In a study by Mark Hamer and Emmanuel Stamatakis from University College London, published in the Journal of Clinical Epidemiology, the researchers show that ‘metabolically’ healthy obese individuals have minimally (if at all) increased risk of cardiovascular mortality.
Their study looked at mortality records in 22,203 men and women community-dwelling adults from the general population in Scotland and England without known history of cardiovascular disease (CVD) at baseline.
Based on blood pressure, high-density lipoprotein-cholesterol, diabetes diagnosis, waist circumference, and low-grade inflammation (C-reactive protein ≥ 3 mg/liter), participants were classified as either metabolically healthy (0 or 1 metabolic abnormality) or unhealthy (two or more metabolic abnormalities).
Compared with metabolically healthy nonobese participants, metabolically ‘healthy’ obese individuals were not at elevated risk of CVD over the seven year observation period.
In contrast both metabolically ‘unhealthy’ nonobese and obese participants were were at a significantly elevated risk for heart disease.
In addition, metabolically ‘unhealthy’ obese participants were also at elevated risk of all-cause mortality compared with their metabolically healthy obese counterparts.
Regular readers of these pages will recall our findings that obesity individuals without metabolic risk factors or other comorbidities or functional limitations, which we would classify as EOSS Stage 0 obesity, do not have an increased mortality risk, but that this markedly increase for Stage 2 and 3 patients.
Although, the present study used the rather arbitrary definition of 0 or 1 metabolic risk factor as ‘healthy’, they certainly are in line with our findings that neither obesity based on BMI or waist circumference alone is a reliable marker of risk.
Rather, it is essential that clinicians consider other risk factors and comorbidities in determining the risk of their obese patients, and remember that nonobese individuals with these same risk factors may be at as much risk as their obese counterparts.
Clearly treatment recommendations based on BMI alone should be now considered obsolete and perhaps best relegated to history books.
Hamer M, & Stamatakis E (2012). Metabolically Healthy Obesity and Risk of All-Cause and Cardiovascular Disease Mortality. The Journal of clinical endocrinology and metabolism PMID: 22508708