WEDNESDAY, Sept. 22 (HealthDay News) -- Absence of a biological father in the home predicts earlier onset of breast development in higher-income families and early development of pubic hair in African-American girls from high-income families, according to research published online Sept. 20 in the Journal of Adolescent Health.
Julianna Deardorff, Ph.D., of the University of California in Berkeley, and colleagues conducted a prospective study of 444 girls aged 6 to 8 to determine whether the known association of early puberty with father absence (previously identified as a factor associated with early menarche) was modified by body mass index (BMI), ethnicity, and family income. Body weight, height, and the onset of breast development and pubic hair were tracked over a two-year period, and demographic information was obtained from caregivers.
When adjusted for BMI, the researchers found that income and ethnicity had a moderating effect on the association of father absence and pubertal onset. In higher-income families, father absence predicted earlier onset of breast development. Only in higher-income African-American families was there an association between father absence and early pubic hair development. BMI did not explain these effects.
"Factors present in the familial and social environment of young girls may explain the relationship between father absence and onset of puberty. By including ethnicity and income, we have uncovered a complex pattern of relationships that warrants further investigation," the authors write.