Modifiable Risk Factors Associated with Diagnosis and Severity of MS

November 2022

A study examined the association of modifiable risk factors, such as smoking, alcohol consumption, and obesity, with the risk of developing multiple sclerosis (MS) and the progression of neurodegeneration. This cross-sectional study included 71,981 individuals aged 40 to 69 years who participated in the United Kingdom Biobank study. A total of 179 had received a diagnosis of MS. Participants underwent optical coherence tomography scans to measure retinal thickness. The thickness of the macular ganglion cell and inner plexiform layer of the retina correlates with brain volume and disability in MS. A thinner layer suggests lower brain volume and neurodegeneration.

The researchers analyzed the frequency of modifiable risk factors in participants with an MS diagnosis compared with participants who were healthy and participants who had other comorbidities. Current or previous smoking, obesity, and a moderate alcohol intake were individually associated with significantly higher odds of having MS using the healthy control group for logistic analysis. When compared with participants with other comorbidities, only current or previous smoking was still associated with significantly higher odds of having MS.

Neurodegeneration was also associated with modifiable behaviors. High alcohol consumption, defined as daily or almost daily intake, was significantly associated with a thinner retinal layer in participants with MS. Smoking status and obesity were not associated with retinal thickness in participants with MS. However, for control participants, current smoking was paradoxically associated with having a thicker retinal layer.

The researchers concluded that smoking was associated with an increased odds of MS diagnosis, which is in agreement with previous studies, and that high alcohol consumption was associated with neurodegeneration. They noted that the findings in this study for an association between high alcohol consumption and a thinner retinal layer in participants with MS are similar to the association between alcohol consumption and brain volume described in previous studies in the general population. Furthermore, high alcohol use was significantly associated with having a thinner retinal layer in healthy controls in this study as well.

In contrast, other studies have suggested that alcohol may reduce disease severity in MS. The researchers cautioned that the tendency of patients with illnesses to reduce alcohol consumption could influence the classification of alcohol consumption in their study and in previous studies. Despite the finding of an association between thinner retinal layers in MS patients and high alcohol consumption, the investigators concluded, “Importantly, the present study does not provide evidence of a health benefit for patients with MS to refrain from alcohol consumption.” Prospective studies are needed to address the question of appropriate alcohol consumption in patients with MS.

Some limitations of the study include the cross-sectional design, the possibility of underestimating or overestimating behaviors on the survey, the lack of information on the quantity or type of alcohol consumed, and the lack of information about disease severity. In addition, the MS group in this study might not be representative of the age range, race, and ethnicity of patients with MS.


Kleerekooper I, Chua S, Foster PJ, et al. Associations of alcohol consumption and smoking with disease risk and neurodegeneration in individuals with multiple sclerosis in the United Kingdom. JAMA Netw Open. 2022;5(3):e220902.

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