Cardiovascular risk rises with increasing adiposity, a new study found.
In a cohort of European adults, those who fell within the “normal” range of body mass index (BMI) — 22 to 23 — had the lowest risk for cardiovascular disease (CVD), according to Stamatina Iliodromiti, MD, of the University of Glasgow, and colleagues.
The study, online in the European Heart Journal, showed that among both men and women, as adiposity increased, so did the associated risk for CVD.
“We felt that the studies to date were contradictory,” Iliodromiti told MedPage Today. “Obesity has taken epidemic dimensions and CVD is the number 1 disease in the world, so we needed a definite answer about how these are associated. By having access to the U.K. biobank — a fantastic resource of a well-phenotyped, large cohort — we could assess fully how BMI is associated with the risk of heart disease and stroke, as there is a large number of participants in each BMI group.
“At the same time, we could assess how other adiposity measures, such as full body fat or fat around the abdomen, which have not been tested before in large studies, are associated with CVD,” she added.
The analysis included 296,535 white individuals who were free of CVD at baseline, followed for an average of 5 years. During this period, 3.3% of women and 5.7% of men had or developed a cardiovascular event, which were identified through hospital and death registries.
For adults with a BMI over 22, each standard deviation increase in BMI — 4.3 for men and 5.2 for women — was associated with a 13% increase in CVD risk (HR 1.13, 95% CI 1.10-1.17).
Having a very low BMI (18.5 or lower) was also tied to a higher incidence of CVD, although the risk was attenuated after adjusted for smoking status and the presence of comorbid conditions.
Several other measures of adiposity also reported similar findings for this increased CVD risk. These included a higher risk associated with one standard deviation increase in waist circumference — five inches (12.6 cm) for women (HR 1.16, 1.13-1.19) and 4.5 inches (11.4 cm) for men (HR 1.10, 1.08-1.13). Similarly, every 6.9% and 5.8% increase in body fat mass percentage for women and men, respectively, was tied to an increased CVD risk (HR 1.12, 1.09-1.15 [women]; 1.06, 1.03-1.09 [men]).
Increases in waist-to-hip and waist-to-height ratios for men and women were also tied to a steady increase in the risk for CVD events.
Interestingly, adjustment for moderate to vigorous physical activity was not protective of CVD risk in individuals with greater adiposity.
“We were not entirely surprised, as we perceived that the protective effect of fat did not make sense, and we indeed showed that in healthy individuals, when we excluded smokers and people with preexisting disease, the protective effect of fat disappeared,” said Iliodromiti.
A potential limitation to the study was the lack of lipid values to adjust for, the researchers noted.
Ultimately, they suggested that measures of central adiposity may be a helpful complement to BMI measures to stratify CVD risk, although the team also acknowledged that BMI is “more easily reproducible.”
Regarding future research, Iliodromiti said the group’s current plans are to look at potential factors that may mediate the increased cardiovascular risk.
The study was funded by the British Heart Foundation, the European Federation of Pharmaceutical Industries Associations, the Innovative Medicines Initiative Joint Undertaking, the European Medical Information Framework, and the Medical Research Council Skills Development Fellowship.
None of the authors reported any conflicts of interest.
Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco