Table 1. Demographic characteristics according to level of bone mineral density.

The data is presented as mean±standard deviation for continuous variables and frequency (%) for categorical variables.

P-values were calculated by chi-square test except for smoking amount in current smokers.

Posthoc comparison was conducted using Bonferroni's correction.

^a)There exists the significant difference between normal and osteopenia groups. ^b)There exists the significant difference between normal and osteoporosis groups. ^c)There exists the significant difference between osteopenia and osteoporosis groups. ^d)P-value was calculated by Jonckheere-Terpstra's trend test.