Table 4. The multiple regression analysis for goblet cell density and tear MUC5AC concentration using age, contact lens, smoking status, and VDT use as variables.

Variables		Goblet Cell Density (cells /mm2)		Tear MUC5AC Concentration (ng/mg)
		Parameter Estimate (95% CI)	P value	Parameter Estimate (95% CI)	P value
Age	10-year increase	3.83 (−3.42 to 11.08)	0.298	11.44 (4.42 to 18.45)	0.002
Contact Lens	User	−4.17 (−20.95 to 12.61)	0.624	2.80 (−13.42 to 19.03)	0.733
Smoking Status	Current	−20.72 (−38.86 to −2.58)	0.026	−21.97 (−39.51 to −4.43)	0.015
VDT use	8 h or more	5.23 (−12.00 to 22.47)	0.549	4.39 (−12.27 to 21.05)	0.603

CI = confidence interval.