Perng Wei, Ringham Brandy M, Glueck Deborah H, Sauder Katherine A, Starling Anne P, Belfort Mandy B, Dabelea Dana
Departments of Nutritional Sciences and
Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI.
Am J Clin Nutr. 2017 Aug;106(2):559-567. doi: 10.3945/ajcn.116.149617. Epub 2017 Jun 28.
Despite widespread use of weight- and length-based anthropometric indexes as proxies for adiposity, little is known regarding the extent to which they correspond with fat mass (FM) or fat-free mass (FFM) during infancy. This study aimed to examine associations of 3 derived indicators-weight-for-age score (WFAZ), weight-for-length score (WFLZ), and body mass index score (BMIZ)-with FM, percentage of FM, and FFM measured by air-displacement plethysmography during the first 5 mo of life. Applying prospectively collected data from 1027 infants in a Colorado prebirth cohort, we used multivariate regression to evaluate associations between the derived indicators and body composition at birth and at 5 mo, and with change (Δ) during follow-up. At birth, all 3 derived indicators were more strongly associated with FFM than with FM. Each unit of WFAZ corresponded with 0.342 kg FFM (95% CI: 0.331, 0.351 kg FFM), compared with 0.121 kg FM (95% CI: 0.114, 0.128 kg FM) ( < 0.0001); similar trends were observed for WFLZ and BMIZ. By 5 mo, WFLZ and BMIZ were more strongly associated with FM than with FFM, whereas WFAZ correlated similarly with the 2 components of body composition. ΔWFLZ and ΔBMIZ were both more strongly related to ΔFM than to ΔFFM; however, a direct comparison of the 2 indexes with respect to change in the percentage of FM indicated that ΔBMIZ was the optimal proxy of adiposity gain ( < 0.0001, pairwise difference). Weight- and length-based indexes are poor surrogates for newborn adiposity. However, at 5 mo, WFLZ and BMIZ are suitable proxies of FM. When assessing adiposity gain, ΔBMIZ is the best indicator of fat accrual during the first 5 postnatal months. This trial was registered at clinicaltrials.gov as NCT02273297.
尽管基于体重和身长的人体测量指标被广泛用作肥胖的替代指标，但对于它们在婴儿期与脂肪量（FM）或去脂体重（FFM）的对应程度知之甚少。本研究旨在探讨3个衍生指标——年龄别体重评分（WFAZ）、身长别体重评分（WFLZ）和体重指数评分（BMIZ）——与出生后头5个月通过空气置换体积描记法测量的FM、FM百分比和FFM之间的关联。应用来自科罗拉多州一个产前队列中1027名婴儿的前瞻性收集数据，我们使用多元回归来评估衍生指标与出生时、5个月时的身体成分之间的关联，以及随访期间的变化（Δ）。出生时，所有3个衍生指标与FFM的关联都比与FM的关联更强。WFAZ每增加一个单位，对应0.342千克FFM（95%CI：0.331，0.351千克FFM），而对应0.121千克FM（95%CI：0.114，0.128千克FM）（<0.0001）；WFLZ和BMIZ也观察到类似趋势。到5个月时，WFLZ和BMIZ与FM的关联比与FFM的关联更强，而WFAZ与身体成分的两个组成部分的相关性相似。ΔWFLZ和ΔBMIZ与ΔFM的相关性都比与ΔFFM的相关性更强；然而，就FM百分比变化对这两个指标进行直接比较表明，ΔBMIZ是肥胖增加的最佳替代指标（<0.0001，成对差异）。基于体重和身长的指标不是新生儿肥胖的良好替代指标。然而，在5个月时，WFLZ和BMIZ是FM的合适替代指标。在评估肥胖增加时，ΔBMIZ是出生后前5个月脂肪积累的最佳指标。本试验在clinicaltrials.gov上注册为NCT02273297。
