Table 3.

Mean Difference in Digit Symbol Substitution Test Scores by Neighborhood Socioeconomic Status from Mixed-Effects Models in Adults Aged 65 Years or Older, With and Without Adjustment for White Matter Hyperintensities, Cardiovascular Health Study, United States, 1992–1993

Race and Tertile	Model 1a				Model 2b				Model 3c
	Baseline		Rate of Change per Year		Baseline		Rate of Change per Year		Baseline		Rate of Change per Year
	Mean Difference	95% CI	Mean Difference	95% CI	Mean Difference	95% CI	Mean Difference	95% CI	Mean Difference	95% CI	Mean Difference	95% CI
White (n = 2,727)
Highest	0	Referent	0	Referent	0	Referent	0	Referent	0	Referent	0	Referent
Middle	−2.68	−3.77, −1.60	−0.001	−0.14, 0.14	−0.93	−1.97, 0.04	−0.002	−0.14, 0.14	−0.96	−1.99, 0.07	−0.002	−0.14, 0.14
Lowest	−4.67	−5.82, −3.52	−0.06	−0.20, 0.08	−1.11	−2.23, 0.02	−0.06	−0.20, 0.08	−1.14	−2.26, −0.02	−0.06	−0.20, 0.08
Black (n = 514)
Highest	0	Referent	0	Referent	0	Referent	0	Referent	0	Referent	0	Referent
Middle	−2.07	−4.62, 0.49	−0.17	−0.46, 0.12	0.17	−2.06, 2.40	−0.17	−0.46, 0.12	0.01	−2.21, 2.23	−0.17	−0.46, 0.12
Lowest	−5.77	−8.40, −3.15	0.11	−0.18, 0.41	−2.03	−4.36, 0.30	0.11	−0.18, 0.41	−2.06	−4.38, 0.26	0.12	−0.18, 0.41

Abbreviations: CHD, coronary heart disease; CI, confidence interval; SES, socioeconomic status; WMH, white matter hyperintensities.

^a Results were adjusted for age (centered), sex, marital status, hypertension, diabetes, CHD, and clinic location; the model included interaction terms for time squared and age × time.

^b Results were adjusted for age (centered), sex, marital status, hypertension, diabetes, CHD, clinic location, and individual SES (education, income, and occupational history); the model included interaction terms for time squared and age × time.

^c Results were adjusted for age (centered), sex, marital status, hypertension, diabetes, CHD, clinic location, individual SES, and WMH (high vs. low); the model included interaction terms for time squared and age × time.