Lifestyle Risk Factors, Obesity and Infectious Disease Mortality in the General Population: Linkage Study of 97,844 Adults from England and Scotland

Abstract

Objective: We examined associations between physical activity, smoking, alcohol, and obesity on infectious disease mortality in a large general population cohort.
Methods: 97,844 participants (aged 47 ± 17 yrs; 46.6% male) recruited from general population surveys were followed up over mean [SD] 9.4±4.5 years. Exposure measurements included self-reported physical activity, smoking, alcohol intake, and objective body mass index and waist to hip ratio. Infectious disease mortality was recorded using linkage to the British National Health Service Central Registry.
Results: There were 9,027 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 in models mutually adjusted for other lifestyle factors. Ex-smokers and current smokers were at increased risk of infectious disease compared with never smoker, with the strongest associations being observed for heavy smoking (>20 cigarettes/day) and pneumonia (3.30; 2.35, 4.63). There were no associations between alcohol consumption and risk of infectious disease. Underweight was associated with increased risk of infectious disease (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 (1.71; 1.10, 2.64).
Conclusions: A physically active lifestyle and lifelong absence from smoking had protective associations against infectious disease mortality.
Funding: Stamatakis is funded by the National Health and Medical Research Council (NHMRC) through a Senior Research Fellowship. Hamer is funded through the NIHR Leicester BRC.
Declaration of Interests: None of the authors have any competing interests to declare.
Ethical Approval Statement: Local research ethics committees approved all aspects of each survey and all participants gave written informed consent.

Keywords: Exercise; smoking; obesity; bacterial infections; virus diseases; mortality