Mericq Verónica, Iñiguez Germán, Bazaes Rodrigo, Bouwman Carolien, Avila Alejandra, Salazar Teresa, Carrasco Fernando
Institute of Maternal and Child Research, Faculty of Medicine, University of Chile, Santiago, Chile.
J Pediatr Endocrinol Metab. 2009 Nov;22(11):1041-50. doi: 10.1515/jpem.2009.22.11.1041.
Small size at birth may result from fetal undernutrition which may occur at different times during gestation. Early postnatal catch-up growth and excess childhood weight gain are associated with an increased risk of adult cardiovascular disease and type 2 diabetes mellitus. The aim of this study was to assess the relative contributions of body composition and energy expenditure on fasting insulin sensitivity during late childhood. We took advantage of two previously described prospective cohorts of children born either at term or prematurely, with a wide range of birth weights adjusted for gestational age. Seventy-one prepubertal children (mean age 7.5 +/- 0.3 years) were examined: 23 term SGA (8 M, 15 F), 12 preterm SGA (7 M, 5 F), 16 term AGA (8 M, 8 F), and 20 preterm AGA (9 M, 11 F). Mean height SDS was -0.18 +/- 0.11 and mean BMI SDS was 0.27 +/- 0.03. Change in weight SDS was significantly higher in children born SGA compared to their AGA counterparts (p < 0.001). Change in weight SDS was highly correlated with fasting insulin (p < 0.03) and leptin (p < 0.001). Fasting insulin correlated only with serum leptin levels. Body composition appeared to be the main determinant of fasting leptin levels. No differences in lipid profile were observed between the different groups. There was a clear tendency to higher insulin and leptin levels in children born SGA compared with their AGA counterparts. IGF-I levels were significantly higher only in SGA term compared to AGA term. Resting energy expenditure (REE) was lower in SGA born at term and higher in SGA born preterm compared to their AGA counterparts. In conclusion, fasting insulin sensitivity is mainly determined by leptin levels which in turn are determined by body composition. IGF-I and REE showed a divergent pattern in SGA term compared to SGA preterm groups. IGF-I levels were determined only by weight change from birth to age 2 years, which may not be as pronounced in VLBW children compared to SGA term and thus may preclude a difference in IGF-I levels in the group of preterm children. The divergent effect in REE in SGA born at term compared to SGA born preterm compared to their AGA counterparts may explain the divergent effects on IGF-I. This difference might be a consequence of different timing in the exposure to intrauterine nutritional deficiency.
出生时体型较小可能是由于孕期不同阶段出现的胎儿营养不足所致。出生后早期的追赶性生长以及儿童期体重过度增加与成人患心血管疾病和2型糖尿病的风险增加相关。本研究的目的是评估儿童晚期身体成分和能量消耗对空腹胰岛素敏感性的相对影响。我们利用了两个先前描述的前瞻性队列，这些儿童要么足月出生，要么早产，根据胎龄调整后的出生体重范围很广。对71名青春期前儿童（平均年龄7.5±0.3岁）进行了检查：23名足月小于胎龄儿（8名男性，15名女性），12名早产小于胎龄儿（7名男性，5名女性），16名足月适于胎龄儿（8名男性，8名女性），以及20名早产适于胎龄儿（9名男性，11名女性）。平均身高标准差分数为-0.18±0.11，平均体重指数标准差分数为0.27±0.03。与适于胎龄儿相比，小于胎龄儿出生后体重标准差分数的变化显著更高（p<0.001）。体重标准差分数的变化与空腹胰岛素（p<0.03）和瘦素（p<0.001）高度相关。空腹胰岛素仅与血清瘦素水平相关。身体成分似乎是空腹瘦素水平的主要决定因素。不同组之间未观察到血脂谱的差异。与适于胎龄儿相比，小于胎龄儿的胰岛素和瘦素水平明显有升高的趋势。仅足月小于胎龄儿的胰岛素样生长因子-I（IGF-I）水平显著高于足月适于胎龄儿。与适于胎龄儿相比，足月出生的小于胎龄儿静息能量消耗（REE）较低，早产出生的小于胎龄儿REE较高。总之，空腹胰岛素敏感性主要由瘦素水平决定，而瘦素水平又由身体成分决定。与早产小于胎龄儿组相比，足月小于胎龄儿组的IGF-I和REE呈现出不同的模式。IGF-I水平仅由出生至2岁时的体重变化决定，与足月小于胎龄儿相比，极低出生体重儿的这种变化可能不那么明显，因此可能排除了早产儿童组中IGF-I水平的差异。与适于胎龄儿相比，足月出生的小于胎龄儿与早产出生的小于胎龄儿REE的不同影响可能解释了对IGF-I的不同影响。这种差异可能是由于子宫内营养缺乏暴露时间不同的结果。
