Pre-menarche pubertal development following unique form of immigration: the case of girls adopted from China.

Our study tested the hypothesis that drastic social-cultural change has an impact on girls' pre-menarche pubertal development. We focused on a unique group of Chinese immigrants who migrated out of China in infancy through international adoption. Our sample included 298 Chinese girls who were 7.3-11.1 years in 2011 (Mean = 8.8, SD = 0.9) and were adopted at 7-24 months (Mean = 12.6, SD = 3.4). We found that 34% showed at least one of four signs of pubertal development: Growth spurt, body fat increase, breast development, and body hair. Logistic regression analyses showed that the odds of growth spurt was raised by the girls' age in 2011, behavior problems in 2005, but lowered by the adoptive families' household income; the odds of body fat increase in 2011 was raised by the adopted Chinese girls' weight in 2007 and behavior problems in 2005, but was lowered by the adoptive mother's education level; the odds for breast development in 2011 was raised by the girls' age in 2011, weight in 2007, and behavior problems in 2009. For body hair, none of the factors predicted the odds. Prevalence of precocious puberty, based on the criterion of breast development before 8 years, was 3.5%. Overall, our study suggests that the pre-menarche pubertal development of adopted Chinese girls may be slightly advanced but also is affected by factors that affect non-adopted girls' pubertal development.