A prospective study of hair dyes and uterine leiomyomata incidence in the study of environment, lifestyle, and fibroids.

OBJECTIVE

To investigate associations between hair dye use and incident uterine leiomyomata (fibroids) among Black participants from the Study of Environment, Lifestyle, and Fibroids.

DESIGN

Prospective cohort study.

SUBJECTS: Reproductive-aged (26-39 years) individuals with an intact uterus residing in the Detroit, Michigan area (n = 868).

EXPOSURE: Self-reported hair dye use (any use vs. no use) in the previous 12 months queried on structured questionnaires.

MAIN OUTCOME MEASURES: Fibroid incidence assessed by transvaginal ultrasounds. We fit Cox proportional hazard models to estimate hazard ratios (HRs) with 95% confidence intervals (CIs), adjusting for age, time in study, educational attainment, annual household income, occupational status, body mass index, age at menarche, parity, use of progestin-only injectable contraceptives within the past 2 years, alcohol consumption, and smoking status.

RESULTS

One hundred and forty nine incident fibroid cases were identified over 3,458 person-years of follow-up. After adjustment for confounders, use of any hair dye product (HR = 1.44; 95% CI = 0.91, 2.26) and rinses that fade (HR = 1.98; 95% CI = 1.04, 3.79) in the previous 12 months was associated with increased fibroid risk, compared with no use, although associations were generally imprecise.

CONCLUSION

In this cohort, use of hair dye products was modestly associated with a higher fibroid risk, which has important public health implications.