Vascular comorbidity in MS and general population--differing trends

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

Ruth Ann Marrie, MD, PhD; John Fisk, PhD; Helen Tremlett, PhD; Christina Wolfson, PhD; Sharon Warren, PhD;
James Blanchard, PhD; Scott B. Patten, MD, PhD; for the CIHR Team in the Epidemiology and Impact of Comorbidity
on Multiple Sclerosis

Departments of Internal Medicine (RAM) and Community Health Sciences (RAM, JB), University of
Manitoba, Winnipeg; Departments of Psychiatry and Medicine (JF), Dalhousie University, Halifax; Department
of Medicine (Neurology) (HT), University of British Columbia, Vancouver; Department of Epidemiology
and Biostatistics and Occupational Health (CW), McGill University, Montreal; Faculty of Rehabilitation
Medicine (SW), University of Alberta, Edmonton; and Department of Community Health Sciences (SBP),
University of Calgary, Canada.

Background:

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

Methods:

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.

Results:

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).

Conclusions:

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