Table 3.

Multivariable-adjusted Relative Risks^* of ALS according to quintile of intake of individual fatty acids

	Quintile 1 (ref)	Quintile 2	Quintile 3	Quintile 4	Quintile 5	P trend§	P het¥
Linoleic acid (18:2n-6; median, grams)	8.00	10.16	11.68	13.32	16.21
No. of cases	228	190	203	186	187
Age adjusted RR* (95% CI)†	1.00	0.83 (0.64–1.07)	0.87 (0.67–1.14)	0.84 (0.69–1.02)	0.82 (0.65–1.04)	0.09	0.18
Multivariable adjusted RR (95% CI)‡	1.00	0.85 (0.62–1.10)	0.90 (0.69–1.17)	0.84 (0.67–1.05)	0.83 (0.66–1.05)	0.10	0.18
Arachidonic acid (20:4n-6; median, grams)	0.07	0.08	0.10	0.13	0.18
No. of cases	229	225	194	173	175
Age adjusted RR* (95% CI) †	1.00	0.99 (0.81–1.21)	0.87 (0.66–1.16)	0.73 (0.51–1.03)	0.80 (0.61–1.04)	0.01	0.16
Multivariable adjusted RR (95% CI)‡	1.00	1.00 (0.81–1.23)	0.90 (0.67–1.20)	0.76 (0.52–1.09)	0.86 (0.64–1.12)	0.07	0.12
α-Linolenic acid (18:3n-3; median, grams)	0.82	1.06	1.27	1.50	1.93
No. of cases	235	202	211	184	162
Age adjusted RR* (95% CI)†	1.00	0.85 (0.67–1.08)	0.89 (0.71–1.12)	0.76 (0.58–1.00)	0.70 (0.57–0.86)	0.001	0.28
Multivariable adjusted RR (95% CI)‡	1.00	0.88 (0.70–1.11)	0.93 (0.74–1.17)	0.79 (0.61–1.04)	0.73 (0.59–0.89)	0.003	0.34
Marine n-3 (median, grams)	0.04	0.07	0.11	0.17	0.30
No. of cases	195	218	224	193	164
Age adjusted RR* (95% CI)†	1.00	1.15 (0.94–1.39)	1.15 (0.95–1.40)	1.03 (0.81–1.30)	0.82 (0.63–1.08)	0.04	0.18
Multivariable adjusted RR (95% CI)‡	1.00	1.16 (0.96–1.41)	1.16 (0.95–1.41)	1.04 (0.82–1.31)	0.84 (0.65–1.08)	0.03	0.28

^‡Adjusted for age (years), sex, 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 (quintiles).

^*RR: relative risk, CI, confidence interval

^§P_trend calculated using median value for each quintile

^¥P_{heterogeneity} is calculated form the Q-statistic and is used to quantify differences between studies