Table 1.
Pooleda Relative Risk of Suicide Mortality According to Quartile of n-3 Polyunsaturated Fatty Acid Intake for Participants in the Nurses' Health Study (1986–2008), Nurses' Health Study II (1993–2007), and the Health Professionals Follow-up Study (1986–2008)
| n-3 PUFA Type and Quartile of Intake | No. of Cases | Person-Years of Follow-up | Age-Adjustedb |
Multivariable Model 1c |
Multivariable Model 2d |
|||
|---|---|---|---|---|---|---|---|---|
| RR | 95% CI | RR | 95% CI | RR | 95% CI | |||
| ALA | ||||||||
| Quartile 1 | 86 | 880,502 | 1 | Reference | 1 | Reference | 1 | Reference |
| Quartile 2 | 50 | 880,371 | 0.59 | 0.41, 0.84 | 0.69 | 0.48, 0.98 | 0.69 | 0.48, 0.99 |
| Quartile 3 | 78 | 873,483 | 0.91 | 0.66, 1.24 | 1.06 | 0.77, 1.45 | 1.12 | 0.80, 1.57 |
| Quartile 4 | 73 | 877,412 | 0.83 | 0.60, 1.13 | 0.98 | 0.70, 1.35 | 1.10 | 0.76, 1.59 |
| P for trend | 0.77 | 0.54 | 0.21 | |||||
| Per incremente | 0.88 | 0.69, 1.13 | 0.99 | 0.78, 1.25 | 1.08 | 0.82, 1.43 | ||
| EPA + DHA | ||||||||
| Quartile 1 | 69 | 876,241 | 1 | Reference | 1 | Reference | 1 | Reference |
| Quartile 2 | 54 | 885,584 | 0.76 | 0.53, 1.08 | 0.83 | 0.58, 1.19 | 0.81 | 0.56, 1.17 |
| Quartile 3 | 84 | 869,215 | 1.21 | 0.88, 1.67 | 1.32 | 0.95, 1.84 | 1.27 | 0.91, 1.77 |
| Quartile 4 | 80 | 880,728 | 1.10 | 0.79, 1.53 | 1.14 | 0.81, 1.60 | 1.08 | 0.76, 1.54 |
| P for trend | 0.33 | 0.31 | 0.52 | |||||
| Per incremente | 1.21 | 1.05, 1.39 | 1.15 | 0.99, 1.33 | 1.12 | 0.95, 1.30 | ||
| Total n-3 PUFAsf | ||||||||
| Quartile 1 | 70 | 875,589 | 1 | Reference | 1 | Reference | 1 | Reference |
| Quartile 2 | 75 | 877,506 | 1.03 | 0.74, 1.43 | 1.22 | 0.87, 1.70 | 1.32 | 0.94, 1.86 |
| Quartile 3 | 69 | 882,400 | 0.95 | 0.68, 1.34 | 1.14 | 0.81, 1.60 | 1.31 | 0.91, 1.88 |
| Quartile 4 | 73 | 876,272 | 0.99 | 0.71, 1.38 | 1.15 | 0.82, 1.62 | 1.46 | 0.98, 2.16 |
| P for trend | 0.78 | 0.62 | 0.11 | |||||
| Per incremente | 1.01 | 0.74, 1.39 | 1.11 | 0.83, 1.50 | 1.43 | 1.01, 2.02 | ||
Abbreviations: ALA, α-linolenic acid; CI, confidence interval; DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; PUFA, polyunsaturated fatty acid; RR, relative risk.
a Results from the 3 cohort-specific regression models were combined using random-effects meta-analysis (for cohort-specific estimates, see Web Table 2).
b Adjusted for age (years; continuous variable) and time interval.
c Further adjusted for smoking status (never smoker, former smoker, current smoker of 1–14 cigarettes/day, current smoker of 15–24 cigarettes/day, or current smoker of ≥25 cigarettes/day), body mass index (weight (kg)/height (m)2; <25, 25–29.9, or ≥30), alcohol consumption (g/day), marital status (married/partnered, widowed, or separated/divorced/single), physical activity (metabolic equivalents/week, in quintiles), and consumption of caffeinated coffee (cups/day). For women, the multivariable regression model further adjusted for menopausal status and use of hormone replacement therapy (postmenopausal with or without hormone replacement therapy, premenopausal, or never use of hormone replacement therapy).
d Further adjusted for cumulative average intake of energy (kcal/day), trans fatty acids (g/day), saturated fatty acids (g/day), and monounsaturated fatty acids (g/day) (all continuous variables). For ALA, multivariable model 2 further adjusted for EPA + DHA and total n-6 PUFAs (all continuous). For EPA + DHA, multivariable model 2 further adjusted for ALA and total n-6 PUFAs (both continuous). For total n-3 PUFAs, multivariable model 2 further adjusted for total n-6 PUFAs (continuous).
e The per-increment scale was 1 g/day for ALA, 0.3 g/day for EPA + DHA, and 1 g/day for total n-3 PUFAs.
f Total n-3 PUFAs = ALA + EPA + DHA.