The association between elevated blood estradiol level and corneal ectasia in women

Purpose: This study aims to investigate the association between blood estradiol level and two different etiologies of corneal ectasia in premenopausal women. Methods: This is an observational case-control study with three groups of women. Group 1 included women with keratoconus. Group 2 included women with post refractive surgery ectasia (PRSE). Group 3 was the control group. Venous blood for the measurement of estradiol was collected in order to assess the relationship between estradiol levels and ectasia. Participant's age, regular cycle (yes/no) and oral contraceptive pills (OCP) use (yes/no) was also documented. We compared the differences in estradiol levels between the 3 groups. Logistic regression was used to detect variables’ effect on participants’ chance to ectasia. Results: Ninety-six women were enrolled: 36 (37%), 29 (30%), and 31 (32%) in the keratoconus, PRSE, and control group, respectively. The mean age of the participants was 29.8 ± 3.2, 31.9 ± 2.6, and 30.7 ± 3.5 years, respectively (p = 0.04, between groups 1 and 2). Estradiol levels [pg/mL] were 38.0 ± 2.4, 43.4 ± 2.4, and 28.6 ± 3.9, respectively (p < 0.001, between any pair of groups). Two multivariate logistic regression models adjusted to age, regular cycle, and OCP use, indicated that higher blood estradiol levels were associated with an increased risk of ectasia (OR = 2.71 and 2.44, respectively; p < 0.001). Conclusion: Corneal ectasia may be associated with elevated blood estradiol levels. Estradiol measurements could be useful in women with keratoconus or in women who undergo refractive surgery.