People who drink large amounts of coffee seem to be less likely to develop multiple sclerosis (MS), according to two new studies that ran for a year.

The first study, from Sweden, included 1,620 MS cases and 2,788 controls. The second study, from the US, enrolled 1,159 MS cases and 1,172 controls. Compared with people who did not drink coffee, MS risk was 30 and 31 per cent lower in those who drank more than 900ml and 948ml of coffee daily during the Swedish and American studies respectively.

People in the Swedish study who drank more than 900ml coffee daily for five or 10 years before the study were 28 and 29 per cent less likely to develop MS than those who never drank coffee. In the American study, drinking more than 948ml of coffee daily for at least five years before the study year was associated with a 36 per cent reduction.

Combining both studies suggested that drinking more than 900ml and 948ml of coffee daily reduced MS risk by 29 per cent. Smoking increases the risk of developing MS.

In never-smokers and ever-smokers, drinking this amount of coffee reduced the risk by 28 per cent and 35 per cent respectively. Coffee contains more than a thousand biologically active chemicals and further studies need to determine those responsible and the mechanisms of action.

^{(Neurol Neurosurg Psychiatry DOI:10.1136/jnnp-2015-312176)}