Older men and women who were once heavy smokers have a significantly higher risk of diabetes and obesity than do nonsmokers or current light smokers, according to Tommi Sulander of Finland's National Public Health Institute, Helsinki, and colleagues.
The investigators examined the associations between smoking status, diabetes, and obesity using data from nationwide biennial surveys conducted in Finland from 1985 to 1995. The study population consisted of 7,482 individuals (3,738 men and 3,744 women) aged 65–79 years.
Survey data were collected by self-report using standardized questionnaires with items concerning weight, smoking status, illnesses, diet, alcohol consumption, and physical activity. Data were analyzed using logistic regression models (Arch. Gerontol. Geriatr. 2006 [Epub doi:10.1016/j.archger.2006.10.007]).
Age was categorized by 5-year intervals. Light smoking was defined as 1–19 cigarettes a day, and heavy smoking was defined as 20 or more cigarettes a day. Smoking status was classified in five categories: nonsmoker, current light smoker, current heavy smoker, ex-light smoker, and ex-heavy smoker. Obesity was defined as a body mass index (kg/m2) of 30 or greater.
Relative to nonsmokers, ex-heavy smokers had higher risks of developing both obesity and diabetes, whereas current light smokers had lower risks for both conditions. In a logistic regression model adjusting only for age and gender, relative obesity risks were 1.38 for ex-heavy smokers and 0.43 for current light smokers. Similarly, relative risks of diabetes were higher for ex-heavy smokers (1.36) and lower for current light smokers (0.51). Rates of obesity and rates of diabetes were comparable among nonsmokers, ex-light smokers, and current heavy smokers.