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The prevalence of hypovitaminosis D among US adults: data from the NHANES III. Zadshir A, Tareen N, Pan D, Norris K, Martins D. Ethn Dis. 2005 Autumn;15(4 Suppl 5):S5-97-101. PMID: 16315387 CONCLUSION: Serum levels of 25(OH) D3 are below the recommended levels for a large portion of the general adult population and in most minorities. Need exists for a critical review and probable revision of current recommendations for adult vitamin D intake to maintain adequate 25(OH) D3 levels.

Holick, M. F., MacLaughlin, J. A. & Doppelt, S. H. (1981) Factors that influence the cutaneous photosynthesis of previtamin D3. Science 211:590-593 When human skin was exposed to simulated solar ultraviolet radiation, epidermal 7-dehydrocholesterol was converted to previtamin D3. During prolonged exposure to simulated solar ultraviolet radiation, the synthesis of previtamin D3 reached a plateau at about 10 to 15 percent of the original 7-dehydrocholesterol content, and previtamin D3 was photoisomerized to two biologically inert isomers, lumisterol3 and tachysterol3. Increases either in skin melanin concentration or in latitude necessitated increases in the exposure time to simulated solar ultraviolet radiation required to maximize the formation, but not the total content, of previtamin D3. In order of importance, the significant determinants limiting the cutaneous production of previtamin D3 are (i) photochemical regulation, (ii) pigmentation, and (iii) latitude.

Vitamin D in preventive medicine: are we ignoring the evidence? Zittermann A. Br J Nutr. 2003 May;89(5):552-72. Review. PMID: 12720576 Vitamin D is metabolised by a hepatic 25-hydroxylase into 25-hydroxyvitamin D (25(OH)D) and by a renal 1alpha-hydroxylase into the vitamin D hormone calcitriol. Calcitriol receptors are present in more than thirty different tissues. Apart from the kidney, several tissues also possess the enzyme 1alpha-hydroxylase, which is able to use circulating 25(OH)D as a substrate. Serum levels of 25(OH)D are the best indicator to assess vitamin D deficiency, insufficiency, hypovitaminosis, adequacy, and toxicity. European children and young adults often have circulating 25(OH)D levels in the insufficiency range during wintertime. Elderly subjects have mean 25(OH)D levels in the insufficiency range throughout the year. In institutionalized subjects 25(OH)D levels are often in the deficiency range. There is now general agreement that a low vitamin D status is involved in the pathogenesis of osteoporosis. Moreover, vitamin D insufficiency can lead to a disturbed muscle function. Epidemiological data also indicate a low vitamin D status in tuberculosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel diseases, hypertension, and specific types of cancer. Some intervention trials have demonstrated that supplementation with vitamin D or its metabolites is able: (i) to reduce blood pressure in hypertensive patients; (ii) to improve blood glucose levels in diabetics; (iii) to improve symptoms of rheumatoid arthritis and multiple sclerosis. The oral dose necessary to achieve adequate serum 25(OH)D levels is probably much higher than the current recommendations of 5-15 microg/d.

Vitamin D and intervention trials in prostate cancer: from theory to therapy. Schwartz GG. Ann Epidemiol. 2009 Feb;19(2):96-102. Epub 2008 Jul 10. PMID: 18619854 doi:10.1016/j.annepidem.2008.03.007 This suggests that whereas vitamin D (e.g., cholecalciferol) might prevent prostate cancer, existing prostate tumors likely would require treatment with 1,25(OH)(2)D and/or its analogs. The major obstacle to the use of 1,25(OH)(2)D in patients therapeutically is the risk of hypercalcemia. Several maneuvers to reduce this risk, including pulse dosing and the use of less calcemic 1,25(OH)(2)D analogs, have been explored in Phase I-III clinical trials. Once merely a promise, vitamin D-based therapies for prostate cancer may soon be medical practice.

"D-vitamiini parantaa yli 65-vuotiaiden ihmisten elämänlaatua ja ehkäisee ennenaikaista sydänkuolemaa, ilmenee Amerikan geriatriyhdistyksen lehden julkaisemasta tutkimuksesta. Myös Suomen THL julkaisi vastikään raportin, jonka mukaan seerumin vähäinen D-vitamiinin pitoisuus liittyi sydäntauteihin ja -kuolemiin. Seerumin D-vitamiinin pitoisuus (25-0HD eli S-D-25), joka on pienempi kuin 25 nmol/l, liittyy suurentuneeseen sydäntautien ja kuoleman riskiin, kirjoittavat amerikkalaiset tutkijat. Heidän aineistonsa käsitti 3408 yli 65-vuotiasta miestä ja naista, joiden terveydentilaa seurattiin Third National Health and Nutrition Examination Survey (NHANES III) -tutkimuksessa. Keskimäärin 7,3 vuoden seuruun aikana kuoli 1493 (44 %) tutkituista. Vähän yli puolet (767) kuolemista johtui sydänkohtauksista."

"D-vitamiini parantaa yli 65-vuotiaiden ihmisten elämänlaatua ja ehkäisee ennenaikaista sydänkuolemaa, ilmenee Amerikan geriatriyhdistyksen lehden julkaisemasta tutkimuksesta. Myös Suomen THL julkaisi vastikään raportin, jonka mukaan seerumin vähäinen D-vitamiinin pitoisuus liittyi sydäntauteihin ja -kuolemiin. Seerumin D-vitamiinin pitoisuus (25-0HD eli S-D-25), joka on pienempi kuin 25 nmol/l, liittyy suurentuneeseen sydäntautien ja kuoleman riskiin, kirjoittavat amerikkalaiset tutkijat. Heidän aineistonsa käsitti 3408 yli 65-vuotiasta miestä ja naista, joiden terveydentilaa seurattiin Third National Health and Nutrition Examination Survey (NHANES III) -tutkimuksessa. Keskimäärin 7,3 vuoden seuruun aikana kuoli 1493 (44 %) tutkituista. Vähän yli puolet (767) kuolemista johtui sydänkohtauksista

The Diet-Heart Hypothesis: Subdividing Lipoproteins Two posts ago, we made the rounds of the commonly measured blood lipids (total cholesterol, LDL, HDL, triglycerides) and how they associate with cardiac risk. It's important to keep in mind that many things associate with cardiac risk, not just blood lipids. For example, men with low serum vitamin D are at a 2.4-fold greater risk of heart attack than men with higher D levels. That alone is roughly equivalent to the predictive power of the blood lipids you get measured at the doctor's office. Coronary calcium scans (a measure of blood vessel calcification) also associate with cardiac risk better than the most commonly measured blood lipids. Lipoproteins Can be Subdivided into Several Subcategories In the continual search for better measures of cardiac risk, researchers in the 1980s decided to break down lipoprotein particles into sub-categories. One of these researchers is Dr. Ronald M. Krauss. Krauss published extensively on the association between lipoprotein size and cardiac risk, eventually concluding (source): The plasma lipoprotein profile accompanying a preponderance of small, dense LDL particles (specifically LDL-III) is associated with up to a threefold increase in the susceptibility of developing [coronary artery disease]. This has been demonstrated in case-control studies of myocardial infarction and angiographically documented coronary disease. Krauss found that small, dense LDL (sdLDL) doesn't travel alone: it typically comes along with low HDL and high triglycerides*. He called this combination of factors "lipoprotein pattern B"; its opposite is "lipoprotein pattern A": large, buoyant LDL, high HDL and low triglycerides. Incidentally, low HDL and high triglycerides are hallmarks of the metabolic syndrome, the quintessential modern metabolic disorder. Krauss and his colleagues went on to hypothesize that sdLDL promotes atherosclerosis because of its ability to penetrate the artery wall more easily

Serum 25-hydroxyvitamin D status of the US population: 1988-1994 compared with 2000-2004. Looker AC, Pfeiffer CM, Lacher DA, Schleicher RL, Picciano MF, Yetley EA. Am J Clin Nutr. 2008 Dec;88(6):1519-27. PMID: 19064511 doi:10.3945/ajcn.2008.26182 Conclusions: Overall, mean serum 25(OH)D was lower in 2000-2004 than 1988-1994. Assay changes unrelated to changes in vitamin D status accounted for much of the difference in most population groups. In an adult subgroup, combined changes in BMI, milk intake, and sun protection appeared to contribute to a real decline in vitamin D status. In summary, age-standardized mean serum 25(OH)D concentrations based on observed values were significantly lower in 2000-2004 than in 1988-1994 in all groups examined. Adjustment for assay changes noticeably reduced the difference between surveys. However, mean serum 25(OH)D concentrations remained significantly lower in males (except Mexican Americans) in NHANES 2000-2004 than in NHANES III, even after adjustment for assay differences. This remaining difference likely represents a real decline in vitamin D status. Changes in BMI, milk intake, and sun protection appeared to contribute to this decline in a subgroup of non-Hispanic white adults. The possibility that trends in overweight, sun protection, and milk intake may continue supports the need to continue monitoring the serum 25(OH)D status of the population

Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Ginde AA, Liu MC, Camargo CA Jr. Arch Intern Med. 2009 Mar 23;169(6):626-32. PMID: 19307527 Conclusions National data demonstrate a marked decrease in serum 25(OH)D levels from the 1988-1994 to the 2001-2004 NHANES data collections. Racial/ethnic differences have persisted and may have important implications for known health disparities. Current recommendations for vitamin D supplementation are inadequate to address the growing epidemic of vitamin D insufficiency.

Designed with practicing dermatologists, dermatology trainees, physicians, and scientists interested in photoprotection in mind, this concise and highly illustrated guide provides the latest knowledge of photoprotection in dermatology and cosmetic science. Clinical Guide to Sunscreens and Photoprotectionalso addresses recent important international and domestic regulatory activity and requirements on the use of novel sun protective chemicals and proper labeling of products to ensure increased consumer awareness.This concisely written, problem-oriented text explores See chapter by Bischoff-Ferrari et al. from page 119 dealing with what dose is needed for 25(OH)D level of 80 nmol/l in 97% of population

Table of Contents Ch. I Is calcidiol an active hormone? 1 Ch. II Vitamin D as a neurosteroid hormone : from neurobiological effects to behavior 29 Ch. III Inhibitors of vitamin D hydroxylases : mechanistic tools and therapeutic aspects 67 Ch. IV Vitamin D analogues as anti-cancer therapies 145 Ch. V Paricalcitol : a vitamin D2 analog with anticancer effects with low calcemic activity 169 Ch. VI Vitamin D use among older adults in U.S. : results form national surveys 1997 to 2002 181 Ch VII Vitamin D deficiency in migrants 199 Vitamin D is a fat-soluble steroid hormone precursor that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. Strictly speaking, it is not a vitamin since human skin can manufacture it, but it is referred to as one for historical reasons. It is often known as calciferol. The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. It promotes bone mineralisation in concert with a number of other vitamins, minerals and hormones. Without vitamin D, bones can become thin, brittle, soft or misshapen. Vitamin D prevents rickets in children and osteomalacia in adults -- skeletal diseases that result in defects that weaken bones. This book gathers international research on the leading-edge of the scientific front.