judge ruling in California that coffee needs a carcinogenic lable.  Third, epigenetis will tell us about individual risk.  I am growing more concerned that the majority of studies published today are merely statistical dances to ensure publication.  Is it good that no RR was found? yes, does that give any indication of absolute risk?  No.  Take home: enjoy your morning cup of joe as nature prescribed--no additives.
Nathan Goodyear

Substantial contribution of extrinsic risk factors to cancer development - 0 views

www.ncbi.nlm.nih.gov/...PMC4836858

cancer lifestyle

shared by Nathan Goodyear on 03 Jan 18 - No Cached
  • Here we provide evidence that intrinsic risk factors contribute only modestly (<10~30%) to cancer development
  • we conclude that cancer risk is heavily influenced by extrinsic factors. These results carry immense consequences for strategizing cancer prevention
  • cancers are proposed to originate from the malignant transformation of normal tissue progenitor and stem cells
  • ...14 more annotations...
  • “Intrinsic processes” include those that result in mutations due to random errors in DNA replication whereas “extrinsic factors” are environmental factors that affect mutagenesis rates (such as UV radiation, ionizing radiation, and carcinogens
  • intrinsic factors do not play a major causal role.
  • intrinsic cancer risk should be determined by the cancer incidence for those cancers with the least risk in the entire group controlling for total stem cell divisions
  • if one or more cancers would feature a much higher cancer incidence, for example, lung cancer among smokers vs. non-smokers, then this most likely reflects additional (and probably extrinsic) risk factors (smoking in this case)
  • Particularly, for breast and prostate cancers, it has long been observed that large international geographical variations exist in their incidences (5-fold for breast cancer, 25-fold for prostate cancer)14, and immigrants moving from countries with lower cancer incidence to countries with higher cancer rates soon acquire the higher risk of their new country
  • Colorectal cancer is another high-incidence cancer that is widely considered to be an environmental disease17, with an estimated 75% or more colorectal cancer risk attributable to diet
  • melanoma, its risk ascribed to sun exposure is around 65–86%
  • non-melanoma basal and squamous skin cancers, ~90% is attributable to UV
  • 75% of esophageal cancer, or head and neck cancer are caused by tobacco and alcohol
  • HPV may cause ~90% cases in cervical cancer23, ~90% cases in anal cancer24, and ~70% in oropharyngeal cancer
  • HBV and HCV may account for ~80% cases of hepatocellular carcinoma
  • H pylori may be responsible for 65–80% of gastric cancer
  • While a few cancers have relatively large proportions of intrinsic mutations (>50%), the majority of cancers have large proportions of extrinsic mutations, for example, ~100% for Myeloma, Lung and Thyroid cancers and ~80–90% for Bladder, Colorectal and Uterine cancers, indicating substantial contributions of carcinogen exposures in the development of most cancers
  • onsistent estimate of contribution of extrinsic factors of >70–90% in most common cancer types. This concordance lends significant credibility to the overall conclusion on the role of extrinsic factors in cancer development
  • Nathan Goodyear on 03 Jan 18
     
    Really great read.  Cancer is a majority lifestyle disease.
Nathan Goodyear

Sex Hormones and Colorectal Cancer: What Have We Learned So Far? - 0 views

jnci.oxfordjournals.org/...jnci.djq444.full

hormones colon colorectal cancer

shared by Nathan Goodyear on 09 Jun 14 - No Cached
  • Nathan Goodyear on 09 Jun 14
     
    This article focus' more on the risks of colorectal cancer in men.  It does perform a mini-review on risks for women.  It appears progesterone is important in prevention of colorectal cancer in women.  Post-menopause, women with HRT have a reduced risk. In contrast, men with androgen deprivation therapy, there is an increase risk of colorectal cancer.
Nathan Goodyear

Risk of Myocardial Infarction in Older Men Receiving Testosterone Therapy - 0 views

aop.sagepub.com/...1060028014539918.full

Testosterone men male hormone hormones cardiovascular risk disease MI myocardial infarction heart attack heart disease

shared by Nathan Goodyear on 22 Jul 14 - No Cached
  • Nathan Goodyear on 22 Jul 14
     
    This study appears to fly in the face of the recent studies on the dangers of Testosterone therapy in those with comorbidities.  This study was a retrospective cohort.  The study found that men in the highest risk for MI, had a reduced MI risk with Testosterone therapy.  Men in the lower risk quartiles had no such benefit.  Of note, the frequency of injections suggests inadequate dosing i.e. 4.4 in first year and 8.2 in follow up.  Most injection regimens will require at least monthly injections, though Testosterone pellets were used.  Of special note, no mention of level testing of Testosterone prior to study and/or during study and follow up.
Nathan Goodyear

Urinary Estrogens and Estrogen Metabolites and Subsequent Risk of Breast Cancer among P... - 0 views

cancerres.aacrjournals.org/...696.full

estrogen metabolites estrogen metabolism ER estrogen receptors ROS hormones cancer breast cancer

shared by Nathan Goodyear on 07 Oct 15 - No Cached
  • both 2- and 4-catechol estrogen metabolites bind to the ER with affinities comparable with estradiol, 4-catechol estrogen metabolites have lower dissociation rates than estradiol and an enhanced ability to upregulate ER-dependent processes
  • 2-catechol estrogen metabolites act as either weak mitogens (39) or weak inhibitors of cell proliferation
  • While 16α-hydroxyestrone binds to the ER with lower affinity than estradiol, it binds covalently (41) and leads to a constitutively activated ER
  • ...15 more annotations...
  • 4-hydroxyestradiol and 16α-hydroxyestrone increasing proliferation and decreasing apoptosis in a manner similar to estradiol; however, these effects were achieved only at concentrations 10-fold higher than estradiol (39). In contrast, 2-hydroxyestradiol did not have substantial proliferative or antiapoptotic effects
  • In our study, the associations with both 2-hydroxyestrone and 16α-hydroxyestrone were nonsignificantly inverse and we did not observe a consistent trend or significant associations between the 2-hydroxyestrone:16α-hydroxyestrone ratio and breast cancer risk
  • Ratios of the 3 hydroxylation pathways were not significantly associated with risk although the 2:16-pathway and 4:16-pathway ratios were suggestively inversely associated
  • a significant inverse association with the ratio of parent estrogens to estrogen metabolites
  • several potentially estrogenic and genotoxic mechanisms
  • Estrogen metabolites also can be genotoxic
  • Catechol estrogens can be oxidized into quinones and induce DNA damage directly through the formation of DNA adducts, or indirectly via redox cycling and generation of reactive oxygen species
  • the oxidized forms of the catechol estrogens differ in their ability to damage DNA through adducts, with oxidized 2-catechols forming stable and reversible DNA adducts and oxidized 4-catechols forming unstable adducts, which lead to depurination and mutations
  • 2- and 4-catechols have been shown to produce reactive oxygen species and induce oxidative DNA damage
  • act independently from the ER
  • 16α-Hydroxyestrone also may be genotoxic
  • While the catechol estrogens have estrogenic and genotoxic potential, the methylated catechol estrogens, which are catechol estrogens with one hydroxyl group methylated, have been hypothesized to lower the risk of breast cancer
  • The suggested mechanisms are indirect, by decreasing circulating levels of catechol estrogens and thereby the opportunity for catechols to exert genotoxic or proliferative effects, or direct, by inhibiting tumor growth and inducing apoptosis
  • the balance between phase I (oxidation) and phase II (methylation) metabolism of estrogen may be important in hormonally related cancer development.
  • Despite the estrogenic and genotoxic potential of many of the estrogen metabolites, we only observed a significantly increased breast cancer risk with one estrogen metabolite, 17-epiestriol, which has particularly strong estrogenic activity and binds to both ERα and ERβ with an affinity comparable with estradiol
  • Nathan Goodyear on 07 Oct 15
     
    review of estrogen metabolites and breast cancer risk in premenopausal women.
pharmacybiz

Paxlovid : MHRA Approves Second Oral Covid-19 Antiviral - 0 views

www.pharmacy.biz/al-covid-19-antiviral-paxlovid

Paxlovid Pharmacy-Business paxlovid-mhra paxlovid-mhra-approval covid-antiviral-drug-uk Antiviral-drugs-UK What's-new-in-medicine-2021

shared by pharmacybiz on 10 Jan 22 - No Cached
  • pharmacybiz on 10 Jan 22
     
    UK regulator has approved a second oral antiviral for early treatment of Covid-19 in high-risk adults, after molnupiravir. The Medicines and Healthcare products Regulatory Agency (MHRA) gave its nod for a new treatment called Paxlovid (PF-07321332 and ritonavir), after finding it safe and effective at reducing the risk of hospitalisation and death in people diagnosed with mild Covid-19 infection. Developed by Pfizer, Paxlovid prevents the multiplying of virus, helping the body to overcome the infection. A clinical trial for the treatment in high risk individuals revealed that a five-days course of Paxlovid reduces the risk of hospitalisation and death by 89 per cent. It further revealed that Paxlovid is most effective when taken in the early stage of infection. Dr June Raine, MHRA chief executive, said: "We now have a further antiviral medicine for the treatment of Covid-19 that can be taken by mouth rather than administered intravenously. This means it can be administered outside a hospital setting, before Covid-19 has progressed to a severe stage."
Nathan Goodyear

Testosterone: a vascular hormone in health and disease - 0 views

joe.endocrinology-journals.org/...R47.full

testosterone hormone health disease hormones men male cardiovascular disease CVD

shared by Nathan Goodyear on 13 May 13 - No Cached
  • Testosterone has beneficial effects on several cardiovascular risk factors, which include cholesterol, endothelial dysfunction and inflammation
  • In clinical studies, acute and chronic testosterone administration increases coronary artery diameter and flow, improves cardiac ischaemia and symptoms in men with chronic stable angina and reduces peripheral vascular resistance in chronic heart failure.
  • testosterone is an L-calcium channel blocker and induces potassium channel activation in vascular smooth muscle cells
  • ...54 more annotations...
  • Animal studies have consistently demonstrated that testosterone is atheroprotective, whereas testosterone deficiency promotes the early stages of atherogenesis
  • there is no compelling evidence that testosterone replacement to levels within the normal healthy range contributes adversely to the pathogenesis of CVD (Carson & Rosano 2011) or prostate cancer (Morgentaler & Schulman 2009)
  • bidirectional effect between decreased testosterone concentrations and disease pathology exists as concomitant cardiovascular risk factors (including inflammation, obesity and insulin resistance) are known to reduce testosterone levels and that testosterone confers beneficial effects on these cardiovascular risk factors
  • Achieving a normal physiological testosterone concentration through the administration of testosterone replacement therapy (TRT) has been shown to improve risk factors for atherosclerosis including reducing central adiposity and insulin resistance and improving lipid profiles (in particular, lowering cholesterol), clotting and inflammatory profiles and vascular function
  • It is well known that impaired erectile function and CVD are closely related in that ED can be the first clinical manifestation of atherosclerosis often preceding a cardiovascular event by 3–5 years
  • no decrease in the response (i.e. no tachyphylaxis) of testosterone and that patient benefit persists in the long term.
  • free testosterone levels within the physiological range, has been shown to result in a marked increase in both flow- and nitroglycerin-mediated brachial artery vasodilation in men with CAD
  • Clinical studies, however, have revealed either small reductions of 2–3 mm in diastolic pressure or no significant effects when testosterone is replaced within normal physiological limits in humans
  • Endothelium-independent mechanisms of testosterone are considered to occur primarily via the inhibition of voltage-operated Ca2+ channels (VOCCs) and/or activation of K+ channels (KCs) on smooth muscle cells (SMCs)
  • Testosterone shares the same molecular binding site as nifedipine
  • Testosterone increases the expression of endothelial nitric oxide synthase (eNOS) and enhances nitric oxide (NO) production
  • Testosterone also inhibited the Ca2+ influx response to PGF2α
  • one of the major actions of testosterone is on NO and its signalling pathways
  • In addition to direct effects on NOS expression, testosterone may also affect phosphodiesterase type 5 (PDE5 (PDE5A)) gene expression, an enzyme controlling the degradation of cGMP, which acts as a vasodilatory second messenger
  • the significance of the action of testosterone on VSMC apoptosis and proliferation in atherosclerosis is difficult to delineate and may be dependent upon the stage of plaque development
  • Several human studies have shown that carotid IMT (CIMT) and aortic calcification negatively correlate with serum testosterone
  • t long-term testosterone treatment reduced CIMT in men with low testosterone levels and angina
  • neither intracellular nor membrane-associated ARs are required for the rapid vasodilator effect
  • acute responses appear to be AR independent, long-term AR-mediated effects on the vasculature have also been described, primarily in the context of vascular tone regulation via the modulation of gene transcription
  • Testosterone and DHT increased the expression of eNOS in HUVECs
  • oestrogens have been shown to activate eNOS and stimulate NO production in an ERα-dependent manner
  • Several studies, however, have demonstrated that the vasodilatory actions of testosterone are not reduced by aromatase inhibition
  • non-aromatisable DHT elicited similar vasodilation to testosterone treatment in arterial smooth muscle
  • increased endothelial NOS (eNOS) expression and phosphorylation were observed in testosterone- and DHT-treated human umbilical vein endothelial cells
  • Androgen deprivation leads to a reduction in neuronal NOS expression associated with a decrease of intracavernosal pressure in penile arteries during erection, an effect that is promptly reversed by androgen replacement therapy
  • Observational evidence suggests that several pro-inflammatory cytokines (including interleukin 1β (IL1β), IL6, tumour necrosis factor α (TNFα), and highly sensitive CRP) and serum testosterone levels are inversely associated in patients with CAD, T2DM and/or hypogonadism
  • patients with the highest IL1β concentrations had lower endogenous testosterone levels
  • TRT has been reported to significantly reduce TNFα and elevate the circulating anti-inflammatory IL10 in hypogonadal men with CVD
  • testosterone treatment to normalise levels in hypogonadal men with the MetS resulted in a significant reduction in the circulating CRP, IL1β and TNFα, with a trend towards lower IL6 compared with placebo
  • parenteral testosterone undecanoate, CRP decreased significantly in hypogonadal elderly men
  • Higher levels of serum adiponectin have been shown to lower cardiovascular risk
  • Research suggests that the expression of VCAM-1, as induced by pro-inflammatory cytokines such as TNFα or interferon γ (IFNγ (IFNG)) in endothelial cells, can be attenuated by treatment with testosterone
  • Testosterone also inhibits the production of pro-inflammatory cytokines such as IL6, IL1β and TNFα in a range of cell types including human endothelial cells
  • decreased inflammatory response to TNFα and lipopolysaccharide (LPS) in human endothelial cells when treated with DHT
  • The key to unravelling the link between testosterone and its role in atherosclerosis may lay in the understanding of testosterone signalling and the cross-talk between receptors and intracellular events that result in pro- and/or anti-inflammatory actions in athero-sensitive cells.
  • testosterone functions through the AR to modulate adhesion molecule expression
  • pre-treatment with DHT reduced the cytokine-stimulated inflammatory response
  • DHT inhibited NFκB activation
  • DHT could inhibit an LPS-induced upregulation of MCP1
  • Both NFκB and AR act at the transcriptional level and have been experimentally found to be antagonistic to each other
  • As the AR and NFκB are mutual antagonists, their interaction and influence on functions can be bidirectional, with inflammatory agents that activate NFκB interfering with normal androgen signalling as well as the AR interrupting NFκB inflammatory transcription
  • prolonged exposure of vascular cells to the inflammatory activation of NFκB associated with atherosclerosis may reduce or alter any potentially protective effects of testosterone
  • DHT and IFNγ also modulate each other's signalling through interaction at the transcriptional level, suggesting that androgens down-regulate IFN-induced genes
  • (Simoncini et al. 2000a,b). Norata et al. (2010) suggest that part of the testosterone-mediated atheroprotective effects could depend on ER activation mediated by the testosterone/DHT 3β-derivative, 3β-Adiol
  • TNFα-induced induction of ICAM-1, VCAM-1 and E-selectin as well as MCP1 and IL6 was significantly reduced by a pre-incubation with 3β-Adiol in HUVECs
  • 3β-Adiol also reduced LPS-induced gene expression of IL6, TNFα, cyclooxygenase 2 (COX2 (PTGS2)), CD40, CX3CR1, plasminogen activator inhibitor-1, MMP9, resistin, pentraxin-3 and MCP1 in the monocytic cell line U937 (Norata et al. 2010)
  • This study suggests that testosterone metabolites, other than those generated through aromatisation, could exert anti-inflammatory effects that are mediated by ER activation.
  • The authors suggest that DHT differentially effects COX2 levels under physiological and pathophysiological conditions in human coronary artery smooth muscle cells and via AR-dependent and -independent mechanisms influenced by the physiological state of the cell
  • There are, however, a number of systematic meta-analyses of clinical trials of TRT that have not demonstrated an increased risk of adverse cardiovascular events or mortality
  • The TOM trial, which was designed to investigate the effect of TRT on frailty in elderly men, was terminated prematurely as a result of an increased incidence of cardiovascular-related events after 6 months in the treatment arm
  • trials of TRT in men with either chronic stable angina or chronic cardiac failure have also found no increase in either cardiovascular events or mortality in studies up to 12 months
  • Evidence may therefore suggest that low testosterone levels and testosterone levels above the normal range have an adverse effect on CVD, whereas testosterone levels titrated to within the mid- to upper-normal range have at least a neutral effect or, taking into account the knowledge of the beneficial effects of testosterone on a series of cardiovascular risk factors, there may possibly be a cardioprotective action
  • The effect of testosterone on human vascular function is a complex issue and may be dependent upon the underlying androgen and/or disease status.
  • the majority of studies suggest that testosterone may display both acute and chronic vasodilatory effects upon various vascular beds at both physiological and supraphysiological concentrations and via endothelium-dependent and -independent mechanisms
  • Nathan Goodyear on 13 May 13
     
    Good deep look into the testosterone and CVD link.
Nathan Goodyear

Improved coronary risk assessment among intermediate risk patients using a clinical and... - 0 views

www.ncbi.nlm.nih.gov/...PMC3666558

CHD coronary heart disease heart disease CHDRA CHD risk assessment assessment

shared by Nathan Goodyear on 01 Nov 16 - No Cached
  • Nathan Goodyear on 01 Nov 16
     
    study suggests biomarkers, CHDRA, with history provides good 5 year CHD risk assessment among those with intermediate risk.
Nathan Goodyear

Testosterone and glucose metabolism in men: current concepts and controversies - 0 views

joe.endocrinology-journals.org/...R37.full

Low T Testosterone metabolic syndrome MetS Diabetes men male glucose hormone hormones g

shared by Nathan Goodyear on 04 Feb 14 - No Cached
  • Around 50% of ageing, obese men presenting to the diabetes clinic have lowered testosterone levels relative to reference ranges based on healthy young men
  • The absence of high-level evidence in this area is illustrated by the Endocrine Society testosterone therapy in men with androgen deficiency clinical practice guidelines (Bhasin et al. 2010), which are appropriate for, but not specific to men with metabolic disorders. All 32 recommendations made in these guidelines are based on either very low or low quality evidence.
  • A key concept relates to making a distinction between replacement and pharmacological testosterone therapy
  • ...59 more annotations...
  • The presence of symptoms was more closely linked to increasing age than to testosterone levels
  • Findings similar to type 2 diabetes were reported for men with the metabolic syndrome, which were associated with reductions in total testosterone of −2.2 nmol/l (95% CI −2.41 to 1.94) and in free testosterone
  • low testosterone is more predictive of the metabolic syndrome in lean men
  • Cross-sectional studies uniformly show that 30–50% of men with type 2 diabetes have lowered circulating testosterone levels, relative to references based on healthy young men
  • In a recent cross-sectional study of 240 middle-aged men (mean age 54 years) with either type 2 diabetes, type 1 diabetes or without diabetes (Ng Tang Fui et al. 2013b), increasing BMI and age were dominant drivers of low total and free testosterone respectively.
  • both diabetes and the metabolic syndrome are associated with a modest reduction in testosterone, in magnitude comparable with the effect of 10 years of ageing
  • In a cross-sectional study of 490 men with type 2 diabetes, there was a strong independent association of low testosterone with anaemia
  • In men, low testosterone is a marker of poor health, and may improve our ability to predict risk
    • Nathan Goodyear
      Nathan Goodyear on 04 Feb 14
       
      probably the most important point made in this article
  • low testosterone identifies men with an adverse metabolic phenotype
  • Diabetic men with low testosterone are significantly more likely to be obese or insulin resistant
  • increased inflammation, evidenced by higher CRP levels
  • Bioavailable but not free testosterone was independently predictive of mortality
  • It remains possible that low testosterone is a consequence of insulin resistance, or simply a biomarker, co-existing because of in-common risk factors.
  • In prospective studies, reviewed in detail elsewhere (Grossmann et al. 2010) the inverse association of low testosterone with metabolic syndrome or diabetes is less consistent for free testosterone compared with total testosterone
  • In a study from the Framingham cohort, SHBG but not testosterone was prospectively and independently associated with incident metabolic syndrome
  • low SHBG (Ding et al. 2009) but not testosterone (Haring et al. 2013) with an increased risk of future diabetes
  • In cross-sectional studies of men with (Grossmann et al. 2008) and without (Bonnet et al. 2013) diabetes, SHBG but not testosterone was inversely associated with worse glycaemic control
  • SHBG may have biological actions beyond serving as a carrier protein for and regulator of circulating sex steroids
  • In men with diabetes, free testosterone, if measured by gold standard equilibrium dialysis (Dhindsa et al. 2004), is reduced
    • Nathan Goodyear
      Nathan Goodyear on 04 Feb 14
       
      expensive, laborious process filled with variables
  • Low free testosterone remains inversely associated with insulin resistance, independent of SHBG (Grossmann et al. 2008). This suggests that the low testosterone–dysglycaemia association is not solely a consequence of low SHBG.
  • Experimental evidence reviewed below suggests that visceral adipose tissue is an important intermediate (rather than a confounder) in the inverse association of testosterone with insulin resistance and metabolic disorders.
  • testosterone promotes the commitment of pluripotent stem cells into the myogenic lineage and inhibits their differentiation into adipocytes
  • testosterone regulates the metabolic functions of mature adipocytes (Xu et al. 1991, Marin et al. 1995) and myocytes (Pitteloud et al. 2005) in ways that reduce insulin resistance.
  • Pre-clinical evidence (reviewed in Rao et al. (2013)) suggests that at the cellular level, testosterone may improve glucose metabolism by modulating the expression of the glucose-transported Glut4 and the insulin receptor, as well as by regulating key enzymes involved in glycolysis.
  • More recently testosterone has been shown to protect murine pancreatic β cells against glucotoxicity-induced apoptosis
  • Interestingly, a reciprocal feedback also appears to exist, given that not only chronic (Cameron et al. 1990, Allan 2013) but also, as shown more recently (Iranmanesh et al. 2012, Caronia et al. 2013), acute hyperglycaemia can lower testosterone levels.
  • There is also evidence that testosterone regulates insulin sensitivity directly and acutely
  • In men with prostate cancer commencing androgen deprivation therapy, both total as well as, although not in all studies (Smith 2004), visceral fat mass increases (Hamilton et al. 2011) within 3 months
  • More prolonged (>12 months) androgen deprivation therapy has been associated with increased risk of diabetes in several large observational registry studies
  • Testosterone has also been shown to reduce the concentration of pro-inflammatory cytokines in some, but not all studies, reviewed recently in Kelly & Jones (2013). It is not know whether this effect is independent of testosterone-induced changes in body composition.
  • the observations discussed in this section suggest that it is the decrease in testosterone that causes insulin resistance and diabetes. One important caveat remains: the strongest evidence that low testosterone is the cause rather than consequence of insulin resistance comes from men with prostate cancer (Grossmann & Zajac 2011a) or biochemical castration, and from mice lacking the androgen receptor.
  • Several large prospective studies have shown that weight gain or development of type 2 diabetes is major drivers of the age-related decline in testosterone levels
  • there is increasing evidence that healthy ageing by itself is generally not associated with marked reductions in testosterone
  • Circulating testosterone, on an average 30%, is lower in obese compared with lean men
  • increased visceral fat is an important component in the association of low testosterone and insulin resistance
  • The vast majority of men with metabolic disorders have functional gonadal axis suppression with modest reductions in testosterone levels
  • obesity is a dominant risk factor
  • men with Klinefelter syndrome have an increased risk of metabolic disorders. Interestingly, greater body fat mass is already present before puberty
  • Only 5% of men with type 2 diabetes have elevated LH levels
  • inhibition of the gonadal axis predominantly takes place in the hypothalamus, especially with more severe obesity
  • Metabolic factors, such as leptin, insulin (via deficiency or resistance) and ghrelin are believed to act at the ventromedial and arcuate nuclei of the hypothalamus to inhibit gonadotropin-releasing hormone (GNRH) secretion from GNRH neurons situated in the preoptic area
  • kisspeptin has emerged as one of the most potent secretagogues of GNRH release
  • hypothesis that obesity-mediated inhibition of kisspeptin signalling contributes to the suppression of the HPT axis, infusion of a bioactive kisspeptin fragment has been recently shown to robustly increase LH pulsatility, LH levels and circulating testosterone in hypotestosteronaemic men with type 2 diabetes
  • A smaller study with a similar experimental design found that acute testosterone withdrawal reduced insulin sensitivity independent of body weight, whereas oestradiol withdrawal had no effects
  • suppression of the diabesity-associated HPT axis is functional, and may hence be reversible
  • Obesity and dysglycaemia and associated comorbidities such as obstructive sleep apnoea (Hoyos et al. 2012b) are important contributors to the suppression of the HPT axis
  • weight gain and development of diabetes accelerate the age-related decline in testosterone
  • Modifiable risk factors such as obesity and co-morbidities are more strongly associated with a decline in circulating testosterone levels than age alone
  • 55% of symptomatic androgen deficiency reverted to a normal testosterone or an asymptomatic state after 8-year follow-up, suggesting that androgen deficiency is not a stable state
  • Weight loss can reactivate the hypothalamic–pituitary–testicular axis
  • Leptin treatment resolves hypogonadism in leptin-deficient men
  • The hypothalamic–pituitary–testicular axis remains responsive to treatment with aromatase inhibitors or selective oestrogen receptor modulators in obese men
  • Kisspeptin treatment increases LH secretion, pulse frequency and circulating testosterone levels in hypotestosteronaemic men with type 2 diabetes
  • change in BMI was associated with the change in testosterone (Corona et al. 2013a,b).
  • weight loss can lead to genuine reactivation of the gonadal axis by reversal of obesity-associated hypothalamic suppression
  • There is pre-clinical and observational evidence that chronic hyperglycaemia can inhibit the HPT axis
  • in men who improved their glycaemic control over time, testosterone levels increased. By contrast, in those men in whom glycaemic control worsened, testosterone decreased
  • testosterone levels should be measured after successful weight loss to identify men with an insufficient rise in their testosterone levels. Such men may have HPT axis pathology unrelated to their obesity, which will require appropriate evaluation and management.
  • Nathan Goodyear on 04 Feb 14
     
    Article discusses the expanding evidence of low T and Metabolic syndrome.
Nathan Goodyear

Increased risk of cognitive impairment or dementia in women who underwent oophorectomy ... - 0 views

www.neurology.org/...1074

dementia cognitive decline menopause Estrogen women HRT HT BHRT hormone hormones

shared by Nathan Goodyear on 06 Aug 13 - No Cached
  • Nathan Goodyear on 06 Aug 13
     
    Untold risk of early ovary removal appears to be cognitive decline and increased risk of dementia.  The earlier the age of removal, the more the increased risk of cognitive decline.  
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