Table 4. Geometric means and geometric standard deviation of urinary NAG activity and Z-score in calcaneal BMD by groups.

Markers	Exposed group	Control group	P*
Urinary NAG level, U/g creatinine†	5.61 ± 0.30	4.54 ± 0.35	0.019
Z-score in BMD	-0.06 ± 1.09	-0.01 ± 1.23	0.508

*P by Student’s t-test; ^†Adjusted with age. NAG, N-acetyl-β-d-glucosaminidase; BMD, bone mineral density.