The “obesity paradox” lives on: In a look-back at a group of adults with suspected or known coronary artery disease, underweight adults had an increased risk of death, whereas overweight and obese adults had a lower risk of death, compared with normal-weight adults.

The paradoxical relation of higher body mass index (BMI) with lower mortality has been observed recently in other patient groups, including those with chronic heart failure and renal disease. At the moment, the reason for this is not understood.

In their study, Dr. Don Poldermans from Erasmus Medical Center, Rotterdam, the Netherlands, and colleagues examined data on 5,950 coronary artery disease patients seen at the center between 1993 and 2005.

Over an average of 6 years, mortality was highest in underweight individuals (39 percent), followed by normal-weight (35 percent), overweight (24 percent) and obese individuals (20 percent), the team reports in the American Journal of Cardiology.

In analyses taking into account potentially confounding factors, underweight patients had a greater than twofold increased risk of dying during the study period compared with normal-weight patients, while overweight and obese patients had significantly lower risks of dying.

“The explanation of the underweight patients and adverse outcome might be the prevalence of chronic obstructive pulmonary disease in this population, or (still unknown) malignancies,” Poldermans told Reuters Health.

SOURCE: American Journal of Cardiology, May 2007.