Somatotype, physical growth, and sexual maturation in young male smokers

Association between healthy lifestyle pattern and early onset of puberty: based on a longitudinal follow-up study

The present study aimed to explore the association between healthy lifestyle pattern and childhood early onset of puberty. Based on a cohort study in Xiamen of China, a total of 1294 children was followed for three and a half years. Children's lifestyles, including dietary behaviour, physical activity, sleep duration, smoking and drinking behaviour and sedentary behaviour, were collected by questionnaires. Healthy lifestyle pattern was determined mainly according to the recommendations by the Dietary Guidelines for Chinese school-age children and Canadian Guidelines for children and youth. The pubertal development was assessed by clinical examination according to Tanner stages. The association between pre-pubertal lifestyle and early onset of puberty was estimated using linear regression and log-binomial regression. We found that children who adhered to a healthy lifestyle had a 0·36-year delay of the age of puberty onset (coef = 0·36, 95 % CI (0·08, 0·65)) and 53 % lower risk of early onset of puberty (risk ratio = 0·47, 95 % CI (0·27, 0·80)), compared with those who had a poor lifestyle. However, the beneficial effect of favourable lifestyles on the early onset of puberty was found only in boys with normal weight. Boys who adhered to active physical activity and low sedentary behaviour had a relatively delayed age of puberty onset (coef = 0·49, 95 % CI (0·26, 0·72)). This is the first time to find that healthy lifestyle pattern was associated with a substantially lower risk of early onset of puberty, especially in boys with normal weight. Advocating an integrated healthy lifestyle is essential for the development of children.

The Moderating Effects of Pubertal Timing on the Longitudinal Associations Between Parent-Child Relationship Quality and Adolescent Substance Use

This prospective, longitudinal study investigated the moderating role of pubertal timing on reciprocal links between adolescent appraisals of parent-child relationship quality and girls' (N=1335) and boys' (N=1203) cigarette and alcohol use across a twelve-month period. Reciprocal effects were found between parent-child relations and on-time maturing boys and girls' cigarette and alcohol use, after estimating stability in these constructs across time. Parent-child relationship quality was associated with increased alcohol use twelve months later for early maturing girls. Cigarette and alcohol use were associated with increased problems in the parent-child relationship for late maturing girls. No off-time effects were observed for off-time maturing boys in the pathways between parent-child relationship quality and substance use. Pubertal timing moderated the pathway linking parent-child relationship quality with cigarette use one year later such that the association was stronger for late maturing girls compared to early and on-time maturing girls. The findings indicate interplay between the psychosocial aspects of maturation, family relationships and adolescent substance use and highlight possible gender-specific influences.

Cigarette smoking prospectively predicts retarded physical growth among female adolescents

PURPOSE

This study tested the hypothesis that cigarette smoking retards physical development during early adolescence among girls.

METHODS

A school-recruited sample of adolescent girls (N = 496) completed surveys assessing smoking behaviors and related variables as well as direct measures of height and weight annually over 3-years. Analyses tested whether smoking trajectories and initial smoking correlated with changes in physical growth over time.

RESULTS

Relative to persistent nonsmoking, persistent smoking was associated with reduced growth in height, weight, and body mass index (BMI). Initiation of smoking, relative to persistent nonsmoking, was associated with reduced growth in weight and BMI but not height. Smoking cessation, relative to persistent smoking, was associated with increased gains in weight and BMI but not height. Results also documented a prospective dose-response relation of initial smoking quantity and frequency to subsequent growth retardation in height, weight, and BMI.

CONCLUSIONS

Findings are generally consistent with the assertion that smoking in early adolescence retards physical development among adolescent girls.

Effects of nicotine on body weight, food consumption and body composition in male rats

The present study examined the effects of nicotine administration and cessation on body weight, food consumption, and body composition in rats. Administration of nicotine was associated with attenuated body weight gains and cessation was associated with accelerated body weight gains. Changes in fat composition paralleled changes in body weight, whereas changes in body water and protein did not. These results suggest that nicotine administration decreases body weight through its effects on fat stores in the body. After cessation of nicotine, body fat rapidly approached levels of control animals.