Background: Results from previous studies on polyunsaturated fatty acid (PUFA) intake and multiple sclerosis (MS) risk are conflicting.
Objective: To prospectively investigate the association between dietary intake of PUFA and MS risk.
Methods: We followed 80,920 women from Nurses' Health Study (1984-2004) and 94,511 women from Nurses' Health Study II (1991-2009) who reported on diet using a validated food frequency questionnaire every 4 years and identified 479 incident MS cases during follow-up. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), for the effect of PUFA intake on MS risk adjusting for age, latitude of residence at age 15, ancestry, cigarette smoking, supplemental vitamin D intake, body mass index, and total energy intake.
Results: Higher intake of total PUFA at baseline was associated with a lower risk of MS (HR top vs bottom quintile: 0.67, 95% CI: 0.49-0.90, p trend = 0.01). Among the specific types of PUFA, only α-linolenic acid (ALA) was inversely associated with MS risk (HR top vs bottom quintile: 0.61, 95% CI: 0.45-0.83, p trend = 0.001). The long-chain fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were not associated with MS risk.
Conclusion: Low dietary PUFA intake may be another modifiable risk factor for MS.
Keywords: Multiple sclerosis; alpha-linolenic acid; epidemiology; polyunsaturated fatty acids; risk factors.