This month in archives of pediatrics & adolescent medicine.

Abstract

I n their study van der Aa et al (page 509) found that more of the variation in sedentary behavior among 20-year-old individuals was accounted for by genetics (48% for males and 34% for females) and nonshared environmental factors (52% for males and 66% for females) than it was for 12-year-old adolescents (35% for males and 19% for females by genetics and 36% for males and 34% for females by nonshared environmental factors). Conversely, shared environmental factors played less of a role in late adolescence.