Table S1.

Questions on sun exposure habits

1. What times of day you usually engage in outdoor activities? (You can choose more than one response option.)
6:00–8:00	8:00–11:00	11:00–13:00	13:00–16:00	16:00–18:00
2. How long you usually spent engaging in outdoor activities at daytime in winter?
<0.5 hour	0.5–1 hour	1–3 hour	3–6 hour	More than 6 hours
(1)	(2)	(3)	(4)	(5)
3. How long you usually spent engaging in outdoor activities at daytime in other seasons?
<0.5 hour	0.5–1 hour	1–3 hour	3–6 hour	More than 6 hours
(1)	(2)	(3)	(4)	(5)
4. When you were outside on sunny days, how often did you wear long-sleeved clothes?
Never	Seldom	Sometimes	Often	Always
(1)	(2)	(3)	(4)	(5)
5. When you were outside on sunny days, how often did you seek shade?
Never	Seldom	Sometimes	Often	Always
(1)	(2)	(3)	(4)	(5)