Son Jang Won, Lee Seong Su, Kim Sung Rae, Yoo Soon Jib, Cha Bong Yun, Son Ho Young, Cho Nam H
Division of Endocrinology and Metabolism, Department of Internal Medicine, Bucheon St Mary's Hospital, College of Medicine, The Catholic University of Korea, Bucheon, Korea.
Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Diabetologia. 2017 May;60(5):865-872. doi: 10.1007/s00125-016-4196-9. Epub 2017 Jan 19.
AIMS/HYPOTHESIS: Asians have a propensity to develop type 2 diabetes with a lower BMI than Western populations. This discrepancy may be due to differences in body fat and muscle mass for a given BMI. However, unlike adiposity, it is unclear whether muscle mass affects the risk of type 2 diabetes in Asian populations.
We conducted a 2-yearly prospective assessment of 6895 participants who were free of diabetes at the baseline examination as part of the Korean Genome Epidemiology Study. The muscle mass index (MMI) was defined as the weight-adjusted appendicular skeletal muscle mass. Using Cox regression models, we evaluated the association between MMI and the risk of developing type 2 diabetes across sex-specific tertiles of MMI. Low muscle mass was defined as the sex-specific lowest tertile of MMI. Main covariates included age, sex, urban or rural residence, family history of diabetes, hypertension, smoking status, education level, monthly income, physical activity, alcohol consumption and diet. In addition, body fat mass, waist circumference and BMI were controlled as categorical variables. Obesity was defined as a BMI of ≥25 kg/m or a waist circumference of ≥90 cm for men and ≥85 cm for women.
During a median follow-up of 9.06 years, 1336 participants developed type 2 diabetes. At baseline, the mean age was 52.1 years and the mean BMI was 24.4 kg/m. The mean MMI for men and women was 32.1% and 26.0%, respectively. There was an inverse association between MMI and the risk of type 2 diabetes. Multivariate-adjusted HRs for the risk of developing type 2 diabetes were 2.05 (95% CI 1.73, 2.43), 1.39 (95% CI 1.17, 1.66) and 1.0 from the lowest to highest sex-specific MMI tertile, with an HR of 1.35 (95% CI 1.26, 1.45) per SD decline in MMI. Further adjustments for fat mass, waist circumference and BMI as categorical variables did not modify the relationship (each p < 0.01). In BMI-stratified analyses, the population-attributable fraction of the lowest tertile of MMI for developing type 2 diabetes was increased by 11.9% in the non-obese group and 19.7% in the obese group.
CONCLUSIONS/INTERPRETATION: Low muscle mass as defined by MMI was associated with an increased risk of type 2 diabetes, independent of general obesity, in middle-aged and older Korean adults.
目的/假设：与西方人群相比，亚洲人在较低体重指数（BMI）时就有患2型糖尿病的倾向。这种差异可能是由于相同BMI下身体脂肪和肌肉量的不同。然而，与肥胖不同的是，目前尚不清楚肌肉量是否会影响亚洲人群患2型糖尿病的风险。
作为韩国基因组流行病学研究的一部分，我们对6895名在基线检查时无糖尿病的参与者进行了为期两年的前瞻性评估。肌肉量指数（MMI）定义为体重调整后的四肢骨骼肌量。我们使用Cox回归模型，评估了MMI与不同性别MMI三分位数人群患2型糖尿病风险之间的关联。低肌肉量定义为特定性别的MMI最低三分位数。主要协变量包括年龄、性别、城乡居住地、糖尿病家族史、高血压、吸烟状况、教育水平、月收入、身体活动、饮酒量和饮食。此外，将体脂肪量、腰围和BMI作为分类变量进行控制。肥胖定义为男性BMI≥25kg/m或腰围≥90cm，女性BMI≥25kg/m或腰围≥85cm。
在中位随访9.06年期间，1336名参与者患了2型糖尿病。基线时，平均年龄为52.1岁，平均BMI为24.4kg/m。男性和女性的平均MMI分别为32.1%和26.0%。MMI与2型糖尿病风险呈负相关。从最低到最高性别特异性MMI三分位数，患2型糖尿病风险的多变量调整后风险比（HR）分别为2.05（95%置信区间1.73，2.43）、1.39（95%置信区间1.17，1.66）和1.0，MMI每降低1个标准差，HR为1.35（95%置信区间1.26，1.45）。将脂肪量、腰围和BMI作为分类变量进行进一步调整并未改变这种关系（各p<0.01）。在按BMI分层的分析中，非肥胖组中MMI最低三分位数导致患2型糖尿病的人群归因分数增加了11.9%，肥胖组增加了19.7%。
结论/解读：在中老年韩国成年人中，由MMI定义的低肌肉量与2型糖尿病风险增加相关，且独立于一般肥胖情况。
