Table 3.

Determinants of vitamin D deficiency among Chinese children and adolescents from the Chinese nutrition and health survey 2010–2012 ¹ (log-binomial regression).

	Total (n = 14,473)		Male (n = 7288)		Female (n = 7185)
	PR	P Value	PR	P Value	PR	P Value
Gender
Male	ref
Female	1.31 (1.22–1.40)	<0.0001
Age group
6–11	ref		ref		ref
12–14	1.61 (1.48–1.74)	<0.0001	1.47 (1.31–1.64)	<0.0001	1.77 (1.58–1.99)	<0.0001
15–17	1.72 (1.59–1.88)	<0.0001	1.65 (1.46–1.85)	<0.0001	1.83 (1.62–2.06)	<0.0001
Region type
Small and medium-sized cities	ref		ref		ref
Large cities	1.37 (1.24–1.50)	<0.0001	1.35 (1.18–1.54)	<0.0001	1.38 (1.21–1.58)	<0.0001
Ordinary rural area	1.34 (1.22–1.46)	<0.0001	1.33 (1.17–1.50)	<0.0001	1.35 (1.19–1.54)	<0.0001
Poor rural areas	1.04 (0.94–1.16)	0.4181	1.01 (0.88–1.17)	0.8521	1.08 (0.93–1.24)	0.3318
Ethnic group
Han	ref		ref		ref
Other	1.00 (0.89–1.12)	0.9609	0.92 (0.78–1.09)	0.3312	1.08 (0.92–1.27)	0.3484
Latitude
South	ref		ref		ref
North	1.07 (0.95–1.20)	0.2958	1.05 (0.89–1.24)	0.5799	1.09 (0.92–1.29)	0.3396
Season
Summer	ref		ref		ref
Spring	2.59 (2.13–3.15)	<0.0001	2.40 (1.82–3.16)	<0.0001	2.87 (2.17–3.80)	<0.0001
Autumn	1.94 (1.66–2.25)	<0.0001	1.91 (1.54–2.37)	<0.0001	1.99 (1.610–2.47)	<0.0001
Winter	2.82 (2.40–3.31)	<0.0001	2.75 (2.20–3.46)	<0.0001	2.94 (2.34–3.68)	<0.0001
Outdoor activity time
>60 min	ref		ref		ref
<30 min	1.05 (0.94–1.16)	0.4193	0.99 (0.86–1.15)	0.9205	1.10 (0.95–1.28)	0.2229
30–60 min	1.06 (0.93–1.19)	0.3856	0.96 (0.81–1.14)	0.6065	1.17 (0.98–1.39)	0.0788
Ambient UVB Level
High	ref		ref		ref
Low	1.59 (1.38–1.84)	<0.0001	1.55 (1.27–1.90)	<0.0001	1.64 (1.33–2.02)	<0.0001
Medium	1.39 (1.27–1.53)	<0.0001	1.33 (1.17–1.52)	<0.0001	1.46 (1.28–1.67)	<0.0001
BMI
Normal	ref
Overweight	1.01 (0.90–1.13)	0.8970	1.11 (0.96–1.29)	0.1621	0.87 (0.73–1.03)	0.0980
Obesity	0.98 (0.86–1.12)	0.4787	0.90 (0.76–1.07)	0.2425	1.13 (0.91–1.41)	0.2635

¹ Univariable logistic regression.