Table 1.

Baseline characteristics of the subjects

Variable	Calcium group (n = 20)	Placebo group (n = 20)	P value
Age (year) *	36.6 ± 7.8	36.6 ± 8.0	1.0
Sex (male, female) **	4, 16	2, 18	0.661

All values are mean ± SD.

^*There were no significant differences between two groups at baseline (Independent t- test)

^**There were no significant differences between two groups at baseline(χ²).