***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Sun exposure is associated with lower death rates for pancreatic cancer in some ecological studies . Skin exposure to UVB light induces cutaneous production of precursors to 25-hydroxyvitamin D [ 25(OH)D ] . Pancreatic islet and duct cells express 25(OH)D(3)-1alpha-hydroxylase that generates the biologically active 1,25(OH)(2 ) vitamin D form . Thus , 25(OH)D concentrations could affect pancreatic function and possibly pancreatic cancer etiology . We conducted a prospect i ve nested case-control study in the Alpha-Tocopherol , Beta-Carotene Cancer Prevention cohort of male Finnish smokers , ages 50 to 69 years at baseline , to test whether more adequate vitamin D status , as determined by prediagnostic serum 25(OH)D concentrations , was associated with lower pancreatic cancer risk . Two hundred incident exocrine pancreatic cancer cases that occurred between 1985 and 2001 ( up to 16.7 years of follow-up ) were matched by age and date of blood draw to 400 controls who were alive and free of cancer at the time the case was diagnosed .  Odds ratios ( OR ) and 95 % confidence intervals ( 95 % CI ) were calculated using conditional logistic regression . Higher vitamin D concentrations were associated with a 3-fold increased risk for pancreatic cancer ( highest versus lowest quintile , > 65.5 versus < 32.0 nmol/L : OR , 2.92 ; 95 % CI , 1.56 - 5.48 , P(trend ) = 0.001 ) that remained after excluding cases diagnosed early during follow-up . Contrary to expectations , subjects with higher prediagnostic vitamin D status had an increased pancreatic cancer risk compared with those with lower status . Our findings need to be replicated in other population s and caution is warranted in their interpretation and implication . Our results are intriguing and may provide clues that further the underst and ing of the etiology of this highly fatal cancer Summary The Women 's Health Initiative ( WHI ) double-blind , placebo-controlled clinical trial r and omly assigned 36,282 postmenopausal women in the U.S. to 1,000 mg elemental calcium carbonate plus 400 IU of vitamin D3 daily or placebo , with average intervention period of 7.0 years . The trial was design ed to test whether calcium plus vitamin D supplementation in a population in which the use of these supplements was widespread would reduce hip fracture , and secondarily , total fracture and colorectal cancer . Introduction This study further examines the health benefits and risks of calcium and vitamin D supplementation using WHI data , with emphasis on fractures , cardiovascular disease , cancer , and total mortality . Methods WHI calcium and vitamin D r and omized clinical trial ( CT ) data through the end of the intervention period were further analyzed with emphasis on treatment effects in relation to duration of supplementation , and these data were contrasted and combined with corresponding data from the WHI prospect i ve observational study ( OS ) . Results Among women not taking personal calcium or vitamin D supplements at baseline , the hazard ratio [ HR ] for hip fracture occurrence in the CT following 5 or more years of calcium and vitamin D supplementation versus placebo was 0.62 ( 95 % confidence interval ( CI ) , 0.38–1.00 ) . In combined analyses of CT and OS data , the corresponding HR was 0.65 ( 95 % CI , 0.44–0.98 ) . Supplementation effects were not apparent on the risks of myocardial infa rct ion , coronary heart disease , total heart disease , stroke , overall cardiovascular disease , colorectal cancer , or total mortality , while evidence for a reduction in breast cancer risk and total invasive cancer risk among calcium plus vitamin D users was only suggestive . Conclusion Though based primarily on a subset analysis , long-term use of calcium and vitamin D appears to confer a reduction that may be substantial in the risk of hip fracture among postmenopausal women . Other health benefits and risks of supplementation at doses considered , including an elevation in urinary tract stone formation , appear to be modest and approximately balanced Evidence for a role of supplemental vitamin D and marine omega-3 fatty acids in preventing cancer and cardiovascular disease ( CVD ) remains inconclusive and insufficient to inform nutritional recommendations for primary prevention . The VITamin D and Omega-A 3 TriaL ( VITAL ) is an ongoing nationwide , r and omized , double-blind , placebo-controlled clinical trial design ed to fill this knowledge gap . The study population consists of 25,874 U.S. adults without cancer or CVD at baseline , who were selected only on age ( men aged ≥50 and women aged ≥55 ) , with an oversampling of African Americans ( n=5,107 ) . In a 2 × 2 factorial design , participants were r and omized to one of four supplement groups : [ 1 ] active vitamin D3 ( cholecalciferol ; 2000 IU/d ) and active marine omega-3 fatty acids ( Omacor ® fish oil , eicosapentaenoic acid [ EPA ] and docosahexaenoic acid [ DHA ] , 1g/d ) ; [ 2 ] active vitamin D and omega-3 placebo ; [ 3 ] vitamin D placebo and active marine omega-3 fatty acids ; or [ 4 ] vitamin D placebo and omega-3 placebo . The mean length of the r and omized treatment period will be 5 years . The r and omization was successful , as evidence d by similar distributions of baseline demographic , health , and behavioral characteristics across treatment groups . The similar distribution of known potential confounders across treatment groups strongly suggests that unmeasured or unknown potential confounders are also equally distributed . VITAL is expected to provide important information on the benefit-risk balance of vitamin D and omega-3 fatty acid supplementation when taken for the primary prevention of cancer and CVD BACKGROUND The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal . METHODS We recruited 36,282 postmenopausal women , 50 to 79 years of age , who were already enrolled in a Women 's Health Initiative ( WHI ) clinical trial . We r and omly assigned participants to receive 1000 mg of elemental [ corrected ] calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo .  Fractures were ascertained for an average follow-up period of 7.0 years . Bone density was measured at three WHI centers . RESULTS Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group ( P<0.01 ) . Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture ( 95 percent confidence interval , 0.72 to 1.08 ) , 0.90 for clinical spine fracture ( 0.74 to 1.10 ) , and 0.96 for total fractures ( 0.91 to 1.02 ) . The risk of renal calculi increased with calcium plus vitamin D ( hazard ratio , 1.17 ; 95 percent confidence interval , 1.02 to 1.34 ) . Censoring data from women when they ceased to adhere to the study medication reduced the hazard ratio for hip fracture to 0.71 ( 95 percent confidence interval , 0.52 to 0.97 ) . Effects did not vary significantly according to prer and omization serum vitamin D levels . CONCLUSIONS Among healthy postmenopausal women , calcium with vitamin D supplementation result ed in a small but significant improvement in hip bone density , did not significantly reduce hip fracture , and increased the risk of kidney stones . ( Clinical Trials.gov number , NCT00000611 . ) BACKGROUND Vitamin D , specifically serum 25(OH)D has been associated with mortality , cancer and multiple other health endpoints in observational studies , but there is a paucity of clinical trial evidence sufficient to determine the safety and effectiveness of population -wide supplementation . We have therefore launched the D-Health Trial , a r and omized trial of vitamin D supplementation for prevention of mortality and cancer . Here we report the methods and describe the trial cohort . METHODS The D-Health Trial is a r and omized placebo-controlled trial , with planned intervention for 5years and a further 5years of passive follow-up through linkage with health and death registers . Participants aged 65 - 84years were recruited from the general population of Australia . The intervention is monthly oral doses of 60,000IU of cholecalciferol or matching placebo . The primary outcome is all-cause mortality . Secondary outcomes are total cancer incidence and colorectal cancer incidence . RESULTS We recruited 21,315 participants to the trial between February 2014 and May 2015 . The participants in the two arms of the trial were well-balanced at baseline . Comparison with Australian population statistics shows that the trial participants were less likely to report being in fair or poor health , to be current smokers or to have diabetes than the Australian population . However , the proportion overweight or with health conditions such as arthritis and angina was similar . CONCLUSIONS Observational data can not be considered sufficient to support interventions delivered at a population level . Large-scale r and omized trials such as the D-Health Trial are needed to inform public health policy and practice BACKGROUND Hypovitaminosis D and a low calcium intake contribute to increased parathyroid function in elderly persons .  Calcium and vitamin D supplements reduce this secondary hyperparathyroidism , but whether such supplements reduce the risk of hip fractures among elderly people is not known . METHODS We studied the effects of supplementation with vitamin D3 ( cholecalciferol ) and calcium on the frequency of hip fractures and other nonvertebral fractures , identified radiologically , in 3270 healthy ambulatory women ( mean [ + /- SD ] age , 84 + /- 6 years ) . Each day for 18 months , 1634 women received tricalcium phosphate ( containing 1.2 g of elemental calcium ) and 20 micrograms ( 800 IU ) of vitamin D3 , and 1636 women received a double placebo . We measured serial serum parathyroid hormone and 25-hydroxyvitamin D ( 25(OH)D ) concentrations in 142 women and determined the femoral bone mineral density at base line and after 18 months in 56 women . RESULTS Among the women who completed the 18-month study , the number of hip fractures was 43 percent lower ( P = 0.043 ) and the total number of nonvertebral fractures was 32 percent lower ( P = 0.015 ) among the women treated with vitamin D3 and calcium than among those who received placebo . The results of analyses according to active treatment and according to intention to treat were similar . In the vitamin D3-calcium group , the mean serum parathyroid hormone concentration had decreased by 44 percent from the base-line value at 18 months ( P < 0.001 ) and the serum 25(OH)D concentration had increased by 162 percent over the base-line value ( P < 0.001 ) . The bone density of the proximal femur increased 2.7 percent in the vitamin D3-calcium group and decreased 4.6 percent in the placebo group ( P < 0.001 ) . CONCLUSIONS Supplementation with vitamin D3 and calcium reduces the risk of hip fractures and other nonvertebral fractures among elderly women This article summarizes the new 2011 report on dietary requirements for calcium and vitamin D from the Institute of Medicine ( IOM ) . An IOM Committee charged with determining the population needs for these nutrients in North America conducted a comprehensive review of the evidence for both skeletal and extraskeletal outcomes . The Committee concluded that available scientific evidence supports a key role of calcium and vitamin D in skeletal health , consistent with a cause- and -effect relationship and providing a sound basis for determination of intake requirements . For extraskeletal outcomes , including cancer , cardiovascular disease , diabetes , and autoimmune disorders , the evidence was inconsistent , inconclusive as to causality , and insufficient to inform nutritional requirements . R and omized clinical trial evidence for extraskeletal outcomes was limited and generally uninformative . Based on bone health , Recommended Dietary Allowances ( RDAs ; covering requirements of ≥97.5 % of the population ) for calcium range from 700 to 1300 mg/d for life-stage groups at least 1 yr of age . For vitamin D , RDAs of 600 IU/d for ages 1–70 yr and 800 IU/d for ages 71 yr and older , corresponding to a serum 25-hydroxyvitamin D level of at least 20 ng/ml ( 50 nmol/liter ) , meet the requirements of at least 97.5 % of the population . RDAs for vitamin D were derived based on conditions of minimal sun exposure due to wide variability in vitamin D synthesis from ultraviolet light and the risks of skin cancer . Higher values were not consistently associated with greater benefit , and for some outcomes U-shaped associations were observed , with risks at both low and high levels . The Committee concluded that the prevalence of vit 
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She said that if we test for vitamin D deficiency , she could almost guarantee that my level would not be in the normal range because of living in the Northeast , where we do n't get a lot of sunshine over the winter .
Your bone density is better if you exercise regularly .
I do some weights and play tennis a lot and walk regularly .
People with low vitamin D levels have an increased risk for osteoporosis .
Context , Evidence , and Guidelines Sub clinical vitamin D deficiency is common in the United States , especially in winter , and has been associated with an increased risk for falls and bone disorders .
Decreased intake of dairy products in adulthood may also be a contributing factor in some patients .
In summary , the USPSTF found that treatment of vitamin D deficiency in asymptomatic persons might reduce mortality risk in institutionalized elderly persons and risk for falls but not fractures .
This study and similar meta-analyses ( 10 ) constitute good evidence that vitamin D plus calcium ( but not vitamin D alone ) prevents fractures .
These studies have consistently shown no effect of supplementation with vitamin D and calcium on vertebral fractures ( 10 ) .
Vitamin D supplementation has also been reported