Effect of the month of birth on the height of young adult males

Objective To explore a possible association between the month of birth and the final adult height in men and see if this could be described in terms of periodicity. Materials and Methods We used anthropometric data of 15,109 young male conscripts of the Greek Army. The data were collected from May 2006 until May 2010 and included men who had been born over a period of 12 years (1980-1991). The data were grouped in 12 monthly periods and analyzed with the use of a sinusoidal model. Results There was a statistically significant month-of-birth effect on height variation, which was described by a sinusoidal model with period T = 12 months, amplitude 0.223 cm and, two extremes which corresponded to the end of April/beginning of May (peak) and to the end of October/beginning of November (nadir). Discussion Our results corroborate previous findings suggesting a seasonality in human height without, however, being able to provide a definitive explanation for this phenomenon.