Serum 25-Hydroxyvitamin D and the Incidence of Acute Viral Respiratory Tract Infections in Healthy Adults Hypovitaminosis D in the Middle East and North Africa Influence of a single oral dose of vitamin D(2) on serum 25-hydroxyvitamin D concentrations in tuberculosis patients. Plasma 25-Hydroxyvitamin D Levels and Risk of Incident Hypertension Low serum 25-hydroxyvitamin D concentrations are associated with greater all-cause mortality in older community-dwelling women. Serum 25-hydroxyvitamin D and risk of breast cancer: results of a large population-based case–control study in Mexican women Association Between Hypovitaminosis D in Elderly Women and Long- and Short-Term Mortality-Results from the Osteoporotic Prospective Risk Assessment Cohort. Pilot Study Evaluating Efficacy of 2 Regimens for Hypovitaminosis D Repletion in Pediatric Inflammatory Bowel Disease Association of low serum 25-hydroxyvitamin D levels and high arterial blood pressure in the elderly. Treatment of hypovitaminosis D in infants and toddlers. Low vitamin D status is an independent predictor of increased frailty and all-cause mortality in older men: the Health in Men Study. Plasma 25-hydroxyvitamin D concentration and subsequent risk of total and site specific cancers in Japanese population: large case-cohort study within Japan Public Health Center-based Prospective Study cohort Chronic kidney disease, hypovitaminosis D, and mortality in the United States. Plasma 1,25-Dihydroxyvitamin D and the Risk of Developing Hypertension: The Prevention of Renal and Vascular End-Stage Disease Study Impact of dietary and lifestyle on vitamin D in healthy student girls aged 11-15 years. Plasma 25-hydroxyvitamin D3 is associated with decreased risk of postmenopausal breast cancer in whites: a nested case–control study in the multiethnic cohort study Is hypovitaminosis D associated with abdominal aortic aneurysm, and is there a dose-response relationship?
Background Declining serum concentrations of 25-hydroxyvitamin D seen in the fall and winter as distance increases from the equator may be a factor in the seasonal increased prevalence of influenza and other viral infections . This study was done to determine if serum 25-hydroxyvitamin D concentrations correlated with the incidence of acute viral respiratory tract infections . Methodology / Findings In this prospect i ve cohort study serial monthly concentrations of 25-hydroxyvitamin D were measured over the fall and winter 2009–2010 in 198 healthy adults , blinded to the nature of the substance being measured . The participants were evaluated for the development of any acute respiratory tract infections by investigators blinded to the 25-hydroxyvitamin D concentrations . The incidence of infection in participants with different concentrations of vitamin D was determined . One hundred ninety-five ( 98.5 % ) of the enrolled participants completed the study . Light skin pigmentation , lean body mass , and supplementation with vitamin D were found to correlate with higher concentrations of 25-hydroxyvitamin D. Concentrations of 38 ng/ml or more were associated with a significant ( p<0.0001 ) two-fold reduction in the risk of developing acute respiratory tract infections and with a marked reduction in the percentages of days ill . Conclusions / Significance Maintenance of a 25-hydroxyvitamin D serum concentration of 38 ng/ml or higher should significantly reduce the incidence of acute viral respiratory tract infections and the burden of illness caused thereby , at least during the fall and winter in temperate zones . The findings of the present study provide direction for and call for future interventional studies examining the efficacy of vitamin D supplementation in reducing the incidence and severity of specific viral infections , including influenza , in the general population and in sub population s with lower 25-hydroxyvitamin D concentrations , such as pregnant women , dark skinned individuals , and the obese Background : The Middle East and North Africa ( MENA ) region registers some of the highest rates of hypovitaminosis D worldwide . Aim : We systematic ally review ed the prevalence of hypovitaminosis D , rickets and osteomalacia , their predictors and impact on major outcomes , in the region . Methods : Medline , Pubmed and Embase search engines , entering keywords and concepts , combined with individual countries of interest , were used . Search was limited years 2000–2012 ; and review articles were used for the period preceding year 2000 . Results : Rickets and osteomalacia still occur in this sunny region . Hypovitaminosis D prevails , with rates varying 30–90 % , considering a desirable serum 25 hydroxy-vitamin D [ 25(OH)D ] of 20 ng/ml . Advancing age , female gender , multi-parity , clothing style , season , socio-economic status and urban living are recognized predictors of hypovitaminosis D in adults . Prolonged breastfeeding without vitamin D supplementation and low dietary calcium intake are the recognized risk factors for rickets and hypovitaminosis D in children .. Associations with pain score and disease activity in rheumatologic disorders , viral load and interleukins in hepatitis C , BMI , lipids and insulin sensitivity , blood pressure , heart failure and mortality are described . Sun exposure in adults decreased prevalence of metabolic syndrome in one study . Few r and omized vitamin D trials revealed that the majority of mothers or children failed to achieve a desirable 25(OH)D level , even with doses by far exceeding current recommendations . A trial in adolescent girls reveals substantial bone and lean mass increments . Conclusion : Hypovitaminosis D is prevalent in MENA . The lack of population s based studies , gaps in studies in infants , pre-pubertal children and pregnant women , hinder the development of region specific guidelines and constitute a major obstacle to impact this chronic and most often sub clinical disease SETTING Newham Chest Clinic , London , UK . OBJECTIVE To determine the safety and efficacy of the administration of bolus-dose vitamin D(2 ) in elevating serum 25-hydroxyvitamin D ( 25[OH]D ) concentrations in tuberculosis ( TB ) patients . DESIGN A multi-ethnic cohort of TB patients was r and omised to receive a single oral dose of 2.5 mg vitamin D(2 ) ( n = 11 ) or  placebo ( n = 14 ) . Serum 25(OH)D and corrected calcium concentrations were determined at baseline and 1 week and 8 weeks post-dose , and compared to those of a multi-ethnic cohort of 56 healthy adults receiving an identical dose of vitamin D(2 ) . RESULTS Hypovitaminosis D ( serum 25[OH]D < 75 nmol/l ) was present in all patients at baseline . A single oral dose of 2.5 mg vitamin D2 corrected hypovitaminosis D in all patients in the intervention arm of the study at 1 week post-dose , and induced a 109.5 nmol/l mean increase in their serum 25(OH)D concentration . Hypovitaminosis D recurred in 10/11 patients at 8 weeks post-dose . No patient receiving vitamin D(2 ) experienced hypercalcaemia . Patients receiving 2.5 mg vitamin D(2 ) experienced a greater mean increase in serum 25(OH)D at 1 week post-dose than healthy adults receiving 2.5 mg vitamin D(2 ) . CONCLUSION A single oral dose of 2.5 mg vitamin D(2 ) corrects hypovitaminosis D at 1 week but not at 8 weeks post-dose in TB patients Hydroxylation of 25(OH)D to 1,25-dihydroxyvitamin D and signaling through the vitamin D receptor occur in various tissues not traditionally involved in calcium homeostasis . Laboratory studies indicate that 1,25-dihydroxyvitamin D suppresses renin expression and vascular smooth muscle cell proliferation ; clinical studies demonstrate an inverse association between ultraviolet radiation , a surrogate marker for vitamin D synthesis , and blood pressure . We prospect ively studied the independent association between measured plasma 25-hydroxyvitamin D [ 25(OH)D ] levels and  risk of incident hypertension  and also the association between predicted plasma 25(OH)D levels and risk of incident hypertension .  Two prospect i ve cohort studies including 613 men from the Health Professionals ’ Follow-Up Study and 1198 women from the Nurses ’ Health Study with measured 25(OH)D levels were followed for 4 to 8 years . In addition , 2 prospect i ve cohort studies including 38 388 men and 77 531 women with predicted 25(OH)D levels were followed for 16 to 18 years . During 4 years of follow-up , the multivariable relative risk of incident hypertension among men whose measured plasma 25(OH)D levels were < 15 ng/mL ( ie , vitamin D deficiency ) compared with those whose levels were ≥30 ng/mL was 6.13 ( 95 % confidence interval [ CI ] : 1.00 to 37.8 ) . Among women , the same comparison yielded a relative risk of 2.67 ( 95 % CI : 1.05 to 6.79 ) . The pooled relative risk combining men and women with measured 25(OH)D levels using the r and om-effects model was 3.18 ( 95 % CI : 1.39 to 7.29 ) . Using predicted 25(OH)D levels in the larger cohorts , the multivariable relative risks comparing the lowest to highest deciles were 2.31 ( 95 % CI : 2.03 to 2.63 ) in men and 1.57 ( 95 % CI : 1.44 to 1.72 ) in women . Plasma 25(OH)D levels are inversely associated with risk of incident hypertension Vitamin D deficiency is associated with osteoporosis , poor muscle strength , falls , and fractures . The relationship between serum vitamin D concentrations and mortality in older community-dwelling women has not been well characterized . We hypothesized that women with lower 25-hydroxyvitamin D ( 25[OH]D ) concentrations were at higher risk of mortality . We examined the association between serum 25[OH]D concentrations and all-cause mortality in a prospect i ve , population -based study of 714 community-dwelling women , aged 70 to 79 years , the Women 's Health and Aging Studies I and II in Baltimore , Md. The studies were originally design ed to evaluate the causes and course of physical disability in older women living in the community .  Vital status was determined through follow-up interviews and matching with the National Death Index . During a median of 72 months of follow-up , 100 ( 14 % ) of 714 women died . Women in the lowest quartile of 25(OH)D ( < 15.3 ng/mL or 38.2 nmol/L ) were at higher risk of death ( hazards ratio , 2.45 ; 95 % confidence interval , 1.12 - 5.36 ; P = .02 ) compared to women in the highest quartile ( > 27.0 ng/mL or 67.4 nmol/L ) of 25(OH)D in a multivariate Cox proportional hazards model adjusting for demographics , season , and conventional risk factors . Older community-dwelling women with low 25(OH)D levels are at an increased risk of death Purpose Epidemiologic studies have suggested that higher levels of circulating vitamin D may reduce breast cancer risk , but no studies have investigated this association among women in developing countries , and very few studies have further investigated this association according to menopausal status . Methods A population -based case – control study in Mexico with 1,000 incident breast cancer cases aged 35–69 years , enrolled shortly after diagnosis ( 0–6 days ) and frequency-matched to 1,074 controls on age , region , and health care system , was used to assess the association between serum 25-hydroxyvitamin  D [ 25(OH)D ] levels with overall , pre- and postmenopausal breast cancer risk . 25(OH)D concentration was measured on a r and om sub- sample of women ( 573 cases and 639 matched controls ) using a liquid chromatography/t and em mass spectrometry method . Odds ratios ( ORs ) and 95 % confidence intervals ( CIs ) were estimated from multivariable conditional logistic regression models . Results Serum 25(OH)D concentration ( per 10 ng/mL increase ) showed a strong inverse association with risk of breast cancer among all ( ptrend = 0.001 ) , pre- ( ptrend = 0.006 ) and postmenopausal women ( ptrend = 0.0001 ) . Compared with a predefined lower concentration of 25(OH)D ( < 20 ng/mL ) , higher levels ( > 30 ng/mL ) were associated with lower overall ( OR = 0.53 , 95 % CI : 0.28–1.00 ; ptrend = 0.002 ) , pre- ( OR = 0.60 , 95 % CI : 0.16–2.17 ; ptrend = 0.07 ) and postmenopausal ( OR = 0.37 , 95 % CI : 0.16–0.82 ; ptrend = 0.004 ) breast cancer risk . Conclusions The results of this large population -based case – control study indicate an inverse association between circulating vitamin D levels and breast cancer risk among pre- and postmenopausal Mexican women OBJECTIVES To investigate the association between low vitamin D levels ( < 50 nmol/L ) and 10-year mortality in women aged 75 and older . DESIGN Prospect i ve with 15 years of follow-up . SETTING Malmö , Sweden . PARTICIPANTS Population -based cohort of 75-year-old women ( N = 1,044 ) . MEASUREMENTS  Serum 25-hydroxyvitamin D ( 25(OH)D ) levels  at age 75 ( n = 1,011 ) , 80 ( n = 642 ) , and 85 ( n = 348 ) were categorized as low ( < 50 nmol/L ) , intermediate ( 50 - 75 nmol/L ) and high ( > 75 nmol/L ) at all ages . Hazard ratios ( HRs ) for all-cause mortality between ages 75 and 90 were calculated according to 25(OH)D category . RESULTS Between ages 80 and 90 , all-cause mortality ( HR = 1.8 , 95 % confidence interval ( CI ) = 1.3 - 2.4 , P < .001 ; adjusted for comorbidities ( aHR ) = 1.9 , 95 % CI = 1.4 - 2.6 , P < .001 ) was significantly higher in women with low 25(OH)D levels than in those with high levels . Osteoporosis had the greatest effect on mortality , but even after excluding women with osteoporotic fracture during the risk of dying associated with low 25(OH)D remained greater ( HR = 1.8 , 95 % CI = 1.2 - 2.7 , P = .002 ; aHR = 1.7 , 95 % CI = 1.2 - 2.5 , P = .006 ) . CONCLUSION In this observational study of women aged 75 and older , 25(OH)D levels of less than 50 nmol/L were associated with greater all-cause mortality for up to 10 years . This difference was at least partially independent of comorbidities and fracture , indicating that low 25(OH)D not only is an indicator of impaired health , but also plays a role in disease outcome Objectives : Vitamin D is critical for skeletal health ; hypovitaminosis D is common in pediatric inflammatory bowel disease ( IBD ) , yet optimal repletion therapy is not well studied . We aim ed to conduct a pilot trial comparing the efficacy of 2 vitamin D regimens of weekly dosing for the repletion of hypovitaminosis D in pediatric IBD . Methods : Subjects identified from our IBD clinic with 25-hydroxyvitamin D ( 25[OH]D ) concentrations < 30 ng/mL were r and omized to 10,000 ( n = 18 ) or 5000 ( n = 14 ) IU of oral vitamin D3/10 kg body weight per week for 6 weeks  . Serum 25(OH)D , Ca , and parathyroid hormone concentrations were measured at baseline , week 8 , and week 12 . Results : In the higher dosing group , serum 25(OH)D increased from 23.7 ± 8.5 ng/mL at baseline to 49.2 ± 13.6 ng/mL at 8 weeks ; P < 0.001 . In the lower dosing group , serum 25(OH)D increased from 24.0 ± 7.0 ng/mL at baseline to 41.5 ± 9.6 ng/mL at 8 weeks ; P < 0.001 . At 12 weeks , serum 25(OH)D concentrations were 35.1 ± 8.4 and 30.8 ± 4.2 ng/mL for the higher and lower dose regimens , respectively . Mean serum Ca and parathyroid hormone concentrations did not significantly change during the study . No patient exhibited hypercalcemia , and no serious adverse events occurred . Conclusions : Both treatment arms were safe and effective at normalizing vitamin D nutriture in pediatric IBD . Although significant repletion of 25(OH)D concentration was achieved in both dosing groups at 8 weeks , this effect was lost by the 12-week follow-up . Maintenance vitamin D therapy following initial repletion is likely required to maintain long-term normalized vitamin D status BACKGROUND Vitamin D and calcium metabolism are involved in vascular smooth muscle cell proliferation , endothelial function and blood pressure ( BP ) regulation . Their physiopathology has been a matter of intensive clinical investigation with variable and sometimes contradictory results . Vitamin D insufficiency is highly prevalent in the general population , particularly among the elderly . We evaluated the association between serum 25(OH)-D levels and arterial BP in this population . METHODS An epidemiological cross-sectional study was design ed to analyse the prevalence of hypovitaminosis D ( ' D'AVIS ' study ) in our reference area . The study was performed on a representative r and om sample of the population over 64 years of age obtained from five primary health care areas . A medical record , arterial BP and biological analysis : serum 25(OH)-D , iPTH , creatinine , urea , calcium , albumin were obtained . RESULTS A total of 237 subjects ( 53 % women ) , aged between 64 and 93 ( mean 71.7 + /- 5.3 ) , were evaluated . The mean serum 25(OH)-D levels were 17.21 + /- 7.57 ng/ml ( interval 5 - 54 ; 86 % had < 25 ng/ml ) . The mean BP was 138.8 + /- 14/80 + /- 7.4 mmHg , and 46 % were on antihypertensive treatment . A significant negative association was observed between serum 25(OH)-D levels and systolic ( r = -0.153 , P = 0.018 ) and diastolic BP ( r = -0.152 , P = 0.019 ) . This association persisted after controlling for possible confounders in the multivariate analyses . CONCLUSIONS Low serum 25(OH)-D levels were inversely and independently associated with BP . Supplemental measures to prevent hypovitaminosis D in this population would be important , not only to protect the skeletal system but also for the possible beneficial effects on the cardiovascular system and the BP regulation CONTEXT Hypovitaminosis D appears to be on the rise in young children , with implication s for skeletal and overall health . OBJECTIVE The objective of the study was to compare the safety and efficacy of vitamin D2 daily , vitamin D2 weekly , and vitamin D3 daily , combined with supplemental calcium , in raising serum 25-hydroxyvitamin D [ 25(OH)D ] and lowering PTH concentrations . DESIGN This was a 6-wk r and omized controlled trial . SETTING The study was conducted at an urban pediatric clinic in Boston . SUBJECTS Forty otherwise healthy infants and toddlers with hypovitaminosis D [ 25(OH)D < 20 ng/ml ] participated in the study . INTERVENTIONS Participants were assigned to one of three regimens : 2,000 IU oral vitamin D2 daily , 50,000 IU vitamin D2 weekly , or 2,000 IU vitamin D3 daily . Each was also prescribed elemental calcium ( 50 mg/kg.d ) . Infants received treatment for 6 wk . MAIN OUTCOME MEASURES Before and after treatment , serum measurements of 25(OH)D , PTH , calcium , and alkaline phosphatase were taken . RESULTS All treatments approximately tripled the 25(OH)D concentration . Preplanned comparisons were nonsignificant : daily vitamin D2 vs. weekly vitamin D2 ( 12 % difference in effect , P = 0.66 ) and daily D2 vs. daily D3 ( 7 % , P = 0.82 ) . The mean serum calcium change was small and similar in the three groups . There was no significant difference in PTH suppression . CONCLUSIONS Short-term vitamin D2 2,000 IU daily , vitamin D2 50,000 IU weekly , or vitamin D3 2,000 IU daily yield equivalent outcomes in the treatment of hypovitaminosis D among young children . Therefore , pediatric providers can individualize the treatment regimen for a given patient to ensure compliance , given that no difference in efficacy or safety was noted among these three common treatment regimens CONTEXT AND OBJECTIVE Hypovitaminosis D and frailty are common in the older population . We aim ed to determine whether 25-hydroxyvitamin D [ 25(OH)D ] concentrations are associated with frailty and mortality . DESIGN We conducted a prospect i ve cohort study . SETTING AND PARTICIPANTS Participants included 4203 older men aged 70 - 88 years in Perth , Western Australia . MAIN OUTCOME MEASURES 25(OH)D was measured by immunoassay  . Frailty was assessed with the 5-point FRAIL ( fatigue , resistance , ambulation , illness , and loss of weight ) scale . Mortality was determined from the death registry via the Western Australian Data Linkage System . RESULTS At baseline , 676 ( 16.1 % ) men were frail , as defined by having ≥3 deficits ( FRAIL scale ≥ 3 ) . In multivariate cross-sectional analysis , low vitamin D status , defined by the lowest quartile of 25(OH)D values ( < 52.9 nmol/L ) , was associated with increased prevalent frailty ( odds ratio , 1.96 ; 95 % confidence interval [ CI ] , 1.52 to 2.52 ) in comparison to the highest quartile of 25(OH)D values ( > 81.6 nmol/L ) . After a mean period of 5.3 years , the adjusted odds ratio of being frail at follow-up for men with low vitamin D and having zero deficit at baseline ( FRAIL scale = 0 ) was 1.56 ( 95 % CI , 1.07 to 2.27 ) . Low vitamin D also predicted all-cause mortality over a period of up to 9.2 years ( hazard ratio , 1.20 ; 95 % CI , 1.02 to 1.42 ) , independent of baseline frailty and other covariates . CONCLUSION Hypovitaminosis D is associated with prevalent and incident frailty in older men . Hypovitaminosis D also predicts all-cause mortality , independent of frailty . The association between vitamin D and mortality is not solely dependent on the occurrence of frailty Abstract Objective To evaluate the association between pre-diagnostic circulating vitamin D concentration and the subsequent risk of overall and site specific cancer in a large cohort study . Design Nested case-cohort study within the Japan Public Health Center-based Prospect i ve Study cohort . Setting Nine public health centre areas across Japan . Participants 3301 incident cases of cancer and 4044 r and omly selected subcohort participants .  Exposure Plasma concentration of 25-hydroxyvitamin D measured by enzyme immunoassay . Participants were divided into quarters based on the sex and season specific distribution of 25-hydroxyvitamin D among subcohorts . Weighted Cox proportional hazard models were used to calculate the multivariable adjusted hazard ratios for overall and site specific cancer across categories of 25-hydroxyvitamin D concentration , with the lowest quarter as the reference . Main outcome measure Incidence of overall or site specific cancer . Results Plasma 25-hydroxyvitamin D concentration was inversely associated with the risk of total cancer , with multivariable adjusted hazard ratios for the second to fourth quarters compared with the lowest quarter of 0.81 ( 95 % confidence interval 0.70 to 0.94 ) , 0.75 ( 0.65 to 0.87 ) , and 0.78 ( 0.67 to 0.91 ) , respectively ( P for trend=0.001 ) . Among the findings for cancers at specific sites , an inverse association was found for liver cancer , with corresponding hazard ratios of 0.70 ( 0.44 to 1.13 ) , 0.65 ( 0.40 to 1.06 ) , and 0.45 ( 0.26 to 0.79 ) ( P for trend=0.006 ) . A sensitivity analysis showed that alternately removing cases of cancer at one specific site from total cancer cases did not substantially change the overall hazard ratios . Conclusions In this large prospect i ve study , higher vitamin D concentration was associated with lower risk of total cancer . These findings support the hypothesis that vitamin D has protective effects against cancers at many sites Low serum 25-hydroxy vitamin D ( 25OHD ) predicts a higher cardiovascular risk in the general population . Because patients with chronic kidney disease are more likely to have low serum 25OHD , we determined the relationship between hypovitaminosis D and death in this group . Analysis was done using a cohort composed of 3011 patients from the Third National Health and Nutrition Examination Survey who had chronic kidney disease but were not on dialysis and who had a mean follow-up of 9 years . In analyses adjusted for demographics , cardiovascular risk factors , serum phosphorus , albumin , hemoglobin , stage of chronic kidney disease , albuminuria , and socioeconomic status , individuals with serum 25OHD levels less than 15 ng/ml had an increased risk for all-cause mortality when compared to those with levels over 30 ng/ml . This significantly higher risk for death with low serum 25OHD was evident in 15 of the 23 subgroups . The higher risk for cardiovascular and non-cardiovascular mortality became statistically nonsignificant on multivariable adjustment . The trend for higher mortality in patients with 25OHD levels 15 - 30 ng/ml was not statistically significant . Our results indicate there is a grade d relationship between serum 25OHD and the risk for death among subjects with chronic kidney disease who are not undergoing dialysis . R and omized , controlled trials are needed to conclusively determine whether vitamin D supplementation reduces mortality Previous observational studies on the vascular effects of vitamin D have predominantly relied on measurement of its inactive precursor , 25-hydroxyvitamin D , whereas the active metabolite 1,25-dihydroxyvitamin D may be of more physiological relevance . We prospect ively studied the associations of 1,25-dihydroxyvitamin D and 25-hydroxyvitamin D with  hypertension risk ( blood pressure ≥140/90 mm Hg or initiation of blood pressure – lowering drugs ) in 5066 participants aged 28 to 75 years , free of hypertension at baseline from the Prevention of Renal and Vascular End-Stage Disease Study , a well-defined cohort with serial follow-up . We measured plasma 1,25-dihydroxyvitamin D and 25-hydroxyvitamin D using liquid chromatography-t and em mass spectrometry .  Mean±SD plasma concentration of 1,25-dihydroxyvitamin  D was 145±47.0 pmol/L and 25-hydroxyvitamin D was 58.6±23.8 nmol/L. During a median follow-up of 6.4 years , 1036 participants ( 20.5 % ) developed hypertension . As expected , low 25-hydroxyvitamin D was associated with a higher hypertension risk ; each 1-SD decrement in 25-hydroxyvitamin D was associated with a 8 % higher hypertension risk ( hazard ratio , 1.08 ; 95 % confidence interval , 1.01–1.16 ) after adjustment for potential confounders . However , the association of 1,25-dihydroxyvitamin D was in the opposite direction ; each 1-SD decrement of 1,25-dihydroxyvitamin D was associated with a 10 % lower hypertension risk ( hazard ratio , 0.90 ; 95 % confidence interval , 0.84–0.96 ) , independent of potential confounders . In contrast to the inverse association between 25-hydroxyvitamin D and hypertension risk , 1,25-dihydroxyvitamin D was positively associated with risk of hypertension . Thus , higher circulating concentrations of 1,25-dihydroxyvitamin D are associated with a higher risk of hypertension OBJECTIVE To study daily intake of calcium , phosphorus and vitamin D , to determine the biochemical findings of rickets and the effect of sunlight exposure and vitamin D supplementation in school girls with hypovitaminosis D. METHODS A cross-sectional study was conducted on school girls aged 11 - 15 years selected r and omly from various areas of Tehran , Iran .  Dietary information and amount of sunlight exposure were estimated by a 7 day recalling method using self-reported question naire . Hypovitaminosis D defined as low serum 25-hydroxyvitamin D concentration with two or more others abnormal biochemical findings . Girls with hypovitaminoses D were r and omly divided into two groups . The faces and h and s of girls in group 1 were exposed to sunlight for one hour per day for twenty days , while those in group 2 were administered vitamin D capsules , 50,000 IU per day for the same period . RESULTS four-hundred fourteen girls evaluated , mean daily calcium intake , sunlight exposure and vitamin D acquirement were 360 mg , 10 minutes and 119 IU , respectively . Mean serum 25-hydroxyvitamin D concentration was 30 ng/ml among all girls whereas in 15 ( 3.63 % ) of 414 girls was 7.8 ng/ml . Abnormal biochemical findings in these girls included hypocalcemia ( n=4 ) , hypophosphatemia ( n=5 ) , raised serum alkaline phosphatase ( n=13 ) , and parathyroid hormone ( n=15 ) . After intervention , mean serum 25-hydroxyvitamin D concentration  in sunlight exposure ( n=8 ) and vitamin D ( n=7 ) supplementation increased to 14.4+/-4 ng/ml and 23+/-4 ng/ml respectively . There was a significant difference between the two groups ( p<0.05 ) . CONCLUSION Vitamin D deficiency developed in rapid growth period of girls without clear clinical rickets in sunny temperate climate city in Iran which vitamin D supplementation improved biochemical findings better than sunlight exposure Background Higher sunlight exposure is correlated with lower incidence of breast cancer in ecological studies , but findings from prospect i ve studies regarding the association of circulating levels of vitamin D with the risk of breast cancer have been null . The objective of this study was to examine the relation between plasma levels of vitamin D  and the risk of postmenopausal breast cancer . Methods We conducted a nested case – control study within the Multiethnic Cohort Study of five race/ethnic groups ( white , African-American , Native Hawaiian , Japanese , and Latino ) from Hawaii and Los Angeles between 2001 and 2006 . Pre-diagnostic plasma levels of 25-hydroxyvitamin D2 [ 25(OH)D2 ] , 25-hydroxyvitamin D3 [ 25(OH)D3 ] and 25(OH)D ( sum of 25(OH)D2 and 25(OH)D3 )  were examined among 707 postmenopausal breast cancer cases and matched controls . Results Using conditional logistic regression models , 20 ng/mL increases of plasma 25(OH)D3 ( odds ratio ( OR ) 0.28 ; 95 % confidence interval ( CI ) 0.14 - 0.56 ) and 25(OH)D ( OR 0.43 ; 95 % CI 0.23 - 0.80 ) were inversely associated with breast cancer risk among white women , but not among women in other race/ethnic groups . Using two-segmented , piecewise-linear logistic regression models , the change-points of the ORs , either for 25(OH)D3 or for 25(OH)D , were detected as 20 ng/mL among whites . Conclusions Circulating 25(OH)D3 and 25(OH)D were associated with a reduced risk of  postmenopausal breast cancer among whites , but not in other ethnic groups , who reside in low latitude regions OBJECTIVE This study aims to investigate the association between plasma 25-hydroxyvitamin D ( 25(OH)D ) concentrations with the presence of abdominal aortic aneurysm ( AAA ) and aortic diameter . DESIGN An observational study of 4233 community-dwelling men aged 70 - 88 years , who participated in a r and omised controlled trial of screening for AAA . METHODS Infrarenal aortic diameter measured by ultrasound and  25(OH)D by immunoassay . RESULTS A total of 311 men ( 7.4 % ) with AAA ( defined as aortic diameter ≥ 30 mm ) comprised the study . Multivariable models were adjusted for age , smoking , cardiovascular disease , hypertension , diabetes , dyslipidaemia , body mass index and serum creatinine concentration . Amongst men with the lowest 25(OH)D quartile of values compared with the highest quartile , the adjusted odds ratio of having an AAA increased in a grade d fashion from 1.23 ( 95 % confidence interval ( CI ) 0.87 - 1.73 ) for AAA ≥ 30 mm to 5.42 ( 95 % CI 1.85 - 15.88 ) for AAA ≥ 40 mm . Similarly , there was a dose-response relationship between 25(OH)D concentrations and the size of the AAA : every 10-nmol l(-1 ) decrease in 25(OH)D levels was associated with 0.49 mm ( 95 % CI 0.11 - 0.87 ) increase in mean aortic diameter . CONCLUSIONS Low vitamin D status is associated with the presence of larger AAA  in older men , and there is a grade d inverse relationship between 25(OH)D concentrations and AAA diameter . Further research is needed to clarify the mechanisms underlying these associations
Neither latitude , region of the world , nor laboratory methodology were found to be associated with the prevalence of hypovitaminosis
BACKGROUND Hypovitaminosis D is considered a global public health issue .
Knowledge of its true dimensions will allow us to design interventions and plan preventive measures that can have a significant impact on human health .
OBJECTIVES The aim of this study was to evaluate the prevalence of hypovitaminosis D , defined as a serum 25-hydroxyvitamin D concentration < 30 ng/ml , in postmenopausal women around the world , as well as to identify the potential associated factors .