Smoking rate, carboxyhemoglobin, and body mass in the Second National Health and Nutrition Examination Survey (NHANES II).

The relationship of body mass and triceps skinfold thickness to both reported number of cigarettes smoked per day and carboxyhemoglobin levels was examined in healthy cigarette smokers in the NHANES II. Among both men and women, higher carboxyhemoglobin levels were related to lower body mass and thinner skinfolds, whereas higher levels of reported daily cigarette smoking were related to increased body mass and thicker skinfolds among men only. These relationships were independent of age, education, caloric intake, physical activity, and exercise. The opposite effects of number of cigarettes smoked per day and a biological index of cigarette smoke exposure on body mass suggest that increased cigarette smoking may covary with factors that would favor increased body weight among men, whereas decreases in body weight with increases in carboxyhemoglobin may reflect the effects of nicotine exposure on energy expenditure in both men and women.