High coffee consumption decreases the odds of developing multiple sclerosis (MS), according to two case–control studies published online ahead of print March 3 in the Journal of Neurology, Neurosurgery & Psychiatry. Anna K. Hedström, MD, PhD, a postdoctoral researcher at the Karolinska Institute, Stockholm, and her associates conducted the studies.
The investigators analyzed coffee consumption among 1,620 adults with MS and 2,788 healthy controls in the Swedish Epidemiological Investigation of Multiple Sclerosis (EIMS). They also examined coffee consumption in 1,159 adults with MS and 1,172 healthy controls in the Kaiser Permanente Medical Care Plan, Northern California Region (KPNC).
In EIMS, the adjusted odds ratio (OR) for developing MS was 0.70 among participants who drank more than six cups of coffee (ie, greater than 900 mL) daily at the index year, which was defined as the year of the initial appearance of symptoms indicative of MS. The corresponding ORs for those who reported high coffee consumption at five or 10 years before the study were 0.72 and 0.71, respectively, but these results were not statistically significant.
In KPNC, those who consumed four or more cups of coffee (ie, more than 948 mL) daily were significantly less likely to develop MS than were those who never drank coffee (OR, 0.69). In addition, people who drank four or more cups of coffee daily at least five years prior to the index year had significantly reduced odds of MS (OR, 0.64).
A meta-analysis of the combined results of the two studies indicated a significant 29% reduction in the likelihood of developing MS among the people with the greatest coffee consumption (ie, greater than 900 mL daily in EIMS and greater than 948 mL in KPNC). The investigators adjusted all the analyses for many demographic and environmental risk factors for MS, including age, gender, residential area, ancestry, smoking habits, exposure to passive smoking, sun exposure habits, and BMI at age 20.
No evidence indicated any associations between increased amounts of tea or soda intake and MS.
“Further studies are required to establish if it is in fact caffeine, or if there is another molecule in coffee underlying the findings, to longitudinally assess the association between consumption of coffee and disease activity in MS, and to evaluate the mechanisms by which coffee may be acting, which could thus lead to new therapeutic targets,” the researchers concluded.
—Lori Laubach