Table 3.

Adjusted odds ratios (95% confidence interval) of becoming shorter or longer sleep according to different levels of selected characteristics among participants who completed two follow-up interviews (n=8265), The Singapore Chinese Health Study 1993-2010

Characteristic and levels		Incident Short (<6 hours)	Incident Long (>8 hours)
Age, per SD (3.7 years)		1.11 (1.02-1.20)	1.26 (1.21-1.32)
Gender female (vs. male)		1.07 (0.89-1.29)	0.94 (0.84-1.05)
Educational Attainment
	No education	1.00	1.00
	Primary school	0.86 (0.71-1.04)	0.81 (0.72-0.90)
	Secondary school	0.77 (0.58-1.01)	0.75 (0.64-0.88)
	Junior college	1.03 (0.59-1.79)	0.54 (0.36-0.80)
	University/technical school	0.48 (0.15-1.58)	0.50 (0.26-0.96)
Duration of moderate-level activity per week
	None	1.00	1.00
	0.5-3 hours	0.85 (0.68-1.06)	0.74 (0.65-0.84)
	4+ hours	1.14 (0.91-1.43)	0.83 (0.72-0.95)
Chronic Disease
Stomach/duodenal ulcer baseline (vs. none)		1.03 (0.70-1.51)	0.88 (0.70-1.11)
Stomach/duodenal ulcer FUP (vs. none)		1.42 (1.05-1.93)	0.91 (0.74-1.11)
Stroke baseline (vs. none)		1.48 (0.74-2.95)	1.63 (1.08-2.47)
Stroke FUP (vs. none)		1.09 (0.77-1.55)	1.68 (1.39-2.02)
Diabetes baseline (vs. none)		0.96 (0.72-1.28)	1.33 (1.13-1.56)
Diabetes FUP (vs. none)		0.98 (0.78-1.23)	1.19 (1.04-1.36)
Baseline cancer (vs. none)		1.19 (0.75-1.86)	1.29 (0.99-1.69)
Incident cancer (vs. none)		0.88 (0.63-1.23)	1.24 (1.04-1.48)
Baseline hip fracture (vs. none)		0.79 (0.10-6.32)	1.29 (0.47-3.58)
Incident hip fracture (vs. none)		0.89 (0.51-1.54)	1.52 (1.16-2.00)

FUP, reported at follow-up interview; Analytic sample restricted to normative (6-8 hour) sleepers at study baseline, therefore the adjusted odds ratio estimates represent the odds of changing from normative (6-8 hour sleep) at baseline to either short and long sleep duration at FUP, compared with the referent group who remained 6-8 hour sleepers at FUP;