Table 4. Worldwide PAFs for dementia risk factors.

	RR for dementia (95% CI)	Risk factor prevalence	Communality	PAF	Weighted PAF*
Early life (<45 years)
Low education	1.6 (1.3–2.0)	40.0%	64%	19.1% (18.3–19.9)	7.5% (7.0–8.0)
Midlife (45–64 years)
Hypertension	1.6 (1.2–2.2)	8.9%	57%	5.1% (2.9–3.6)	2.0% (0.6–0.9)
Obesity	1.6 (1.3–1.9)	3.4%	60%	2.0% (1.7–2.3)	0.8% (2.9–3.6)
Hearing loss	1.9 (1.4–2.7)	31.7%	46%	23.0% (22.2–23.8)	9.1% (8.6–9.7)
Later life (≥65 years)
Smoking	1.6 (1.2–2.2)	27.4%	51%	13.9% (13.2–14.6)	5.5% (4.1–6.0)
Depression	1.9 (1.6–2.3)	13.2%	59%	10.1% (9.5–10.7)	4.0% (3.6–4.4)
Physical inactivity	1.4 (1.2–1.7)	17.7%	27%	6.5% (6.0–7.0)	2.6% (2.3–2.9)
Low social contact	1.6 (1.3–1.9)	11.0%	46%	5.9% (5.5–6.4)	2.3% (2.0–2.6)
Diabetes	1.5 (1.3–1.8)	6.4%	70%	3.2% (2.9–3.6)	1.2% (1.0–1.4)
Total adjusted for communality	..	..	..	..	35.0% (34.1–35.9)

Data were obtained from Livingston and colleagues.² PAF=population attributable fraction. RR=relative risk.

^*Weighted PAF is the relative contribution of each risk factor to the overall PAF when adjusted for communality.