HealthDay News — Both metabolically healthy obese and metabolically unhealthy normal weight individuals are at higher risk for developing type 2 diabetes and cardiovascular disease, study findings indicate.
Metabolically healthy obese individuals were more than three times as likely than their normal weight counterparts, and metabolically unhealthy normal weight individuals were more than twice as likely than their metabolically healthy counterpart to develop diabetes or cardiovascular disease, according to Koko Aung, MD, MPH, the University of Texas Health Science Center in San Antonio and colleagues.
“Screening for obesity and other metabolic abnormalities should be routinely performed in clinical practice to institute appropriate preventive measures,” the researchers wrote.
Previous studies suggest that metabolic abnormalities may influence risk for diabetes and cardiovascular disease, so the researchers examined the association between metabolic factors and incident type 2 diabetes in 2,814 individuals and CVD in 3,700 people aged 25 to 64 years who had participated in the San Antonio Heart Study.
Metabolically healthy obesity was defined as a BMI ≥30 kg/m² with one or no metabolic abnormalities. Metabolically unhealthy normal weight was defined as <25 kg/m² with two or more metabolic abnormalities.
Participants were followed for a mean 7.4 years, during which incidence of diabetes and cardiovascular disease were recorded. Findings were published online in the Journal of Clinical Endocrinology & Metabolism.
After controlling for demographic factors, family type 2 diabetes history and fasting glucose, BMI correlated with incident type 2 diabetes (odds ratio for each standard deviation, 1.7; 95% CI: 1.5–2.0), the researchers found.
Risk for type 2 diabetes was also increased among metabolically unhealthy normal weight individuals (OR, 2.5; 95% CI: 1.1–5.6) and metabolically healthy obese individuals (OR, 3.9; 95% CI: 2.0–7.4). After adjustment for demographics and Framingham risk scores, BMI was also related to incident CVD (OR, 1.3; 95% CI: 1.1–1.6).
Metabolically unhealthy normal weight individuals and metabolically healthy obese individuals had increased odds for incident CVD (odds ratios, 2.9 and 3.9, respectively).
“Risk of developing diabetes rose in a stepwise fashion with increasing BMI” in both categories of participants (P<0.001 for both trends), though “only metabolically healthy individuals had a graded increase in incident cardiovascular disease,” the researchers wrote (P<0.001 for trend).
Metabolically unhealthy individuals had higher systolic BP, triglycerides, and 10-year coronary heart disease risk that metabolically healthy obese participants. High-density lipoprotein levels, waist circumference, fasting insulin and HOMA-IR were all lower in metabolically unhealthy individuals. There was no significant difference between groups for plasma glucose.
The study limitations included the researcher’s definition of a metabolically healthy state, patient characteristics of the reference group and lack of subclinical inflammation in metabolic health measurements.