Risk Factors for Development of Keratoconus: A Matched Pair Case-Control Study

Figures & data

Figure 1 Translated questionnaire form.

Table 1 The Prevalence Rate of Possible Risk Factors in Patients and Control Groups

Risk Factor	Patients n = 83		Control n = 83
	n	%	n	%
Eye rubbing	47	56.6	19	22.9
Eye trauma	8	9.6	4	4.8
Positive family history	19	22.9	2	2.4
Parent consanguinity	60	72.3	33	39.8
Contact lens use	6	7.2	8	9.6
Obesity	19	22.9	12	14.5
Smoking	30	36.1	29	34.9
Sunlight ≥4 hours per day	18	21.7	25	30.1
Low socioeconomic status	27	32.5	34	41.0

Table 2 The Risk Related to Each Factor, Determined from Univariable and Multivariable Analyses

Risk Factors	Number of Pairs with Only Cases Exposed	Number of Pairs with Only Controls Exposed	Univariable Analysis			Multivariable Analysis
			P value	Crude OR	95% CI	P value	Adjusted OR	95% CI
Eye rubbing	37	9	<0.001	4.11	1.94–9.68	0.002	4.93	1.82–13.34
Positive family history	19	2	<0.001	9.50	2.29–8.11	0.006	25.52	2.56–254.36
Parent consanguinity	36	9	<0.001	4.00	1.89–9.44	0.02	2.89	1.16–7.16
Trauma	7	3	0.343	2.33	0.53–13.98
Contact lens use	3	5	0.724	0.60	0.09–3.08
Obesity	17	10	0.284	1.70	0.73–4.15
Smoking	21	20	1.000	1.05	0.54–2.04
Sunlight ≥4 hours per day	14	21	0.311	0.66	0.31–1.37
Low socioeconomic status	15	22	0.342	0.68	0.32–1.37

Abbreviations: OR, odds ratio; CI, confidence interval.