The Prevalence of Symptomatic Dry Eye Disease Among Coal Workers in Huainan Region of China

Figures & data

Table 1 Overall Characteristics of Coal Workers

Characteristics	Total (N)	Age (Years) Mean ± SD	Working Years Mean ± SD	Total OSDI Score M(Q25, Q75)	Asymptomatic DED (N, %)	Symptomatic DED
						Mild (N, %)	Moderate (N, %)	Severe (N, %)
Total Population	3683	41.87±7.64	16.69±7.61	14.58 (4.17, 30.21)	1815 (49.3%)	612 (16.6%)	418 (11.3%)	838 (22.8%)
Underground coal workers	3112	42.13±7.50	15.61±7.15	14.58 (4.17, 31.25)	1513 (48.6%)	488 (15.7%)	362 (11.6%)	749 (24.1%)

Table 2 Dry Eye Status of Coal Workers Working at Different Depths

Characteristics	−650 m	−750 m	−850 m and Deeper	P value
Age (years) Mean +/- SD	41.84±7.65	42.21±7.67	42.33±7.06	0.337
Working years Mean +/- SD	16.62±7.90	15.29±6.93	15.23±6.54	0.001*
Total OSDI Score M(Q25, Q75)	14.58 (4.17, 33.33)	12.50 (4.17, 31.25)	14.58 (4.17, 31.25)	0.165
Asymptomatic DED (N, %)	449 (47.7%)	646 (50.2%)	418 (47.3%)	0.333
Mild symptomatic DED (N, %)	134 (14.2%)	201 (15.6%)	153 (17.3%)
Moderate symptomatic DED (N, %)	107 (11.4%)	145 (11.3%)	110 (12.5%)
Severe symptomatic DED (N, %)	252 (26.8%)	295 (22.9%)	202 (22.9%)	0.07
Total Population (N, %)	942 (30.3%)	1287 (41.3%)	883 (28.4%)

Note: *P < 0.05.

Table 3 Comparison of Coal Workers with Different Levels of Dust Exposure

Characteristics	A group	B group	C group	P value
Age (years) Mean +/- SD	40.46±8.24	41.53±7.92	42.85±6.91	0.001*
Working Years Mean +/- SD	17.49±7.95	17.26±7.92	15.71±6.96	0.001*
Total OSDI Score M(Q25, Q75)	10.42 (2.08, 25.00)	12.50 (2.08, 27.08) ab	16.67 (4.17, 35.42) b	0.001*
Asymptomatic DED (N, %)	302 (52.9%)	890 (53.0%)	623 (43.5%)	0.001*
With DED (N, %)	269 (47.1%)	790 (47.0%)	809 (56.5%)
Mild symptomatic DED (N, %)	124 (21.7%)	260 (15.5%)	228 (15.9%)
Moderate symptomatic DED (N, %)	56 (9.8%)	175 (10.4%)	187 (13.1%)
Severe symptomatic DED (N, %)	89 (15.6%)	355 (21.1%)	394 (27.5%)	0.001*
Total Population (N, %)	571 (15.5%)	1680 (45.6%)	1432 (38.9%)

Note: *P < 0.05.

Figure 1 OSDI score increases with increasing levels of dust exposure.

Figure 2 The prevalence of severe symptomatic DED increases with increasing levels of dust exposure.

Table 4 Effect of Age, Working Years and Level of Dust Exposure on Symptomatic DED

Variables	b value	Standard Error of b value	Wald Chi-Square value	P value	OR value	95% CI of OR value
Age (yrs)	0.03	0.01	16.79	0.001	1.03	1.01–1.04
Working Years	0.02	0.01	12.10	0.001	1.02	1.01–1.04
Level of Dust Exposure	0.23	0.05	20.81	0.001	1.26	1.14–1.39

Note: *The control group is the mild dust exposure group.