Obesity and risk of subsequent hospitalisation with pneumonia

Obesity may be associated with increased risk of pneumonia, but available data on this relationship are sparse and inconsistent. We followed a prospective cohort of 22,578 males and 25,973 females from the Danish Diet, Cancer and Health Study, aged 50-64 yrs and free from major chronic diseases at baseline (1993-1997), for first-time hospitalisation with pneumonia (median follow-up 12 yrs). Compared with males of normal weight, adjusted hazard ratios (HRs) for pneumonia were 1.4 (95% CI 1.2-1.7) for males with moderate obesity (body mass index (BMI) 30.0-34.9 kg·m⁻²), and 2.0 (95% CI 1.4-2.8) for males with severe obesity (BMI ≥ 35.0 kg·m⁻²), controlling for lifestyle and educational variables. Among females the associations were weaker, with adjusted HRs of 0.8 (95% CI 0.6-1.0) for moderate obesity, and 1.2 (95% CI 0.8-1.6) for severe obesity. Adjustment for major chronic diseases diagnosed during follow-up eliminated the associations between obesity and pneumonia risk. Obesity is associated with higher risk of hospitalisation with pneumonia among males but not among females, which is apparently explained by occurrence of other chronic diseases.