Many epidemiological studies have indicated a positive association between coffee intake and lung cancer risk, but such findings were suggested to be confounded by smoking. Furthermore, only a few of these studies have been conducted in Asia. Here, we investigated the association between coffee intake and lung cancer risk in one of the largest prospective cohort studies in Japan.
We investigated the association of coffee drinking and subsequent incidence of lung cancer among 41,727 men and 45,352 women in the Japan Public Health Center-based Prospective Study using Cox proportional hazards regression, with adjustment for potential confounders and by strata of smoking status. Coffee and other dietary intakes were assessed once at baseline with a food frequency questionnaire (FFQ).
During 1,481,887 person-years of follow-up between 1990 and 2011, a total of 1,668 lung cancer cases were identified. In a multivariate regression model, coffee consumption was not associated with risk of lung cancer (HR 1.16; 95% CI, 0.82–1.63; Ptrend = 0.285 for men and HR 1.49; 95% CI, 0.79–2.83; Ptrend = 0.942 for women). However, there was a significant increase in the risk for small cell carcinoma (HR 3.52; 95% CI, 1.49–8.28; Ptrend < 0.001).
Our prospective study suggests that habitual consumption of coffee is not associated with an increased risk of lung cancer incidence, despite observing a significant increase in the risk for small cell carcinoma.