Coffee consumption and the risk of chronic obstructive pulmonary disease

Objective: To investigate the relationship between coffee consumption and the risk of COPD.
Methods: A case-control study was conducted in Japan. A total of 277 eligible patients, aged 50-75 years with COPD diagnosed within the past four years, were referred by respiratory physicians, while 340 control subjects were recruited from the community. All participants underwent spirometric measurements of respiratory function. Information on demographics, lifestyle characteristics and habitual coffee consumption was obtained by face-to-face interview using a validated questionnaire.
Results: The prevalence of coffee drinking was higher among cases (81.6%) than controls (74%). A two-fold significant increase in COPD risk was evident for frequent coffee consumption (p < 0.01). Relative to never drinkers, the adjusted odds ratio was 1.94 (95% confidence interval 1.19 to 3.16) for drinking 2 to 3 cups or more daily.
Conclusions: A positive association was found between coffee consumption and the COPD risk. Further studies in other populations are needed to confirm the effect of long-term coffee drinking on the disease development.