CIGARETTE SMOKING, SECOND-HAND-SMOKE, AND ADOLESCENT BONE MASS IN WUHAN, CHINA

Abstract

Research addressing the role of lifestyle and environmental factors on bone development during times of peak bone acquisition in adolescence is limited. Although the relationship between cigarette smoking and bone loss during adulthood is well established, the effect of smoking and second-hand-smoke on bone mass in adolescents is unknown. The high prevalence of smoking among the adults living in China, and the adolescent period being a critical time for both bone accretion and smoking initiation, were the incentives for this investigation. To determine whether these factors were detrimental to the adolescent skeletal system, we measured cortical (forearm) and trabecular (os calcis) bone mineral density (BMD) and content (BMC) using peripheral dual energy x-ray absorptiometry (DXA) in 466 girls and boys ages 10 to 16 years and living in Wuhan, China. In 166 girls, forearm BMC was best predicted by body mass index (24%), age (5%), and menarche (2%) for a combined variance of 31%, while 8% of the variance in os calcis BMC was predicted by body mass index (BMI) alone with no contribution by age or menarche. In 300 boys, a total of 24% of the variance in forearm BMC was explained by BMI (18%) and age (6%); os calcis BMC was only predicted by BMI (21%). The addition of active cigarette smoking and second-hand-smoke into the multiple linear regression models for forearm and os calcis bone mineral contant did not make significant contributions to the variances in either girls or boys. The reasons may have been due to the low levels and duration of tobacco use and exposure among the adolescents we studied. Selecting an older sample of adolescents who smoke more frequently and for a long duration may have uncovered a different relationship. Nevertheless, this was the first study that investigated the role of smoking and second-hand-smoke on bone mass during adolescence.