***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: Background : Calcium , vitamin D , and dairy products are highly correlated factors , each with potential roles in breast carcinogenesis . Few prospect i ve studies have examined these relationships in postmenopausal women . Methods : Participants in the Cancer Prevention Study II Nutrition Cohort completed a detailed question naire on diet , vitamin and mineral supplement use , medical history , and lifestyle in 1992 to 1993 . After exclusion of women with a history of cancer and incomplete dietary data , 68,567 postmenopausal women remained for analysis . During follow-up through August 31 , 2001 , we identified 2,855 incident cases of breast cancer . Multivariate-adjusted rate ratios ( RR ) were calculated using Cox proportional hazards models . Results : Women with the highest intake of dietary calcium ( > 1,250 mg/d ) were at a lower risk of breast cancer than those reporting ≤500 mg/d [ RR , 0.80 ; 95 % confidence interval ( 95 % CI ) , 0.67 - 0.95 ; Ptrend = 0.02 ] ; however , neither use of supplemental calcium nor vitamin D intake was associated with risk . Consumption starting at two or more servings of dairy products per day was likewise inversely associated with risk ( RR , 0.81 ; 95 % CI , 0.69 - 0.95 ; Ptrend = 0.002 , compared with < 0.5 servings/d ) . The associations were slightly stronger in women with estrogen receptor – positive tumors comparing highest to lowest intake : dietary calcium  ( RR , 0.67 ; 95 % CI , 0.51 - 0.88 ; Ptrend = 0.004 ) ; dairy products ( RR , 0.73 ; 95 % CI , 0.57 - 0.93 ; Ptrend = 0.0003 ) , and dietary vitamin D ( RR , 0.74 ; 95 % CI , 0.59 - 0.93 ; Ptrend = 0.006 ) . Conclusions : Our results support the hypothesis that dietary calcium and /or some other components in dairy products may modestly reduce risk of postmenopausal breast cancer . The stronger inverse associations among estrogen receptor – positive tumors deserve further study . ( Cancer Epidemiol Biomarkers Prev 2005;14(12):2898–904 Several lines of evidence suggest that vitamin D may reduce incidence of breast cancer , but few epidemiologic studies have addressed the relation of plasma vitamin D metabolites to the risk of this disease . We prospect ively examined the relationship between plasma levels of 25-hydroxyvitamin D [ 25(OH)D ] and 1,25-dihydroxyvitamin D [ 1,25(OH)2D ] and  risk of breast cancer  in a case-control study nested within the Nurses ' Health Study cohort .  Blood sample s were collected from study participants in 1989 - 1990 . Breast cancer cases developing between blood collection and June 1 , 1996 , were matched to cancer-free controls on the basis of age , menopausal status , and other factors . Stored plasma sample s from 701 cases and 724 controls were available for metabolite analysis . Cases had a lower mean 25(OH)D level than controls ( P = 0.01 ) , but mean 1,25(OH)2D levels were similar ( P = 0.49 ) . High levels of both metabolites were associated with a nonsignificant lower risk of breast cancer . Women in the highest quintile of 25(OH)D had a relative risk of 0.73 ( 95 % confidence interval = 0.49 - 1.07 ; Ptrend = 0.06 ) compared with those in the lowest quintile . For 1,25(OH)2D , the comparable relative risk was 0.76 ( 95 % confidence interval = 0.52 - 1.11 ; Ptrend = 0.39 ) . For both metabolites , the association was stronger in women ages 60 years and older , but results were not statistically significant . Our findings suggest that high levels of 25(OH)D , and perhaps 1,25(OH)2D , may be modestly associated with reduced risk of breast cancer We investigated the association between plasma 25(OH)D and the subsequent  colorectal cancer incidence risk by a nested case – control study in The Japan Public Health Center-based Prospect i ve Study , covering 375 newly diagnosed cases of colorectal cancer from 38 373 study subjects during a 11.5-year follow-up after blood collection . Two controls were matched per case on sex , age , study area , date of blood draw , and fasting time . In a conditional logistic regression model with matched pairs adjusted for smoking , alcohol consumption , body mass index , physical exercise , vitamin supplement use , and family history of colorectal cancer , plasma 25(OH)D was not significantly associated with colorectal cancer in men or in women . However , the lowest category of plasma 25(OH)D was associated with an elevated risk of rectal cancer in both men ( odds ratio ( OR ) , 4.6 ; 95 % confidence interval ( CI ) , 1.0–20 ) and women ( OR , 2.7 , 95 % CI , 0.94–7.6 ) , compared with the combined category of the other quartiles . Our results suggest that a low level of plasma 25(OH)D may increase the risk of rectal cancer 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 Background Early life exposures , including diet , have been implicated in the etiology of breast cancer . Methods A nested case-control study was conducted among participants in the Nurses ' Health Study who completed a 24-item question naire about diet during high school .  There were 843 eligible cases diagnosed between onset of study ( 1976 ) and before the return of the high school diet question naire ( 1986 ) , who were matched 10:1 with controls on the basis of age . Results Women who had , during adolescence , a higher consumption of eggs , vegetable fat and fiber  had a lower risk of breast cancer , whereas risk of breast cancer was increased among women who consumed more butter . Conclusions A possible association of elements of adolescent diet with risk of breast cancer is reported , but the findings require confirmation in prospect i ve study BACKGROUND Numerous observational studies have found supplemental calcium and vitamin D to be associated with reduced risk of common cancers . However , interventional studies to test this effect are lacking . OBJECTIVE The purpose of this analysis was to determine the efficacy of calcium alone and calcium plus vitamin D in reducing incident cancer risk  of all types . DESIGN This was a 4-y , population -based , double-blind , r and omized placebo-controlled trial . The primary outcome was fracture incidence , and the principal secondary outcome was cancer incidence . The subjects were 1179 community-dwelling women r and omly selected from the population of healthy postmenopausal women aged > 55 y in a 9-county rural area of Nebraska centered at latitude 41.4 degrees N. Subjects were r and omly assigned to receive 1400 - 1500 mg supplemental calcium/d alone ( Ca-only ) , supplemental calcium plus 1100 IU vitamin D3/d ( Ca + D ) , or placebo . RESULTS When analyzed by intention to treat , cancer incidence was lower in the Ca + D women than in the placebo control subjects ( P < 0.03 ) . With the use of logistic regression , the unadjusted relative risks ( RR ) of incident cancer in the Ca + D and Ca-only groups were 0.402 ( P = 0.01 ) and 0.532 ( P = 0.06 ) , respectively . When analysis was confined to cancers diagnosed after the first 12 mo , RR for the Ca + D group fell to 0.232 ( CI : 0.09 , 0.60 ; P < 0.005 ) but did not change significantly for the Ca-only group . In multiple logistic regression models , both treatment and serum 25-hydroxyvitamin D concentrations were significant , independent predictors of cancer risk . CONCLUSIONS Improving calcium and vitamin D nutritional status substantially reduces  all-cancer risk in postmenopausal women . This trial was registered at clinical trials.gov as NCT00352170 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 BACKGROUND Calcium and vitamin D have a potential protective effect against  colorectal cancer .  OBJECTIVE We investigated the association of dietary intake of calcium and vitamin D with the risk of colorectal cancer  in a large prospect i ve cohort study of middle-aged Japanese men and women . DESIGN A total of 74 639 subjects ( 35 194 men and 39 445 women ) who participated in the Japan Public Health Center-based Prospect i ve Study were followed from 1995 - 1999 to the end of 2004 , during which time 761 cases of colorectal cancer ( 464 men , 297 women ) were newly identified .  Dietary intake of nutrients  was calculated with the use of a 138-item self-administered food-frequency question naire . RESULTS After adjusting for potential confounding factors , the multivariate hazard ratio in the highest qu 
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The results of the intervention studies are suggestive of a protective role of high doses of vitamin D in cancer , but they have been criticized in the literature .
We , therefore , conclude that there is accumulating evidence for sunlight as a protective factor for several types of cancer .
The same conclusion can be made concerning high vitamin D levels and the risk of colorectal cancer .