Blog | Thursday, November 14, 2013

QD: News Every Day--'Fat but fit' brought into question


Overweight and obesity may be risk factors for myocardial infarction (MI) and ischemic heart disease regardless of whether the person has metabolic syndrome, a study found.

Researchers noted that metabolic syndrome is no more valuable than body-mass index (BMI) in identifying individuals at risk, and that weight loss should be encouraged either way to reduce risk of MI and ischemic heart disease.

Researchers examined 71,527 individuals from the Copenhagen General Population Study and categorized them by BMI as normal weight, overweight or obese, and by whether they had metabolic syndrome.

Results appeared online at JAMA Internal Medicine.

During a median follow-up 3.6 years, 634 individuals had an MI and 1,781 individuals received a diagnosis of ischemic heart disease. Cumulative incidences of myocardial infarction and ischemic heart disease were higher in overweight and obese people compared to those with normal weight (both log-rank trend P <0.001). Multivariable adjusted HRs for MI compared to normal weight individuals were 1.38 (95% CI, 1.14 to 1.67) in overweight and 2.04 (95% CI, 1.64 to 2.54) in obese patients. HRs for ischemic heart disease were 1.25 (95% CI, 1.12 to 1.40) and 1.64 (95% CI, 1.44 to 1.86).

Metabolic syndrome was associated with increased cumulative incidences of MI and ischemic heart disease (both log-rank P <0.001). In individuals with compared to without metabolic syndrome, the multivariable adjusted HR for myocardial infarction was 1.54 (95% CI, 1.32 to 1.81) and for ischemic heart disease was 1.38 (95% CI, 1.26 to 1.52).

Risk of MI increased with higher BMI categories independently of metabolic syndrome. For myocardial infarction, multivariable adjusted HRs compared to normal weight individuals without metabolic syndrome were 1.26 (95% CI, 1.00 to 1.61) in overweight and 1.88 (95% CI, 1.34 to 2.63) in obese individuals without metabolic syndrome and 1.39 (95% CI, 0.96 to 2.02) in normal weight, 1.70 (1.35 to 2.15) in overweight, and 2.33 (95% CI, 1.81 to 3.00) in obese individuals with metabolic syndrome.

Risk of ischemic heart disease increased with higher BMI categories independently of metabolic syndrome. For ischemic heart disease, multivariable adjusted HRs compared to normal weight individuals without metabolic syndrome were 1.08 (95% CI, 0.95 to 1.24) in overweight and 1.45 (95% CI, 1.20 to 1.77) in obese individuals without metabolic syndrome and 1.03 (95% CI, 0.82 to 1.30) in normal weight, 1.30 (95% CI, 1.13 to 1.49) in overweight, and 1.67 (95% CI, 1.44 to 1.93) in obese individuals with metabolic syndrome.

Researchers suggested that physicians reduce obesity even in the absence of metabolic syndrome.

“Also, because abdominal adiposity seems to precede the development of the other abnormalities in the syndrome, overweight and obesity may in some individuals be an early warning sign for future metabolic disturbances,” they wrote.

An editorial stated that heavier people without metabolic syndrome aren’t necessarily “metabolically healthy overweight or obese,” but rather, they are instead likely to eventually get metabolic syndrome.

The editorial stated, “Clinicians tend to dichotomize conditions determined by continuous clinical measures (eg, hypertension with blood pressure and diabetes mellitus with fasting serum glucose level) mainly as a tool for making treatment decisions, and these decision points are dependent in part on the risks and benefits of the treatment options. However, clinicians do not per se treat MetS. Instead, they treat the individual components that have a well-established dose-response relationship with IHD (ischemic heart disease). To be useful in clinical practice or for research, MetS would have to define a synergistic effect beyond the independent associations of its component risk factors for IHD. Perhaps its main utility is as a heuristic guide to considering the underlying physiologic processes and common pathways, since different risk factors stem from obesity, especially abdominal obesity, rather than as a summary risk score or a trigger for pharmacologic therapy.”