Ferrara C M, Goldberg A P
Division of Gerontology, School of Medicine, University of Maryland at Baltimore, Baltimore Veterans Affairs Medical Center, 21201-1524, USA.
Diabetes Care. 2001 Feb;24(2):245-9. doi: 10.2337/diacare.24.2.245.
Insulin resistance (IR) in older individuals is associated with risk factors for coronary artery disease. The glucose clamp measures IR directly, but the homeostasis model assessment (HOMA) of IR, referred to here as HOMA-IR, is based on fasting glucose and insulin and is less invasive and labor intensive. This method requires validation in the elderly.
We assessed the validity of HOMA-IR as an index of IR by comparing it to glucose infusion rates (GIRs) measured by a glucose clamp (600 pmol x m(-2) x min(-1)) in 45 obese men (61 +/- 8 years of age, mean +/- SD) with normal glucose tolerance (NGT) (n = 21) or impaired glucose tolerance (IGT) (n = 24). We also evaluated relationships between body composition, exercise capacity, and IR.
Subjects with NGT had lower BMI (28 +/- 3 vs. 31 +/- 3 kg/m2), waist circumference (97 +/- 9 vs. 105 +/- 9 cm), waist-to-hip ratio (WHR) (0.93 +/- 0.06 vs. 0.97 +/- 0.05), and percent body fat (25 +/- 6 vs. 30 +/- 6) than subjects with IGT. Subjects with NGT also had lower areas above basal during the 2-h oral glucose tolerance test for glucose (274 +/- 95 vs. 419 +/- 124 mmol x min/l) and insulin (38,142 +/- 18,206 vs. 58,383 +/- 34,408 pmol x min/l) and lower HOMA-IR values (2.2 +/- 0.8 vs. 4.2 +/- 2.6) than subjects with IGT. GIR (micromol x kg(-1) FFM x min(-1)) was higher in subjects with NGT than in subjects with IGT (53 +/- 11 vs. 43 +/- 14). HOMA-IR correlated with GIR in subjects with NGT (r = -0.59), but not in subjects with IGT (r = -0.13). GIR correlated with VO2max in subjects with NGT (r = 0.58) and IGT (r = 0.42), but with WHR only in subjects with NGT (r = -0.53). HOMA-IR correlated with VO2max (r = -0.57) and waist circumference (r = 0.54) in subjects with NGT, but with percent body fat in subjects with IGT (r = 0.54).
These findings indicate that HOMA-IR should not be used as an index of IR in older individuals who may be at risk for IGT, and suggest that lifestyle changes that increase VO2max and decrease body fat may reduce IR in older people.
老年个体的胰岛素抵抗（IR）与冠状动脉疾病的危险因素相关。葡萄糖钳夹法可直接测量IR，但IR的稳态模型评估（HOMA），在此称为HOMA-IR，基于空腹血糖和胰岛素，侵入性较小且劳动强度较低。该方法需要在老年人中进行验证。
我们通过将HOMA-IR与45名肥胖男性（61±8岁，均值±标准差）的葡萄糖钳夹法测得的葡萄糖输注率（GIR）（600 pmol·m⁻²·min⁻¹）进行比较，评估HOMA-IR作为IR指标的有效性，这些男性具有正常糖耐量（NGT）（n = 21）或糖耐量受损（IGT）（n = 24）。我们还评估了身体成分、运动能力和IR之间的关系。
与IGT受试者相比 NG T受试者的体重指数（28±3 vs. 31±3 kg/m²）、腰围（97±9 vs. 105±9 cm）、腰臀比（WHR）（0.93±0.06 vs. 0.97±0.05）和体脂百分比（25±6 vs. 30±6）更低。NGT受试者在2小时口服葡萄糖耐量试验期间的葡萄糖（274±95 vs. 419±124 mmol·min/l）和胰岛素（38,142±18,206 vs. 58,383±34,408 pmol·min/l）基础上的面积也更低，且HOMA-IR值（2.2±0.8 vs. 4.2±2.6）比IGT受试者更低。NGT受试者的GIR（微摩尔·千克⁻¹去脂体重·分钟⁻¹）高于IGT受试者（53±11 vs. 43±14）。在NGT受试者中HOMA-IR与GIR相关（r = -0.59），但在IGT受试者中不相关（r = -0.13）。在NGT受试者（r = 0.58）和IGT受试者（r = 0.42）中GIR与最大摄氧量相关，但仅在NGT受试者中与WHR相关（r = -0.53）。在NGT受试者中HOMA-IR与最大摄氧量（r = -0.57）和腰围（r = 0.54）相关，但在IGT受试者中与体脂百分比相关（r = 0.54）。
这些发现表明，HOMA-IR不应被用作可能有IGT风险的老年个体的IR指标，并表明增加最大摄氧量和减少体脂的生活方式改变可能会降低老年人的IR。
