Table 2.

Sample sizes (N) for a secondary prevention trial enrolling persons with amyloidosis (state 2) with AD dementia (state 7) as the primary endpoint for three age distributions at enrollment. Follow-up durations are T=5 years and T=7 years. The intervention’s effects are θ₂₄=0.50 and θ₂₄ =0.67. P₁ and P₂ are the absolute risks of occurrence of the primary endpoint within T years. Power=0.90 and two sided significance level=.05.

	θ24=0.50						θ24=0.67
	T=5 years			T=7 years			T=5 years			T=7years
AGE	P1	P2	N	P1	P2	N	P1	P2	N	P1	P2	N
Young	0.007	0.004	20727	0.018	0.010	8840	0.007	0.005	54951	0.018	0.013	23906
Uniform	0.014	0.008	10983	0.031	0.018	5633	0.014	0.010	29719	0.031	0.022	15635
Old	0.020	0.011	7898	0.042	0.024	4148	0.020	0.014	21424	0.042	0.031	11563

Age distributions are: young is w(a)=0.25 at ages a= 60, 65, 70 and 75; uniform is w(a)=0.167 at ages 60, 65, 70, 75, 80 and 85; old is w(a)=0.25 at ages 70, 75, 80 and 85. Incomplete follow-up is due only to death. N is the sample size from both groups combined (N/2 per group).