Table 3. Logistic regression model assessing the independent effects of urbanization, sociodemographic characteristics, lifestyle habits, and comorbidities on mild cognitive impairment and dementia.

Variables	Mild Cognitive Impairment				Dementia
	Crude OR	95% CI	Adjusted ORa	95% CI	Crude OR	95% CI	Adjusted ORa	95% CI
Levels of Urbanization
Urban areas	1.00		1.00		1.00		1.00
Suburban areas	1.21b	1.06–1.38	1.07	0.92–1.23	1.42b	1.17–1.73	1.43b	1.13–1.81
Rural areas	1.55b	1.36–1.76	1.17b	1.01–1.35	1.82b	1.51–2.19	1.73b	1.37–2.19
Sex
Men	1.00		1.00		1.00		1.00
Women	1.54b	1.39–1.70	1.25b	1.10–1.43	1.73b	1.50–1.99	1.50b	1.22–1.83
Age, years
65–69	1.00		1.00		1.00		1.00
70–74	1.24b	1.05–1.46	1.08	0.91–1.28	1.06	0.77–1.46	0.95	0.68–1.34
75–79	1.90b	1.61–2.24	1.53b	1.29–1.82	2.53b	1.88–3.40	2.19b	1.60–3.00
80–84	2.36b	1.98–2.81	2.07b	1.73–2.48	5.31b	3.98–7.09	4.96b	3.63–6.77
≥85	3.76b	3.11–4.56	3.42b	2.79–4.19	15.98b	12.00–21.28	16.56b	12.06–22.74
Education, years
0	4.46b	3.46–5.76	3.49b	2.64–4.61	4.44b	3.08–6.40	2.32b	1.48–3.65
≤6	1.70b	1.32–2.20	1.59b	1.21–2.08	1.76b	1.22–2.54	1.53	0.99–2.38
7–12	1.05	0.79–1.40	1.08	0.81–1.46	1.14	0.76–1.72	1.12	0.69–1.82
>12	1.00		1.00		1.00		1.00
Lifestyle habits
Smoking (Ref. = No)	0.85b	0.75–0.97	1.10	0.94–1.30	0.63b	0.51–0.76	0.87	0.66–1.03
Drinking (Ref. = No)	0.78b	0.67–0.92	0.99	0.82–1.19	0.56b	0.42–0.70	0.80	0.58–1.10
Regular exercise (Ref. = No)	0.51b	0.46–0.57	0.64b	0.58–0.72	0.14b	0.11–0.17	0.19b	0.15–0.24
Social activityc (Ref. = No)	0.57b	0.51–0.63	0.74b	0.66–0.84	0.25b	0.20–0.30	0.40b	0.32–0.49
Comorbidities (Ref. = No)
Hypertension	1.09	0.99–1.20	1.00	0.89–1.11	1.24b	1.08–1.42	0.89	0.75–1.05
Diabetes mellitus	1.21b	1.07–1.36	1.18b	1.04–1.34	1.80b	1.55–2.10	1.82b	1.51–2.20
Stroke	2.54b	2.08–3.10	2.53b	2.04–3.14	6.86b	5.59–8.41	7.40b	5.71–9.59
Head injury	1.46b	1.14–1.86	1.60b	1.24–2.08	2.10b	1.57–2.80	2.24b	1.55–3.24
Cancer	0.86	0.67–0.10	0.95	0.73–1.23	1.38b	1.04–1.85	1.49b	1.04–2.12

CI, confidence interval; OR, odds ratio; Ref., reference.

^aEstimated from multivariate logistic regression with levels of urbanization, sex, age, education year, lifestyle habits (smoking, drinking, regular exercise, social activity), and comorbidities (hypertension, diabetes mellitus, stroke, head injury, cancer) simultaneously included in the model.

^bP < 0.05.

^cTo test the interaction terms for social activity with other lifestyle factors. For MCI, social activity has significant interaction with exercise (P = 0.008), but not with smoking (P = 0.75) and alcohol intake (P = 0.05). As for dementia, there was no significantly interactive effect of social activity with smoking (P = 0.12), alcohol intake (P = 0.65), and exercise (P = 0.24).