A prospective evaluation of the relationships between smoking dosage and body mass index in an adolescent, biracial cohort.

Although there is clearly an inverse relationship between smoking and body weight, recent studies suggest that weight attenuation via smoking is slow and may take decades to accrue. This investigation prospectively evaluated the relationships between smoking dosage (or lack thereof) and relative weight change in 1697 adolescents followed over 4 years. A 4 (smoking groups: 0, 1, 2, or 3 or more years of smoking exposure)x2 (ethnicity: Caucasian or African American)x2 (gender: male or female) analysis of variance (ANOVA) was performed to assess weight gain attenuation associated with increasing exposure to smoking. The overall results revealed a significant three-way interaction between smoking dosage, gender, and ethnicity. Specifically, smoking initiation was associated with an increase in body mass index (BMI) for 2 years after initiation. For those youth smoking 3 or more years, body weights were almost identical compared to never-smokers. No significant reductions in body weight were observed in any gender or ethnic group for up to 3 years after smoking initiation. It is concluded that smoking initiation is not associated with adolescent body weight change for at least a 3-year period.