Differing trends in the incidence of vascular comorbidity in MS and the general population

Although the adverse effects of vascular comorbidities are increasingly recognized in multiple sclerosis (MS), the epidemiology of these conditions remains poorly understood.

Using population-based administrative data, we identified 44,452 Canadians with MS and 220,849 age-, sex- and geographically matched controls. We applied validated definitions to estimate the incidence of diabetes, hypertension, hyperlipidemia, and ischemic heart disease (IHD) from 1995 to 2005.

Of the MS cases, 31,757 (71.4%) were in female participants, with a mean (SD) age at the index date of 43.8 (13.7) years. Over time, the age-standardized incidence of diabetes rose more in the MS population (incidence rate ratio [IRR] per year 1.06; 95% confidence interval [CI] 1.03-1.08) than in the matched population (IRR per year 1.02; 95% CI 1.01-1.03). Temporal trends in the age-standardized incidence of hyperlipidemia, hypertension, and IHD were similar in both populations. Among those aged 20-44 years, the incidence of IHD was higher in the MS population (IRR 1.59; 95% CI 1.19-2.11). The increased incidence of IHD in the MS population was attenuated among those aged 60 years and older (IRR 1.01; 95% CI 0.97-1.06).

The incidence rates of diabetes, hypertension, and hyperlipidemia are rising within the MS population. Programs to systematically prevent and treat these conditions are needed.