Table 6.

Theoretical effects of selected variables on event-free years of life (n = 1490).

Variable	Alzheimer’s Disease		All-Cause Dementia
	Hazard Ratio	Scaled β	Hazard Ratio	Scaled β
Age, 1 year	1.16	1.00	1.15	1.00
APOE-ε4 carriership, yes	3.12	−7.59	2.78	−7.30
RBC DHA, Q5 to Q1	2.01	−4.65	1.76	−4.03

HR = hazard ratio; RBC DHA = red blood cell docosahexaenoic acid; Q = quintile. Data based on age-adjusted models. Scaled β can be interpreted as the equivalent years of life free of AD and all-cause dementia associated with each variable and is estimated by taking the beta (ln HR) for each variable divided by the beta for age. Therefore, changing from RBC DHA from Q5 to Q1 would be associated with an estimated reduction of 4.65 years free of AD and 4.03 years free of dementia. Carrying an APOE-ε4 allele would be associated with an estimated reduction of 7.59 and 7.30 years free of AD and all-cause dementia, respectively.