Table 2: Age, body mass index, and smoking parameters between children with dry eye compared to those without dry eye.

ParameterNondry eye group (32)Dry eye group (80) 𝑡 𝑃
Mean  ±  SDMean  ±  SD

Age (years)7.91 ± 2.63 6 . 9 ± 2 . 2 9 −1.35 0.19
Body mass index 2 3 . 3 0 ± 2 . 9 9 2 3 . 0 9 ± 3 . 7 4 −0.22 0.83
Number of cigarettes per day 0 . 6 5 2 ± 2 . 5 5 1 7 . 7 0 ± 1 4 . 1 9 5.40 <0.0001
Duration of smoking exposure (hours /day) 0 . 7 0 ± 2 . 3 8 1 0 . 0 0 ± 3 . 7 7 8.45 <0.0001
Urinary cotinine levels (μg/L) 1 5 . 0 3 ± 8 . 1 1 6 6 . 6 4 ± 1 5 . 7 1 14.22 <0.0001
Urinary cotinine/creatinine ratio (ng/mg) 5 0 . 6 2 ± 2 2 . 7 2 2 1 0 . 1 7 ± 4 8 . 3 6 14.62 <0.0001