Explaining differences in birthweight between ethnic populations. The Generation R Study

OBJECTIVE: To examine whether differences in birthweight of various ethnic groups residing in The Netherlands can be explained by determinants of birthweight. DESIGN: Population-based birth cohort study. SETTING: Data of pregnant women and their partners in Rotterdam, The Netherlands. POPULATION: We examined data of 6044 pregnant women with a Dutch, Moroccan, Turkish, Capeverdean, Antillean, Surinamese-Creole, Surinamese-Hindustani and Surinamese-other ethnic background. METHODS: Regression analyses were used to assess the impact of biomedical, socio-demographic and lifestyle-related determinants on birthweight differences. MAIN OUTCOME MEASURE: Birthweight was established immediately after delivery in grams. RESULTS: Compared with mean birthweight of offspring of Dutch women (3485 g, SD 555), the mean birthweight was lower in all non-Dutch populations, except in Moroccans. Differences ranged from an 88-g lower birthweight in offspring of the Turkish women to a 424-g lower birthweight in offspring of Surinamese-Hindustani women. Differences in gestational age, maternal and paternal height largely explained the lower birthweight in the Turkish, Antillean, Surinamese-Creole and Surinamese-other populations. Differences in birthweight between the Dutch and the Capeverdean and Surinamese-Hindustani populations could only partly be explained by the studied determinants. CONCLUSIONS: These results confirm significant differences in birthweight between ethnic populations that can only partly be understood from established determinants of birthweight. The part that is understood points to the importance of determinants that cannot easily be modified, such as parental height. Further study is necessary to obtain a fuller understanding.