Lee Sojung, Arslanian Silva A
University of Pittsburgh, School of Medicine,Weight management and Wellness Center, Pediatric Clinical and Translational Research Center, Children's Hospital of Pittsburgh, 3705 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA.
J Clin Endocrinol Metab. 2008 Nov;93(11):4547-51. doi: 10.1210/jc.2008-1024. Epub 2008 Sep 9.
The prevalence of obesity is higher in Blacks with racial divergence in adiposity in girls starting during adolescence. Our hypothesis is that in Black children, puberty associated increase in fat oxidation is diminished and could play a role in predisposing to fat accretion triggered during puberty. Thus, we examined the relationships between race, pubertal development, and postabsorptive fat oxidation in youth.
This was a cross-sectional design of healthy Black (n=50) and white (n=51) youth. Resting metabolic rate (RMR) and substrate oxidation rate were measured after an overnight fast with indirect calorimetry. Body composition was measured by dual-energy x-ray absorptiometry.
Within each race, RMR (kcal/kg fat free mass.min) was lower (puberty effect; P<0.05) in the pubertal vs. prepubertal group independent of gender. In girls, RMR was lower (race effect; P<0.05) in Blacks vs. whites. In girls but not boys, Blacks had lower (race effect; P=0.033) fat oxidation (micromol/kg fat free mass.min) compared with whites independent of pubertal status. Furthermore, the difference in fat oxidation between the prepubertal vs. pubertal groups tended to be greater (puberty x race interaction; P=0.089) in white girls (3.7+/-0.5 vs. 6.5+/-0.5) than in Black girls (3.4+/-0.6 vs. 4.5+/-0.5). These data suggest that the lower fat oxidation and RMR during puberty in Black girls could be a risk factor predisposing to obesity. This metabolic phenotype could potentially explain the divergence in adiposity in Black girls during adolescence against the backdrop of an obesogenic environment.
肥胖症在黑人中的患病率较高，女孩青春期开始时就存在种族间的肥胖差异。我们的假设是，在黑人儿童中，青春期相关的脂肪氧化增加有所减少，这可能在青春期引发的脂肪堆积易感性中起作用。因此，我们研究了青少年的种族、青春期发育和吸收后脂肪氧化之间的关系。
这是一项针对健康黑人（n = 50）和白人（n = 51）青少年的横断面设计研究。禁食过夜后，采用间接量热法测量静息代谢率（RMR）和底物氧化率。通过双能X线吸收法测量身体成分。
在每个种族中，无论性别，青春期组的静息代谢率（千卡/千克去脂体重·分钟）均低于青春期前组（青春期效应；P<0.05）。在女孩中，黑人的静息代谢率低于白人（种族效应；P<0.05）。在女孩而非男孩中，无论青春期状态如何，黑人的脂肪氧化（微摩尔/千克去脂体重·分钟）均低于白人（种族效应；P = 0.033）。此外，青春期前组与青春期组之间的脂肪氧化差异在白人女孩（3.7±0.5对6.5±0.5）中往往比黑人女孩（3.4±0.6对4.5±0.5）更大（青春期×种族交互作用；P = 0.089）。这些数据表明，黑人女孩青春期较低的脂肪氧化和静息代谢率可能是肥胖的一个危险因素。这种代谢表型可能潜在地解释了在致肥胖环境背景下黑人女孩青春期肥胖差异的原因。
