Table 4:
Risk of total dementia and Alzheimer’s Disease for 1-IQR unit of AA1 in 3,564 older US adults free of stroke at baseline
| Hazard Ratio (95% CI) for 1-IQR unit | ||
|---|---|---|
|
| ||
| Years of Follow-up | Dementia (499 new cases) | Alzheimer’s Disease (465 new cases) |
| 5.0 | 0.77 (0.60, 0.98) | 0.83 (0.64, 1.08) |
| 7.5 | 0.68 (0.53, 0.88) | 0.73 (0.57, 0.94) |
| 10.0 | 0.62 (0.47, 0.83) | 0.67 (0.51, 0.88) |
| 12.5 | 0.58 (0.42, 0.80) | 0.62 (0.46, 0.84) |
| 15.0 | 0.55 (0.39, 0.78) | 0.59 (0.42, 0.81) |
| 17.5 | 0.53 (0.36, 0.76) | 0.56 (0.39, 0.79) |
| 20.0 | 0.51 (0.34, 0.75) | 0.54 (0.37, 0.78) |
long-term exposure was assessed by using cumulative average of fatty acid measures, i.e., FA levels in 1992 were related to risk from 1992–98; the average of FA levels in 1992 and 1998, to risk from 1998–2005; and the weighted average of FA levels in 1992, 1998, and 2005, to risk after 2005, with 50% weight assigned to the most recent measurement, and 25% assigned to each previous measurement.
1-interquartile median range (IQR) of circulating AA=4.9%.
Multivariate model included multiplicative interaction term AA as continuous variable with log of time to dementia, sex, race (whites or nonwhite) and enrollment site (4 sites) and time-varying age (years), and age-squared, education (years of education through 12th grade, any education beyond 12th grade), income (<$12 000, $12 000-$24 999, $25 000-$49 999, or >$50 000/year), APOE status (at least one ε−4 vs none), and time-varying information on smoking status (never, current or former smokers), alcohol intake (drinks/week), leisure-time physical activity (kcal/week), vegetable and fruit intake (servings/day).
Abbreviations: IQR interquintile median range; AA, arachidonic acid