Smoking and physical inactivity patterns during midlife as predictors of all-cause mortality and disability: a 39-year prospective study

This study estimated the long-term mortality hazards and disability risks associated with various combinations of smoking and physical inactivity measured over time in a sample of middle-aged adults. Data have been collected from a national sample of Swedish adults, originally interviewed in 1968 and followed until 2007 (N = 1,682). Smoking and physical activity status were measured at baseline and 13 years later (1981). Different patterns of change and stability in smoking and physical inactivity over this 13 year period were used as predictors of mortality through 2007. Also, associations between different patterns of these health behaviors and the odds of disability (measured in 2004) were estimated among survivors (n = 925). Results suggest that mortality rates were elevated among persistent (HR = 1.7; 95 % CI = 1.5–2.0) and new smokers (HR = 2.5; 95 % CI = 1.6–4.1), but not among discontinued smokers. However, mortality rates remained elevated among discontinued smokers who were also persistently inactive (HR = 1.9; 95 % CI = 1.3–2.6). Additional findings suggest that persistent physical inactivity during midlife was associated with increased odds of late life disability (OR = 1.8; 95 % CI = 1.1–2.7), but that smoking had no clear additive or multiplicative effects on disability. As such, these findings indicate that while persistent smoking during midlife primarily impacts subsequent mortality, persistent physical inactivity during midlife appears to counteract the survival benefits of smoking cessation, while also imposing a long-term risk on late life disability among those who do survive to old age.