(c).

Independent variable	Lifting 5 kg			Climbing 2-3 steps
	Coefficient	Odds ratio (95% CI)	p value	Coefficient	Odds ratio (95% CI)	p value
Age (years)	0.09	1.10 (1.09–1.10)	<0.001	0.10	1.10 (1.09–1.10)	<0.001
Female versus male	0.62	1.85 (1.79–1.92)	<0.001	0.22	1.25 (1.19–1.32)	<0.001
No education versus any education	0.24	1.27 (1.21–1.33)	<0.001	0.19	1.21 (1.14–1.28)	<0.001
Inadequate versus adequate income	0.09	1.09 (1.05–1.13)	<0.001	0.30	1.35 (1.29–1.41)	<0.001
Married (couple) versus unmarried	−0.08	0.93 (0.84–1.02)	0.115	−0.41	0.66 (0.58–0.76)	<0.001
Married (not together) versus unmarried	0.06	1.06 (0.97–1.17)	0.214	−0.24	0.79 (0.69–0.89)	<0.001
Living with others versus alone	0.09	1.10 (1.03–1.17)	0.004	0.32	1.38 (1.27–1.51)	<0.001
Did not work in the past 7 days	0.97	2.64 (2.53–2.76)	<0.001	1.39	4.04 (3.73–4.37)	<0.001
Any chronic disease∗	0.53	1.70 (1.64–1.76)	<0.001	0.77	2.16 (2.06–2.26)	<0.001
Rural versus urban	−0.08	0.92 (0.89–0.96)	<0.001	−0.04	0.96 (0.91–1.01)	0.126
Bangkok versus South	0.30	1.35 (1.25–1.45)	<0.001	−0.25	0.78 (0.70–0.86)	<0.001
Central versus South	0.05	1.05 (0.99–1.11)	0.138	−0.19	0.83 (0.77–0.89)	<0.001
North versus South	0.35	1.42 (1.33–1.51)	<0.001	−0.42	0.66 (0.61–0.72)	<0.001
Northeast versus South	0.35	1.42 (1.34–1.51)	<0.001	−0.16	0.85 (0.79–0.92)	<0.001
Year 2007 versus 2002	−0.64	0.53 (0.50–0.55)	<0.001	0.31	1.37 (1.28–1.45)	<0.001
Year 2011 versus 2002	−0.53	0.59 (0.57–0.62)	<0.001	0.09	1.09 (1.02–1.16)	0.007
Constant	−8.62		<0.001	−10.50		<0.001