A large, longitudinal US study found that ischaemic stroke risk increased consistently with metabolic syndrome severity even in patients without diabetes, from which they developed an online scoring tool to identify patients at risk.
Doctors can predict patients’ risk for ischaemic stroke based on the severity of their metabolic syndrome, a conglomeration of conditions that includes high blood pressure, abnormal cholesterol levels and excess body fat around the abdomen and waist, a US study finds. The study found that stroke risk increased consistently with metabolic syndrome severity even in patients without diabetes.
Doctors can use this information – and a scoring tool developed by a University of Virginia Health System (UVA) Children’s paediatrician and his collaborator at the University of Florida – to identify patients at risk and help them reduce that risk.
“We had previously shown that the severity of metabolic syndrome was linked to future coronary heart disease and type 2 diabetes,” said UVA’s Dr Mark DeBoer. “This study showed further links to future ischemic strokes.”
DeBoer developed the scoring tool, an online calculator to assess the severity of metabolic syndrome, with Dr Matthew J Gurka, of the department of health outcomes and biomedical informatics at the University of Florida-Gainesville.
To evaluate the association between ischemic stroke and metabolic syndrome, DeBoer and Gurka reviewed more than 13,000 participants in prior studies and their stroke outcomes. Among that group, there were 709 ischemic strokes over a mean period of 18.6 years assessed in the studies. (Ischemic strokes are caused when blood flow to the brain is obstructed by blood clots or clogged arteries. Haemorrhagic strokes, on the other hand, are caused when blood vessels rupture.)
The researchers used their tool to calculate “Z scores” measuring the severity of metabolic syndrome among the study participants. They could then analyse the association between metabolic syndrome and ischemic stroke risk.
The subgroup with the highest association between metabolic syndrome and risk for ischemic stroke was white women, the researchers found. In this group, the research team was able to identify relationships between the individual contributors to metabolic syndrome, such as high blood pressure, and stroke risk.
The researchers note that race and sex did not seem to make a major difference in stroke risk overall, and they caution that the increased risk seen in white women could be the results of chance alone. “Nevertheless,” they write in a new scientific article outlining their findings, “these results are notable enough that they may warrant further study into race and sex differences.”
The overall relationship between metabolic syndrome severity and stroke risk was clear, however. And this suggests people with metabolic syndrome can make lifestyle changes to reduce that risk. Losing weight, exercising more, choosing healthy foods – all can help address metabolic syndrome and its harmful effects.
DeBoer hopes that the tool he and Gurka developed will help doctors guide patients as they seek to reduce their stroke risk and improve their health and well-being.
“In case there are still individuals out there debating whether to start exercising or eating a healthier diet,” DeBoer said, “this study provides another wake-up call to motivate us all toward lifestyle changes.”
Background and Purpose: Ischemic stroke is associated with the metabolic syndrome (MetS) as diagnosed using dichotomous criteria; however, these criteria exhibit racial/ethnic discrepancies. Our goal was to assess whether ischemic stroke risk extended over the spectrum of worsening MetS severity using a sex- and race/ethnicity-specific MetS-severity Z score.
Methods: We used Cox-proportional hazards models to assess the relationship between baseline MetS-Z score and incident ischemic stroke among participants of the Atherosclerosis Risk in Communities study and Jackson Heart Study who were free from diabetes, coronary heart disease or stroke at baseline, evaluating 13 141 white and black individuals with mean follow-up of 18.6 years.
Results: We found that risk of ischemic stroke increased consistently with MetS severity, with a hazard ratio of 1.75 (95% CI, 1.35–2.27) for those >75th percentile compared to those <25th percentile. This risk was highest for white females (hazard ratio, 2.63 [CI, 1.70–4.07]) though without significant interaction by sex and race. Relationships between stroke and all the individual components of MetS were only noted for white females, though again without sex-race interactions. Hazard ratio’s for systolic blood pressure and stroke were significant among all sex/racial subgroups.
Conclusions: Ischemic stroke risk increased over the spectrum of MetS severity in the absence of baseline diabetes mellitus, further implicating potential etiologic risks from processes underlying MetS. Individuals with elevated MetS severity should be counselled toward lifestyle modification to lower ischemic stroke risk.
Mark D DeBoer, Stephanie L Filipp, Mario Sims, Solomon K Musani, Matthew J Gurka
University of Virginia Health System material
Tool (available for free)