Secular Trend of Birth Height and Weight in a Population of Iranian Neonates during ۱۹۹۱ and ۲۰۱۱

Background: The secular trend in growth is a well-documented and recurrent phenomenon in many developed and developing countries. In this study, we examined the secular trends in birth length and weight among Iranian neonates.Methods: This cross-sectional population-based survey was conducted between ۱۹۹۱ and ۲۰۱۱. Using a two-stage stratified cluster sampling, the birth weights and heights of neonates born in Shahroud, Iran were studied using health records from different households. The mean birth weights and heights for neonates were calculated every year. Secular trends were analyzed using linear regression models and joinpoint regression.Results: A random sample of ۱۱,۱۶۵ neonates was evaluated, and the mean birth weight of neonates during the investigation period was calculated. The mean birth weight changed from ۳۲۳۲.۱±۴۴۴.۱ g in ۱۹۹۱ to ۳۲۰۴.۱±۴۳۶.۹ g in ۲۰۱۱, and the mean birth height changed from ۴۹.۵±۲.۲ cm to ۴۹.۳±۱.۹ cm. The mean birth weights and heights between ۱۹۹۱ and ۲۰۱۱ were not significantly different; however, the birth weight increased by ۶.۷۵ g annually between ۲۰۰۰ and ۲۰۱۱ (P < ۰.۰۲۱), and the mean birth height increased by ۰.۰۳ cm annually between ۲۰۰۳–۲۰۱۱ and ۱۹۹۱–۲۰۰۳ (P = ۰.۰۰۹).Conclusions: The mean birth height and weight of neonates in Shahroud did not change significantly from ۱۹۹۱ to ۲۰۱۱; however, we found a significant improvement after ۲۰۰۰.Background: The secular trend in growth is a well-documented and recurrent phenomenon in many developed and developing countries. In this study, we examined the secular trends in birth length and weight among Iranian neonates. Methods: This cross-sectional population-based survey was conducted between ۱۹۹۱ and ۲۰۱۱. Using a two-stage stratified cluster sampling, the birth weights and heights of neonates born in Shahroud, Iran were studied using health records from different households. The mean birth weights and heights for neonates were calculated every year. Secular trends were analyzed using linear regression models and joinpoint regression. Results: A random sample of ۱۱,۱۶۵ neonates was evaluated, and the mean birth weight of neonates during the investigation period was calculated. The mean birth weight changed from ۳۲۳۲.۱±۴۴۴.۱ g in ۱۹۹۱ to ۳۲۰۴.۱±۴۳۶.۹ g in ۲۰۱۱, and the mean birth height changed from ۴۹.۵±۲.۲ cm to ۴۹.۳±۱.۹ cm. The mean birth weights and heights between ۱۹۹۱ and ۲۰۱۱ were not significantly different; however, the birth weight increased by ۶.۷۵ g annually between ۲۰۰۰ and ۲۰۱۱ (P < ۰.۰۲۱), and the mean birth height increased by ۰.۰۳ cm annually between ۲۰۰۳–۲۰۱۱ and ۱۹۹۱–۲۰۰۳ (P = ۰.۰۰۹). Conclusions: The mean birth height and weight of neonates in Shahroud did not change significantly from ۱۹۹۱ to ۲۰۱۱; however, we found a significant improvement after ۲۰۰۰.

Keywords:

Anthropometry , Birth weight , Trends , Iran.