Published: Nov 20, 2013 | Updated: Nov 20, 2013
By Cole Petrochko, Staff Writer, MedPage Today

Full Story:  http://www.medpagetoday.com/Endocrinology/Diabetes/43040

Metabolically unhealthy normal-weight patients, and obese but metabolically healthy patients both had significantly increased risk for diabetes and cardiovascular disease, researchers found.

A population-based sample of participants from the San Antonio Heart Study showed increased odds of developing diabetes among individuals who were metabolically unhealthy but of normal weight (OR 2.5, 95% CI 1.1-5.6) and who were metabolically healthy and obese (OR 3.9, 95% CI 2.0-7.4), according to Carlos Lorenzo, MD, of the University of Texas Health Science Center in San Antonio, and colleagues.

Patients who were metabolically unhealthy but of normal weight also had an increased risk of developing cardiovascular disease (OR 2.9, 95% CI 1.3-6.4) as did those who were obese but metabolically healthy (OR 3.9, 95% CI 1.9-7.8), they wrote online in the Journal of Clinical Endocrinology and Metabolism.

The authors also noted that prior studies have found associations between body mass index (BMI) and cardiovascular disease and diabetes. Past research also has shown a small but significant link between BMI and mortality. And a cohort study of youths who were followed to young adulthood showed that later diabetes risk was associated with weight gained when they were younger.

These data support guidelines issued by the National Heart, Lung, and Blood Institute in November, 2013, which urged doctors to focus on obesity, and its treatment, during patient visits.

In the current study, the authors looked at risks of developing diabetes or cardiovascular disease in a population of 4,202 participants.

Participants were white or Mexican-American, were ages 25 to 64, and reported data on demographics, cigarette smoking, medication use, and anthropometric measurements, including systolic and diastolic blood pressure, diabetes status at baseline and follow-up, plasma glucose and serum lipids, serum insulin, and BMI and obesity status.

Metabolic unhealthiness was established through elevated blood pressure, elevated triglyceride and glucose levels, insulin resistance, and decreased high-density lipoprotein levels.

Participants were followed-up with for a median 7.4 years, during which incidence of diabetes and cardiovascular disease were recorded.

Transition to being metabolically unhealthy was significantly associated with older age, male sex, and Mexican-American ethnicity (P<0.001 for all).

Overall, incident diabetes occurred in 9.3% of participants, and incident cardiovascular disease occurred in 3.4%. BMI was significantly associated with the development of both, at two-fold odds (95% CI 1.7-2.2, P<0.001) for diabetes and 40% increased odds (95% CI 1.2-1.7,P<0.001) for cardiovascular disease.

Metabolically unhealthy individuals had higher systolic blood pressure, triglycerides, and 10-year coronary heart disease risk that metabolically healthy obese participants. They also had significantly lower high-density lipoprotein levels, lower waist circumference, lower fasting insulin, and lower HOMA-IR. There was no significant difference between groups for plasma glucose.

“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 investigators wrote (P<0.001 for trend).

After controlling for insulin resistance, which the authors explained was not measured in clinical practice, as well as for age, sex, ethnicity, and smoking, the odds ratio for cardiovascular disease incidence increased to 3.1 for normal weight but metabolically unhealthy participants, and to 3.4 for obese but metabolically healthy participants; diabetes incidence in these groups rose to 2.8 and 4.

The authors noted that their study was limited by their definition of a metabolically healthy state, characteristics of their reference group, and lack of subclinical inflammation in metabolic health measurements.