Introduction: Obesity and metabolic risk factors induce microvascular dysfunction, a marker of early vascular disease that predicts cardiovascular events. Whether obese individuals with a metabolically healthy profile have impaired microvascular function remains unclear.
Objectives: The aim of this study was to evaluate the relation of obesity phenotypes stratified by metabolic status to microvascular function.
Methods: We meta-analyzed aggregate data from 3 large cohorts (Brazilian Longitudinal Study of Adult Health, the Framingham Heart Study and the Gutenberg Heart Study; N= 16830 participants, age range 19-90, 48.7% women). Regression slopes between cardiovascular risk factors and microvascular function, measured by peripheral arterial tonometry (PAT), were calculated for each cohort. Individuals were classified as normal-weight, overweight or obese by body mass index (BMI) and further stratified by healthy or unhealthy metabolic status based on metabolic syndrome defined by the ATP-III criteria.
Results: Male sex, BMI and the presence of metabolic risk factors were associated with more impaired PAT measures (P<0.0001 for baseline pulse amplitude, P<0.01 for PAT ratio). There was stepwise impairment of vascular measures from normal weight to obesity in both metabolic status strata (all P<0.0001). Metabolically healthy obese had more impaired vascular function than metabolically healthy normal-weight individuals (baseline pulse amplitude 6.12±0.017 vs. 5.61±0.010; PAT ratio 0.58±0.008 vs. 0.76±0.005, respectively, all P<0.0001). Within the same BMI category, metabolically healthy individuals had better vascular function than their metabolically unhealthy counterparts (all P<0.0001).
Conclusion: Metabolically healthy obese individuals have impaired microvascular function, though the degree of impairment is less marked than in metabolically unhealthy obese individuals. Our findings suggest that obesity is detrimental to vascular health irrespective of metabolic status.