The combined relations of adiposity and smoking on mortality

Smoking and high adiposity are strong independent health risk factors but are also interrelated. Smoking is related to a lower body mass index (BMI) but not necessarily with a smaller waist circumference. Smoking cessation is associated with increased body weight and a substantial increase in waist circumference. How this affects mortality risk is unknown.

This study examined the combined relations of smoking status with BMI and waist circumference and smoking status to all-cause mortality.

Data were from 149 502 men and 88 184 women aged 51-72 y participating in the National Institutes of Health-AARP Diet and Health Study. All-cause mortality was assessed over 10 y of follow-up from 1996 to 2006.

Current smokers with a BMI (in kg/m(2)) <18.5 or >or=35 had a mortality risk 6-8 times that of persons within the normal BMI range who never smoked. Current smokers with a large waist circumference had a mortality risk about 5 times that of never smokers with a waist circumference in the second quintile.

Both smoking and adiposity are independent predictors of mortality, but the combination of current or recent smoking with a BMI >or= 35 or a large waist circumference is related to an especially high mortality risk.