An increased bladder cancer risk has been suggested among users of hair dyes. We evaluated this association among females in a hospital-based case-control study in Spain (152 female incident cases, 166 female controls). The effect of hair dye use was also evaluated among potentially susceptible subgroups defined by NAT1, NAT2, CYP1A2, GSTM1, GSTT1 and GSTP1 genotypes. Use of any hair dye (OR=0.8, CI 0.5-1.4) or of permanent hair dyes (OR=0.8, CI 0.5-1.5) was not associated with increased risk. Small non-significant increases in risks were observed in a lagged analysis that ignores exposures within ten years of diagnosis (OR=1.3, CI 0.8-2.2). No trend in risk with increasing exposure was seen for duration of use, average use or cumulative use. None of the polymorphisms examined significantly modified the hair dye associated risk. Overall, this study does not support an association between hair dye use and bladder cancer.
"Also, the New England study found, similar to the California study , that the risk was more pronounced among exclusive users of permanent hair dyes who had the NAT2 slow acetylation phenotype (OR, 7.3; 95 % CI, 1.6–32.6). By contrast, a previous study from Spain, the Spanish Bladder Cancer Study, failed to confirm an increased risk of bladder cancer in a population of personal hair dye users and found no increased risk in NAT2 slow acetylators . As data on specific genetic polymorphisms involved in the metabolism of aromatic amines was not available in the current study, we were not able to examine the influence of genetic susceptibility on the risk of bladder cancer associated with hair dye use. "
[Show abstract][Hide abstract] 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.
Cancer Causes and Control 05/2012; 23(7):1139-48. DOI:10.1007/s10552-012-9982-1 · 2.74 Impact Factor
"However, given that hair coloring principally produces dermal contact with hair dye ingredients and taking into account that hair dye ingredients such as para-phenylenediamine may be acetylated in the skin by NAT1, and not by NAT2 (Kawakubo et al., 2000; Nohynek et al. 2004b, 2005; Skare et al., 2007), it is likely that NAT2 plays a minor, if any, role in the detoxification and/or activation when aromatic amines are in contact with the skin. Very recent and well-conducted epidemiology studies on the association of hair dyes and bladder cancer in Europe (Kogevinas et al., 2006) and the US (Lin et al., 2006), as well as two meta-analysis of all epidemiology data on personal use of hair dyes and cancer (Takkouche et al., 2005; Kelsh et al., 2008) confirmed that there is no evidence of a causal association between personal use of hair dyes and urinary bladder or other cancers. Finally, a recent and large cohort study in more than 70,000 women over 7 years detected no increased incidence of any cancer in hair dye users (Mendelson et al., 2009). "
[Show abstract][Hide abstract] ABSTRACT: We attempt to review the safety assessment of personal care products (PCP) and ingredients that are representative and pose complex safety issues. PCP are generally applied to human skin and mainly produce local exposure, although skin penetration or use in the oral cavity, on the face, lips, eyes and mucosa may also produce human systemic exposure. In the EU, US and Japan, the safety of PCP is regulated under cosmetic and/or drug regulations. Oxidative hair dyes contain arylamines, the most chemically reactive ingredients of PCP. Although arylamines have an allergic potential, taking into account the high number of consumers exposed, the incidence and prevalence of hair dye allergy appears to be low and stable. A recent (2001) epidemiology study suggested an association of oxidative hair dye use and increased bladder cancer risk in consumers, although this was not confirmed by subsequent or previous epidemiologic investigations. The results of genetic toxicity, carcinogenicity and reproductive toxicity studies suggest that modern hair dyes and their ingredients pose no genotoxic, carcinogenic or reproductive risk. Recent reports suggest that arylamines contained in oxidative hair dyes are N-acetylated in human or mammalian skin resulting in systemic exposure to traces of detoxified, i.e. non-genotoxic, metabolites, whereas human hepatocytes were unable to transform hair dye arylamines to potentially carcinogenic metabolites. An expert panel of the International Agency on Research of Cancer (IARC) concluded that there is no evidence for a causal association of hair dye exposure with an elevated cancer risk in consumers. Ultraviolet filters have important benefits by protecting the consumer against adverse effects of UV radiation; these substances undergo a stringent safety evaluation under current international regulations prior to their marketing. Concerns were also raised about the safety of solid nanoparticles in PCP, mainly TiO2 and ZnO in sunscreens. However, current evidence suggests that these particles are non-toxic, do not penetrate into or through normal or compromised human skin and, therefore, pose no risk to human health. The increasing use of natural plant ingredients in personal care products raised new safety issues that require novel approaches to their safety evaluation similar to those of plant-derived food ingredients. For example, the Threshold of Toxicological Concern (TTC) is a promising tool to assess the safety of substances present at trace levels as well as minor ingredients of plant-derived substances. The potential human systemic exposure to PCP ingredients is increasingly estimated on the basis of in vitro skin penetration data. However, new evidence suggests that the in vitro test may overestimate human systemic exposure to PCP ingredients due to the absence of metabolism in cadaver skin or misclassification of skin residues that, in vivo, remain in the stratum corneum or hair follicle openings, i.e. outside the living skin. Overall, today's safety assessment of PCP and their ingredients is not only based on science, but also on their respective regulatory status as well as other issues, such as the ethics of animal testing. Nevertheless, the record shows that today's PCP are safe and offer multiple benefits to quality of life and health of the consumer. In the interest of all stakeholders, consumers, regulatory bodies and producers, there is an urgent need for an international harmonization on the status and safety requirements of these products and their ingredients.
[Show abstract][Hide abstract] ABSTRACT: Testing of stuck-open faults requires sequences of input vectors.
The authors discuss test invalidation problems produced by hazard
switching due to internal delays or timing skews in input changes. To
avoid invalidation possibilities in stuck-open fault-test sequences, the
proposed solutions lead to structural modifications of the circuit or
robust test sequences composed of more than two vectors
European Test Conference, 1989., Proceedings of the 1st; 05/1989
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