Being overweight or obese are risk factors for myocardial infarction (heart attack) and ischemic heart disease (IHD) regardless of whether individuals also have the cluster of cardiovascular risk factors known as metabolic syndrome, which includes high blood pressure, high cholesterol and high blood sugar, according to a study published by JAMA Internal Medicine.
Being overweight or obese likely causes MI and IHD but whether co-existing metabolic syndrome is necessary for the conditions to develop is unknown, according to the study authors.
Børge G. Nordestgaard, M.D., D. M.Sc., and Mette Thomsen, M.D., from Herlev Hospital, Copenhagen University Hospital, Denmark, investigated the associations by examining data from 71,527 participants in a general population study.
During nearly four years of follow-up, researchers identified 634 cases of MIs and 1,781 cases of IHDs. Relative to people with normal weight, the hazards of MI were increased with overweight and obesity and were statistically equivalent whether or not patients had metabolic syndrome. There were also increasing cumulative incidences of MI and IHD among individuals both with and without metabolic syndrome from normal weight through overweight to obese individuals, according to the study results.
"These findings suggest that overweight and obesity are risk factors for MI and IHD regardless of the presence or absence of metabolic syndrome and that metabolic syndrome is no more valuable than BMI (body mass index) in identifying individuals at risk," the study concludes.
In a related commentary, Chandra L. Jackson, Ph.D., M.S., and Meir J. Stampfer, M.D., Dr.P.H., of the Harvard School of Public Health, Boston, write: "Besides questions related to how much added value there is to assessing MetS [metabolic syndrome] (beyond its component elements), the findings from this study have important implications and clearly corroborate the clinical and public health message that adiposity is not benign and that achieving and maintaining a healthy body weight (typically, BMI [body mass index], >18.5 to <25.0 kg/m 2 ) is of paramount importance."
"The findings of Thomsen and Nordestgaard add important new evidence to counter the common belief in the scientific and lay communities that the adverse health effects of overweight are generally inconsequential as long as the individual is metabolically healthy," they continue.
"In contrast, this study adds further evidence for the increased risks associated with overweight, even among those who might be considered metabolically healthy. These results also underscore the importance of focusing on weight gain prevention due to the difficulty in achieving and maintaining weight loss to reverse being overweight or obese," they conclude.
JAMA Intern Med. Published online November 11, 2013. DOI: 10.1001/jamainternmed.2013.10522
JAMA Intern Med. Published online November 11, 2013. DOI: 10.1001/jamainternmed.2013.8298