Ethnic Differences in Neonatal Body Composition in a Multi-Ethnic Population and the Impact of Parental Factors: A Population-Based Cohort Study

BackgroundNeonates from low and middle income countries (LAMIC) tend to have lower birth weight compared with Western European (WE) neonates. Parental height, BMI and maternal parity, age and educational level often differ according to ethnic background, and are associated with offspring birth weight. Less is known about how these factors affect ethnic differences in neonatal body composition.ObjectivesTo explore differences in neonatal body composition in a multi-ethnic population, and the impact of key parental factors on these differences.MethodsA population-based cohort study of pregnant mothers, fathers and their offspring, living in Oslo, Norway. Gender- and gestational-specific z-scores were calculated for several anthropometric measurements, with the neonates of WE ethnic origin as reference. Mean z-scores for neonates with LAMIC origin, and their parents, are presented as outcome variables.Results537 singleton, term neonates and their parents were included. All anthropometric measurements were smaller in neonates with LAMIC origin. Abdominal circumference and ponderal index differed the most from WE (mean z-score: −0.57 (95% CI:−0.69 to −0.44) and −0.54 (−0.66 to −0.44), and remained so after adjusting for parental size. Head circumference and skin folds differed less, and length the least (−0.21 (−0.35 to −0.07)). These measures became comparable to WEs when adjusted for parental factors.ConclusionsLAMIC origin neonates were relatively “thin-fat”, as indicated by reduced AC and ponderal index and relatively preserved length and skin folds, compared with neonates with WE origin. This phenotype may predispose to type 2 diabetes.【背景】低收入和中等收入国家（low and middle income countries, LAMIC）的新生儿相较于西欧（Western European, WE）族裔新生儿，出生体重普遍偏低。父母身高、体质量指数（body mass index, BMI），以及产妇的孕产次、年龄与受教育水平往往因民族背景不同而存在差异，且与子代出生体重相关。目前针对上述因素如何影响不同民族新生儿身体组成差异的研究尚少。 【目的】探索多民族人群中新生儿身体组成的差异，以及关键父母因素对这些差异的影响。 【方法】本研究为一项基于人群的队列研究，纳入居住于挪威奥斯陆的孕妇、其配偶及子代。以西欧族裔新生儿作为参照组，针对多项人体测量指标计算按性别和胎龄分层的Z评分（z-score）。最终以LAMIC族裔新生儿及其父母的平均Z评分作为结果变量。 【结果】本研究共纳入537名单胎足月新生儿及其父母。LAMIC族裔新生儿的各项人体测量指标均低于西欧族裔新生儿。其中腹围与身长体重指数（ponderal index）与西欧族裔新生儿的差异最为显著（平均Z评分分别为-0.57，95%置信区间：-0.69~-0.44；以及-0.54，95%置信区间：-0.66~-0.44），在校正父母体格参数后该差异仍存在。头围与皮褶厚度的差异相对较小，身长的差异最小（-0.21，95%置信区间：-0.35~-0.07）。在校正父母因素后，上述指标均与西欧族裔新生儿无显著差异。 【结论】相较于西欧族裔新生儿，LAMIC族裔新生儿呈现相对“瘦型肥胖”的表型：腹围及身长体重指数降低，但身长与皮褶厚度相对保留。该表型可能增加其日后罹患2型糖尿病的风险。