***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: 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 To lend clarity to inconsistent prior findings of an inverse association between ultraviolet radiation ( UVR ) exposure and risk of lymphoid malignancies , we examined the association of prospect ively ascertained residential ambient UVR exposure with risk of  non-Hodgkin lymphomas ( NHLs ) , multiple myeloma ( MM ) , and classical Hodgkin lymphoma in the California Teachers Study cohort . Among 121 216 eligible women , 629 were diagnosed with NHL , 119 with MM , and 38 with Hodgkin lymphoma between 1995 - 1996 and 2007 . Cox proportional hazards regression was used to estimate incidence rate ratios ( RRs ) with 95 % confidence intervals ( CIs ) . Residential UVR levels within a 20-km radius were associated with reduced risk of overall NHL ( RR for highest vs lowest statewide quartile of minimum UVR [ ≥ 5100 vs < 4915 W-h/m(2 ) ] , 0.58 ; 95 % CI , 0.42 - 0.80 ) , especially diffuse large B-cell lymphoma ( RR , 0.36 ; 95 % CI , 0.17 - 0.78 ) and chronic lymphocytic leukemia/small lymphocytic lymphoma ( RR , 0.46 ; 95 % CI , 0.21 - 1.01 ) , and MM ( RR for maximum UVR , 0.57 ; 95 % CI , 0.36 - 0.90 ) . These associations were not modified by skin sensitivity to sunlight , race/ethnicity , body mass index , or neighborhood socioeconomic status . Dietary vitamin D also was not associated with risk of lymphoid malignancies . These results support a protective effect of routine  residential UVR  exposure against lymphomagenesis through mechanisms possibly independent of vitamin 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 Background : UV radiation and pigmentary characteristics may be associated with non – Hodgkin lymphoma ( NHL ) risk , but few prospect i ve studies exist . We investigated these associations in a Norwegian-Swedish cohort . Methods : The cohort included women ages 30 to 50 years at enrolment in 1991 to 1992 . Host factors , and exposure to sun and artificial tanning devices in life-decades 0 to 50 years were collected by question naire . Relative risks ( RR ) with 95 % confidence intervals ( CI ) were estimated by Poisson regression . Results : Among 104,953 women with complete follow-up through 2006 ( Sweden ) and 2007 ( Norway ) , 158 were diagnosed with NHL . Women with brown hair had an increased risk of NHL compared with dark brown – haired/black-haired women ( RR , 1.72 ; 95 % CI , 1.08 - 2.74 ) ; decreased risks were found among women with gray , green or mixed ( RR , 0.50 ; 95 % CI , 0.32 - 0.77 ) , or blue ( RR , 0.54 ; 95 % CI , 0.35 - 0.81 ) eyes compared with those with brown eyes , and among those with high propensity to burn compared with those with low propensity ( RR , 0.57 ; 95 % CI , 0.36 - 0.91 ) . Annual number of sunburns and bathing vacations in any age decade , or ever use of artificial tanning devices were not significantly associated with NHL risk . After exposure at ages 10 to 39 years , RRs for ever versus never exposed were 0.99 ( 95 % CI , 0.65 - 1.50 ) for sunburn , 1.00 ( 95 % CI , 0.64 - 1.54 ) for bathing vacations , and 0.99 ( 95 % CI , 0.67 - 1.46 ) for artificial tanning device use . Conclusion : Whereas several pigmentary characteristics were associated with NHL risk , our results do not support an association between UV radiation and NHL . Impact : Studies of UV radiation and NHL are warranted for etiologic underst and ing and public health recommendations . Cancer Epidemiol Biomarkers Prev ; 19(6 ) ; 1569–76 . © 2010 AACR Introduction Experimental evidence indicates vitamin D may play an important role in breast cancer etiology but epidemiologic evidence to date is inconsistent . Vitamin D comes from dietary intake and sun exposure and plasma levels of 25-hydroxyvitamin D ( 25(OH)D ) are considered the best measure of vitamin D status . Methods We conducted a prospect i ve nested case-control study within the Nurses ' Health Study II ( NHSII ) . Plasma sample s collected in 1996 to 1999 were assayed for 25(OH)D  in 613 cases , diagnosed after blood collection and before 1 June 2007 , and in 1,218 matched controls .  Multivariate relative risks ( RR ) and 95 % confidence intervals ( CI ) were calculated by conditional logistic regression , adjusting for several breast cancer risk factors . Results No significant association was observed between plasma 25(OH)D levels and breast cancer risk ( top vs. bottom quartile multivariate RR = 1.20 , 95 % CI ( 0.88 to 1.63 ) , P-value , test for trend = 0.32 ) . Results were similar when season-specific quartile cut points were used . Results did not change when restricted to women who were premenopausal at blood collection or premenopausal at diagnosis . Results were similar between estrogen receptor (ER)+/progesterone receptor (PR)+ and ER-/PR- tumors ( P-value , test for heterogeneity = 0.51 ) . The association did not vary by age at blood collection or season of blood collection , but did vary when stratified by body mass index ( P-value , test for heterogeneity = 0.01 ) . Conclusions Circulating 25(OH)D levels were not significantly associated with breast cancer risk in this predominantly premenopausal population 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 Objective To examine the association between pre-diagnostic circulating vitamin D concentration ,  dietary intake of vitamin D and calcium  , and the  risk of colorectal cancer in European population s. Design Nested case-control study . Setting The study was conducted within the EPIC study , a cohort of more than 520 000 participants from 10 western European countries . Participants 1248 cases of incident colorectal cancer , which developed after enrolment into the cohort , were matched to 1248 controls Main outcome measures Circulating vitamin D concentration ( 25-hydroxy-vitamin-D , 25-(OH)D ) was measured by enzyme immunoassay . Dietary and lifestyle data were obtained from question naires . Incidence rate ratios and 95 % confidence intervals for the risk of colorectal cancer by 25-(OH)D concentration and levels of dietary calcium and vitamin D intake were estimated from multivariate conditional logistic regression models , with adjustment for potential dietary and other confounders . Results 25-(OH)D concentration showed a strong inverse linear dose-response association with risk of colorectal cancer ( P for trend < 0.001 ) . Compared with a pre-defined mid-level concentration of 25-(OH)D ( 50.0 - 75.0 nmol/l ) , lower levels were associated with higher colorectal cancer risk ( < 25.0 nmol/l : incidence rate ratio 1.32 ( 95 % confidence interval 0.87 to 2.01 ) ; 25.0 - 49.9 nmol/l : 1.28 ( 1.05 to 1.56 ) , and higher concentrations associated with lower risk ( 75.0 - 99.9 nmol/l : 0.88 ( 0.68 to 1.13 ) ; ≥100.0 nmol/l : 0.77 ( 0.56 to 1.06 ) ) . In analyses by quintile of 25-(OH)D concentration , patients in the highest quintile had a 40 % lower risk of colorectal cancer than did those in the lowest quintile ( P<0.001 ) . Subgroup analyses showed a strong association for colon but not rectal cancer ( P for heterogeneity=0.048 ) .  Greater dietary intake of calcium  was associated with a lower colorectal cancer risk . Dietary vitamin D  was not associated with disease risk . Findings did not vary by sex and were not altered by corrections for season or month of blood donation . Conclusions The results of this large observational study indicate a strong inverse association between levels of pre-diagnostic 25-(OH)D concentration and  risk of colorectal cancer in western European population s. Further r and omised trials are needed to assess whether increases in circulating 25-(OH)D concentration can effectively decrease the risk of colorectal cancer Background : Ecological studies have suggested that vitamin D production through ultraviolet ( UV ) solar irradiance could reduce breast cancer ( BC ) risk . Although studies restricted to dietary vitamin 
    Output:
    
We found that almost all epidemiological studies suggest that chronic ( not intermittent ) sun exposure is associated with a reduced risk of colorectal- , breast- , prostate cancer and NHL .
In colorectal- and to a lesser degree in breast cancer  vitamin D levels were found to be inversely associated with cancer risk .
In prostate cancer and NHL , however , no associations were found .
These findings are discussed and it is concluded that the evidence that sunlight is a protective factor for colorectal- , prostate- , breast cancer and non-Hodgkin 's lymphoma is still accumulating .
The same conclusion can be drawn concerning high vitamin D levels and the risk of colorectal cancer and possibly breast cancer .
Particularly in prostate cancer and NHL other sunlight potentiated and vitamin D independent pathways , such as modulation of the immune system and the circadian rhythm , and the degradation of folic acid might play a role in reduced cancer risk as well