Dewau Reta, Byrne Stephanie, Hyppönen Elina, Lee Sang Hong, Benyamin Beben
Australian Centre for Precision Health, University of South Australia, Adelaide, South Australia, Australia.
UniSA Allied Health and Human Performance, University of South Australia, Adelaide, South Australia, Australia.
Am J Hum Biol. 2025 Sep;37(9):e70134. doi: 10.1002/ajhb.70134.
Child height is influenced by genetic and environmental factors. However, it is unclear how these factors vary by geographical region and by study design, particularly in low- and middle-income countries (LMIC), where data is scarce. Understanding these variations will aid the identification of factors that may be hindering growth in specific populations.
We analyzed height data of children under 5 years of age from 17 066 twin pairs and 2 024 672 parent-offspring pairs using the Demographic and Health Surveys conducted in 69 countries. We estimated genetic and environmental contributions to child height using a mixture distribution model for twins to account for unknown zygosity and a parent-offspring regression for singletons. A mixture distribution model assumes that the sample comprises a mixture of monozygotic and dizygotic twins and estimates heritability based on the distribution of phenotypic similarity across twin pairs, without requiring prior classification of zygosity.
Twin studies consistently estimated heritability at 0.35 (95% CI, 0.34-0.37) across all regions. The estimated proportion of phenotypic variance attributable to shared environmental factors was 0.63 (95% CI, 0.62-0.63), while the contribution of unique environmental factors was 0.02 (95% CI, 0.02-0.02). Conversely, there was variation in the heritability estimates from parent-offspring studies, ranging from 0.27 (95% CI, 0.26-0.30) in North Africa, West Asia and Europe to 0.47 (95% CI, 0.46-0.48) in Latin America and Caribbean.
The observed discrepancies between twin and family study estimates underscore the complex interplay between genetic and environmental factors. These variations suggest that environmental factors play a critical role in determining height outcomes during childhood. Further research is needed to explore these environmental factors in greater detail with the aim of developing region-specific interventions to address height disparities, particularly in underprivileged regions.
儿童身高受遗传和环境因素影响。然而，尚不清楚这些因素如何因地理区域和研究设计而异，尤其是在低收入和中等收入国家（LMIC），那里数据稀缺。了解这些差异将有助于识别可能阻碍特定人群生长的因素。
我们使用在69个国家进行的人口与健康调查，分析了17066对双胞胎和2024672对亲子对中5岁以下儿童的身高数据。我们使用双胞胎的混合分布模型来估计遗传和环境对儿童身高的贡献，以考虑未知的合子性，对单胎则使用亲子回归分析。混合分布模型假设样本由同卵双胞胎和异卵双胞胎的混合组成，并根据双胞胎对之间表型相似性的分布来估计遗传力，而无需事先对合子性进行分类。
双胞胎研究一致估计所有地区的遗传力为0.35（95%置信区间，0.34 - 0.37）。归因于共同环境因素的表型方差估计比例为0.63（95%置信区间，0.62 - 0.63），而独特环境因素的贡献为0.02（95%置信区间，0.02 - 0.02）。相反，亲子研究的遗传力估计存在差异，从北非、西亚和欧洲的0.27（95%置信区间，0.26 - 0.30）到拉丁美洲和加勒比地区的0.47（95%置信区间，0.46 - 0.48）不等。
双胞胎研究和家庭研究估计之间观察到的差异凸显了遗传和环境因素之间复杂的相互作用。这些差异表明环境因素在决定儿童期身高结果方面起着关键作用。需要进一步研究以更详细地探索这些环境因素，目的是制定针对特定区域的干预措施来解决身高差距问题，特别是在贫困地区。
