Data from Coffee Drinking and Risk of Lung Cancer—A Meta-Analysis

Abstract

<div>Abstract<p><b>Background:</b> Previous epidemiologic results on coffee consumption and lung cancer risk have not been consistent. Furthermore, not all studies have addressed the potential role of tobacco as a confounder in this association. A meta-analysis was conducted to assess the effect of coffee consumption on lung cancer risk independent of tobacco use.</p><p><b>Methods:</b> A systematic review and a meta-analysis based on random effects models were performed using studies from the PubMed and EMBASE databases, and the references from the retrieved articles. Included were 8 prospective cohorts and 13 case–control studies, which provided data for 19,892 cases and 623,645 non-cases, timeframe 1986–2015.</p><p><b>Results:</b> The meta-relative risk (RR) for coffee drinking, not controlling for tobacco smoking, was 1.09 [95% confidence interval (CI), 1.00–1.19], the reference group was never drinkers. There was significant heterogeneity among the study results (<i>Q</i> = 84.39, <i>I</i>² = 75.1%, <i>P</i><sub>heterogeneity</sub> < 0.001). Among non-smokers, coffee was not associated with lung cancer risk (RR, 0.92; 95% CI, 0.75–1.10), the reference group was never drinkers. The meta-RR for 1 cup per day increase, unadjusted for smoking, was 1.04 (95% CI, 1.03–1.05); the corresponding RR for non-smokers was 0.95 (95% CI, 0.83–1.09).</p><p><b>Conclusions:</b> The pooled estimates indicated that when the potential confounding effect from smoking is controlled for, coffee drinking does not appear to be a lung cancer risk factor. Further pooled analyses, with larger non-smokers population size, are encouraged to confirm these results.</p><p><b>Impact:</b> This study illustrates that the association between coffee consumption and lung cancer can be confounded by tobacco smoking. <i>Cancer Epidemiol Biomarkers Prev; 25(6); 951–7. ©2016 AACR</i>.</p></div>