Obesity at age 50 to 64 and risk of subsequent hospitalisation with pneumonia

Objectives: To examine the impact of body mass index (BMI) and waist circumference on the risk of hospitalisation with pneumonia.

Methods: We followed 49,627 persons from the Danish "Diet, Cancer and Health" study, who were 50-64 yearsold and free of hospital-diagnosed comorbidity at baseline.(1993-1997). We categorized BMI into five groups (<22.5, 22.5-24.9, 25.0-29.9, 30.0-34.9, 35+) and waist circumference into quintiles. Data on pneumoniarelated hospitalisations up to 2008 were obtained from the National Patient Registry. We used Cox regression analyses to compute incidence rate ratios (IRRs) for pneumonia according to BMI and waist circumference,controlling for smoking and alcohol intake.

Results 1,130 (5%) men and 1,068 (4%) women had hospitalised pneumonia (median follow-up 11.5 and 11.7 years, respectively), corresponding to incidence rates of 4.3 and 3.4 per 1000 person-years. Compared with men with a BMI of 22.5-24.9 the adjusted IRRs were increased for both low and high BMI: 1.4 (95% CI:1.1-1.7) for BMI < 22.5, 1.1 (1.0-1.3) for BMI = 25.0-29.9, 1.5 (1.2-1.8) for BMI = 30.0-34.9, and 2.2 (1.6-3.1) for BMI of 35+. For women the adjusted IRRs were 1.2 (1.0-1.4) for BMI < 22.5, 0.9 (0.7-1.0) for BMI = 25.0-29.9, 0.8 (0.7-1.1) for BMI = 30.0-34.9, and 1.2 (0.9-1.7) for BMI of 35+. IRRs of pneumonia among men and women in the highest quintile of waist circumference were 1.8 (1.5-2.2) and 1.4 (1.0-1.9), respectively.

Conclusion: General and abdominal obesity increased the risk of hospitalised pneumonia. particularly among men. Low BMI increased the risk of pneumonia among both gender.