Hair dyes and risk of glioma among Nebraska women

An insight into the risk factors of brain tumors and their therapeutic interventions

Brain tumors are an abnormal growth of cells in the brain, also known as multifactorial groups of neoplasm. Incidence rates of brain tumors increase rapidly, and it has become a leading cause of tumor related deaths globally. Several factors have potential risks for intracranial neoplasm. To date, the International Agency for Research on Cancer has classified the ionizing radiation and the N-nitroso compounds as established carcinogens and probable carcinogens respectively. Diagnosis of brain tumors is based on histopathology and suitable imaging techniques. Labeled amino acids and fluorodeoxyglucose with or without contrast-enhanced MRI are used for the evaluation of tumor traces. T2-weighted MRI is an advanced diagnostic implementation, used for the detection of low-grade gliomas. Treatment decisions are based on tumor size, location, type, patient's age and health status. Conventional therapeutic approaches for tumor treatment are surgery, radiotherapy and chemotherapy. While the novel strategies may include targeted therapy, electric field treatments and vaccine therapy. Inhibition of cyclin-dependent kinase inhibitors is an attractive tumor mitigation strategy for advanced-stage cancers; in the future, it may prove to be a useful targeted therapy. The blood-brain barrier poses a major hurdle in the transport of therapeutics towards brain tissues. Moreover, nanomedicine has gained a vital role in cancer therapy. Nano drug delivery system such as liposomal drug delivery has been widely used in the cancer treatment. Liposome encapsulated drugs have improved therapeutic efficacy than free drugs. Numerous treatment therapies for brain tumors are in advanced clinical research.

Personal use of permanent hair dyes and cancer risk and mortality in US women: prospective cohort study

OBJECTIVE

To evaluate the associations between personal use of permanent hair dyes and cancer risk and mortality.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

117 200 women enrolled in the Nurses' Health Study, an ongoing prospective cohort study of female nurses in the United States. The women were free of cancer at baseline, reported information on personal use of permanent hair dyes, and were followed for 36 years.

EXPOSURE

Status, duration, frequency, and integral use (cumulative dose calculated from duration and frequency) of permanent hair dyes. Age at first use and time since first use of permanent hair dyes.

MAIN OUTCOME MEASURES

Associations of personal use of permanent hair dyes with risk of overall cancer and specific cancers, and cancer related death. Age and multivariable adjusted hazard ratios and 95% confidence intervals were estimated by using Cox proportional hazard models.

RESULTS

Ever users of permanent hair dyes had no significant increases in risk of solid cancers (n=20 805, excluding non-melanoma skin cancers; hazard ratio 0.98, 95% confidence interval 0.96 to 1.01) or hematopoietic cancers overall (n=1807; 1.00, 0.91 to 1.10) compared with non-users. Additionally, ever users did not have an increased risk of most specific cancers (cutaneous squamous cell carcinoma, bladder cancer, melanoma, estrogen receptor positive breast cancer, progesterone receptor positive breast cancer, hormone receptor positive breast cancer, brain cancer, colorectal cancer, kidney cancer, lung cancer, and most of the major subclasses and histological subtypes of hematopoietic cancer) or cancer related death (n=4860; 0.96, 0.91 to 1.02). Basal cell carcinoma risk was slightly increased for ever users (n=22 560; 1.05, 1.02 to 1.08). Cumulative dose was positively associated with risk of estrogen receptor negative breast cancer, progesterone receptor negative breast cancer, hormone receptor negative breast cancer, and ovarian cancer. An increased risk of Hodgkin lymphoma was observed only for women with naturally dark hair (based on 70 women, 24 with dark hair), and a higher risk of basal cell carcinoma was observed for women with naturally light hair.

CONCLUSION

No positive association was found between personal use of permanent hair dye and risk of most cancers and cancer related mortality. The increased risk of basal cell carcinoma, breast cancer (estrogen receptor negative, progesterone receptor negative, hormone receptor negative) and ovarian cancer, and the mixed findings in analyses stratified by natural hair color warrant further investigation.

Final Report on the Safety Assessment of Disperse Blue 71

Disperse Blue 7 is an anthraquinone dye used in cosmetics as a hair colorant in five hair dye and color products reported to the Food and Drug Administration (FDA). Hair dyes containing Disperse Blue 7, as “coal tar” hair dye products, are exempt from the principal adulteration provision and from the color additive provision in sections 601 and 706 of the Federal Food, Drug, and Cosmetic Act of 1938 when the label bears a caution statement and “patch test” instructions for determining whether the product causes skin irritation. Disperse Blue 7 is also used as a textile dye. The components of Disperse Blue 7 reportedly include Disperse Turquoise ALF Granules, Disperse Turquoise LF2G, Reax 83A, Tamol SW, and Twitchell Oil. No data were available that addressed the acute, short-term, or chronic toxicity of Disperse Blue 7. A mouse lymph node assay used to predict the sensitization potential of Disperse Blue 7 was negative. Although most bacterial assays for genotoxicity were negative in the absence of metabolic activation, consistently positive results were found with metabolic activation in Salmonella strains TA1537, TA1538, and TA98, which were interpreted as indicative of point mutations. Studies using L5178Y mouse lymphoma cells appeared to confirm this muta-genic activity. Mammalian assays for chromosome damage, however, were negative and animal tests found no evidence of dominant lethal mutations. Cases reports describe patients patch tested with Disperse Blue 7 to determine the source of apparent adverse reactions to textiles. In most patients, patch tests were negative, but there are examples in which the patch test for Disperse Blue 7 was positive. In general, anthraquinone dyes are considered frequent causes of clothing dermatitis. The Cosmetic Ingredient Review Expert Panel determined that there was a paucity of data regarding the safety of Disperse Blue 7 as used in cosmetics. The following data are needed in order to arrive at a conclusion on the safety of Disperse Blue 7 in cosmetic products: (1) methods of manufacture, including clarification of the relationship between Disperse Blue 7 and Disperse Turquoise ALF and Disperse Turquoise LF2G mixed with Reax 83A, Tamol SW, and Twitchell Oil; (2) analytical methods by which Disperse Blue 7 is measured; (3) impurities; (4) concentration of use as a function of product type; (5) confirmation that this is a direct hair dye; and (6) clarification of genotoxicity study results (e.g., Disperse Turquoise ALF and Disperse Turquoise LF2G were genotoxic in bacteria—what is the specific relation to Disperse Blue 7? Disperse Blue 7 at 60% purity was genotoxic in bacteria—is the other 40% the inert Reax 83A, Tamol SW, and Twitchell Oil?). Until such data are provided, the available data are insufficient to support the safety of Disperse Blue 7 as a hair dye ingredient in cosmetic formulations.

Descriptive epidemiology and risk factors of primary central nervous system tumors: Current knowledge

Although comparisons are difficult due to differences in methodologies, the annual incidence rates of central nervous system (CNS) tumors range from 8.5 to 21.4/100,000 population according to cancer registries, with a predominance of neuroepithelial tumors in men and meningiomas in women. An increase in the incidence of CNS tumors has been observed during the past decades in several countries. It has been suggested that this trend could be due to aging of the population, and improvements in diagnostic imaging and healthcare access, but these factors do not explain differences in incidence by gender and histological subtypes. Several etiological hypotheses related to intrinsic (sociodemographic, anthropometric, hormonal, immunological, genetic) and exogenous (ionizing radiation, electromagnetic fields, diet, infections, pesticides, drugs) risk factors have led to analytical epidemiological studies to establish relationships with CNS tumors. The only established environmental risk factor for CNS tumors is ionizing radiation exposure. However, for other risk factors, studies have been inconsistent and inconclusive due to systematic differences in study design and difficulties in accurately measuring exposures. Thus, the etiology of CNS tumors is complex and may involve several genetic and/or environmental factors that may act differently according to histological subtype.

Hair dye use and risk of human cancer

Over 50% of the adult population will use hair dyes at some point in their lifetimes. Hair dyes consist of various chemicals and the composition of these chemicals vary by hair dye types. Chemicals p-phenylenediamine and aminophenyl have been suggested as possible carcinogens or mutagens in experimental studies. The scientific community has been interested in this potential public health impact and the results of published epidemiological studies are summarized here. The current evidence provides limited evidences on the association between personal hair dye use and human cancer risk, except for the possibility of hematopoietic cancers and to a lesser extent, bladder cancer. Risk appears to be affected by time period of use and by specific genetic polymorphisms. Future studies should investigate potential gene and environment interaction to assess possible genetic susceptibility. Several methodological issues should also be considered in future studies including completed hair dye use information such as on timing, duration, frequency and type of hair dye product use.

Association between cancer and contact allergy: a linkage study

Background Contact allergy is a prevalent disorder. It is estimated that about 20% of the general population are allergic to one or more of the chemicals that constitute the European baseline patch test panel. While many studies have investigated associations between type I allergic disorders and cancer, few have looked into the association between cancer and contact allergy, a type IV allergy. By linking two clinical databases, the authors investigate the possible association between contact allergy and cancer. Methods Record linkage of two different registers was performed: (1) a tertiary hospital register of dermatitis patients patch tested for contact allergy and (2) a nationwide cancer register (the Danish Cancer Register). After linking the two registers, only cancer subtypes with 40 or more patients registered were included in the analysis. The final associations were evaluated by logistic regression analysis. Results An inverse association between contact allergy and non-melanoma skin- and breast cancer, respectively, was identified in both sexes, and an inverse trend for brain cancer was found in women with contact allergy. Additionally, a positive association between contact allergy and bladder cancer was found. Conclusion The inverse associations support the immunosurveillance hypothesis (ie, individuals with an allergy are less likely to get cancer due to a triggered immune system), while the positive association with bladder cancer could be due to accumulations of chemical metabolites in the bladder. The authors' findings add to the limited knowledge about contact allergy and the risk of cancer.

Final Amended Report on the Safety Assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl Thioglycolate, Glyceryl Thioglycolate, Isooctyl Thioglycolate, Isopropyl Thioglycolate, Magnesium Thioglycolate, Methyl Thioglycolate, Potassium Thioglycolate, Sodium Thioglycolate, and Thioglycolic Acid

This safety assessment includes Ammonium and Glyceryl Thioglycolate and Thioglycolic Acid Butyl, Calcium, Ethanolamine, Ethyl, Isooctyl, Isopropyl, Magnesium, Methyl, Potassium, and Sodium Thioglycolate, as used in cosmetics. Thioglycolates penetrate skin and distribute to the kidneys, lungs, small intestine, and spleen; excretion is primarily in urine. Thioglycolates were slightly toxic in rat acute oral toxicity studies. Thioglycolates are minimal to severe ocular irritants. Thioglycolates can be skin irritants in animal and in vitro tests, and can be sensitizers. A no-observable-adverse-effect level for reproductive and developmental toxicity of 100 mg/kg per day was determined using rats. Thioglycolates were not mutagenic, and there was no evidence of carcinogenicity. Thioglycolates were skin irritants in some clinical tests. Clinically significant adverse reactions to these ingredients used in depilatories are not commonly seen, suggesting current products are formulated to be practically nonirritating under conditions of recommended use. Formulators should take steps necessary to assure that current practices are followed.

Personal use of hair dye and cancer risk in a prospective cohort of Chinese women

Although widely studied over the past 40 years, personal use of hair dye generally has not been associated with overall cancer risk. The association between hair dye use and risk of bladder and hematopoietic cancers has been less conclusive. Most hair dye studies have been case-control studies conducted in Caucasian populations. We examined the relationship between personal hair dye use and cancer risk in a prospective cohort of 70,366 Chinese women. After an average of 7 years of follow up, 2437 women were newly diagnosed with cancer by 31 December 2005. Cox proportional hazard models were used to estimate relative risks (RR) and 95% confidence intervals (CI) of cancer risk associated with hair dye use, adjusting for potential confounding factors. Compared with women who reported no hair dye use, ever users had an overall cancer risk of 0.89 (95% CI 0.82, 0.97). No significant association was observed for several common cancers, including cancers of the breast (RR 0.93, 95% CI 0.78, 1.09), lung (RR 0.81, 95% CI 0.62, 1.09), stomach (RR 0.90, 95% CI 0.66, 1.21), and colorectum (RR 1.04, 95% CI 0.84, 1.28). We also found no significant association with most other cancers, including bladder cancer (RR 1.14, 95% CI 0.56, 2.35) and hematopoietic cancers overall (RR 0.89, 95% CI 0.59, 1.35) or their subtypes, including non-Hodgkin lymphoma, multiple myeloma, and leukemia. We generally found no evidence of an association between personal use of hair dye and cancer risk, although our study is limited by small numbers for certain cancer types.

[Epidemiology of primary brain tumor]

Two main approaches are generally used to study the epidemiology of primary brain tumors. The first approach is to identify risk factors, which may be intrinsic or related to external causes. The second main approach is descriptive. Intrinsic factors potentially affecting risk include genetic predisposition and susceptibility, gender, race, birth weight and allergy. Radiation exposure is the main extrinsic factor affecting risk. A large body of work devoted, among others, to electromagnetic fields and especially cellular phones, substitutive hormonal therapy, pesticides, and diet have been published. To date, results have been discordant. Descriptive epidemiological studies have reported an increasing annual incidence of primary brain tumors in industrialized countries. The main reasons are the increasing age of the population and better access to diagnostic imaging. Comparing incidences from one registry to another is difficult. Spatial and temporal variations constitute one explanation and evolutions in coding methods another. In all registries, weak incidence of primary brain tumors constitute a very important limiting factor. Renewed interest from the neuro-oncological community is needed to obtain pertinent and essential data which could facilitate improved knowledge on this topic.

Final Report on the Safety Assessment of 3-Methylamino-4-Nitrophenoxyethanol as Used in Hair Dyes

3-Methylamino-4-Nitrophenoxyethanol is a semipermanent (direct) hair colorant used in 21 hair dyes and colors at use concentrations up to 0.15%. When applied to human skin in vitro, 0.42% of the applied 3-Methylamino-4-Nitrophenoxyethanol was recovered in the receptor fluid. In an acute toxicity study using rats, 3-Methylamino-4-Nitrophenoxyethanol at 1000 mg/kg resulted in hypoactivity, piloerection, dyspnea, and lateral recumbency in animals that later died. The surviving rats exhibited none of these signs. No abnormalities were found at necropsy. Subchronic toxic-ity tests using rats fed 25, 100, or 400 mg/kg day-1 3-Methylamino-4-Nitrophenoxyethanol for up to 93 days resulted in yellow urine and tails with all three dose levels and yellow fur occurred in the two high-dose groups. The no observed adverse effect level (NOAEL) for 3-Methyl-amino-4-Nitrophenoxyethanol was 100 mg/kg day-1. Two percent 3-Methylamino-4-Nitrophenoxyethanol was a slight ocular irritant but not a dermal irritant using rabbits and it was not a sensitizer using the murine local lymph node Assay. There were no embryotoxic or teratogenic effects observed in doses up to 750 mg/kg day-1 in rats; the NOAEL was defined as 100 mg/kg. 3-Methylamino-4-Nitrophenoxyethanol was not genotoxic in in vitro assays including multiple strains of Salmonela typhimurium and Escherichia coli, Chinese Hamster ovary cells, and human lymphocyte cultures. No carcinogenicity studies were available, nor were any clinical tests reported. As reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel, there are gaps in the data available for of 3-Methylamino-4-Nitrophenoxyethanol. In particular, there is an absence of data from chronic animal studies. The Expert Panel considered that the low percutaneous absorption and that the available developmental toxicity data and the subchronic toxicity data, both of which resulted in relatively high NOAEL values, alleviate concern about the absence of chronic exposure data. In addition, several studies demonstrated that 3-Methylamino-4-Nitrophenoxyethanol is not genotoxic. Direct hair dyes, of which 3-Methylamino-4-Nitro-phenoxyethanol is one, although not the focus in all investigations, appear to have little evidence of an association with adverse events as reported in hair dye epidemiology studies. The lack of phototoxicity data was not considered to be a concern because this is a direct hair dye ingredient, which has little skin contact and residual color is attached to hair, not normally to skin. No human skin sensitization or irritation data were available. However, hair dyes containing 3-Methylamino-4-Nitrophenoxyethanol, as coal tar hair dye products, are exempt from the principal adulteration provision and from the color additive provisions in sections 601 and 706 of the Federal Food, Drug, and Cosmetic Act, when the label bears a caution statement and patch test instructions for determining whether the product causes skin irritation. The Expert Panel expects that following this procedure will prospectively identify individuals who would have an irritation/sensitization reaction and allow them to avoid significant exposures and concluded that 3-Methylamino-4-Nitrophenoxyethanol is safe as a cosmetic ingredient in the practices of use and use concentrations described in this safety report.

Final report on the safety assessment of HC Red No. 7

HC Red No. 7 functions as a semipermanent (direct) hair colorant in one cosmetic product at 1%. Analytical studies found the relative purity of HC Red No. 7 to be > 98.5%. Impurities may include 2-nitro-benzene-1,4-diamine; 3-(4-amino-3-nitro-phenyl)-oxazolin-2-one; 2-chloroethyl 4-amino-3-nitrophenylcarbamate; residual solvents ethanol, DMF, or isopropyl acetate; chloride ions; and heavy metals. Around 0.10% of the applied HC Red No. 7 was absorbed in human dermatomed skin samples. In an acute oral toxicity study in rats, the maximum nonlethal dose was 300 mg/kg. The no observed effect level (NOEL) in a subchronic oral toxicity study in rats was 50 mg/kg day(- 1). HC Red No. 7 was not a dermal or ocular irritant in rabbits, but lymphoproliferative responses in mice indicated that HC Red No. 7 should be considered a moderate sensitizer. The NOEL for maternal toxicity was 50 mg/kg/day and the no observed adverse effect level (NOAEL) for embryonic development was 200 mg/kg/day in a prenatal toxicity study of HC Red No. 7 using rats. HC Red No. 7 was nonmutagenic at the hprt locus but mutagenic at the TK locus in mouse lymphoma cells, was mutagenic in several Salmonella typhimurium strains, was not active in an unscheduled DNA synthesis assay, and was unclear in a micronucleus assay in human lymphocyte cultures. No carcinogenicity studies were available, nor were any clinical tests reported. Available hair dye epidemiology studies are insufficient to conclude a causal relationship between hair dye use and cancer or other diseases, but more relevant is that direct hair dyes, although not the focus in all investigations, appear to have little evidence of an association with adverse events as reported in epidemiology studies. As reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel, HC Red No. 7 appears to be a moderate sensitizer in animals. No human sensitivity data concerning this ingredient have been reported. However, hair dyes containing HC Red No. 7, as coal tar hair dye products, are exempt from the principal adulteration provision and from the color additive provisions in sections 601 and 706 of the Federal Food, Drug, and Cosmetic Act, when the label bears a caution statement and patch test instructions for determining whether the product causes contact dermatitis. The Expert Panel expects that following this procedure will identify prospective individuals who would have an irritation/sensitization reaction and allow them to avoid significant exposures. The CIR Expert Panel also noted that mutagenicity studies available for HC Red No. 7 gave both positive and negative results. Based on the available data, it was concluded that, at most, this ingredient is a weak mutagen. Due to its low dermal absorption potential and its use as a semipermanent hair dye, the CIR Expert Panel believes there is low risk of genotoxicity and that HC Red No. 7 is safe as a hair dye ingredient in the practices of use and concentrations as described in this safety assessment.

Final report on the safety assessment of HC Yellow No. 5

HC Yellow No. 5 is a direct hair dye. Hair dyes containing HC Yellow No. 5, as "coal tar" hair dye products, are exempt from the principal adulteration provision and from the color additive provision of the Federal Food, Drug, and Cosmetic Act of 1938 when the label bears a caution statement and "patch test" instructions for determining whether the product causes skin irritation. Preliminary testing on or by individuals should be done using an open patch test that is evaluated at 48 h after application of the test material. Users, therefore, would be able to determine their individual reactions to hair dye products containing HC Yellow No. 5. Absorption of HC Yellow No. 5 is minimal through skin (< 0.2%). The oral LD(50) for rats is 555.56 mg/kg. No significant toxic effects were observed after chronic oral exposure of HD Yellow No. 5 to dogs. Mild dermal irritation, but no dermal sensitization or ocular irritation was observed in laboratory animals. Results of fertility and reproductive performance, teratology, and developmental studies were negative. HC Yellow No. 5 was found to be nonmutagenic and noncytotoxic in standard laboratory assays. A current review of the hair dye epidemiology literature identified that use of direct hair dyes, although not the focus in all investigations, appears to have little evidence of an association with cancer or other adverse events. Based on the available safety test data on HC Yellow No. 5, the Panel determined that this ingredient likely would not have carcinogenic potential as used in hair dyes. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that HC Yellow No. 5 is safe as a hair dye ingredient in the practices of use and concentration as described in this safety assessment.

Final report on the safety assessment of disperse Blue 7

Disperse Blue 7 is an anthraquinone dye used in cosmetics as a hair colorant in five hair dye and color products reported to the Food and Drug Administration (FDA). Hair dyes containing Disperse Blue 7, as "coal tar" hair dye products, are exempt from the principal adulteration provision and from the color additive provision in sections 601 and 706 of the Federal Food, Drug, and Cosmetic Act of 1938 when the label bears a caution statement and "patch test" instructions for determining whether the product causes skin irritation. Disperse Blue 7 is also used as a textile dye. The components of Disperse Blue 7 reportedly include Disperse Turquoise ALF Granules, Disperse Turquoise LF2G, Reax 83A, Tamol SW, and Twitchell Oil. No data were available that addressed the acute, short-term, or chronic toxicity of Disperse Blue 7. A mouse lymph node assay used to predict the sensitization potential of Disperse Blue 7 was negative. Although most bacterial assays for genotoxicity were negative in the absence of metabolic activation, consistently positive results were found with metabolic activation in Salmonella strains TA1537, TA1538, and TA98, which were interpreted as indicative of point mutations. Studies using L5178Y mouse lymphoma cells appeared to confirm this mutagenic activity. Mammalian assays for chromosome damage, however, were negative and animal tests found no evidence of dominant lethal mutations. Cases reports describe patients patch tested with Disperse Blue 7 to determine the source of apparent adverse reactions to textiles. In most patients, patch tests were negative, but there are examples in which the patch test for Disperse Blue 7 was positive. In general, anthraquinone dyes are considered frequent causes of clothing dermatitis. The Cosmetic Ingredient Review Expert Panel determined that there was a paucity of data regarding the safety of Disperse Blue 7 as used in cosmetics. The following data are needed in order to arrive at a conclusion on the safety of Disperse Blue 7 in cosmetic products: (1) methods of manufacture, including clarification of the relationship between Disperse Blue 7 and Disperse Turquoise ALF and Disperse Turquoise LF2G mixed with Reax 83A, Tamol SW, and Twitchell Oil; (2) analytical methods by which Disperse Blue 7 is measured; (3) impurities; (4) concentration of use as a function of product type; (5) confirmation that this is a direct hair dye; and (6) clarification of genotoxicity study results (e.g., Disperse Turquoise ALF and Disperse Turquoise LF2G were genotoxic in bacteria - what is the specific relation to Disperse Blue 7? Disperse Blue 7 at 60% purity was genotoxic in bacteria - is the other 40% the inert Reax 83A, Tamol SW, and Twitchell Oil?). Until such data are provided, the available data are insufficient to support the safety of Disperse Blue 7 as a hair dye ingredient in cosmetic formulations.

Environmental risk factors for brain tumors

Primary brain tumors, whether malignant or nonmalignant, have devastating consequences. Unfortunately, few known causes exist. Despite decades of epidemiologic research to identify environmental causes of brain tumors, very little progress has been made. The purpose of this paper is to review the most recent studies in the epidemiology of brain tumors. Popular topics of interest in adult brain tumor epidemiology include electromagnetic fields (particularly cellular phones), occupational exposures, nitroso-containing compounds (especially smoking), hair products, and allergic and immunologic factors. Some of these topics are also applicable to the etiology of childhood brain tumors, but additional areas of interest in the pediatric population focus on parental exposure prior to conception, maternal exposure during pregnancy, and childhood exposure to infectious agents. After an extensive review of the literature since 2001, we present the most relevant studies. Although there are many proposed associations with brain tumors, none possess the statistical significance to confidently ascribe causation. However, new findings and associations, particularly those in allergy and immunology, will present interesting opportunities for further development.