Table 2. Results of Multivariate Stepwise Linear Regression of Associations of Measured Factors With Intergenerational Difference in AAO of Alzheimer Disease.
| Factor | β (95% CI) | P Value |
|---|---|---|
| Intercept | 8.38 (−2.02 to 18.78) | .11 |
| Forced entry | ||
| Female | −1.13 (−4.11 to 1.86) | .46 |
| Education, mean (SD), y | −0.58 (−1.08 to −0.09) | .02 |
| Selected factors | ||
| Father affected | −9.52 (−13.79 to −5.25) | <.001 |
| Mother affected | −6.68 (−11.61 to −1.75) | .01 |
| Parent with early-onset dementia | 21.30 (15.01 to 27.59) | <.001 |
| History of hypertension | 3.81 (0.88 to 6.74) | .01 |
| APOE ε4/2 or ε4/3 | 5.00 (2.11 to 7.88) | .001 |
| Symptomatic at study entry (retrospective determination of AAO) | −3.46 (−6.40 to −0.52) | .02 |
| Excluded factors | ||
| Active depression within 2 y | −0.12 (NA) | .07 |
| History of cardiovascular disease | 0.10 (NA) | .15 |
| History of tobacco use, >30 pack-yearsa | 0.10 (NA) | .15 |
| History of hypercholesterolemia | −0.11 (NA) | .15 |
| Body mass index | −0.06 (NA) | .35 |
| History of diabetes | −0.06 (NA) | .37 |
| African American race | −0.05 (NA) | .45 |
| APOE ε4/4 | −0.04 (NA) | .60 |
| History of unhealthy alcohol use | −0.02 (NA) | .74 |
| History of traumatic brain injury | −0.01 (NA) | .91 |
Abbreviations: AAO, age at symptomatic onset; NA, not applicable.
a
Calculated as packs of cigarettes used per day × number of years of use.