Interactions between serum leptin, the insulin-like growth factor-I system, and sex, age, anthropometric and body composition variables in a healthy population randomly selected
Interactions between serum leptin, the insulin-like growth factor-I system, and sex, age, anthropometric and body composition variables in a healthy population randomly selected
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DOI：
10.1046/j.1365-2265.2003.01698.x
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发表时间：
2003-02-01
影响因子：
3.2
通讯作者：
Soler, J
中科院分区：
文献类型：
--
作者：
Gómez, JM;Maravall, FJ;Soler, J
目的瘦素分泌受多种因素影响，GH/IGF轴在调节机体组成中起重要作用，但瘦素与IGF- i系统之间的生理相互作用尚不清楚。在这项研究中，我们调查了一组随机选择的健康成年人瘦素、IGF-I系统与性别、年龄、人体测量和身体组成变量之间的关系。设计横断面研究。患者研究纳入268名受试者，在性别和年龄分布上代表了L'Hospitalet de Llobregat市的全部人口：男性134名，年龄41.4岁，15-70岁；134名女性，年龄40.7岁，年龄在15-70岁之间。测量方法：计算身体质量指数（BMI），使用生物电阻抗分析仪测定身体成分。用放射免疫分析法（RIA）测定血清瘦素浓度。血清总IGF-I浓度经酸-乙醇提取后，也用RIA测定。采用酶免疫测定法测定血清游离IGF-I浓度。采用RIA法测定血清IGFBP3浓度。血浆基础TSH浓度通过特定的电化学发光法测定。结果：在男性中，BMI在所有的十年中都是相似的，腰臀比在过去的三十年中有所增加。无脂质量下降了10年。我们观察到瘦素在第四个十年中增加，而IGF-I、游离IGF-I和IGFBP3在整个十年中下降。基础TSH在过去二十年中有所增加。在过去的几十年里，女性的身体质量指数、腰臀比和脂肪量显著增加。在过去的几十年里，瘦素浓度增加，总IGF-I、游离IGF-I和IGFBP3下降，但基础TSH浓度没有变化。在男性中，瘦素与BMI、腰臀比、全身水分、无脂质量和脂肪质量呈正相关，这些人体测量和身体组成变量与游离IGF-I和IGFBP3呈负相关，与总IGF-I无相关性。在女性中，瘦素与BMI、腰臀比、全身水分、无脂质量、脂肪质量呈正相关，与总IGF-I、IGFBP3呈负相关，与游离IGF-I无相关性。在男性中，总IGF-I与腰臀比呈负相关，与其他变量无相关性，游离IGF-I与BMI、腰臀比呈负相关，IGFBP3无相关性。在女性中，总IGF-I、游离IGF-I和IGFBP3与BMI、腰臀比和脂肪量呈负相关。多元线性回归分析产生了一个模型，可以解释男性60.5%的瘦素变异和女性40%的瘦素变异。值得注意的是，只有年龄、体重指数、脂肪量和腰臀比对瘦素变异性有独立的显著贡献。最终模型还分别解释了男性和女性中总IGF-I变异的28.2%和60.4%，以及游离IGF-I变异的17.2%和27.4%。年龄和瘦素对男性游离IGF-I变异有影响，而年龄和脂肪量与女性总IGF-I显著且独立相关。结论：在随机选择的无慢性疾病或无药物治疗且经生化证实的甲状腺功能正常的对照人群中，我们发现男性和女性瘦素水平与IGF-I系统、人体测量和身体组成变量之间存在显著相关性，但瘦素不调节IGF-I系统，IGF-I系统也不调节瘦素的合成和分泌。
OBJECTIVE Leptin secretion is influenced by many factors and the GH/IGF axis plays an important role in the regulation of body composition, but the physiological interactions between leptin and the IGF-I system remain unknown. In this study we investigated the relationship between leptin, the IGF-I system, and sex, age, anthropometric and body composition variables in a group of healthy adults randomly selected.DESIGN A cross-sectional study.PATIENTS The study included 268 subjects, representative of the whole population of the city of L'Hospitalet de Llobregat in sex and age distribution: 134 men aged 41.4 years, range 15-70 years; and 134 women, aged 40.7 years, range 15-70 years.MEASUREMENTS Body mass index (BMI) was calculated, and body composition was determined by using a bioelectrical impedance analyser. Serum leptin concentrations were determined by using a radioimmunoassay (RIA). Serum total IGF-I concentrations, after acid-ethanol extraction, were also measured by RIA. Serum free IGF-I concentrations were determined by an enzymoimmunometric assay. Serum IGFBP3 concentrations were determined by RIA. Plasma basal TSH concentrations were determined by a specific electrochemiluminescence assay.RESULTS In men the BMI was similar in all decades and waist/hip ratio increased in the last three decades. Fat-free mass decreased by decade. We observed an increase in leptin in the fourth decade with a decrease in IGF-I, free IGF-I and IGFBP3 throughout the decades. Basal TSH showed an increase in the last two decades. In women, BMI, waist/hip ratio and fat mass increased significantly in the last decades. Leptin concentrations increased in the last decades and total IGF-I, free IGF-I and IGFBP3 decreased by decade without changes in basal TSH concentration. In men, there was a positive correlation between leptin and BMI, waist/hip ratio, total body water, fat-free mass and fat mass, and these anthropometric and body composition variables showed a negative correlation with free IGF-I and IGFBP3, without any correlation with total IGF-I. In women, there was a positive correlation between leptin and BMI, waist/hip ratio, total body water, fat-free mass, and fat mass, which showed a negative correlation with total IGF-I and IGFBP3, without any correlation with free IGF-I.In men, total IGF-I was negatively correlated with waist/hip ratio without any correlation with the other variables and free IGF-I was negatively correlated with BMI and waist/hip ratio, and IGFBP3 did not show any correlation. In women, total IGF-I, free IGF-I and IGFBP3 were negatively correlated with BMI, waist/hip ratio and fat mass. The multiple linear regression analysis produced a model that explained 60.5% of leptin variability in men and 40% in women. Notably, only age, BMI, fat mass and waist/hip ratio brought an independent significant contribution to leptin variability. The final model also explained 28.2% and 60.4% of total IGF-I variability and 17.2% and 27.4% of free IGF-I variability in men and women, respectively. Age and leptin contributed to free IGF-I variability in men, and age and fat mass were significantly and independently associated with total IGF-I in women.CONCLUSIONS In this well-characterized population of controls randomly selected without chronic disease or drug administration and with biochemically confirmed euthyroidism, we found that both men and women had a significant correlation between leptin levels and the IGF-I system, and anthropometric and body composition variables, but that leptin did not regulate the IGF-I system, and that the IGF-I system did not regulate leptin synthesis and secretion.