***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: Many N-nitroso compounds ( NOC ) are carcinogens . In this controlled study of 21 healthy male volunteers , levels of NOC on a high ( 420 grams ) red meat diet were significantly greater ( P = 0.001 ) than on a low ( 60 grams ) meat diet but not significantly greater when an equivalent amount of vegetable protein was fed . An 8-mg supplement of haem iron also increased fecal NOC ( P = 0.006 ) compared with the low meat diet , but 35-mg ferrous iron had no effect . Endogenous N-nitrosation , arising from ingestion of haem but not inorganic iron or protein , may account for the increased risk associated with red meat consumption in colorectal cancer OBJECTIVE To examine the intake of antioxidant vitamins and carotenoids as well as fruits and vegetables in relation to the development of age-related maculopathy ( ARM ) . METHODS We conducted a prospect i ve follow-up study of women in the Nurses ' Health Study and men in the Health Professionals Follow-up Study . We followed 77 562 women and 40 866 men who were at least 50 years of age and had no diagnosis of ARM or cancer at baseline for up to 18 years for women and up to 12 years for men .  Fruit and vegetable intakes  were assessed with a vali date d semiquantitative food-frequency question naire up to 5 times for women and up to 3 times for men during follow-up . RESULTS A total of 464 ( 329 women and 135 men ) incident cases of early ARM and 316 ( 217 women and 99men ) cases of neovascular ARM , all with visual loss of 20/30 or worse due primarily to ARM , were diagnosed during follow-up . Fruit intake was inversely associated with the risk of neovascular ARM . Participants who consumed 3 or more servings per day of fruits had a pooled multivariate relative risk of 0.64 ( 95 % confidence interval , 0.44 - 0.93 ; P value for trend = .004 ) compared with those who consumed less than 1.5 servings per day . The results were similar in women and men . However , intakes of vegetables , antioxidant vitamins , or carotenoids  were not strongly related to either early or neovascular ARM . CONCLUSION These data suggest a protective role for fruit intake on the risk of neovascular ARM BACKGROUND The relation between intakes of total fat and specific types of fat and  age-related macular degeneration ( AMD )  remains unclear . OBJECTIVE Our objective was to examine prospect ively the association between fat intake and AMD . DESIGN We conducted a prospect i ve follow-up study of participants in the Nurses ' Health Study and the Health Professionals Follow-up Study . At baseline ( 1984 for women and 1986 for men ) , the study included 42743 women and 29746 men aged > or = 50 y with no diagnosis of AMD who were followed until 1996 .  Fat intake  was assessed with a food-frequency question naire . RESULTS We accrued 567 patients with AMD with a visual loss of 20/30 or worse . The pooled multivariate relative risk ( RR ) for the highest compared with the lowest quintile of total fat intake was 1.54 ( 95 % CI : 1.17 , 2.01 ; P for trend = 0.008 ) . Linolenic acid was positively associated with risk of AMD ( top versus bottom quintile of RR : 1.49 ; 95 % CI : 1.15 , 1.94 ; P for trend = 0.0009 ) . Docosahexaenoic acid had a modest inverse relation with AMD ( top versus bottom quintile of RR : 0.70 ; 95 % CI : 0.52 , 0.93 ; P for trend = 0.05 ) , and > 4 servings of fish/wk was associated with a 35 % lower risk of AMD compared with < or = 3 servings/mo ( RR : 0.65 ; 95 % CI : 0.46 , 0.91 ; P for trend = 0.009 ) . CONCLUSIONS Total fat intake was positively associated with risk of AMD , which may have been due to intakes of individual fatty acids , such as linolenic acid , rather than to total fat intakes per se . A high intake of fish may reduce the risk of AMD BACKGROUND Dietary factors are known risk factors for age-related macular degeneration ( AMD ) -- the leading cause of visual loss among persons aged > or = 65 y.  High-glycemic-index diets have been hypothesized as a risk factor for AMD , but prospect i ve data are unavailable . OBJECTIVE The objective was to examine the association between  dietary glycemic index  and the 10-y incidence of AMD  in the Blue Mountain Eye Study population . DESIGN This was a population -based cohort study with 3,654 participants ( > or = 49 y ) examined at baseline ( 1992 - 1994 ) ; 2,335 patients were reexamined after 5 y and 1952 after 10 y. The Wisconsin System was used to grade 10-y incident early and late AMD from retinal photographs . A food-frequency question naire was used to collect dietary information at baseline , and an Australian data base was used to calculate the mean glycemic index . RESULTS Over 10 y , 208 of 1,810 persons ( cumulative incidence : 14.1 % ) developed early AMD . After age , smoking , other risk factors , and dietary constituents were adjusted for , a higher mean dietary glycemic index was associated with an increased 10-y risk of early AMD in a comparison of quartiles 1 and 4 [ relative risk ( RR ) : 1.77 ; 95 % CI : 1.13 , 2.78 ; P for trend = 0.03 ] . Conversely , a greater consumption of cereal fiber ( RR : 0.68 ; 95 % CI : 0.44 , 1.04 ; P for trend = 0.05 ) and breads and cereals ( predominantly lower glycemic index foods such as oatmeal ) ( RR : 0.67 ; 95 % CI : 0.44 , 1.02 ; P for trend = 0.03 ) was associated with a reduced risk of incident early AMD . No relation was observed with late AMD . CONCLUSIONS A high-glycemic-index diet is a risk factor for early AMD -- the recognized precursor of sight-threatening late AMD . Low-glycemic-index foods such as oatmeal may protect against early AMD Habitual consumption of dairy products has been shown to play an important role in the prevention of several chronic diseases . We aim ed to prospect ively assess the relationship between the change in dairy product consumption ( both regular fat and low/reduced fat ) and the 15-year incidence of  age-related macular degeneration ( AMD ) . In the Blue Mountains Eye Study , 2037 participants aged 49 years or above at baseline were re-examined at follow-up in 1997 - 9 , 2002 - 4 and /or 2007 - 9 . AMD was assessed from retinal photographs . Dietary data were collected using a semi-quantitative FFQ , and servings of dairy product consumption calculated . Over the 15-year follow-up , there were 352 , 268 and eighty-four incident cases of any , early and late AMD , respectively . After adjusting for age , sex , current smoking , white cell count and fish consumption , a significant linear trend ( P for trend = 0·003 ) was observed with decreasing consumption of total dairy foods and the 15-year incidence of late AMD , comparing the lowest v. highest quintile of intake ( OR 2·80 , 95 % CI 1·21 , 3·04 ) . Over the 15 years , decreased consumption of reduced-fat dairy foods was associated with an increased risk of incident late AMD , comparing the lowest to highest quintile of intake ( OR 3·10 , 95 % CI 1·18 , 8·14 , P for trend = 0·04 ) . Decreasing total dietary Ca intake over the 15 years was also associated with an increased risk of developing incident late AMD ( multivariable-adjusted P for trend = 0·03 ) . A lower consumption of dairy products ( regular and low fat ) and Ca was independently associated with a higher risk of developing incident late AMD in the long term . Additional cohort studies are needed to confirm these findings PURPOSE To establish risk factors for five-year incidence of age-related macular degeneration ( AMD ) . DESIGN Population -based , prospect i ve cohort study , and risk analysis . METHODS A r and om sample from the Reykjavik Population Census for individuals 50 years and older was selected . We took fundus stereo color photographs and used st and ard grading system to study the five-year incidence of drusen , pigmentary abnormalities , and AMD and to examine possible risk factors . A question naire including information on disease , medication , diet , and lifestyle from the Reykjavik Eye Study data base provided additional information . RESULTS Current alcohol consumption decreased the risk for drusen . Being married rather than divorced or widowed decreased the risk for soft drusen ; being single decreased the risk of hypopigmentation as compared with being divorced or married . Both consuming dietary fiber-rich vegetables and meat and meat products once a week or less frequently was a risk factor for developing soft drusen and decreased the risk of pigmentary abnormalities . Those who had smoked 20 pack-years or more as compared with nonsmokers had decreased survival rate over the five years ( odds ratio ( OR ) 0.46 , 95 % confidence interval ( CI ) 0.27 to 0.80 ; P = .006 ) . CONCLUSIONS Risk factors for drusen appear to differ from risk factors for pigmentary abnormalities . The effect of smoking on developing AMD is partly masked by selective mortality PURPOSE To evaluate the associations between intakes of eicosapentaenoic acid ( EPA ) and docosahexaenoic acid ( DHA ) and the intermediate and advanced stages of age-related macular degeneration ( AMD ) . DESIGN Prospect i ve cohort study . PARTICIPANTS We followed 75 889 women from the Nurses ' Health Study and 38 961 men from the Health Professionals Follow-Up Study who were at least 50 years old , from 1984 to 2012 and 1986 to 2010 , respectively . Cohort participants are mostly white ( ≥95 % ) . METHODS We assessed  dietary intake by a vali date d food frequency question naire ( FFQ ) at baseline and every 4 years . We calculated cumulative average intakes of EPA and DHA from FFQs and also computed predicted erythrocyte and plasma scores directly from food intake using regression models . Cox proportional hazards models were used to compute the associations with AMD outcomes . MAIN OUTCOME MEASURES We confirmed 1589 incident intermediate and 1356 advanced AMD cases ( primarily neovascular AMD ) with a visual acuity of 20/30 or worse , owing primarily to AMD , by medical record review . RESULTS For intermediate AMD , the pooled hazard ratio ( HR ) between the 2 cohorts for DHA comparing the extreme quintiles of intake was 0.78 ( 95 % confidence interval [ CI ] , 0.66 - 0.92 ; P trend , 0.008 ) and for EPA + DHA was 0.83 ( 95 % CI , 0.71 - 0.98 ; P trend , 0.03 ) . The pooled HR for fatty fish , comparing ≥5 servings per week to almost never , was 0.61 ( 95 % CI , 0.46 - 0.81 ; P trend , < 0.001 ) . For advanced AMD , the pooled HR for DHA was 1.01 ( 95 % CI , 0.84 - 1.21 ; P trend , 0.75 ) and for fatty fish was 0.80 ( 95 % CI , 0.59 - 1.08 ; P trend , 0.11 ) . Secondary analyses using predicted erythrocyte and plasma scores of EPA and DHA yielded slightly stronger inverse associations for intermediate AMD and similar results for advanced AMD . CONCLUSIONS Higher intakes of EPA and DHA  may prevent or delay the occurrence of visually significant intermediate AMD . However , the totality of current evidence for EPA and DHA and advanced AMD is discordant , though there was no association with advanced AMD in the present study PURPOSE Vascular risk factors , including alcohol intake , have been hypothesized to play a role in the development of age-related macular degeneration ( AMD ) . We examined the relationship of alcohol intake with AMD in the Physicians ' Health Study ( PHS ) . METHODS The PHS was a r and omized trial of aspirin and beta-carotene among 22,071 U.S. male physicians age 40 to 84 years at entry . A total of 21,041 physicians with complete data on alcohol consumption and no AMD at baseline were included in this analysis . Proportional hazards models were used 
    Output:
    
In addition , an increased risk was observed for meat , but only in the subgroup of early AMD