Hormonal contraceptive use among women of childbearing age was associated with a more than 2-fold higher risk of developing glaucoma, although risk was still relatively low.
As the second leading cause of blindness worldwide, glaucoma has been shown in prior research to be significantly associated with combined oral contraceptive use. However, researchers note that risk factors for the condition are largely unknown in the younger population, particularly women, with nonoral hormonal contraceptive use also not assessed.
“Hormonal contraceptives are the most widely prescribed class of medication among non-pregnant women of childbearing age in the United States and approximately 400 million women among this demographic use them worldwide,” noted the study authors.
Seeking to better understand the role of gender and sex hormones in the pathogenesis of glaucoma, researchers conducted a retrospective cohort study with a case-control analysis of patient data derived from IQVIA's electronic medical record from 2008 to 2018.
Women aged 15 to 45 years who were either nonusers of hormonal contraceptives or users of either nonoral (eg, intrauterine device [IUD], vaginal rings, intramuscular injections) or oral contraception were included in the study (N = 4,781,504).
Examining the main outcome measure of first diagnosis of glaucoma, as defined by the first International Classification of Diseases, Tenth Revision (ICD-10) or Ninth Revision (ICD-9) code for glaucoma or ocular hypertension, each case of the condition was matched to 4 controls by age, body mass index, and follow-up time.
“Cases had to have had at least 2 codes in one year with the first code designed as the index date or date of diagnosis,” added researchers.
Of the patient cohort, 2366 cases of glaucoma (0.05%; mean [SD] age, 34.9 [6.0] years) were identified who were then matched with 9464 controls (mean [SD] age, 34.8 [6.0] years). Notably, more cases than controls were African American, had hypertension, and had taken oral steroids (P < .0001).
In assessing risk of glaucoma, regular users of hormonal contraceptives exhibited an elevated risk compared with nonusers (adjusted incident rate ratio [aIRR], 1.57; 95% CI, 1.29-1.92). Moreover, current users were found to be at greatest risk for glaucoma (aIRR, 2.38; 95% CI, 1.81-3.13), more than 2 times greater than past users (aIRR, 1.08; 95% CI, 0.82-1.43).
Based on combined hormonal contraceptive use in the 2 years prior to the first diagnosis of glaucoma, risk of the condition increased as more prescriptions were combined, in which participants who used greater than 4 prescriptions (aIRR, 1.54; 95% CI, 1.32-1.81) were more likely than those with 1 or 2 prescriptions (aIRR, 0.82; 95% CI, 0.70-0.95) to develop glaucoma. Past hormonal contraceptive users did not experience an increased glaucoma risk compared with nonusers.
Researchers said that future studies with larger samples are warranted to reassess the study findings. In the meantime, senior study author Mahyar Etminan, PharmD, MSc, of The University of British Columbia, said in a statement that the risk of glaucoma with hormonal contraceptives is low and should not dissuade women from taking these medications.
“Women on hormonal contraceptives who experience visual changes should have these symptoms examined by an ophthalmologist," she added.
Hogden K, Mikelberg F, Sodhi M, et al. The association between hormonal contraceptive use and glaucoma in women of reproductive age. Br J Clin Pharmacol. Published online June 22, 2021. doi:10.1111/bcp.14920