An increase in the developmental tempo affects the secular trend in height in male Austrian conscripts birth cohorts 1951-2002.

Objectives: Using population-based data on height in Austria from birth cohort 1951 to 2002, we aim to evaluate the secular trends in height and developmental tempo among Austrian young men.

Methods: Data were obtained from the Austrian conscription medical examination. We included 1 205 112 conscripts (18-<20 years) who were born between 1951 and 2002 and 853 645 conscripts (17-<19 years) who were born between 1961 and 2002. Height was measured during the medical examination and was used to evaluate the secular trends of mean height over time. Furthermore, the mean difference in height between conscripts of 17- and 18 years old were compared across birth cohorts.

Results: The mean height of conscripts aged 17 years increased by 2.2 cm (p < .0001) in between 1961 and 2002. The mean height of conscripts aged 18 years increased by 4.3 cm (p < .0001) between 1951 and 2002. However, the increase in mean height has slowed down since the 1970 s. The difference in mean height between 17 and 18 years old widened from about 0.1 cm in 1961 to 0.3 cm around 1970 and then steadily narrowed again to 0.1 cm at the end of the study period.

Conclusions: The increasing trend in height slows at the end of the 20th century, the developmental tempo at the population level, however, continued to increase. The difference in mean height between 17 and 18 years old narrowed, which may indicate that young men reached their final height earlier.