Background: Leptin and adiponectin interact with each other in the modulation of obesity and insulin resistance (IR) and it is also important to consider the role of cardiorespiratory and muscular fitness in these relationships.

Aim: To analyse the relationship between IR with adipocytokines in children, and to test the mediation effect of %BF (percentage of body fat) in the association of IR with leptin, adiponectin, and L/A ratio.

Subjects and methods: This cross-sectional study comprised a sample of 150 schoolchildren, aged 6–11 years, from school in Porto Alegre, Brazil. The following variables were evaluated: cardiorespiratory fitness (CRF), muscular fitness (MF), percentage of body fat (%BF), and biochemical variables (leptin, adiponectin, glucose, and insulin).

Results: IR was associated with leptin and L/A ratio, after adjustments for age, sex, sexual maturation, and CRF. When adjusted for age, sex, sexual maturation, and MF, an association was found between IR with leptin and L/A ratio. Moreover, %BF was a mediator in the association between IR and leptin, as well as IR and L/A ratio, explaining 54% and 57% of these associations, respectively.

Conclusion: Leptin and L/A ratio are positively associated with IR after adjustments. Also, %BF is a mediator in the associations between IR and leptin and L/A ratio.

背景：瘦素和脂联素在肥胖症和胰岛素抵抗（IR）的调节中相互作用，并且在这些关系中考虑心肺和肌肉健康的作用也很重要。

目的：分析儿童IR与脂肪细胞因子之间的关系，并检测％BF（体脂百分比）与IR与瘦素，脂联素和L / A比的关系的介导作用。

主题和方法：这项横断面研究包括来自巴西阿雷格里港的150名6-11岁学童的样本。评估了以下变量：心肺适应性（CRF），肌肉适应性（MF），体脂百分比（％BF）和生化变量（瘦素，脂联素，葡萄糖和胰岛素）。

结果：在调整了年龄，性别，性成熟度和CRF之后，IR与瘦素和L / A比相关。调整年龄，性别，性成熟度和MF后，发现IR与瘦素和L / A比之间存在关联。此外，％BF是IR和瘦素之间的介体，以及IR和L / A比率的介体，分别解释了这些结合的54％和57％。

结论：调整后，瘦素和L / A比值与IR呈正相关。此外，％BF是IR与瘦素和L / A比之间的关联的介体。