Egg intake and bladder cancer risk: A meta-analysis.

Egg intake has been hypothesized to promote carcinogenesis due to its potential to increase circulating levels of cholesterol. Epidemiological findings regarding the association between egg consumption and risk of bladder cancer have been inconsistent. We performed a meta-analysis of the available data. Relevant studies were identified by a PubMed database search of articles dating from between January 1980 and December 2011. We identified 4 cohort and 9 case-control studies of egg intake and risk of bladder cancer. Both fixed- and random-effects models were used to calculate the summary risk estimates (REs). The combined RE of bladder cancer for the highest compared with the lowest egg intake was 0.94 (95% CI, 0.69-1.18) and weak evidence of heterogeneity was observed. The association between egg intake and risk of bladder cancer differed significantly by geographic region, with a 28% reduced risk in Japanese. Our results provided no strong evidence of a significant association of egg consumption with bladder cancer incidence but showed a protective effect in Japanese.