Supplementary information files for Inequalities in adiposity trends between 1979 and 1999 in Guatemalan children

© the authors, CC-BY 4.0Supplementary files for article Inequalities in adiposity trends between 1979 and 1999 in Guatemalan childrenBackground: Guatemala suffered from civil war and high levels of inequality and childhood stunting in the second half of the 20th century, but little is known about inequalities in secular trends in adiposity.Objectives: To investigate differences in childhood body mass index (BMI) and skinfold thickness trajectories from 1979 to 1999 between three groups of children: High socioeconomic position (SEP) Ladino, Low SEP Ladino, and Low SEP Indigenous Maya.Methods: The sample comprised 19 346 children aged 7–17 years with 54 638 observations. The outcomes were height, BMI, triceps skinfold thickness (TST), and subscapular skinfold thickness (SST) Z-scores according to the Centers for Disease Control and Prevention (CDC) references. Sex-specific multilevel models were used to estimate and compare mean trajectories from 1979 to 1999 between the three groups.Results: Mean Z-scores were always highest for High SEP Ladino children and lowest for Low SEP Maya children. Despite their very short stature, the Low SEP groups had SST trajectories that were above the 50th centile. The BMI trajectories were relatively flat and within one major centile band of the CDC median, with differences between the three groups that were small (0.2–0.3 Z-scores) and did not attenuate over time. Conversely, the TST Z-score trajectories demonstrated larger positive secular trends (e.g., from −1.25 in 1979 to −0.06 in 1999 for Low SEP Maya boys), with differences between the three groups that were large (0.5–1.2 Z-scores) and did attenuate over time (in boys). Secular trends and between-group difference in the SST Z-score trajectories were less pronounced, but again we found stronger evidence in boys that the estimated inequalities attenuated over time.Conclusions: Secular trends and inequalities in skinfolds differ from those for BMI in Guatemalan children. Differences between groups in skinfolds attenuated over time, at least in boys, but whether this is good news is questionable given the very short stature yet relatively large subscapular skinfolds of the Low SEP groups.

© 作者，CC BY 4.0协议。本文补充材料：《1979至1999年危地马拉儿童体脂趋势的不平等性》
研究背景：20世纪后半叶，危地马拉深陷内战，同时存在严重的社会不平等与儿童生长迟缓问题，但学界对体脂长期趋势中的不平等性尚缺乏了解。
研究目标：探讨1979年至1999年间，三类儿童的儿童期体质量指数（body mass index, BMI）与皮褶厚度变化轨迹的差异：高社会经济地位（socioeconomic position, SEP）拉迪诺儿童、低社会经济地位拉迪诺儿童，以及低社会经济地位原住民玛雅儿童。
研究方法：本研究纳入19346名7至17岁的儿童，共获得54638条观测数据。结局指标包括身高、体质量指数、三头肌皮褶厚度（triceps skinfold thickness, TST）与肩胛下皮褶厚度（subscapular skinfold thickness, SST）的Z评分，均以美国疾病控制与预防中心（Centers for Disease Control and Prevention, CDC）的参考标准进行校准。本研究采用性别分层的多水平模型，估算并比较1979年至1999年间三类儿童的平均变化轨迹。
研究结果：高社会经济地位拉迪诺儿童的平均Z评分始终最高，低社会经济地位玛雅儿童的平均Z评分则始终最低。尽管低社会经济地位群体的身高普遍偏矮，但其肩胛下皮褶厚度的变化轨迹均高于第50百分位。体质量指数的变化轨迹相对平缓，且处于美国疾病控制与预防中心中位数所在百分位区间的1个主要百分位范围内，三类群体间的差异较小（0.2~0.3个Z评分），且未随时间推移而缩小。与之相反，三头肌皮褶厚度的Z评分变化轨迹呈现出更显著的正向长期趋势（例如，低社会经济地位玛雅男性儿童的该指标从1979年的-1.25升至1999年的-0.06），三类群体间的差异较大（0.5~1.2个Z评分），且在男性群体中随时间推移逐渐缩小。肩胛下皮褶厚度Z评分的长期趋势与群体间差异则相对不明显，但同样在男性群体中获得了更有力的证据，证明估算出的不平等性随时间推移有所缓解。
研究结论：危地马拉儿童的皮褶厚度相关长期趋势与不平等性，与体质量指数的相关特征存在差异。至少在男性群体中，不同群体间的皮褶厚度差异随时间推移有所缩小，但鉴于低社会经济地位群体身高普遍偏矮，但其肩胛下皮褶厚度却相对较高，这一结果是否意味着积极意义仍有待商榷。