***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 
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    Input: Objective Multiple studies have shown clear evidence of vitamin D ’s anti-tumor effects on prostate cancer cells in laboratory experiments , but the evidence has not been consistent in humans . We sought to examine the association between vitamin D and prostate cancer risk in a cohort of older men . Methods We conducted a prospect i ve case-cohort study nested within the multicenter Osteoporotic Fractures in Men ( MrOS ) study .  Baseline serum 25-OH vitamin D  was measured in a r and omly selected sub-cohort of 1,433 men ≥65 years old without a history of prostate cancer and from all participants with an incident diagnosis of prostate cancer ( n = 297 ) . Cox proportional hazards models were used to evaluate the associations between quartiles of total 25-OH vitamin D and incident prostate cancer , as well as Gleason score . Results In comparison with the lowest quartile of 25-OH vitamin D , the hazard ratio for the highest quartile of 25-OH vitamin D was 1.22 ( CI 0.50–1.72 , p = 0.25 ) , no trend across quartiles ( p = 0.94 ) or association with Gleason score was observed . Adjustment for covariates did not alter the results . Conclusions In this prospect i ve cohort of older men , we found no association between serum 25-OH vitamin D levels and subsequent risk of prostate cancer Abstract Background : Calcium , phosphorus , fructose , and animal protein are hypothesized to be associated with prostate cancer risk , potentially via their influence on 1,25-dihydroxyvitamin D3 . We examined these nutrients and overall diet and prostate cancer risk in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study ( ATBC Study ) . Material s and methods : The ATBC Study was a r and omized 2 × 2 trial of alpha-tocopherol and beta-carotene on lung cancer incidence conducted among Finnish male smokers ; 27,062 of the men completed a food-use question naire at baseline , and comprise the current study population . There were 184 incident clinical ( stage 2–4 ) prostate cancer cases diagnosed between 1985 and 1993 . We used Cox proportional hazards models to examine associations between dietary intakes and prostate cancer . Results : We did not observe significant independent associations for calcium and phosphorus and prostate cancer risk . However , men with lower calcium and higher phosphorus intake had a multivariate relative risk of 0.6 ( 95 % CI 0.3–1.0 ) compared to men with lower intakes of both nutrients , adjusting for age , smoking , body mass index , total energy , education , and supplementation group . Of the other foods and nutrients examined , none was significantly associated with risk . Discussion : This study provides , at best , only weak evidence for the hypothesis that calcium and phosphorus are independently associated with prostate cancer risk , but suggests that there may be an interaction between these nutrients This population -based , case-control study in King County , Washington examined associations of energy , fat , vitamin D , and calcium with  risk of prostate cancer in 605 incident cases ( ages 40 - 64 years ) identified from the Seattle-Puget Sound Surveillance Epidemiology and End Results registry and 592 controls recruited from the same underlying population using r and om-digit telephone sampling .  Self-administered food frequency question naires were used to assess diet over the 3 - 5-year period before diagnosis or interview date . Total energy  was associated with increased risk for both local and regional/distant stage disease . The adjusted odds ratios [ 95 % confidence intervals ( CIs ) ] contrasting highest to lowest quintile of energy intake were 2.15 ( 95 % CI , 1.35 - 3.43 ) for local and 1.96 ( 95 % CI , 1.08 - 3.56 ) for regional/distant disease . Fat was associated with regional/distant disease only . Adjusted odds ratios comparing the highest to lowest quintiles of percentage energy from total , saturated , and monounsaturated fats were 2.01 ( 1.03 - 3.92 ) , 1.82 ( 0.93 - 3.56 ) , and 2.00 ( 1.03 - 3.87 ) , respectively . For calcium , adjusted odds ratios contrasting the highest to lowest quartiles were 1.07 ( 0.63 - 1.84 ) for local and 2.12 ( 1.02 - 4.38 ) for regional/distant disease . There were no associations of vitamin D , total polyunsaturated fatty acids , or the highly unsaturated , long-chain eicosapentainoic and docosahexaenoic fatty acids with prostate cancer risk . These results suggest that high energy intake is a risk factor for both localized and nonlocalized prostate cancer , whereas dietary fat and calcium increase the risk of regional/distant disease only . These results are consistent with general dietary guidelines to moderate consumption of total energy and fat , and they motivate further research to consider the potential benefits and risks of high calcium intake A major problem in review ing the published results of different epidemiologic studies of the relation between a quantitative variable and the risk of disease is that the results are presented in many different ways . The purpose of this paper is to exemplify methods by which results expressed either as risks ( or rates ) according to quantlle groups of the quantitative variable or as results derived from a  logistic regression analysis can be reexpressed in a uniform manner , as a mean difference in the quantitative variable between the cases of disease and the other subjects in the study . An important assumption of the methods is that the quantitative variable has an approximately normal distribution , and a way of investigating the appropriateness of this assumption is given . The methods can be applied to both prospect i ve and case-control studies and are exemplified by a number of studies of serum albumin concentrations and mortality . In some applications , these methods can be used as a precursor to formal meta- analysis , for example , when differential control of potential confounding factors is not a problem . At the least , the methods can be useful either in quantitatively review ing published studies before undertaking new research or in putting the results of a new study into the context of previously published ones BACKGROUND Dairy intake may increase  prostate cancer  risk , but whether this is due to calcium 's suppression of circulating vitamin D remains unclear . Findings on calcium and vitamin D intake and prostate cancer are inconsistent . OBJECTIVE We examined the association of dairy , calcium , and vitamin D intake with  prostate cancer .  DESIGN In a prospect i ve study of 3612 men followed from 1982 - 1984 to 1992 for the first National Health and Nutrition Examination Epidemiologic Follow-up Study , 131 prostate cancer cases were identified .  Dietary intake was estimated from question naires completed in 1982 - 1984 . Relative risk ( RR ) and 95 % CIs were estimated by using Cox proportional hazards models adjusted for age , race , and other covariates . RESULTS Compared with men in the lowest tertile for dairy food intake , men in the highest tertile had a relative risk ( RR ) of 2.2 ( 95 % CI : 1.2 , 3.9 ; trend P = 0.05 ) . Low-fat milk was associated with increased risk ( RR = 1.5 ; 95 % CI : 1.1 , 2.2 ; third compared with first tertile ; trend P = 0.02 ) , but whole milk was not ( RR = 0.8 ; 95 % CI : 0.5 , 1.3 ; third compared with first tertile ; trend P = 0.35 ) . Dietary calcium was also strongly associated with increased risk ( RR = 2.2 ; 95 % CI : 1.4 , 3.5 ; third compared with first tertile ; trend P = 0.001 ) . After adjustment for calcium intake , neither vitamin D nor phosphorus was clearly associated with risk . CONCLUSIONS Dairy consumption may increase prostate cancer risk through a calcium-related pathway . Calcium and low-fat milk have been promoted to reduce risk of osteoporosis and colon cancer . Therefore , the mechanisms by which dairy and calcium might increase prostate cancer risk should be clarified and confirmed Abstract Objective : The hormone 1,25-dihydroxyvitamin D ( 1,25(OH)2D ) promotes prostate epithelial cell differentiation in vitro and thus , several groups have hypothesized that men who systemically have lower levels of 1,25(OH)2D may be at increased risk for prostate cancer . To address this hypothesis , we evaluated the association of circulating concentrations of 1,25(OH)2D and its precursor 25-hydroxyvitamin D ( 25(OH)D ) with subsequent risk of prostate cancer . Methods : Prostate cancer cases were 460 men in the Health Professionals Follow-up Study who were diagnosed through 1998 after providing a blood specimen in 1993/95 . 90.2 % of the cases were organ confined or had minimal extraprostatic extension . An equal number of controls who had had a screening PSA test after blood draw  were individually matched to cases on age , history of a PSA test before blood draw , and time of day , season , and year of blood draw .  Plasma 1,25(OH)2D and 25(OH)D concentrations  were determined by radio-immunosorbant assay blindly to case – control status . Odds ratios ( OR ) of prostate cancer and 95 % confidence intervals ( CI ) were estimated from conditional logistic regression models mutually adjusting for quartiles of 1,25(OH)2D and 25(OH)D concentrations and for suspected prostate cancer risk factors . Quartile cutpoints were determined separately by season of blood draw using the distributions among controls . Results : Mean concentrations of 1,25(OH)2D and 25(OH)D were slightly , but not statistically significantly ( p= 0.06 and 0.20 , respectively ) , higher in cases ( 34.3 ± 7.1 pg/ml and 24.6 ± 7.7 ng/ml , respectively ) than in controls ( 33.5 ± 7.1 pg/ml and 23.9 ± 8.2 ng/ml , respectively ) . The OR of prostate cancer comparing men in the top to bottom quartile of 1,25(OH)2D was 1.25 ( 95 % CI : 0.82–1.90 , p-trend = 0.16 ) . For 25(OH)D the OR of prostate cancer comparing the top and bottom quartiles was 1.19 ( 95 % CI : 0.79–1.79 , p-trend = 0.59 ) . These findings did not vary by level of the other metabolite , age at diagnosis , family history of prostate cancer , or factors that are thought to influence 25(OH)D levels . Conclusion : In this prospect i ve study , we did not observe an inverse association between plasma concentrations of 1,25(OH)2D or 25(OH)D and incident prostate cancer , although we can not rule out potential effects at later stages of the disease Intake of calcium and /or dairy products has been associated with increased risk of prostate cancer  in some epidemiological studies . One potential biological mechanism is that high calcium intake down-regulates 1,25 dihydroxy vitamin D(3 ) , which may increase cell proliferation in the prostate . We examined the association between calcium , dairy intake , and prostate cancer incidence in the Cancer Prevention Study II Nutrition Cohort , a prospect i ve cohort of elderly United States adults . Participants in the study completed a detailed question naire on diet , medical history , and lifestyle at enrollment in 1992 - 1993 . After excluding men with a history of cancer or incomplete dietary information , 65,321 men remained for analysis . During follow-up through August 31 , 1999 , we documented 3811 cases of incident prostate cancer . Multivariate-adjusted rate ratios ( RRs ) were calculated using Cox proportional hazards models . Total calcium intake ( from diet and supplements ) was associated with modestly increased risk of prostate cancer [ RR = 1.2 , 95 % confidence interval ( CI ) = 1.0 - 1.6 for > or=2000 versus < 700 mg/day , P trend = 0.02 ) . High dietary calcium intake ( > or=2000 versus < 700 mg/day ) was also associated with increased risk of prostate cancer ( RR = 1.6 , 95 % CI = 1.1 - 2.3 , P trend = 0.10 ) , although moderate levels of dietary calcium were not associated with increased risk . Dairy intake was not associated with prostate cancer risk . The association between prostate cancer and total calcium intake was strongest for men who reported not having prostate-specific antigen testing before 1992 ( RR = 1.5 , 95 % CI = 1.1 - 2.0 , P trend < 0.01 for > or= 2000 mg/day of total calcium ; RR = 2.1 , 95 % CI = 1.3 - 3.4 > or=2000 mg/day of dietary calcium , P trend = 0.04 ) . Our results support the hypothesis that very high calcium intake , above the recommended intake for men , may modestly increase risk of prostate cancer PURPOSE Substantial experimental and epidemiological data indicate that 1,25-dihydroxyvitamin D3 ( calcitriol ) has potent antiproliferative effects on human prostate cancer cells . 
    Output:
    
Conclusion Published literature provides little evidence to support a major role of vitamin D in preventing prostate cancer or its progression