TABLE 4.

Fully adjusted multivariable analyses of longitudinal associations between social health and dementia

	No dementia n (%)	Dementia n (%)	HR	95% CI	p Value
Dementia trigger	11,092 (96.5%)	406 (3.5%)
Socially isolated (vs. not)	216 (96%)	9 (4%)	0.94	(0.46, 1.89)	0.86
Low social support (vs. not)	215 (93.5%)	15 (6.5%)	1.75	(1.04, 2.94)	0.03
Lonely (vs. not)	536 (95.9%)	23 (4.1%)	0.92	(0.59, 1.43)	0.71
Mutually adjusted
Socially isolated (vs. not)			0.76	(0.37, 1.59)	0.47
Low social support (vs. not)			1.87	(1.09, 3.21)	0.02
Lonely (vs. not)			0.91	(0.58, 1.42)	0.69
Composite social health
Positive	10,223 (96.6%)	362 (3.4%)	Reference
Discordanta	333 (94.1%)	21 (5.9%)	1.54	(0.98, 2.42)	0.06
Lonely	536 (95.9%)	23 (4.1%)	0.94	(0.60, 1.47)	0.79
Dementia case	11,269 (98%)	229 (2%)
Socially isolated (vs. not)	219 (97.3%)	6 (2.7%)	1.22	(0.54, 2.75)	0.64
Low social support (vs. not)	221 (96.1%)	9 (3.9%)	1.78	(0.91, 3.48)	0.09
Lonely (vs. not)	549 (98.2%)	10 (1.8%)	0.72	(0.37, 1.41)	0.34
Mutually adjusted
Socially isolated (vs. not)			1.00	(0.42, 2.38)	0.99
Low social support (vs. not)			1.79	(0.88, 3.63)	0.11
Lonely (vs. not)			0.72	(0.37, 1.40)	0.34
Composite social health
Positive	10,378 (98%)	207 (2%)	Reference
Discordanta	342 (96.6%)	12 (3.4%)	1.54	(0.86, 2.76)	0.15
Lonely	549 (98.2%)	10 (1.8%)	0.74	(0.38, 1.44)	0.38

Note: Derived from a population of 11,498 followed for mean 4.5 ± 1.2 SD years. Dementia trigger had 51,151 person years of observation (mean 4.4 ± 1.3 SD years; median 4.5, IQR 5.5-3.5 years; range 0.2 - 7.3 years). Dementia cases had 51,400 person years of observation (mean 4.5 ± 1.2 SD years; median 4.5, IQR 5.5-3.5 years; range 0.2–7.3 years). Adjusted for age (continuous), gender, level of education (≤12 or >12 years), place of birth (Australia or not Australia), BMI (continuous) and CES-D score (<8 or ≥8).

Abbreviations: CI, confidence interval; HR, hazard ratio.

^aDiscordant Social Health = socially isolated and/or low social support, but not lonely.