The Effect of Primary and Secondary Tobacco Smoke Exposure on Bone Health Across Adolescence in Females.

BACKGROUND AND OBJECTIVES: Primary tobacco smoke exposure has been associated with poorer bone health in adults; however, there is a dearth of information on such exposure in healthy growing adolescents, a time when a significant percentage of bone mass is acquired. We evaluated the impact of primary and secondary tobacco smoke exposure on bone mass and density across adolescence in females, hypothesizing that an understudied measure of primary and secondary tobacco smoke exposure would provide a more accurate picture of the impact on bone accrual. MATERIALS AND METHODS: In a cohort sequential design, healthy females aged 11-17 years (N = 262) were recruited from a midwestern children's hospital and community to participate in four annual visits. Annual dual energy x-ray absorptiometry measured bone mineral content (BMC) and density (BMD) of the whole body, hip, and lumbar spine. Self-report measures of smoking were collected at annual visits and by phone at 3-month intervals. RESULTS: Cumulative smoke exposure was associated with higher BMC Z-scores at all sites (0.02-0.03, p < 0.01) and Spine BMD scores (0.02, p < 0.05), although effects were small. For hip BMD Z-score, the magnitude of effect of cumulative smoke exposure was greater in younger girls (p = 0.002). CONCLUSION: Unanticipated findings suggest that (1) levels of cumulative smoke exposure, higher than those represented in these data, may be necessary to negatively impact bone health in adolescence, and (2) high bone accrual in early adolescence is robust, regardless of the amount of tobacco smoke exposure. Immediate adverse effects of smoking during early adolescence may not occur, even if lifelong risk is incurred. Future longitudinal studies will be necessary to confirm our findings.