Association between hair relaxer use and uterine fibroids among women of reproductive age presenting to a national referral hospital in Kenya: a case control study

Uterine fibroids (UFs) precipitate significant morbidity in low and middle income countries, yet evidence on their contextual drivers remains scarce. The objective here was to assess the association between HR use and UFs independent of known risk factors as well as to quantify HR use impact in the population of women of reproductive age. A facility-based case control study was employed to assess the HR-UF association among 264 women presenting to the gynaecologic clinic within Kenyatta National Hospital between 23rd October and 19th December 2024. All cases were prospectively recruited while controls were simple randomly sampled from the clinics appointment schedule and frequency-matched to cases by day of presentation. A logistic regression model was used to evaluate the HR-UF association, adjusting for the effect of potential confounders. Thereafter, a population attributable fraction (PAF) (along with its confidence interval) was estimated. The odds of UFs among HR users was approximately five times higher than non-users (OR=5.12, 95% CI: 3.00-8.73, P<0.001). This relationship was not confounded by the studied covariates. The PAF estimate for the association was 59.2% (95% CI: 47.2-71.7) - suggesting that about three-fifths of UFs in this population could be prevented if HRs were not used. These findings call for more rigorous enforcement of existing legislations that regulate the supply and use of HRs in the country, with a view to safeguarding consumer health.