An Empirically Derived Definition of Metabolically Healthy Obesity Based on Risk of Cardiovascular and Total Mortality.
The present criteria for obesity lack consideration that would differentiate healthy obesity from unhealthy one as not all obese individuals have a higher risk of cardiovascular diseases and mortality. Anika Zembic and colleagues conducted research under the title “An Empirically Derived Definition of Metabolically Healthy Obesity Based on Risk of Cardiovascular and Total Mortality” published in the JAMA Network Open. The summary of this study is provided below:
Objective:
To obtain a new definition of metabolic health (MH) and assess its relationship with cardiovascular disease (CVD) mortality and total mortality.
Method:
In this cohort study, data from the third National Health and Nutrition Examination Survey (NHANES-III) was utilized. An association between complex multistage probability sampling, biomarkers, anthropometric factors, and blood pressure (BP) with total and CVD mortality was assessed among participants with obesity. The cox proportional hazards regression was used. The area under the receiver operating characteristic was calculated to recognize predictive factors for mortality to be used to define MH. Youden index was used to determine cut-off levels. The comparison with the independent UK Biobank cohort, a population-based prospective study validated the findings.
All nonpregnant participants between 18 to 75 years with no history of CVD, body mass index more than or equal to 18.5, and who fasted more than 6 hours before examination in NHANES-III were included. Participants without blood measurements in the UK Biobank cohort were excluded. The study was conducted between 2015 to 2020.
Findings:
Investigators have put forward a new definition to identify individuals with metabolically healthy obesity (MHO), based on self-reported diabetes, systolic BP, use of BP medication, and waist to hip ratio (WHR). This definition can be used in clinical as well as research settings. Additionally, findings suggest that people classified under MHO by this definition are not at increased risk for CVD or total mortality. On the other hand, metabolically unhealthy individuals have a considerably higher risk, which is not explained by conventional definitions of MH.
Limitation:
The study had a lack of data on changes in body weight and metabolic factors due to the original design of NHANES-III. Hence, the outcome associated with changes in MH that reportedly alter CVD risk was not being investigated. Secondly, findings should be generalized with caution as body fat distribution might differ according to race/ethnicity and the proposed WHR cutoff might not be suitable for all populations, especially Asian populations. The C index was unavailable for the surveyphreg procedure.
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