Lifestyle risk factors, obesity and infectious disease mortality in the general population: Linkage study of 97,844 adults from England and Scotland

We examined associations between lifestyle variables and infectious disease mortality in a large general population cohort. A sample of 97,844 men and women (aged 47.1 ± 17.7 yrs.; 46.6% male) recruited from general population, household-based surveys were followed up over mean [SD] 9.4 ± 4.5 years. Exposure measurements included self-reported physical activity, cigarette smoking, alcohol intake, and objective body mass index and waist to hip ratio. There were 9027 deaths, of which 14.1% were attributed to infectious diseases. Compared to physically inactive participants both insufficiently active (Hazard ratio = 0.61; 95% CI, 0.50, 0.75) and sufficiently active (at least 150 min/wk. moderate – vigorous activity) (0.60; 0.45, 0.78) was associated with reduced risk of infectious disease mortality in models mutually adjusted for other lifestyle factors. Ex-smokers and current smokers were at increased risk of infectious disease mortality compared with never smoker, with the strongest associations being observed for heavy smoking (>20 cigarettes/day) and pneumonia (3.30; 2.35, 4.63). Underweight was associated with increased risk of infectious disease mortality (3.65; 2.64, 5.06) compared with normal weight; the risk of viral infection was lower in overweight (0.56; 0.44, 0.72) and obesity (0.39; 0.26, 0.58). Central obesity was, however, related to higher risk of bacterial infections, but only in normal weight centrally obese participants (1.71; 1.10, 2.64). A physically active lifestyle and lifelong absence from cigarette smoking had protective associations against infectious disease mortality. Obesity has divergent associations dependent on peripheral and visceral fat depots, and the specific outcome.