High blood pressure and heart disease are linked to greater loss of brain mass, or atrophy in white matter and whole brain volume, in people with multiple sclerosis (MS), a study following patients for five years shows.
No association between cardiovascular disease and an increased number of brain lesions was found. Still, better management of these conditions may improve outcomes for MS patients in the long-term, its researchers say.
The study, “Hypertension and heart disease are associated with development of brain atrophy in multiple sclerosis: a 5-year longitudinal study,” was published in the journal European Journal of Neurology.
MS patients are more prone to develop cardiovascular problems, including high blood pressure or hypertension, than the public at large. These conditions, in turn, are increasingly being associated with worse disease outcomes. Some studies suggested that MS patients with cardiovascular problems also show more extensive brain lesions and lower brain volumes.
Up to now, however, studies have not been able to draw clear conclusions.
A team of researchers at the University at Buffalo, New York, set out to determine the influence of cardiovascular diseases on the clinical outcomes and severity of brain lesions and atrophy in a large sample of MS patients followed for a long-term.
They examined 194 MS patients and 43 controls (without neurological disease); all were enrolled in an early study of the cardiovascular, environmental and genetic (CEG) risk factors in MS.
Patients were followed for a mean period of 5.4 years. Changes in brain lesions and brain volume were measured using magnetic resonance imaging (MRI).
Among the MS group, 14.9% were diagnosed with clinically isolated syndrome (CIS), 59.8% with relapsing-remitting MS (RRMS), and 25.3% with progressive MS (42 patients had secondary progressive MS, and 7 had primary progressive MS).
After controlling for age, sex, and disease duration, hypertension was found to be significantly associated with an accelerated loss of brain mass, seen by the greater volume occupied by the lateral ventricles, the interconnected fluid-filled cavities of the brain, in hypertensive versus non-hypertensive MS patients (24.5% vs. 14.1%).
Patients with heart disease also experienced a larger decline in brain white matter and whole brain volume, compared to patients without heart disease. The reductions in volume were, respectively, of 4.2% vs. 0.7% for white matter, and 3.4% vs 1.6% for whole brain volume.
Smoking and excessive weight (body mass index over 25) combined with heart disease further worsened brain atrophy, reducing brain white matter by 5.3%.
But data showed that the presence of cardiovascular diseases did not contribute to an increase in brain lesions over this follow-up, suggesting that the accelerated brain atrophy did not increase disability during that period.
“This 5-year longitudinal study is one of the first to show that hypertension and heart disease contribute to accelerated central, WB [whole brain], and WM [white matter] atrophy in MS patients. However, during the study period of 5.4 years, the increased accumulation of brain atrophy did not result in disability progression,” the researchers concluded.
“Careful cardiovascular assessment, monitoring, and treatment of MS patients might be warranted and will potentially improve their overall disease outcome” the team suggested.