MEDSCAPE... Drinking coffee may reduce the risk for multiple sclerosis (MS), according to new data from two large population-based studies, one from Sweden and one from the United States.
"Caffeine intake has been associated with a reduced risk of Parkinson's and Alzheimer's diseases, and our study shows that coffee intake may also protect against MS, supporting the idea that the drug may have protective effects for the brain," study author Ellen Mowry, MD, from Johns Hopkins University School of Medicine in Baltimore, Maryland, noted in a statement.
The findings will be presented at the upcoming American Academy of Neurology (AAN) 67th Annual Meeting in April.
Independently Verified
The Swedish cohort included 1629 people with MS and 2807 healthy people, and the US cohort (from Kaiser Permanente Northern California) included 1159 people with MS and 1172 healthy people.
The researchers analyzed coffee consumption in people with MS 1 and 5 years before the onset of symptoms and 10 years before symptom onset in the Swedish cohort. They also analyzed the coffee consumption in people without MS at similar time periods. They adjusted for several factors, including age, sex, smoking history, body mass index, and sun exposure habits.
In the Swedish cohort, consuming at least 6 cups of coffee daily during the index year was associated with a lower adjusted odds ratio (OR) for MS (OR, 0.67; 95% confidence interval [CI], 0.47 - 0.95).
Drinking this amount of coffee daily for 5 or 10 years was similarly protective (OR, 0.70 [95% CI, 0.50 - 0.99]; OR, 0.72 [95% CI, 0.48 - 1.06], respectively).
In the US cohort, people who consumed four or more cups of coffee daily before the index year also had a similarly reduced likelihood of MS (OR, 0.67; 95% CI, 0.47 - 0.95).
"A strength of this study is that the finding was independently verified in two different populations of people (Sweden and US studies), and the magnitude of the association was similar in the two studies," Dr Mowry told Medscape Medical News.
The mechanism is unclear, and Dr Mowry said it would be "speculative to pinpoint one mechanism. Interestingly, caffeine has been shown to impact the function of specific immune cells within the brain called microglia. However, impacts on other aspects of the immune and/or nervous systems are plausible as well."
Experts Weigh In
Commenting on the findings, Lily Jung Hensen, MD, a neurologist at Swedish Neurosciences Institute, Seattle, Washington, said, "The number of cases reviewed, and the consistency of the odds ratio for the two populations certainly seems supportive…of coffee being protective against MS, particularly with what we have seen in Parkinson's disease and Alzheimer's disease."
"That said, we obviously also need to have a better understanding of the potential health risks of drinking this much coffee. If in fact we can prove that there is benefit, perhaps some therapeutic derivative could be determined that would offer neuroprotection without the side effects of such high coffee consumption," she said.
Marie B. D'hooghe, MD, from the National Multiple Sclerosis Center, Melsbroek, Belgium, called the data "intriguing" and said she is "looking forward to reading the full paper."
"We always need to be cautious," she added. "Bias and errors cannot be excluded. The participating research groups certainly have a solid reputation."
The new findings support a recent study by Dr D'hooghe and colleagues, which found that higher coffee consumption (as well as regular intake of fish and alcohol) may delay disease progression in patients with relapsing-onset MS, as reported by Medscape Medical News.
The study was supported by the Swedish Medical Research Council; the Swedish Research Council for Health, Working Life and Welfare; the Knut and Alice Wallenberg, AFA, and Swedish Brain Foundations; the Swedish Association for Persons with Neurological Disabilities; the US National Institute of Neurological Disorders and Stroke; the National Institute of Environmental Health Sciences; and the National Institute on Aging. The authors have disclosed no relevant financial relationships.
To be presented at the 67th American Academy of Neurology (AAN) Annual Meeting, April 18-25, 2015.