Metabolic syndrome and risk of stroke incidence in a rural community in Japan

Abstract

Objective　To investigate the relationship between metabolic syndrome (MetS) and stroke incidence in a rural population by a prospective cohort study over 18.6 years.

Methods　From 1996 to 1998, 4,068 subjects (aged 40-74 years) underwent a health checkup in O city, Ehime Prefecture, Japan, and 3,969 subjects were included, excluding those with a history of stroke, to determine whether they had suffered a stroke or died from stroke by the end of December 2018. The subjects were stratified into six groups on the presence of high waist circumference at baseline and the number of risk factors (0, 1, or 2 or more) for high blood pressure, dyslipidemia, and high blood glucose, according to the diagnostic criteria for MetS in Japan. Kaplan-Meier analysis of MetS survival curves and Cox proportional hazards models were used to calculate sex- and age-adjusted hazard ratios and population attributable fractions (PAFs) for total stroke, hemorrhagic stroke, and cerebral infarction.

Results　During the follow-up period, 376 patients were identified as having had a stroke; the percentage of MetS in the stroke group was 15.2% compared to 9.4% in the non-stroke group, a significant difference. The sex- and age-adjusted hazard ratios for total stroke and cerebral infarction were approximately 2-fold higher in the groups with 1 risk and 2 or more risks, regardless of waist circumference, than in the group with normal waist circumference and no risks. PAF to total stroke incidence was highest in the group with normal waist circumference and 1 risk factor (18.9%).

Conclusions　The contribution of MetS to stroke incidence was not significant. Consistent with previous findings, the risk of stroke was increased in non-obese individuals who had at least one risk factor, such as high blood pressure.