Is Consanguinity a Risk Factor for Keratoconus?

Abstract

To determine whether consanguinity is a risk factor for keratoconus (KC). A questionnaire was distributed to all patients presenting to St. John Eye Hospital, Jerusalem, Israel. Questionnaire included data on demographic characteristics and potential risk factors. Patients were divided into two groups: cases with KC, in at least one eye, who were diagnosed by the attending ophthalmologist on the basis of abnormal corneal topography and at least one of the common signs of the disease; and controls presenting for problems other than KC and free of systemic and ocular conditions associated with KC. Multivariate logistic analyses were performed to identify risk factors for KC. Seventy cases and 140 controls participated in the study. Groups were similar with respect to sex and age. Univariate analyses found a significant association between KC and parental first-cousin consanguinity, eye rubbing, allergy, positive family history, education (>12 years), and sunglass wear, whereas asthma, eczema, smoking, and second-cousin consanguinity were not. Multivariate analyses showed that total consanguinity (first-cousin and second-cousin) (adjusted odds ratio, 3.96; p = 0.001), eye rubbing and absence of sunglass wear were significant risk factors. Education was also associated with KC, but family history was not so in the multivariate analysis. This study supports the hypothesis that consanguinity is a significant risk factor for KC and provides strong support for a genetic contribution to the disease. Wearing sunglasses in this environment is beneficial, and the study confirmed that eye rubbing, allergy, and education are also significantly associated with KC after adjusting for other predictors.