Fruits, vegetables and lung cancer: A pooled analysis of cohort studies

Abstract

Inverse associations between fruit and vegetable consumption and lung cancer risk have been consistently reported. However, identifying the specific fruits and vegetables associated with lung cancer is difficult because the food groups and foods evaluated have varied across studies. We analyzed fruit and vegetable groups using standardized exposure and covariate definitions in 8 prospective studies. We combined study-specific relative risks (RRs) using a random effects model. In the pooled database, 3,206 incident lung cancer cases occurred among 430,281 women and men followed for up to 6 -16 years across studies. Controlling for smoking habits and other lung cancer risk factors, a 16 -23% reduction in lung cancer risk was observed for quintiles 2 through 5 vs. the lowest quintile of consumption for total fruits (RR ‫؍‬ 0.77; 95% CI ‫؍‬ 0.67-0.87 for quintile 5; p-value, test for trend < 0.001) and for total fruits and vegetables (RR ‫؍‬ 0.79; 95% CI ‫؍‬ 0.69 -0.90; p-value, test for trend ‫؍‬ 0.001). For the same comparison, the association was weaker for total vegetable consumption (RR ‫؍‬ 0.88; 95% CI ‫؍‬ 0.78 -1.00; p-value, test for trend ‫؍‬ 0.12). Associations were similar between never, past, and current smokers. These results suggest that elevated fruit and vegetable consumption is associated with a modest reduction in lung cancer risk, which is mostly attributable to fruit, not vegetable, intake. However, we cannot rule out the possibility that our results are due to residual confounding by smoking. The primary focus for reducing lung cancer incidence should continue to be smoking prevention and cessation.

Lifelong vegetarianism and risk of breast cancer: A population‐based case‐control study among South Asian migrant women living in England

“…43 Intake of vegetables in Western countries is lower than in South Asian populations. The median intake of total vegetables, including pulses, among the controls in our study was 355 g/day, much higher than in the cohorts included in the pooled analysis (range: 77-226 g/day 32 ). Thus, the lower intake of vegetables and dietary fibre might have reduced the likelihood of finding associations in studies conducted among Western populations.…”

Apple intake and cancer risk: a systematic review and meta-analysis of observational studies

“…Therefore, further studies are necessary to clarify the potential preventive effects of apples on lung cancer in smokers and never smokers. In contrast to lung cancer, the risk of colorectal and breast cancer resulted to Kubik (2008) (17) / female/non-smokers Wright (2008) (36) /female/never smokers Wright (2008) (36) /female/full cohort Linseisen (2007) (38) /female+male/never smokers Wright (2008) (36) /female/former smokers Linseisen (2007) (38) /female+male/full cohort Wright (2008) (36) /male/full cohort Wright (2008) (36) /male/former smokers Linseisen (2007) (38) /female+male/current smokers Smith-Warner (2003) (48) /female+male/full cohort Wright (2008) (36) /male/current smokers Wright (2008) (36) /male/never smokers Arts (2001) (43) /male/full cohort Feskanich (2000) (45) /female/full cohort Knekt (2002) (42) /male/full cohort Büchner (2010) (32) /female+male/full cohort Büchner (2010) (32) /female+male/current smokers Wright (2008) (36) /female/current smokers Linseisen (2007) (38) *The analysis was performed when two or more studies were available, †The risk estimates were calculated using the random-effect model. ‡Number of studies used to calculate the risk is indicated in parentheses.…”

“…These discrepancies may be in part due to the low number of cohort studies, two for colonrectum (39,49) and three for breast (30,40,47) . It should be considered, however, that two pooled analyses were Theodoratou (2007) (20) Deneo-Pellegrini (1996) (28) Koushik (2007) (49) /male+female Lin (2006) (39) /male Lin (2006) (39) /female…”

“…One was a multinational study conducted in nine countries worldwide (Italy, Spain, Poland, Northern Ireland, India, Cuba, Canada, Australia and Sudan) (21) Cohort studies were published between 1998 and 2012; nine were conducted in the USA (30,31,(34)(35)(36)(37)39,40,45) and eight were conducted in Europe (32,33,38,(41)(42)(43)(44)46) . Pooled analysis were conducted in the USA, Canada, Europe and Australia and included from seven to fourteen prospective studies (47)(48)(49)(50) . Seven cohort studies were on lung cancer (1 912 199 cohort and 12 913 incident cases), two on colorectal cancer (796 305 cohort and 6367 incident cases), three on breast cancer (479 219 cohort and 9195 incident cases), and one each on oesophageal, pancreatic, bladder, kidney, endometrial, head-neck, urothelial, stomach and all types of cancer.…”

Dietary and other risk factors in women having fibrocystic breast conditions with and without concurrent breast cancer: A nested case‐control study in Shanghai, China

“…A meta-analysis of 14 casecontrol studies and 3 cohort studies showed a reduced risk of breast cancer in relation to vegetable consumption, but with significant heterogeneity among studies, and only a weak, non-significant, association with fruit intake. 34 A subsequent pooled analysis of 9 cohort studies 35 found that neither fruit nor vegetable intake was significantly associated with breast cancer risk, suggesting that the associations observed in case-control studies may have been due to differential reporting of dietary intakes by cases and controls. The cohort studies were conducted in North America and Western Europe.…”