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: 1.64). 120(1):31-8.
Source: PubMed

ABSTRACT 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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: A fast, simple and sensitive method for determining of lead in hair dyes using graphite furnace atomic absorption spectrometry with slurry sampling was developed. Multivariate optimization was used to establish optimal analytical parameters through a fractional factorial and a central composite design. The samples were submitted for direct analysis without prior digestion and were diluted in 2.5% v/v HNO3 and 1.5% v/v H2O2. Palladium (chemical modifier) and rhodium (permanent modifier) were selected from several potential modifiers. The optimal conditions were a pyrolysis time of 10 s (liquid and dust dyes) 20 s (cream dyes), a pyrolysis temperature of 789 °C (liquid dyes) or 750°C (cream and dust dyes) and an atomization temperature of 1800 °C for all dyes. Under optimum conditions, the calibration graph is linear in the 1.50 − 50.0 µ g L concentration range, with a detection limit of 0.33, 0.44 and 0.39 µ g L for liquid, dust and cream hair dyes, respectively. The relative standard deviation ranged from 1.63 to 4.56%. The recovery rate ranged from 85 to 108%, and no significant differences were found between the results obtained with the proposed method and the microwave decomposition analysis method of real samples. The concentration ranges obtained for lead in the hair dyes samples were 1.00 - 11.3 µ g L for liquid dyes, 14.0 - 100 µg kg for dust dyes, and 19.9 - 187 µg kg for cream dyes.
    Analytical Letters 01/2012; DOI:10.1080/00032719.2012.710868 · 0.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Despite considerable research, the issue of hair dyes and bladder cancer is still open to discussion. In January 2013, we searched in PubMed/EMBASE to identify observational studies investigating the association between personal use of hair dyes and bladder cancer incidence/mortality. Pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) were calculated using random-effects models. Fifteen case-control and 2 cohort studies were available for meta-analysis (8,504 cases/deaths, 14,102 controls and 617,937 persons-at-risk). Compared to no use, the pooled RR of bladder cancer for personal use of any type of hair dyes was 0.93 (95% CI, 0.82-1.05), with moderate heterogeneity among studies (I2=34.1%, p=0.07). Similar RRs were found for females (RR=0.95) and males (RR=0.81). Based on 7 studies, the pooled RR for personal use of permanent hair dyes was 0.92 (95% CI, 0.77-1.09). Compared to no use, no association was observed for the highest categories of duration of use and lifetime frequency of use of both any type of dyes and permanent dyes. The pooled RR from the 4 studies reporting results for use of dark-colored dyes was 1.29 (95% CI, 0.98-1.71). This meta-analysis allows to definitely exclude any appreciable excess risk of bladder cancer among personal hair dye users.
    Annals of epidemiology 01/2013; DOI:10.1016/j.annepidem.2013.11.003 · 2.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The performance of employees of small and medium-sized enterprises (SMEs) is usually evaluated by supervisors' perceptions, recognitions and preferences. This phenomenon is very common in Taiwanese family controlled enterprises. To improve this inequitable performance evaluation structure, a multi-criteria decision method associated with fuzzy sets is proposed. The ranking approach integrates the Nominal group technique (NGT), fuzzy sets theory and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method to determine the ranking of employees. Based on the multi-criteria decision theory, a win-win approach is developed for managers and employees. The approach can help decision makers evaluate the employee performance in a more rational structure.


Available from