Table 3.

Association of frequency of doing housework with dementia after further exclusions.

Frequency of doing housework	N cases/N total	ID (95%CI) per 1,000 persons-years	Model 1 HR (95% CI)	p value	Model 2 HR (95% CI)	p value	Model 3 HR (95% CI)	p value	Model 4 HR (95% CI)	p value
Excluding participants who suffer from stroke or CVD at baseline
Rarely or never	258/2724	13.8 (12.0–15.6)	Ref		Ref		Ref		Ref
Sometimesa	19/210	9.0 (5.1–14.6)	0.67 (0.40–1.11)	0.12	0.81 (0.48–1.34)	0.4	0.81 (0.49–1.35)	0.43	0.83 (0.50–1.39)	0.478
Regularlyb	32/576	7.6 (5.4–10.4)	0.57 (0.40–0.80)	0.001	0.69 (0.49–0.98)	0.04	0.69 (0.49–0.98)	0.04	0.71 (0.50–1.00)	0.055
almost everyday	164/3818	4.9 (4.2–5.7)	0.37 (0.30–0.45)	<0.001	0.48 (0.39–0.60)	<0.001	0.45 (0.36–0.57)	<0.001	0.46 (0.37–0.58)	<0.001
Further excluding dementia that occurred during the first year of follow-up
Rarely or never	84/2713	13.0 (11.3–14.8)	Ref		Ref		Ref		Ref
Sometimesa	10/209	8.4 (4.7–13.9)	0.67 (0.39–1.12)	0.127	0.80 (0.47–1.35)	0.394	0.80 (0.47–1.36)	0.412	0.83 (0.49–1.40)	0.474
Regularlyb	20/597	7.6 (5.40–10.5)	0.60 (0.43–0.85)	0.004	0.73 (0.52–1.03)	0.074	0.73 (0.51–1.03)	0.073	0.75 (0.53–1.06)	0.105
almost everyday	87/3929	4.8 (4.1–5.6)	0.38 (0.31–0.47)	<0.001	0.49 (0.40–0.61)	<0.001	0.47 (0.37–0.59)	<0.001	0.48 (0.38–0.60)	<0.001

^aSometimes at least once for a month.

^bRegularly at least once for a week.

N, number; Ref, reference; ID, Incidence density; HR, hazard ratio; CI, Confidence interval.

Model 1 is unadjusted.

Model 2 adjusted for age and sex.

Model 3 adjusted for age, sex, marital status, education, living arrangement and economic level.

Model 4 adjusted for age, sex, marital status, education, living arrangement, economic level, BMI, sleeping duration, smoking status, drinking status, exercise, Stroke or cerebrovascular disease, garden work, playing card/mahjong, community activity.