Ohlsson C, et al. - Via a population-based retrospective cohort study that included 4,090 boys and spanned 50 years done in Gothenburg, Sweden, researchers discovered whether there was a secular trend for earlier pubertal timing among boys. Most were white and the mean (SD) age at peak height velocity (PHV) was 13.9 (1.1) years, out of the 4,090 subjects. An important relationship between year of birth and age at PHV was exhibited by a linear regression model. For every decade raise in the birth year, age at PHV was 1.5 months earlier. Age at PHV was 1.2 months earlier per decade rise in the birth year, post-adjusting for childhood body mass index (BMI). In the population between 1947 and 1996, all tests were repeated in the subgroup of boys born in Sweden and with parents born in Sweden with alike outcomes, symbolizing that the secular trend was not defined by demographic variances. Hence, evidence of a secular trend for earlier pubertal timing in boys that was partly defined by a risen childhood BMI was ascertained, but other factors that were unknown contributed.