High alcohol use was associated with more severe neurodegeneration and smoking was linked with greater probability of MS diagnosis, according to a U.K. study published in JAMA Network Open.

“Both genetic and environmental factors are known to play important roles in the pathophysiology of MS,” Iris Kleerekooper, PhD, of Queen Square MS Centre and the department of neuroinflammation at University College London Institute of Neurology, and colleagues wrote. “Understanding the role of modifiable risk factors, such as smoking, alcohol intake and obesity, is important to guide clinical counseling.”

Kleerekooper and colleagues investigated these risk factors by analyzing data from of 71,981 individuals, aged 40 to 69 years, from the community-based UK Biobank study on health behaviors and retinal thickness. Of those, 20,065 were healthy controls, 51,737 had comorbidities and 179 had MS.

Participants completed a questionnaire on health-related behaviors, demographics and socioeconomic data, and researchers used multivariable generalized estimating equations to determine whether alcohol use and smoking were linked with macular ganglion cell layer and inner plexiform layer (mGCIPL) thickness. They also examined whether those correlations differed for MS patients.

Results demonstrated that smoking, moderate alcohol consumption and obesity were significantly associated with MS case status compared with healthy control individuals. High alcohol intake was associated with a thinner mGCIPL in MS patients (P = .02). In the alcohol interaction model, researchers found that high alcohol intake was associated with thinner mGCIPL in control individuals (P < .001); however, there was no statistically significant association in individuals with MS. Data also revealed that smoking was not associated with mGCIPL thickness in MS patients but was associated with increased mGCIPL thickness in the control group (P < .001).

“The presented findings suggest that current recommendations for the general population regarding smoking and moderating alcohol consumption may be particularly relevant for individuals who have been diagnosed with MS or who are at risk for the disease,” Kleerekooper and colleagues wrote.