Author + information
- Xuhong Hou, MD, PhD,
- Peizhu Chen, BS,
- Gang Hu, MD, PhD,
- Yue Chen, MD, PhD,
- Siyu Chen, BS,
- Xiaojing Ma, MD, PhD,
- Lei Chen, MD, PhD,
- Zhaojun Yang, MD, PhD,
- Wenying Yang, MD,
- Weiping Jia, MD, PhD∗ (, )
- China National Diabetes and Metabolic Disorders Study Group
- ↵∗Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, China
The American Association of Clinical Endocrinologists and the American College of Endocrinology (AACE/ACE) position statement proposed a complications-centric obesity management strategy for pre-diabetes, metabolic syndrome (MetS), and type 2 diabetes mellitus (1). Considering that cardiometabolic disease (CMD) is also common in normal-weight persons (2), we investigated the distribution of CMD stages among overweight/obese people, as well as those with normal weight.
The China National Diabetes and Metabolic Disorders Study is a representative cross-sectional survey of Chinese adults (3). 45,093 participants aged ≥20 years with complete metabolic index data were included in this analysis. Drawing from the CMD staging system (4) and the AACE/ACE obesity diagnostic algorithm (1), CMD was classified as no CMD, mild-to-moderate CMD, or severe CMD. Mild-to-moderate CMD included 1 or 2 of the following risk factors: central obesity (waist circumference ≥90 cm in men and ≥85 cm in women); elevated triglycerides; reduced high-density lipoprotein cholesterol; and elevated blood pressure. Severe CMD included pre-diabetes, MetS, type 2 diabetes mellitus, or cardiovascular disease. MetS was defined as having 3 or more CMD risk factors described in the preceding text. Pre-diabetes was defined as fasting plasma glucose ≥100 mg/dl and <126 mg/dl, and/or 2-h plasma glucose ≥140 mg/dl and <200 mg/dl and with no previous diagnosis of diabetes. Overweight/obesity was defined as body mass index (BMI) ≥25 kg/m2. Cardiovascular disease was as previously defined (5).
The proportions were weighed on the basis of the 2006 Chinese population structure using SUDAAN (version 10; RTI International, Research Triangle Park, North Carolina). The regression models were constructed using data from participants with BMI from the 0.1 to 99.9 percentiles using Stata/SE (version 13.1, StataCorp LP, College Station, Texas). First, the linear spline functions of BMI (kg/m2) were created with 6 knots (18.5, 23, 24, 25, 28, and 30). A multinomial logistic regression of CMD stages was then performed against a linear spline of BMI, which had a lower Akaike information criterion than the model with BMI as a continuous variable. Finally, we plotted the probability of CMD stages against BMI using the local polynomial smoothed line method. A p value <0.05 (2-tailed) was significant.
About 20.9% of the total population were of normal weight and had no CMD (192.6 million adults); 26.6% were of normal weight, but had mild-to-moderate CMD (245.2 million adults); 19.6% were of normal weight, but had severe CMD (180.5 million adults); 1.9% had overweight/obesity, but no CMD (17.6 million adults); 10.4% had overweight/obesity and mild-to-moderate CMD (96.1 million adults); and 20.7% had overweight/obesity and severe CMD (190.5 million adults), respectively. The probability of severe CMD, but not mild-to-moderate CMD, quickly increased with increasing BMI from 18.5 kg/m2 to 30 kg/m2, then slowed down and reached about 80% at BMI of 35 kg/m2 (Figure 1).
The present study found a much lower proportion of metabolically healthy overweight or obesity (1.9%) and a higher proportion of metabolically unhealthy normal weight (46.2%) compared with that in previous studies with white populations (2). There are 2 major reasons for the difference: the present study used a strict criterion of CMD for metabolic health, and Chinese adults have a higher risk of CMD than their white counterparts at a given BMI cutoff. However, as a cross-sectional study, a low BMI may be caused by pre-existing CMD or other chronic diseases.
In summary, our results showed that about 75% of Chinese adults had mild-to-severe CMD, of whom about six-tenths were of normal weight. Prevention and treatment of CMD should be considered for Chinese adults with both normal weight and overweight/obesity.
The authors thank all of the members of the China National Diabetes and Metabolic Disorders Study Group for their contributions to the study.
Please note: This study was funded by the Chinese Medical Association Foundation and the Chinese Diabetes Society, the Biomedical Engineering Cross Research Foundation of Shanghai Jiao Tong University (YG2015MS18). The funders had no role in the design, data collection, and analysis of this study, in the preparation and approval of the letter. The authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Xuhong Hou and Peizhu Chen contributed equally to this work.
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