A PROSPECTIVE-STUDY OF PERMANENT HAIR DYE USE AND HEMATOPOIETIC CANCER

Background: Use of permanent hair dye has been suggested as a risk factor for several types of cancer, although epidemiologic data have not generally supported this hypothesis. Retrospective studies have reported a possible association between hair dyes and hematopoietic cancers. Purpose: Our purpose was to investigate if permanent hair dye was associated with risks of incident lymphoma, leukemia, and multiple myeloma in the Nurses' Health Study, a prospective cohort study of 99067 women aged 30-55 years in 1976. Methods: Questionnaires regarding medical history and other health-related variables mere sent to Nurses' Health Study participants every 2 years from 1976 to 1990. The follow-up for mortality in this cohort exceeds 98%. We identified 244 newly diagnosed cases of hematopoietic cancers, confirmed by pathology reports. Permanent hair dye use was ascertained over four cycles of questionnaires from 1976-1982; status of hair dye use established in 1982 was then used for the remainder of the follow-up time (through 1990). Age-specific incidence rates were calculated and used to compute relative risks (RRs) with 95% confidence intervals (CIs). Results: We found no evidence of a positive association between ever use of permanent hair dye and all hematopoietic cancers (age-adjusted RR = 0.9; 95% CI = 0.7-1.2) or specific types (Hodgkin's lymphoma [RR = 0.9; 95% CI = 0.4-2.1], non-Hodgkin's lymphoma [RR = 1.1; 95% CI = 0.8-1.6], multiple myeloma [RR = 0.4; 95% CI = 0.2-0.9], chronic lymphocytic leukemia [RR = 0.6; 95% CI = 0.3-1.5], and other leukemias [RR = 0.8; 95% CI = 0.3-1.9]). Further examination of age at first use, duration, frequency, and time since first use and risk of all hematopoietic cancers or non-Hodgkin's lymphoma (the largest diagnostic group), indicated no material associations. Conclusion: In this prospective cohort study, permanent hair dye use is not adversely related to risks of hematopoietic cancers.