Polyunsaturated fatty acids and the risk of multiple sclerosis

Multiple Sclerosis Journal
Q1
Feb 2017
Citations:81
Influential Citations:1
Observational Studies (Human)
81
S2 IconPDF Icon

Enhanced Details

Methods
Two prospective cohorts of US female nurses (NHS and NHSII). NHS began in 1976 with 121,700 women aged 30-50; NHSII began in 1989 with 116,671 women aged 25-42. Baseline dietary PUFA intake was assessed by validated semi-quantitative FFQs (1984 for NHS, 1991 for NHSII). Exclusions: incomplete baseline FFQs, implausible caloric intakes, or MS diagnosed before baseline. Final analytic samples: 80,920 NHS and 94,511 NHSII. MS cases identified by self-report and confirmed by treating neurologist; follow-up through 1 June 2004 (NHS) and 1 June 2009 (NHSII). PUFA-MSU risk associations were estimated with Cox proportional hazards models, with multivariable adjustments for age, latitude at age 15, ancestry, smoking, vitamin D supplementation, BMI at age 18, and total energy intake; analyses were conducted separately in each cohort and pooled with fixed effects.
Results
Higher total PUFA intake at baseline was associated with lower MS risk (top vs bottom quintile HR 0.67, 95% CI 0.49-0.90; p for trend 0.01). Among PUFA types, plant-derived alpha-linolenic acid (ALA) showed a significant inverse association (top vs bottom quintile HR 0.65, 95% CI 0.45-0.93; p for trend 0.02); linoleic acid (LA) had an inverse association in age- and energy-adjusted analyses but was not significant after adjusting for ALA (HR 0.91, 95% CI 0.63-1.30; p for trend 0.75). EPA and DHA were not associated with MS risk. In isocaloric substitution models, replacing 0.5% of energy from carbohydrates with ALA reduced MS risk (HR 0.60, 95% CI 0.36-0.99); replacing 0.5% of energy from other fats with ALA reduced risk (HR 0.65, 95% CI 0.44-0.97). Overall, low PUFA intake may be a modifiable MS risk factor, with the association driven by plant-derived ALA rather than marine n-3 fatty acids.
Limitations
Dietary assessment based on self-reported FFQs with measurement error and modest correlation with true PUFA intake; study populations comprised US female nurses, predominantly white, limiting generalizability; possible residual confounding cannot be ruled out.

Abstract

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 fo...