Table 4. PIF and Total Estimated Reductions in US Dementia Cases Expected With a 15% Proportional Risk Factor Reduction in 2020 by Race and Ethnicity^a.

Risk factor	Total population		Hispanic		Non-Hispanic Asian		Non-Hispanic Black		Non-Hispanic White
	PIF, % (95% CI)	Fewer cases, No. (95% CI)b	PIF, % (95% CI)	Fewer cases, No. (95% CI)b	PIF, % (95% CI)	Fewer cases, No. (95% CI)b	PIF, % (95% CI)	Fewer cases, No. (95% CI)b	PIF, % (95% CI)	Fewer cases, No. (95% CI)b
Less education	0.9 (0.4-1.5)	52 600 (23 600-85 100)	2.1 (1.0-3.2)	12 500 (5900-19 100)	0.6 (0.2-0.9)	1200 (500-1900)	0.9 (0.4-1.5)	6500 (2900-10 500)	0.5 (0.2-0.8)	20 100 (8900-33 000)
Hearing loss	1.3 (0.6-2.4)	77 300 (34 400-137 300)	1.6 (0.7-2.8)	9400 (4200-16 500)	0.9 (0.4-1.6)	1900 (800-3400)	0.8 (0.4-1.5)	6000 (2600-11 000)	1.3 (0.6-2.3)	54 700 (24 300-97 300)
TBI	1.8 (1.3-2.6)	104 900 (73 700-148 500)	1.1 (0.8-1.7)	6800 (4700-9800)	0.7 (0.5-1.0)	1500 (1000-2100)	1.0 (0.7-1.5)	7500 (5200-10 800)	2.1 (1.5-2.9)	87 000 (61 500-122 000)
Hypertension	3.0 (0.9-5.2)	176 200 (55 200-299 600)	2.8 (0.9-4.8)	16 700 (5200-28 200)	2.8 (0.9-4.8)	6000 (1800-10 300)	4.0 (1.3-6.5)	29 200 (9700-46 900)	2.9 (0.9-5.0)	121 000 (37 600-207 500)
Excessive alcohol	0.1 (0.0-0.2)	6200 (1900-9600)	0.1 (0.0-0.1)	400 (100-500)	0.0 (0.0-0.0)	0 (0-100)	0.1 (0.0-0.1)	600 (200-900)	0.1 (0.0-0.2)	5200 (1600-8100)
Obesity	3.1 (2.0-4.3)	182 100 (113 500-251 300)	3.4 (2.1-4.6)	20 000 (12 600-27 400)	1.2 (0.7-1.8)	2600 (1500-3800)	3.7 (2.3-5.0)	26 800 (17 000-36 300)	3.1 (1.9-4.3)	130 000 (80 900-179 500)
Smoking	0.7 (0.2-1.4)	42 300 (11 000-80 700)	0.6 (0.2-1.1)	3500 (900-6800)	0.4 (0.1-0.8)	900 (200-1800)	1.0 (0.3-1.8)	7100 (1900-13 400)	0.7 (0.2-1.4)	30 100 (7800-57 500)
Depression	0.9 (0.6-1.3)	54 500 (34 100-78 100)	1.3 (0.8-1.9)	7800 (5000-11 100)	0.6 (0.3-0.8)	1200 (700-1700)	0.8 (0.5-1.2)	6100 (3800-8800)	0.9 (0.6-1.3)	38 200 (23 900-54 900)
Social isolation	1.0 (0.6-1.4)	58 100 (32 000-80 100)	1.9 (1.1-2.5)	11 200 (6400-15 100)	0.7 (0.4-1.0)	1500 (800-2000)	1.0 (0.6-1.4)	7400 (4100-10 200	0.9 (0.5-1.3)	38 200 (21 000-52 800)
Physical inactivity	3.0 (1.4-4.4)	175 100 (79 600-258 300)	3.2 (1.5-4.7)	19 200 (8800-28 100)	2.8 (1.2-4.1)	5900 (2600-8700)	3.4 (1.6-4.9)	24 700 (11 400-35 800)	3.0 (1.3-4.4)	123 600 (56 100-182 800)
Diabetes	1.9 (1.3-2.8)	109 100 (75 200-160 700)	2.6 (1.8-3.7)	15 200 (10 600-21 800)	2.7 (1.9-3.9)	5700 (4000-8200)	2.4 (1.6-3.4)	17 100 (11 900-24 700)	1.7 (1.2-2.5)	70 800 (48 600-104 900)
Air pollution	0.3 (0.2-0.4)	19 400 (13 700-21 300)	0.6 (0.5-0.7)	3800 (2700-4100)	0.8 (0.6-0.9)	1700 (1200-1800)	0.6 (0.4-0.7)	4300 (3100-4700)	0.3 (0.2-0.3)	10 600 (7500-11 700)
Combined factorsc	7.3 (3.7-10.9)	427 000 (216 600-636 300)	8.7 (4.6-12.6)	51 500 (27 300-75 000)	6.2 (3.2-9.3)	13 200 (6700-19 800)	8.4 (4.3-12.2)	60 700 (31 000-88 600)	7.0 (3.5-10.5)	293 000 (148 100-438 400)

Abbreviations: PIF, potential impact fraction; TBI, traumatic brain injury.

^a A 15% proportional reduction is based on the proportion of US adults in each racial or ethnic group that would be considered exposed to each risk factor after a hypothetical intervention that reduced the fraction in the high-risk category by three-twentieths (eg, moving from 22.8% of individuals living in census tracts with NO₂ exposure 8.7 ppb or greater to 19.4% by improving air quality).

^b Number of cases based on recent published estimates of 5 814 000 prevalent dementia cases among all US adults, 4 186 000 prevalent cases among White, 726 000 prevalent cases among Black, 594 000 prevalent cases among Hispanic, and 212 000 prevalent cases among Asian individuals in 2020.²⁷

^c Combined estimate is weighted by risk factor communality. See the Methods section for details.