Personal use of hair dyes and the risk of bladder cancer: Results of a meta-analysis

Division of Radiation Oncology, Department of Clinical Oncology, Marshfield Clinic Cancer Center, Marshfield, WI, USA.
Public Health Reports (Impact Factor: 1.55). 01/2005; 120(1):31-8.
Source: PubMed


This study examined the methodology of observational studies that explored an association between personal use of hair dye products and the risk of bladder cancer.
Data were pooled from epidemiological studies using a general variance-based meta-analytic method that employed confidence intervals. The outcome of interest was a summary relative risk (RRs) reflecting the risk of bladder cancer development associated with use of hair dye products vs. non-use. Sensitivity analyses were performed to explain any observed statistical heterogeneity and to explore the influence of specific study characteristics of the summary estimate of effect.
Initially combining homogenous data from six case-control and one cohort study yielded a non-significant RR of 1.01 (0.92, 1.11), suggesting no association between hair dye use and bladder cancer development. Sensitivity analyses examining the influence of hair dye type, color, and study design on this suspected association showed that uncontrolled confounding and design limitations contributed to a spurious non-significant summary RR. The sensitivity analyses yielded statistically significant RRs ranging from 1.22 (1.11, 1.51) to 1.50 (1.30, 1.98), indicating that personal use of hair dye products increases bladder cancer risk by 22% to 50% vs. non-use.
The available epidemiological data suggest an association between personal use of hair dye products and increased risk of bladder cancer.

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    • "Our findings are consistent with most previous epidemiological studies [14–24] that have generally reported no association between hair dye use and bladder cancer risk. Similarly, a few meta-analyses have been conducted [28–30]. The interpretation of findings from the meta-analysis by Hunchareck and Kupelnick [30] differs from that of Takkouche et al. [29]. "
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    ABSTRACT: Several studies have suggested an increased risk of bladder cancer among hairdressers, who are occupationally exposed to hair dyes. There has also been concern about a possible increased risk of bladder cancer among users of hair dyes. However, the association between personal hair dye use and bladder cancer risk remains inconclusive. In this study, we examined associations between personal use of permanent and temporary hair dyes and bladder cancer risk in a population-based case-control study involving 1,385 cases (n = 246 women) and 4,754 controls (n = 2,587 women). Participants filled out a questionnaire with regard to history of personal hair dye use and risk factors for bladder cancer. Unconditional logistic regression was used to calculate odds ratios (OR) and 95 % confidence intervals (CI), adjusted for age, smoking status, duration of smoking and intensity of smoking. Analyses were restricted to women as less than 5 % of all men in the study ever used hair dyes. About 50 % of the women ever used hair dyes. Use of temporary hair dyes (OR, 0.77; 95 % CI, 0.58-1.02) or use of permanent hair dyes (OR, 0.87; 95 % CI, 0.65-1.18) was not associated with bladder cancer risk. No clear association between hair dyes and bladder cancer risk was found when dye use was defined by type, duration or frequency of use, dye color, or extent of use. Also, results were similar for aggressive- and non-aggressive bladder cancer. Age, educational level, and smoking status did not modify the association between hair dye use and bladder cancer risk. The present study does not support an association between personal hair dye use and bladder cancer risk. Also, various types of hair dye, intensity of exposure to hair dyes or dye color do not appear to be important factors for bladder cancer development.
    Full-text · Article · May 2012 · Cancer Causes and Control
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    ABSTRACT: To identify studies of the prevalence of cutaneous complications of hairdressing in (1) hairdressers and the general population and (2) those more common in people of African ancestry. Three versions of MEDLINE were searched from January 1966 through December 2004 and with a repeated search in August 2005 using 2 groups of search terms: group 1, terms used for hair care and specific study designs: survey, cross-sectional study, and cohort study; group 2, the terms African hair, Afro-Caribbean hair, African American hair, central centrifugal cicatricial alopecia, acne keloidalis nuchae, traction alopecia, and synonyms for each. All identified cross-sectional and cohort studies of cutaneous adverse effects were included and their quality assessed using criteria developed by Radulescu et al. Four studies used either questionnaires or patch testing to estimate the prevalence of cutaneous adverse effects of hair chemicals in the general population and found a prevalence of contact dermatitis, secondary to use of hair dye, of 5.3% and of allergy to paraphenylenediamine of 0.1% to 2.3%. Working as a hairdresser is associated with a prevalence of contact dermatitis ranging from 16.4% in larger cohort studies that included a clinical examination to 80% in the smaller, questionnaire-based studies. Three studies of people of African ancestry found a prevalence of acne keloidalis nuchae ranging from 1.3% to 13.7% and of traction alopecia of 1%. None of these were in the general population. Working as a hairdresser is associated with an increased risk of contact allergy and/or hand dermatitis. Studies of skin disorders of individuals of African ancestry are needed to quantify the health burden and clarify causal variables of these disorders. It is not clear how much the unique shape of the African hair follicle contributes to the development of these conditions.
    Full-text · Article · Apr 2006 · Archives of Dermatology
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