According to a new study, researchers evaluates that Obesity remains a risk factor for cardiovascular disease even among those who are otherwise "metabolically healthy." The study was published online in The Lancet Diabetes & Endocrinology.

The analysis, which included 90,257 women followed for a median of 24 years, revealed that "metabolically healthy" women that is, without baseline diabetes, hypertension, or hypercholesterolemia had a significantly lower risk for cardiovascular disease (CVD) than did women with those conditions, regardless of body mass index (BMI).

However, even among those who were metabolically healthy, the women with overweight or obesity had a greater risk for CVD than did those of normal weight.  In addition, regardless of BMI, most women who were metabolically healthy at baseline did not remain so over time, and the transition to being metabolically unhealthy was associated with greater cardiovascular risk. 

The greatest contribution of this study is providing important insights about how changes or maintenance of weight and metabolic status affect the prognosis of cardiovascular disease.

Even for "Metabolically Healthy," High BMI Worsens CVD Risk 

The authors used data from the 1980 Nurses' Health Study questionnaire as baseline, when the participants were aged 30 to 55 years. The follow-up included questionnaires mailed every 2 years. Investigated outcomes were fatal and nonfatal myocardial infarction (MI) and stroke, and their combination as total CVD. The women were classified into normal weight (BMI, 18.5 to 24.9 kg/m²), overweight (BMI, 25.0 to 29.9 kg/m²), and obese (BMI ≥ 30 kg/m²). Metabolic health was defined by the absence of hypertension, diabetes, and hypercholesterolemia.

Development of Metabolic Risk Worsens CVD Outcomes

After adjustments for age, race, and other variables, the development of diabetes or hypertension over time was associated with significantly greater CVD (MI and/or stroke) risk among all baseline BMI groups, but the risk was greater with higher BMI. Still, even without developing any of the metabolic risk factors, women with metabolically healthy overweight and obesity remained at increased risk compared with those with metabolically healthy normal weight, with multivariate-adjusted HRs of 1.20 and 1.39, respectively.   

Few Remained Metabolically Healthy Over Time

Within each BMI group, those remaining metabolically healthy had substantially lower cardiovascular risk during follow-up than women who were metabolically unhealthy at any time point. But still, metabolically healthy obese women who remained so through the year 2000 were at 1.57-fold greater cardiovascular risk than those of normal weight who remained metabolically healthy.

Implication: Preventing Metabolic Syndrome Key    

The findings suggest that  Current definitions of metabolic health are insufficient to identify a subgroup of obesity not at risk. Additionally, the editorialists say, "increasing physical activity and exercise to improve levels of cardiorespiratory fitness is especially important to lower the cardiovascular disease risk in almost all groups of patients, including women with obesity."