CRP Can Identify Low CV Risk in Metabolically ‘Healthy’ Obese Patients
The old adage about not judging a book by its cover appears to be true, at least to some extent, in the case of obese patients with a favorable metabolic profile. Despite their excess body fat, the cardiovascular risk of these patients appears to be quite low, a population study suggests.
In a paper published online June 3, 2016 ahead of print in the Journal of the American Heart Association, researchers led by Diederik F. van Wijk, MD, PhD (Academic Medical Center, Amsterdam, the Netherlands), found that obese people with no evidence of metabolic syndrome—who they termed ‘metabolically healthy’—had C-reactive protein (CRP) levels that were similar to those of metabolically healthy people who were not obese.
van Wijk and colleagues say their data suggest that the inflammatory marker “could help identify those metabolically healthy obese persons who are at low CHD risk.”
Strong CRP Correlations Found
For the European Prospective Investigation of Cancer-Norfolk (EPIC-Norfolk) study, the researchers assessed CRP levels among 3,682 metabolically healthy and 3,597 metabolically unhealthy men and women between the ages of 39 and 79 years old living in the United Kingdom. Participants, who were followed for nearly 11 years, were considered metabolically healthy if they had one or fewer criteria of metabolic syndrome.
For all participants, CRP levels increased with increasing number of metabolic syndrome criteria, and were higher in those with vs without abdominal obesity.
Over the follow up period, 11% of people developed CHD. The risk was higher in those who were obese and metabolically unhealthy versus obese and metabolically healthy (HR 1.88; 95% CI 1.20-2.94). Similarly, comparison of metabolically healthy obese persons with CRP levels < 2 mg/L and metabolically healthy nonobese persons with similar levels showed no increased risk of CHD (HR 0.91; 95% CI 0.60-1.39). Subgroup analyses to investigate interaction by sex indicated no differences in these findings between men and women.
According to van Wijk and colleagues, the findings suggest “that CRP adds prognostic information for the obese population, although the presence or absence of cardiometabolic risk factors may influence the predictive value of CRP in abdominally obese persons.”
Jennifer L. Kuk, PhD (York University, Toronto, Canada), who commented on the study for TCTMD, said that while looking at CRP is helpful since it is thought to be an indicator of early disease, one problem with using it as a detection tool is that it is very nonspecific and the causes of elevated CRP are not always evident.
Still, the CRP information gleaned by the study may be useful in future studies, she added, to assess how obese people with elevated levels respond to various interventions such as weight loss, dietary changes, and statins.
Looking Past the Weight
Kuk said the “big question” in all of this is why some obese people develop metabolic abnormalities while others do not. Lifestyle factors such as diet and exercise despite being overweight may play a role, she noted, as could genetics.
“We still don’t understand the genetics and even if we found that it was genetic then it’s kind of a ‘Debbie Downer’ story: you’re doomed to it and therefore there’s really nothing you can do,” Kuk said.
She maintained that the main take-aways of the current study for physicians should be to shift their focus from body weight to overall health, and to stop making assumptions about future health risks.
“What we’re realizing is you can’t just look at someone’s body weight and say whether or not they are healthy or unhealthy. There are certainly variations in terms of what the health profile looks like and what the future health profile looks like for people with obesity,” Kuk said. “People should stop judging each other based on their body weight and look to whether they are living the healthiest life that they can while still enjoying a reasonable quality of life.”
- EPIC-Norfolk is supported by program grants from the Medical Research Council UK and Cancer Research UK.
- Van Wijk and Kuk report no relevant conflicts of interest.
van Wijk DF, Boekholdt SM, Arsenault BJ, et al. C-reactive protein identifies low-risk metabolically healthy obese persons: the European prospective investigation of Cancer–Norfolk prospective population study. J Am Heart Assoc. 2016;Epub ahead of print.