Cardiovascular (CV) risk factors have been associated with changes in clinical and MRI outcomes in patients with multiple sclerosis (MS). However, previous studies have not set an age-limit, while older patients may be affected by cerebral small vessel disease-related damage in addition to MS.
To investigate the impact of cardiovascular risk factors on brain atrophy in patients with multiple sclerosis under the age of 50.
One-hundred and twenty-four (79 relapsing-remitting, 45 progressive) MS patients (74 females, age 36 ± 8, range 18 – 50), and 95 age- and sex-matched healthy controls (HC) (47 females, age 35 ± 8, range 18 – 50) underwent brain 3T MRI with pulse sequences for assessing lesions and atrophy, and complete neurological examination. Traditional CV risk factors were assessed: having smoked ≥5 pack-years (py), and presence of hypertension, dyslipidemia, diabetes/prediabetes. More stringent cut-offs were also assessed: having smoked ≥10py, and hypertension, dyslipidemia or diabetes under treatment. Linear models adjusted for age, sex, disease duration, phenotype and treatment were used to determine the impact of CV risk factors on MRI variables.
Nineteen HC and 48 MS patients had one traditional CV risk factor, 4 HC and 15 MS patients had more than one. Ten HC and 30 MS patients had one stringent CV risk factor, 3 and 8 had more than one. Most of our subjects had a smoking history as a CV risk factor (16 HC and 42 MS patients among traditional, 8 HC and 23 MS patients among stringent). In MS patients, the presence of at least two traditional CV risk factors was associated with reduced normalized grey matter volume (NGMV) (p=0.01), white matter volume (NWMV) (p=0.03) and brain volume (NBV) (p=0.003), and not with T2-lesion volume (T2-LV) (p=0.27). Among traditional CV risk factors, only hypertension (n=8) was associated with MRI measures (NWMV and NBV). In MS patients, the presence of one stringent CV risk factor was associated with reduced NGMV (p=0.006), NWMV (p=0.003) and NBV (p<0.001), and higher T2-LV (p=0.03). In HC, no differences were observed according to either traditional or stringent risk factor presence.
The presence of CV risk factors is associated with brain atrophy in MS patients, even under age 50. CV risk factors seem to have synergistic effects, determining brain atrophy even for levels of exposure that may often be overlooked by clinicians, when present in combination.