The relationship between body mass and cigarette smoking using a biochemical index of smoking exposure.

This study evaluated the relationship between smoking and body mass using objective indices of both smoking exposure (COHb) and body mass. The subjects were 4240 adults who participated in the Second National Health and Nutrition Examination Survey (NHANES II). Measurements of dietary intake, physical activity, demographics, body mass index (BMI) and blood carboxy-haemoglobin (COHb) were used in these analyses. After controlling for covariables of body mass, the results indicated that smokers displayed a significantly lower mass compared with non-smokers. Smokers with higher levels of COHb had lower BMIs than smokers at lower COHb levels. White smokers had lower BMIs with increasing COHb exposure whereas black smokers had BMIs at high COHb exposure similar to those of non-smokers. Results indicated that smokers weighed less than non-smokers and that the weight control 'benefits' of smoking were most pronounced in white subjects who were heavy smokers.