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CHD risk higher in obesity without metabolic syndrome
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Patients who are overweight or obese with healthy cholesterol levels and BPs have a higher risk for CHD compared with those at a healthy weight, according to a case-cohort analysis published in the European Heart Journal.
“Our findings suggest that if a patient is overweight or obese, all efforts should be made to help them get back to a healthy weight, regardless of other factors,” Camille Lassale, PhD, of the department of epidemiology and public health at University College London, said in a press release. “Even if their blood pressure, blood sugar and cholesterol appear within the normal range, excess weight is still a risk factor.”
Researchers analyzed data from the EPIC study, specifically 7,637 participants with incident CHD that occurred during a mean follow-up of 12.2 years compared with a control group of 10,474 subcohort participants (mean age, 54 years; 63% women; mean BMI, 26.1 kg/m2) without a history of MI or stroke at baseline.
WHO guidelines were used to define participants who were obese (BMI 30 kg/m2), overweight (25 kg/m2 to < 30 kg/m2) and normal weight (18.5 kg/m2 to < 25 kg/m2). Participants were defined as unhealthy or having metabolic syndrome if they had three or more metabolic abnormalities: hypertriglyceridemia, elevated BP, low HDL, elevated waist circumference or hyperglycemia.
Metabolic syndrome was strongly positively associated with the risk for CHD in participants who were unhealthy normal weight (HR = 2.15; 95% CI, 1.79-2.57), unhealthy overweight (HR = 2.33; 95% CI, 1.97-2.76) and unhealthy obese (HR = 2.54; 95% CI, 2.21-2.92) compared with participants who were healthy and of normal weight.
The risk for CHD was higher in participants who were healthy overweight (HR = 1.26; 95% CI, 1.14-1.4) and obese (HR = 1.28; 95% CI, 1.03-1.58) vs. those without metabolic syndrome of normal weight.
Results from various sensitivity analyses — only participants with complete data, the exclusion of the first 2 years of follow-up and elimination of waist circumference from metabolic syndrome criteria — were consistent with the main findings, according to the researchers.
“[These results are] of particular importance as overweight people (BMI 25 and < 30) with no traditional cardiometabolic risk factors are not recommended for weight-loss treatment by recent U.K. or U.S. guidelines,” Lassale and colleagues wrote. “The risk of CHD in metabolically healthy overweight or obese individuals was significantly lower than in the ‘metabolically unhealthy’ groups, suggesting that obese and overweight individuals without metabolic abnormalities are at intermediate cardiovascular risk between metabolically healthy normal-weight individuals and metabolically unhealthy individuals.” – by Darlene Dobkowski
Disclosures: The authors report no relevant financial disclosures.
Perspective
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Rishi Puri, MBBS, PhD, FRACP
This is an important analysis that hopefully once and for all dispels the notion of obesity being a benign condition when parameters like cholesterol, sugar levels and BP are within the normal range. It is a key study harboring the largest number of incident CV events (> 7,600) over a fairly lengthy follow-up period (more than 12 years) to show fairly convincingly that being overweight and obese each portends an adverse prognosis from a CV perspective, regardless of BP, glucose and lipid levels.
Importantly, these investigators also defined obesity according to waist circumference.
There are important implications for clinical practice, especially given weight loss is seldom systematically recommended in guidelines for overweight people with BMIs between 25 kg/m2 and 29 kg/m2. These findings tell us that we need to emphasize weight control and weight reduction strategies much before patients reach the threshold for being defined as “obese.”
In the past, there has been somewhat of a fascination by some of the concepts of being obese, yet potentially metabolically “healthy” (ie, normal BP, lipids and glucose levels). I was never convinced that this necessarily represented good or even “smart” science, given the limitations in the design of many of these prior studies and short-sighted nature of the “metabolically healthy obesity” hypothesis, and the current and ongoing global obesity epidemic that we face.
We need to remember that being overweight adversely effects almost every organ system, not just the CV system. I’m glad there are researchers undertaking the right type of studies to dispel the myth of “healthy obesity,” thus enabling us to focus on areas where we can curb population weight gain and more effectively tackle significant and sustained weight loss in obese persons.
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