Hair dye use and the risk of developing systemic lupus erythematosus: A cohort study

This is the authors' abstract. We don't add key points for this paper.

OBJECTIVE: To investigate the role of hair dye use in the etiology of systemic lupus erythematosus (SLE). METHODS: Participants included 106,391 women enrolled in the Nurses' Health Study, a prospective cohort study. The subjects were ages 30-55 years in 1976, and were free from SLE and any other connective tissue disease at the time of enrollment. In 1976, 1978, 1980, and 1982, subjects were classified as never-users or ever-users of permanent hair dye, based on self-report. Incidence rates of SLE meeting American College of Rheumatology classification criteria were ascertained and confirmed by chart review. RESULTS: Compared with never-users of permanent hair dye, the age-adjusted relative risks (RR) for the development of SLE among ever-users (n = 85 cases) was 0.96 (95% confidence interval [95% CI] 0.63-1.47). Duration of hair dye use was not related to risk of SLE. Women with 15 or more years of use had no increased risk (RR = 0.92, 95% CI 0.46-1.83). There was no relationship between frequency of use or time since first use and risk of SLE. The results were similar when less stringent criteria for SLE were used. CONCLUSION: We found no evidence that permanent hair dye use, age at first use, frequency of use, or duration of use is associated with the development of SLE.