Metabolically healthy obesity, transition to unhealthy metabolic status, and vascular disease in Chinese adults: A cohort study

Abstract

Background Metabolically healthy obesity (MHO) and its transition to unhealthy metabolic status have been associated with risk of cardiovascular disease (CVD) in Western populations. However, it is unclear to what extent metabolic health changes over time and whether such transition affects risks of subtypes of CVD in Chinese adults. We aimed to examine the association of metabolic health status and its transition with risks of subtypes of vascular disease across body mass index (BMI) categories. Methods and findings The China Kadoorie Biobank was conducted during 25 June 2004 to 15 July 2008 in 5 urban (Harbin, Qingdao, Suzhou, Liuzhou, and Haikou) and 5 rural (Henan, Gansu, Sichuan, Zhejiang, and Hunan) regions across China. BMI and metabolic health information were collected. We classified participants into BMI categories: normal weight (BMI 18.5–23.9 kg/m²), overweight (BMI 24.0–27.9 kg/m²), and obese (BMI ≥ 28 kg/m²). Metabolic health was defined as meeting less than 2 of the following 4 criteria (elevated waist circumference, hypertension, elevated plasma glucose level, and dyslipidemia). The changes in obesity and metabolic health status were defined from baseline to the second resurvey with combination of overweight and obesity. Among the 458,246 participants with complete information and no history of CVD and cancer, the mean age at baseline was 50.9 (SD 10.4) years, and 40.8% were men, and 29.0% were current smokers. During a median 10.0 years of follow-up, 52,251 major vascular events (MVEs), including 7,326 major coronary events (MCEs), 37,992 ischemic heart disease (IHD), and 42,951 strokes were recorded. Compared with metabolically healthy normal weight (MHN), baseline MHO was associated with higher hazard ratios (HRs) for all types of CVD; however, almost 40% of those participants transitioned to metabolically unhealthy status. Stable metabolically unhealthy overweight or obesity (MUOO) (HR 2.22, 95% confidence interval [CI] 2.00–2.47, p < 0.001) and transition from metabolically healthy to unhealthy status (HR 1.53, 1.34–1.75, p < 0.001) were associated with higher risk for MVE, compared with stable healthy normal weight. Similar patterns were observed for MCE, IHD, and stroke. Limitations of the analysis included lack of measurement of lipid components, fasting plasma glucose, and visceral fat, and there might be possible misclassification. Conclusions Among Chinese adults, MHO individuals have increased risks of MVE. Obesity remains a risk factor for CVD independent of major metabolic factors. Our data further suggest that metabolic health is a transient state for a large proportion of Chinese adults, with the highest vascular risk among those remained MUOO.

Trajectories of body mass index and risk for coronary heart disease: A 38-year follow-up study

“…Individuals with obesity constitute a heterogeneous population and the concept of “metabolically healthy obesity” has been discussed frequently in existing medical literature [ 39 – 41 ]. However, a cohort study, which was performed among Chinese adults, showed that individuals with metabolically healthy obesity had an increased risk of major cardiovascular events and that 40% of them transitioned to metabolically unhealthy obesity health status during a 10-year follow up [ 40 ]. A recent large case-control cohort analysis found that, irrespective of metabolic health, people with overweight and obesity had higher CHD risk than their counterparts with normal weight, thus challenging the concept of “metabolically healthy obesity” [ 41 ].…”

Trends in Obesity and Metabolic Status Among a Health Check-Up Population in Beijing and Hunan Between 2012 and 2020

“…In our study, the prevalence of MHO was 4.33% and 2.95% in Beijing and Hunan in 2020, respectively. In the China Kadoorie Biobank study, the MHO phenotype accounted for 3.3% of the total population during the period 2004 to 2008 in China [24]. According to a previous study, the prevalence of MHO has been shown to range between 4.2% and 13.6% in a random sample from a Chinese adult population, depending on the de nition used for MHO [25].…”

Short-Term Changes in Metabolically Healthy Overweight/Obesity Status Impact the Susceptibility to Type 2 Diabetes in Chinese Adults

“…6,7 Despite the inconsistent findings regarding the association between metabolic health and the risk for diabetes, the unstable nature of MHO may deteriorate to metabolically unhealthy overweight/obesity (MUO) overtime, and ultimately increase the risk for the development of diabetes. [8][9][10] The Nurses' Health Study delineated a decline of healthy metabolic profile with increased age after a 30-year follow-up and suggested an early intervention to impede the transition from healthy to unhealthy metabolic status in both overweight and obese populations. 9 Thus, it is urgent to investigate the shortterm MHO-to-MUO transition impact on the T2D risk and identify the predictors for this imminent transition.…”