Caffeine and alcohol intakes have no association with risk of multiple sclerosis

Background: The association between alcohol and caffeine intakes and risk of multiple sclerosis (MS) is unclear; no prospective studies have examined this relationship. Objective: We examined intakes of alcohol and caffeine in relation to risk of multiple sclerosis. Methods: Intakes of alcohol and caffeine were examined in relation to the risk of MS in two large cohorts of women, the Nurses Health Study (NHS; 92,275 women followed from 1980 to 2004) and Nurses Health Study II (NHS II; 95,051 women followed from 1991 to 2005). Their diet was assessed at baseline and every four years thereafter. During the follow-up, 282 cases of MS were confirmed with onset of symptoms after baseline. Twenty-four cases were missing information on alcohol intake, leaving a total of 258 cases for the alcohol analyses. Results: Neither total alcohol consumption, nor consumption of beer, wine, or liquor was related to MS risk. The multivariable-adjusted pooled relative risk (RR) found by comparing categories of alcohol intake to 0 gm/day was 1.07 (95% CI: 0.32-1.99) for 0.1-4.9 gm/day, 1.01 (0.32-1.99) for 5.0-14.9 gm/day, 1.21 (0.69-2.15) for 15.0-29.9 gm/day, and 0.80 (0.32-1.99) for 30+ gm/day; (p for trend=0.89). Caffeine intake was also not significantly associated with MS risk. The multivariable adjusted pooled RR comparing highest to lowest quintile of caffeine intake was 1.14; 95% CI: 0.79-1.66; p for trend=0.71. Consideration of caffeinated and decaffeinated coffee separately also yielded null results. Conclusion: These results do not support an association between alcohol and caffeine intakes and MS risk.