Trends in women's height and the effect of early childbearing on height retardation: An analysis of the height of Bangladeshi women born between 1974 and 1998.

Background: Depending on race, ethnicity, and region, genetic variants determine human height by 65% to 80%, while the remaining variance of 20% to 35% is influenced by nutrition and other individual or environmental exposures in the early years of life. An improvement in nutrition and health in the early years in a population underprivileged in health and nutrition will likely increase the group's average height. Due to outstanding improvements in these areas in recent decades, we hypothesised that the average height of Bangladeshi women has increased. Moreover, because pregnancy at an early age affects women's health and nutrition, we hypothesised that women who began childbearing early would experience growth retardation compared to women who had pregnancies at a later age. Methods: We used data from five national surveys conducted between 2004 and 2018 that collected height data from ever-married women aged 15-49 years. We analysed the height of women aged 20-29 years (born between 1974 and 1998) and examined the mean height by birth years, age at first birth (AFB), economic status, religion and region. We conducted multiple linear regression models, controlling for the differential effects of the socio-demographic characteristics on women's height over time and by AFB. Results: The average height of women born between 1974 and 1998 significantly increased by 0.03 cm annually, with fluctuations between 150.3 and 151.6 cm. We also found an association between age at childbearing and height in adulthood - women who began childbearing before age 17 were approximately one centimetre shorter in adulthood than those who began childbearing at a later age. Conclusions: We found evidence of an increasing trend in women's height in Bangladesh and an inhibiting effect of early teenage childbearing on attaining the potential growth of women. The findings call for further studies to investigate early childbearing and its consequences on women's and their children's growth in diverse settings, considering socio-cultural customs influencing early marriage and childbearing.