Figure 2. Multivariable adjusted relationship between total and individual long chain n-3 fatty acids with risk of ALS using restricted cubic splines.

For each fatty acid, the solid lines and shaded region represent the risk estimate and corresponding 95% CI, respectively. The dotted red vertical lines correspond to the 5^th, 25^th, 50^th, 75^th and 95^th percentiles for each fatty acid and plotted lines represent changes in intake relative to the median intake of specified PUFA across studies. To create these estimates, studies were pooled into a single data set and stratified by study, gender, age and year of questionnaire. Each curve is additionally adjusted for smoking status (never, past, current), total vitamin E intake (quartiles), total major carotenoid intake (quartiles), body mass index (<23, 23–25, 25–30, ≥30), physical activity (low, average, high), education level (<high school, high school, >high school) and energy intake.