Table 1.

Clinical characteristics of the participants

Characteristic	Mean ± SD
	Case	Control
Number	105	401
Male/female	52/53	251/150
Age (years)	1.77 ± 1.07	7.17 ± 3.89△
BMI (kg/m2)	18.43 ± 4.21	18.14 ± 3.37
Calcium (mmol/L)	2.33 ± 0.16	2.42 ± 0.13△
Phosphate (mmol/L)	1.69 ± 0.24	1.67 ± 0.19
Alkaline phosphatase (IU/L)	207.33 ± 54.64	231.72 ± 69.52△
Serum 25(OH)D (ng/ml)a	11.82 ± 6.95	23.58 ± 8.20△
Regular vitamin D useb
Yes	19	193△
No	86	208

^aSerum collected from November to April, 2010.

^bIntake of 400 IU/d.

^△Significant P values are indicated by a triangle (^△P < 0.05).