Environmental and genetic pathways between early pubertal timing and dieting in adolescence: distinguishing between objective and subjective timing.

BACKGROUND: Early pubertal timing in girls is associated with elevated risk for dieting and eating pathology. The relative importance of biological versus socio-environmental mechanisms in explaining this association remains unclear. Moreover, these mechanisms may differ between objective measures of pubertal development and girls' subjective perceptions of their own maturation.
METHOD: The sample comprised 924 sister pairs from the National Longitudinal Study of Adolescent Health. Objective pubertal timing (menarcheal age), girls' perceptions of pubertal status and timing relative to peers, dieting and disordered eating behaviors were assessed during a series of confidential in-home interviews.
RESULTS: Behavioral genetic models indicated that common genetic influences accounted for the association between early menarcheal age and increased risk for dieting in adolescence. In contrast, girls' subjective perceptions of their timing relative to peers were associated with dieting through an environmental pathway. Overall, subjective and objective measures of pubertal timing accounted for 12% of the variance in dieting.
CONCLUSIONS: Genetic differences in menarcheal age increase risk for dieting among adolescent girls, while girls' perceptions of their maturation represent an environmentally mediated risk.