Associations of metabolically healthy obesity with prevalence and progression of coronary artery calcification: Results from the Heinz Nixdorf Recall Cohort Study

Abstract

Background and aims: There is controversy on the potentially benign nature of metabolically healthy obesity (MHO), i.e., obese persons with few or no metabolic abnormalities. So far, associations between MHO and coronary artery calcification (CAC), a measure of subclinical atherosclerosis, have mainly been studied cross-sectionally in Asian populations. We assessed cross-sectional and longitudinal MHO CAC associations in a Caucasian population.

Methods and results: In the Heinz Nixdorf Recall Study, a population-based cohort study in Germany, CAC was assessed by electron-beam tomography at baseline and at 5-year follow-up. For cross-sectional and longitudinal analyses, we included 1585 participants free of coronary heart disease at baseline, with CAC measurements at baseline and at follow-up, and with either normal weight (BMI 18.5-24.9 kg/m²) or obesity (BMI ≥30.0 kg/m²) at baseline. We used four definitions of MHO. In our main analysis, we defined obese persons as metabolically healthy if they met ≤1 of the NCEP ATP III criteria for the definition of the metabolic syndrome - waist circumference was not taken into account because of collinearity with BMI. Persons with MHO had a higher prevalence of CAC than metabolically healthy normal weight (MHNW) persons (prevalence ratio = 1.59 (95% confidence interval 1.38-1.84) for the main analysis). Persons with MHO had slightly larger odds of CAC progression than persons with MHNW (odds ratios ranged from 1.17 (0.69-1.99) to 1.48 (1.02-2.13) depending on MHO definition and statistical approach).

Conclusion: Our analyses on MHO CAC associations add to the evidence that MHO is not a purely benign health condition.

Keywords: Cohort study; Coronary artery calcification; Coronary artery calcium; Metabolic syndrome; Metabolically healthy obesity; Subclinical atherosclerosis.