目的·评估超重、肥胖青少年认知功能的改变，并探索认知功能与成纤维细胞生长因子21（fibroblast growth factor 21，FGF21）的关联。方法·选取上海市某高级中学的175名青少年，根据体质量指数（body mass index，BMI）分为正常体型组（n=50）、超重组（n=50）和肥胖组（n=75）。收集并比较青少年的一般资料、人体测量学资料及实验室检测指标。采用Flanker任务（侧抑制任务）和n-back任务（倒数n项测试范式）行为学试验的正确率（accuracy，ACC）和反应时评估3组青少年的认知功能，通过酶联免疫吸附试验检测其血清FGF21水平。通过偏相关分析、多元线性回归模型评估青少年行为学试验表现与人体测量学资料、实验室检测指标的相关性。结果·与正常体型组相比，肥胖组青少年的收缩压、舒张压及空腹血糖、糖化血红蛋白、三酰甘油水平较高（均P<0.05）。在Flanker任务的一致或不一致性刺激条件下，任意2组青少年的ACC间差异均无统计学意义；与正常体型组、超重组相比，肥胖组青少年的反应时均有延长（均P<0.05）。在n-back任务中，任意2组青少年的ACC间差异均无统计学意义，而肥胖组青少年在1-back和2-back任务中的反应时较正常体型组、超重组更长（均P<0.05）。与正常体型组相比，肥胖组青少年血清FGF21水平较高（P=0.000）。偏相关分析的结果显示，Flanker和n-back任务中青少年的反应时与其BMI、体脂肪量、腰围、腰臀比、FGF21水平等相关（均P<0.05）。多元线性回归分析进一步证实，BMI与青少年认知相关行为学任务中反应时延长相关（均P<0.05），且FGF21水平与2-back任务的ACC（P=0.000）、不一致性刺激的反应时（P=0.048）相关。结论·超重、肥胖青少年存在认知功能障碍，BMI、血清FGF21水平与该类青少年认知功能的改变相关。

Objective ·To evaluate the changes in cognitive function in overweight and obese adolescents, and explore the association between cognitive function and fibroblast growth factor 21 (FGF21). Methods ·A total of 175 adolescents from a senior high school in Shanghai were divided into normal weight group (n=50), overweight group (n=50) and obese group (n=75) based on their body mass index (BMI). General information, anthropometric data and laboratory testing indicators of the adolescents were collected and compared. The cognitive function of the three groups of adolescents was assessed by using the accuracy (ACC) and reaction time of Flanker task and n-back task. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum FGF21 level of the three groups of adolescents. Partial correlation analysis and multiple linear regression model were used to evaluate the correlation between cognitive task performance and anthropometric data and laboratory testing indicators. Results ·Compared with the normal weight group, systolic blood pressure, diastolic blood pressure, and the levels of fasting plasma glucose, glycosylated hemoglobin and triacylglycerol in the obese group were higher (all P<0.05). Under congruent or incongruent stimulus conditions in the Flanker task, there was no significant difference in ACC between any two groups; compared with the normal weight and overweight groups, the reaction time of the adolescents in the obese group was prolonged (all P<0.05). In the n-back task, there were no significant differences in ACC between any two groups, while the obese group had longer reaction time in the 1-back and 2-back tasks compared to the normal weight and overweight groups (all P<0.05). Compared with the normal weight group, serum FGF21 levels of the adolescents in the obese group were higher (P=0.000). Partial correlation analysis showed that the reaction time of the adolescents in Flanker and n-back tasks was correlated with their BMI, body fat mass, waist circumference, waist-to-hip ratio and FGF21 level (all P<0.05). Multiple linear regression analysis further confirmed that BMI was associated with prolonged reaction time in cognitive-related behavioral tasks in the adolescents (all P<0.05), and FGF21 level was associated with ACC in the 2-back task (P=0.000) and reaction time in the incongruent stimulus condition (P=0.048). Conclusion ·Overweight and obese adolescents have cognitive impairments, and BMI and serum FGF21 levels are associated with changes in their cognitive function.