Hair dye use and risk of bladder cancer in the New England bladder cancer study

Enhancement of detoxification of xenobiotic aromatic amine dyes by N-acetyltransferase 1 (NAT1) enzyme on human keratinocytes cells through structural modification

The metabolic conversion of aromatic amines to N-acetylated forms in skin and keratinocytes depends on N-acetyltransferase-1 (NAT1). Common hair color ingredient such as para-phenylenediamine (PPD) causes allergic contact dermatitis. We explored how different electronic substituents on PPD aided NAT1 enzyme biotransform oxidative arylamine (AA) compounds G1-G13 by N-acetylation, NAT-1 activity assays, metabolism, and in vitro clearance investigations in human keratinocytes, while identifying NAT-1 protein levels by Western blot and qRT-PCR. Electron-donating groups (EDG) compounds G2,G3,and G8, N-acetylate at a higher rate (58-62 nmol/mg/min), increase NAT1 activity by 20-25 %, and showed 3.4-3.8 times faster elimination and clearance rates than electron withdrawing groups (EWG) compounds G6 and G11. We found that chemicals substituted with EDG at ortho position increase aromatic system electron density, improving N-acetylation and detoxification on HaCaT cells. Our research facilitates the effective identification of aromatic amine hair dyes characterized by rapid metabolism, detoxification, and environmental safety.

Hair product use and urinary biomarker concentrations of non-persistent endocrine disrupting chemicals among reproductive-aged Black women

BACKGROUND

Studies have shown an association between hair product use and adverse health outcomes. Scientists have hypothesized that exposure to endocrine-disrupting chemicals (EDCs) drives these associations, but few studies have directly evaluated associations between hair product use and biomarkers of EDCs. Even more limited are studies of Black women, who frequently use EDC-containing products (e.g., hair relaxers).

OBJECTIVE

We estimated associations between hair product use and EDC biomarker concentrations.

METHODS

We leveraged cross-sectional data from the Study of Environment, Lifestyle, and Fibroids, a cohort of females aged 23-34 years who self-identified as Black/African American from the Detroit-metropolitan area (USA; n = 425). On structured questionnaires, participants reported their past 24-h and past 12-month use of hair products, including relaxers/straighteners/perms, styling products, moisturizers, oils, and hair food. We quantified urinary concentrations of 19 phthalate/phthalate alternative metabolites, 7 phenols, and 4 parabens using high performance liquid chromatography isotope dilution tandem mass spectrometry. EDC biomarker concentrations were creatinine-adjusted and natural log-transformed. We used multivariable linear regression to estimate mean percent differences in EDC biomarker concentrations and 95% confidence intervals (CIs) associated with hair product use, adjusting for sociodemographic confounders.

RESULTS

Hair product use was associated with greater concentrations of multiple EDC biomarkers. Notably, use of hair products in the previous 24 h (compared with non-use) was associated with 16.2% (95% CI = 0.7%, 35.9%), 35.0% (95% CI = 2.6%, 77.6%), and 32.3% (95% CI = 8.8%, 92.0%) higher concentrations of mono-isobutyl phthalate, methyl paraben, and ethyl paraben, respectively. Use of hair relaxers/straighteners/perms, styling products, moisturizers, oils, and hair food in the past 12 months was also associated with higher concentrations of multiple phthalate, phenol, and paraben biomarkers.

CONCLUSION

Hair product use was associated with higher biomarker concentrations of multiple phthalates, phenols, and parabens. These findings suggest that hair products are potentially important exposure sources for hormonally-active chemicals among Black women.

Polymorphisms in drug-metabolizing genes and urinary bladder cancer susceptibility and prognosis: Possible impacts and future management

Epidemiological studies have shown the association of genetic variants with risks of occupational and environmentally induced cancers, including bladder (BC). The current review summarizes the effects of variants in genes encoding phase I and II enzymes in well-designed studies to highlight their contribution to BC susceptibility and prognosis. Polymorphisms in genes codifying drug-metabolizing proteins are of particular interest because of their involvement in the metabolism of exogenous genotoxic compounds, such as tobacco and agrochemicals. The prognosis between muscle-invasive and non-muscle-invasive diseases is very different, and it is difficult to predict which will progress worse. Web of Science, PubMed, and Medline were searched to identify studies published between January 1, 2010, and February 2023. We included 73 eligible studies, more than 300 polymorphisms, and 46 genes/loci. The most studied candidate genes/loci of phase I metabolism were CYP1B1, CYP1A1, CYP1A2, CYP3A4, CYP2D6, CYP2A6, CYP3E1, and ALDH2, and those in phase II were GSTM1, GSTT1, NAT2, GSTP1, GSTA1, GSTO1, and UGT1A1. We used the 46 genes to construct a network of proteins and to evaluate their biological functions based on the Reactome and KEGG databases. Lastly, we assessed their expression in different tissues, including normal bladder and BC samples. The drug-metabolizing pathway plays a relevant role in BC, and our review discusses a list of genes that could provide clues for further exploration of susceptibility and prognostic biomarkers.

Sexual dimorphism in bladder cancer: a review of etiology, biology, diagnosis, and outcomes

Bladder carcinoma represents a prevalent malignancy, wherein the influence of sex extends across its incidence, biological attributes, and clinical outcomes. This scholarly exposition meticulously examines pertinent investigations, elucidating the nuanced impact of sex on bladder cancer, and posits cogent avenues for future research and intervention modalities. In the initial discourse, an exhaustive scrutiny is undertaken of the etiological underpinnings of bladder cancer, encompassing variables such as tobacco consumption, occupational exposures, and genetic aberrations. Subsequently, a comprehensive dissection unfolds, delving into the intricate biological disparities inherent in sex vis-à-vis the initiation and progression of bladder cancer. This analytical framework embraces multifaceted considerations, spanning sex hormones, sex chromosomal dynamics, metabolic enzymatic cascades, and the intricate interplay with the microbiome. Lastly, a synthesized exposition encapsulates the ramifications of gender differentials on the diagnostic and prognostic landscapes of bladder cancer, underscoring the imperative for intensified investigative endeavors directed towards elucidating gender-specific variances and the formulation of tailored therapeutic strategies.

A Review of the Chemistry and Biological Activities of Natural Colorants, Dyes, and Pigments: Challenges, and Opportunities for Food, Cosmetics, and Pharmaceutical Application

Natural pigments are important sources for the screening of bioactive lead compounds. This article reviewed the chemistry and therapeutic potentials of over 570 colored molecules from plants, fungi, bacteria, insects, algae, and marine sources. Moreover, related biological activities, advanced extraction, and identification approaches were reviewed. A variety of biological activities, including cytotoxicity against cancer cells, antioxidant, anti-inflammatory, wound healing, anti-microbial, antiviral, and anti-protozoal activities, have been reported for different pigments. Considering their structural backbone, they were classified as naphthoquinones, carotenoids, flavonoids, xanthones, anthocyanins, benzotropolones, alkaloids, terpenoids, isoprenoids, and non-isoprenoids. Alkaloid pigments were mostly isolated from bacteria and marine sources, while flavonoids were mostly found in plants and mushrooms. Colored quinones and xanthones were mostly extracted from plants and fungi, while colored polyketides and terpenoids are often found in marine sources and fungi. Carotenoids are mostly distributed among bacteria, followed by fungi and plants. The pigments isolated from insects have different structures, but among them, carotenoids and quinone/xanthone are the most important. Considering good manufacturing practices, the current permitted natural colorants are: Carotenoids (canthaxanthin, β-carotene, β-apo-8'-carotenal, annatto, astaxanthin) and their sources, lycopene, anthocyanins, betanin, chlorophyllins, spirulina extract, carmine and cochineal extract, henna, riboflavin, pyrogallol, logwood extract, guaiazulene, turmeric, and soy leghemoglobin.

[Gender-associated differences in bladder cancer]

BACKGROUND AND OBJECTIVES

Although the incidence of bladder cancer among women is lower, they tend to more often have advanced disease at presentation with a more aggressive course. It is still unclear which factors are responsible for the poorer prognosis of bladder cancer in women.

MATERIALS AND METHODS

Original papers and reviews from 2004 until 2022 were identified in a PubMed search and evaluated.

RESULTS

Multiple factors are likely responsible for the different courses of bladder cancer in women versus men. In the literature, epidemiologic and clinical aspects are discussed. Furthermore, genetic and hormonal causes and the role of the urobiome have been the focus of discussion more recently.

CONCLUSIONS

Earlier diagnosis and better surgical treatment could lead to a more favorable course of bladder cancer in women. Further analyses of genetic, hormonal, und microbiological factors could open new perspectives in the prevention, diagnosis, and treatment of bladder cancer.

Risk of Carcinogenicity Associated with Synthetic Hair Dyeing Formulations: A Biochemical View on Action Mechanisms, Genetic Variation and Prevention

Article tries to visualize the potential for carcinogenic trigger in humans with a preference for oxidative synthetic of hair dyeing formulations, especially which belong to the category of permanent colours. According to the International Agency for Cancer, hair dyes for personal use are not strictly classified as carcinogen to humans. However, some controversy exists that requires clarification. Some epidemiological studies support the association between the risk of cancer development and personal use of hair dyes (pooled relative risk RR = 1.50. 95% CI: 1.30-1.98). The world-wide sale of hair dyeing cosmetics have exceeded 15 billion dollars by the year 2012 and has maintained an annual growth rate of 8-10%. This raises concerns and need to be addressed. The review article briefly discusses about the different hair dye components based on their chemical nature, permanence, interaction of dye components with different parts of the hair shaft, action mechanisms, health risk assessment, associated challenges and possible alternatives. There appears variability towards the pathological changes incurred in the human system upon the use of synthetic hair formulations. This probably appears due to the presence of interindividual genetic variation of enzymes handling these xenobiotics. The redox mechanism of major hair dye components appears to be involved in the carcinogenic trigger. Most of the hair dye constituents pose serious health issues. However, we do have few better alternatives to prevent the toxicity associated with hair dye constituents without compromising the need of today's fashion statement and expectations of the youth.

Hair Dye Ingredients and Potential Health Risks from Exposure to Hair Dyeing

Given the worldwide popularity of hair dyeing, there is an urgent need to understand the toxicities and risks associated with exposure to chemicals found in hair dye formulations. Hair dyes are categorized as oxidative and nonoxidative in terms of their chemical composition and ingredients. For several decades, the expert panel's Cosmetic Ingredient Review (CIR) has assessed the safety of many of the chemicals used in hair dyes; however, a comprehensive review of hair dye ingredients and the risk of exposure to hair dyeing has not been documented. Herein, we review the safety of the various chemicals in oxidative and nonoxidative hair dyes, toxicities associated with hair dyeing, and the carcinogenic risks related to hair dyeing. While many compounds are considered safe for users at the concentrations in hair dyes, there are conflicting data about a large number of hair dye formulations. The CIR expert panel has ratified a number of coloring ingredients for hair dyes and banned a series of chemicals as carcinogenic to animals and unsafe for this application. The use of these chemicals as raw materials for producing hair dyes may result in the synthesis of other contaminants with potential toxicities and increased risk of carcinogenesis. It is an open question whether personal or occupational hair dyeing increases the risk of cancer; however, in specific subpopulations, a positive association between hair dye use and cancer occurrence has been reported. To address this question, a better understanding of the chemical and mechanistic basis of the reported toxicities of hair dye mixtures and individual hair dye ingredients is needed. It is anticipated that in-depth chemical and systems toxicology studies harnessing modern and emerging techniques can shed light on this public health concern in the future.

Association between hair dye use and cancer in women: a systematic review and meta-analysis of case-control studies

Background

The use of hair dye for cosmetic purposes appears to be increasing worldwide. As 50-80% of women use hair dye throughout their lifetimes, the possible association between hair dye use and cancer is a public health concern.

Method

This systematic review was performed by retrieving studies from PubMed, Scopus, WOS, and ProQuest databases. The inclusion criteria were case-control studies evaluating the association between hair dye use and cancer in women. Women with cancer who have used any hair dye were the focus of our study.

Results

The present study combined 28 studies, to assess the association between hair dye use and cancer. The pooled odds ratio (OR) of hematopoietic system cancers among those who have generally ever used any type of hair dyes was 1.10 (95% CI:1.01-1.20) in 17 studies. In 11 studies investigating hair dye made before and after 1980 as a risk factor for cancer, the pooled OR for cancer was 1.31(95% CI:1.08-1.59). Likewise, in the 13 studies that evaluated the association of light and dark hair dye with cancer, the risk among those using dark hair dye increased by 9%, compared to non-users (OR=1.09; 95% CI:0.95-1.25).

Conclusion

The present study suggests that, although the use of hair dye may increase the risk of cancer among users, a more detailed evaluation is required to assess the type of hair dye use in terms of guidelines and metrics.

Hair dye use and prostate cancer risk: A prospective analysis in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort

BACKGROUND

According to the International Agency for Research on Cancer, some hair dye chemicals are considered mutagenic and carcinogenic in humans. One hospital-based study reported a positive association between hair dye use and prostate cancer risk, but no prospective analyses have been conducted.

METHODS

This study investigated the association between hair dye use and prostate cancer risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort, a large, well-characterized cohort of 29,133 male Finnish smokers. Participants completed questionnaires regarding lifestyle, medical, and risk factor information, including the use of hair dye, which was available for 98.8% of the cohort (28,795 men). Prostate cancer cases were identified through linkage with the Finnish Cancer Registry and the Finnish Mortality Register. Hazard ratios (HRs) and confidence intervals (CIs) were estimated via multivariable Cox proportional hazards regression.

RESULTS

During a 28-year period of observation, 2703 incident prostate cancer cases were diagnosed. As reported at the baseline, 75 men used hair dye, and 13 of these men were subsequently diagnosed with prostate cancer. After adjustments for potential confounders, men who used hair dyes experienced substantially higher prostate cancer risk than men who did not (HR, 1.77; 95% CI, 1.03-3.05).

CONCLUSIONS

This first prospective investigation of hair dye use and prostate cancer suggests that personal hair dye use may be related to increased risk. The findings warrant re-examination in other prospective cohorts along with studies evaluating specific hair dyes and possible underlying biological mechanisms.

Associations of hair dye and relaxer use with breast tumor clinicopathologic features: Findings from the Women's circle of Health Study

BACKGROUND

Building upon our earlier findings of significant associations between hair dye and relaxer use with increased breast cancer risk, we evaluated associations of select characteristics of use with breast tumor clinicopathology.

METHODS

Using multivariable-adjusted models we examined the associations of interest in a case-only study of 2998 women with breast cancer, overall and stratified by race and estrogen receptor (ER) status, addressing multiple comparisons using Bonferroni correction.

RESULTS

Compared to salon application of permanent hair dye, home kit and combination application (both salon and home kit application) were associated with increased odds of poorly differentiated tumors in the overall sample. This association was consistent among Black (home kit: OR 2.22, 95 % CI: 1.21-5.00; combination: OR 2.46, 95 % CI: 1.21-5.00), but not White women, and among ER+ (home kit: OR 1.47, 95 % CI: 0.82-2.63; combination: OR 2.98, 95 % CI: 1.62-5.49) but not ER-cases. Combination application of relaxers was associated with increased odds of tumors >2.0 cm vs. <1.0 cm (OR = 1.82, 95 % CI: 1.23-2.69). Longer duration and earlier use of relaxers and combination application of permanent hair dyes and relaxers were associated with breast tumor features including higher tumor grade and larger tumor size, which often denote more aggressive phenotypes, although the findings did not maintain significance with Bonferroni correction.

CONCLUSIONS

These novel data support reported associations between hair dye and relaxer use with breast cancer, showing for the first time, associations with breast tumor clinicopathologic features. Improved hair product exposure measurement is essential for fully understanding the impact of these environmental exposure with breast cancer and to guide risk reduction strategies in the future.

Working Conditions and Health Risk Assessment in Hair Salons

Objective:The aim of this study was to assess the chemical and physical work conditions in hair salons and to analyze health risk of exposure to VOCs for the hairdressers of hair salons. Methods: This study was carried out at 4 selected hair salons close to universities in Surat Thani province, Thailand. VOCs were collected by area sampling using charcoal tubes (9 samples per salon). The air samples were analyzed using GC/FID. The noise levels, illumination, and temperature were measured by using sound level meter, lux meter, and WBGT, respectively. Results: Toluene, cyclohexanone, xylene, and hexane were the most frequently found across the hair salons. All of the VOCs concentration was highest in the mixing area. All of hair salons had cancer risk exceeding 1 × 10-6 and HI > 1.0, indicating that indoor air pollution may affect hairdresser's health. The average VOCs concentrations after installation of local exhaust ventilation and open the door for 30 minutes before closing the hair salon, was significantly lower than before and after installation of the local exhaust ventilation. The WBGT indoors varied within 22 to 28°C, sound pressure levels within 71 to 76 dBA, and illumination within 70 to 400 lux. The noise levels and temperature in the hair salons were satisfactory on the scale of the Ministry of Labor (Thailand). Conclusions:Installing and using proper ventilation in hair salon are recommended to eliminate health effects. Hairdresser worked in poor lighting that should be improved to appropriate levels (>1000 lux).

Current Management of Localized Muscle-Invasive Bladder Cancer: A Consensus Guideline from the Genitourinary Medical Oncologists of Canada

BACKGROUND: Despite recent advances in the management of muscle-invasive bladder cancer (MIBC), treatment outcomes remain suboptimal, and variability exists across current practice patterns. OBJECTIVE: To promote standardization of care for MIBC in Canada by developing a consensus guidelines using a multidisciplinary, evidence-based, patient-centered approach who specialize in bladder cancer. METHODS: A comprehensive literature search of PubMed, Medline, and Embase was performed; and most recent guidelines from national and international organizations were reviewed. Recommendations were made based on best available evidence, and strength of recommendations were graded based on quality of the evidence. RESULTS: Overall, 17 recommendations were made covering a broad range of topics including pathology review, staging investigations, systemic therapy, local definitive therapy and surveillance. Of these, 10 (59% ) were level 1 or 2, 7 (41% ) were level 3 or 4 recommendations. There were 2 recommendations which did not reach full consensus, and were based on majority opinion. This guideline also provides guidance for the management of cisplatin-ineligible patients, variant histologies, and bladder-sparing trimodality therapy. Potential biomarkers, ongoing clinical trials, and future directions are highlighted. CONCLUSIONS: This guideline embodies the collaborative expertise from all disciplines involved, and provides guidance to further optimize and standardize the management of MIBC.

Gender discrepancies in bladder cancer: potential explanations

INTRODUCTION

Gender differences in urothelial carcinoma of the bladder (UCB) exist. Although men have a higher incidence of UCB, women tend to have poorer outcomes. We have explored and summarized the evidence for gender differences of UCB diagnosis and prognosis, together with reasons for these disparities.

AREAS COVERED

The incidence of UCB is 3-4 times higher in men than women. However, women are more likely to be diagnosed with advanced disease. Women have a higher stage-for-stage mortality compared to men, and their greatest risk of death appears to be within the first 2 years of diagnosis. Survival outcomes following radical cystectomy (RC) and radiotherapy are also poorer in women. Delays in diagnosis, differences in female anatomy, as well as poorer surgical outcomes post-RC appear to contribute significantly to the disparities noted between genders. Other factors such as exposure to risk factors, differential hormone signaling, and carcinogen breakdown may also have a role.

EXPERT OPINION

The gender divide in UCB outcomes has to be addressed. Improved medical and patient education and centralization of RC are recommended.

Clinical and therapeutic implications of sex steroid hormone receptor status in urothelial bladder cancer

Studies on the clinical profile of urothelial bladder cancer (UBC) have shown significant gender differences, namely, higher occurrence in males (male-to-female ratio of 3.5:1) and an advanced stage of disease at the time of diagnosis with rapid progression of the disease after initial diagnosis seen more commonly in females. The relationship between gender and UBC is complex and probably influenced by biological and epidemiological factors. Potential contributory factors such as sex steroid hormone pathway, gender difference in environmental carcinogen exposure, metabolic enzyme activity, and disparities in the intensity of diagnostic evaluation could probably explain the demographic trends in UBC. This comprehensive review of Medline publications during the period 2009–2019 attempts to identify the possible role of sex hormone receptors in gender variation and sexual dimorphism in the occurrence and progression of UBC. The clinical implications of identifying sex steroid receptors on factors such as disease prognostication and the therapeutic role of anti-androgens in the prevention and progression of UBC are critically reviewed. There is now significant evidence in literature to suggest the possible role of sex steroid hormone receptor-mediated signals in the genesis and progression of UBC. These receptors include androgen receptors, estrogen receptors, progesterone receptors, and various other orphan receptors. Excessive or reduced expression of these receptors, as well as alterations in their upstream or downstream pathways, correlate well with the clinical and therapeutic outcomes of UBC.

Spotlight on gender-specific disparities in bladder cancer

Men are at a higher risk of developing bladder cancer, but women present with more advanced disease and have more unfavourable outcomes. Although epidemiologic and genetical studies have underlined the multifactorial aetiology and gender-related differences of bladder cancer, there is lack of evidence-based recommendation for gender-specific management of bladder cancer. We summarize the evidence and most recent findings on gender-specific differences in bladder cancer incidence, diagnosis, treatment and outcome, spotlighting the gender disparities in genetic and hormonal risk factors, pelvic anatomy, diagnostic setting and surgical choices. We reviewed the literature published on PubMed between 1981 and 2018. Males have a threefold to fourfold higher risk of bladder cancer as compared to females; however, women have higher stage-for-stage mortality, being diagnosed with more advanced disease, mostly due to a delay in haematuria evaluation. Numerous studies indicate an increased risk of disease recurrence or progression in women with non-muscle-invasive bladder cancer treated with trans-urethral resection, with or without intravesical chemotherapy or immunotherapy, compared to males. In particular, recent molecular evidence show that there is an excess of female Ta mutant tumours. At the time of radical cystectomy, women have a significantly longer length of hospital stay, operative time, higher blood loss and higher 90-day mortality and perioperative complication rate. Moreover, females are less likely to receive a continent diversion. Future research should guarantee greater inclusion of women in trials and focus on improving the effectiveness of therapies in women, perhaps exploring different therapeutic approaches in men and women. Specific data on functional and oncological outcomes can be analysed to define predictive factors able to guide the surgeon in decisions based on evidence. It is urgently needed to limit gender-related discrepancies in early diagnosis and treatment of bladder cancer. Public awareness and bladder cancer female patients' consciousness on gender inequalities must be similarly uprisen.

Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women

Many hair products contain endocrine-disrupting compounds and carcinogens potentially relevant to breast cancer. Products used predominately by black women may contain more hormonally-active compounds. In a national prospective cohort study, we examined the association between hair dye and chemical relaxer/straightener use and breast cancer risk by ethnicity. Sister Study participants (n = 46,709), women ages 35-74, were enrolled between 2003 and 2009, and had a sister with breast cancer but were breast cancer-free themselves. Enrollment questionnaires included past 12-month hair product use. Cox proportional hazards models estimated adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between hair products and breast cancer; effect measure modification by ethnicity was evaluated. During follow-up (mean = 8.3 years), 2,794 breast cancers were identified. Fifty-five percent of participants reported using permanent dye at enrollment. Permanent dye use was associated with 45% higher breast cancer risk in black women (HR = 1.45, 95% CI: 1.10-1.90), and 7% higher risk in white women (HR = 1.07, 95% CI: 0.99-1.16; heterogeneity p = 0.04). Among all participants, personal straightener use was associated with breast cancer risk (HR = 1.18, 95% CI 0.99-1.41); with higher risk associated with increased frequency (p for trend = 0.02). Nonprofessional application of semipermanent dye (HR = 1.28, 95% CI 1.05-1.56) and straighteners (HR = 1.27, 95% CI 0.99-1.62) to others was associated with breast cancer risk. We observed a higher breast cancer risk associated with any straightener use and personal use of permanent dye, especially among black women. These results suggest that chemicals in hair products may play a role in breast carcinogenesis.

Review on gender differences in non-muscle invasive bladder cancer

Differences in the epidemiology, diagnosis and outcomes according to gender in patients diagnosed with non-muscle invasive bladder cancer (NMIBC) has been widely reported. In this article we present gender-specific differences in NMIBC in terms of epidemiology, risk factors, first clinical presentation, management and clinical outcomes based on systematically review evidence of existing literature. A literature search of English-language publications that included an analysis of the association of gender differences in patients with NMIBC was performed using PubMed. Sixty-four studies were selected for analysis with consensus of all authors. The incidence and mortality for urothelial bladder cancer (UBC) are higher in men, whereas cancer specific mortality to incidence ratio is significantly lower for men than for women. This phenomenon could be partially explained by differences in exposure to bladder cancer carcinogens. However female gender is associated with higher stage at presentation. Thirteen studies with a total of 11,069 patients diagnosed with NMIBC were included for analysis according to outcomes. In studies that found statistically significant differences in outcomes between sexes, female gender was reported as risk factor for disease recurrence, progression or cancer specific mortality. None of included studies found worse outcomes in men when compared to women with NMIBC. Results of our review suggest that female gender in patients diagnosed with NMIBC is associated—though inconsistently—with higher stage at presentation and poorer outcomes. Numerous factors may influence gender gap in incidence rate, clinical management and reported outcomes. Consensus on comparable data collection in routine practice and prospective trials including clinical outcomes are required to identify gender-specific differences in patients diagnosed with NMIBC.

A Meta-Analysis on the Relationship Between Hair Dye and the Incidence of Non-Hodgkin's Lymphoma

BACKGROUND

Epidemiologic studies have suggested hair dye to be a risk factor for many cancers. However, previous studies on the association between the personal use of hair dye and risk of non-Hodgkin's lymphoma (NHL) have been inconclusive.

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases, as well as the references cited in included studies, were searched for relevant studies up to February 10, 2015. Odds ratios (OR) with 95% confidence intervals (CI) were applied to assess the strength of the association. Publication bias was evaluated using a funnel plot by Egger's and Begg's tests.

RESULTS

A total of 16 studies were included in the analysis, including 13 case-control studies and 3 cohort studies. The present meta-analysis results revealed that the risk of NHL in a high population of hair dye users was 14% (OR 1.14, 95% CI 1.01-1.29). Furthermore, individuals who used more than 20 pack-years of hair dye had increased risk of NHL.

CONCLUSION

The outcomes indicate that hair dye use increases the risk of NHL, especially for females. Hence, people who frequently use hair dyes or have been using hair dyes for more than 20 years should minimize their exposure to hair dye products to prevent the risk of NHL.

Synthesis and Evaluation of Herbal Based Hair Dye

Background:

Herbal based hair dyes are being preferred on large scale, due to the vast number of advantages it exerts to overcome the ill-effects of a chemical based hair dye. We have attempted to prepare and standardize this preparation to ensure its quality as well as stability aspects.

Objective:

The current research was aimed at the preparation of herbal hair dye and the evaluation of its various parameters as organoleptic, physico-chemical, phytoconstituents, rheological aspects, patch test and stability testing for its efficacy and shelf life.

Materials and Methods:

The herbal dye was prepared in-house according to the proposed composition, using all the natural ingredients. The dye was evaluated for its organoleptic, physico-chemical and stability parameters.

Results:

The parameters were found to be comparable and sufficient for the evaluation of herbal dye. The values of different evaluations justified the usage of the hair dye.

Conclusion:

Herbal based hair dye has been prepared and evaluated using the various parameters. It offers a natural alternate, which can be used, irrespective of any side effects. The results can be incorporated while developing the pharmacopoeial standards.

NAT1 genotypic and phenotypic contribution to urinary bladder cancer risk: a systematic review and meta-analysis

N-acetyltransferase 1 (NAT1), a polymorphic Phase II enzyme, plays an essential role in metabolizing heterocyclic and aromatic amines, which are implicated in urinary bladder cancer (BCa). This systematic review investigates a possible association between the different NAT1 genetic polymorphisms and BCa risk. Medline, PubMed, EMBASE, Scopus, Web of Science, OpenGrey, and BASE databases were searched to identify eligible studies. The random-effect model was used to calculate pooled effects estimates. Statistical heterogeneity was tested with Chi-square and I². Twenty case-control studies, including 5606 cases and 6620 controls, met the inclusion criteria. Pooled odds ratios (OR) analyses showed a statistically significant difference in NAT1*10 versus non-NAT1*10 acetylators in the total sample (OR: 0.87; 95% CI: 0.79-0.96) but was borderline among Caucasians (OR: 0.88 with 95% CI: 0.77-1.01). No statistically significant differences in BCa risk were found for: NAT1*10 versus NAT1*4 wild type (OR: 0.97; 95% CI: 0.78-1.19), NAT1 'Fast' versus 'Normal' acetylators (OR: 1.03; 95% CI: 0.84-1.27), and NAT1 'Slow' versus 'Fast' (OR: 2.32; 95% CI: 0.93-5.84) or 'Slow' versus 'Normal' acetylators (OR: 1.84; 95% CI: 0.92-3.68). When stratifying by smoking status, no statistically significant differences in BCa risk were found for NAT1*10 versus non-NAT1*10 acetylators among the different subgroups. Our study suggests a modest protective role for NAT1*10 and a possible risk contributory role for slow acetylation genotypes in BCa risk. Further research is recommended to confirm these associations.

Does hair dye use really increase the risk of prostate cancer?

Recently, Shu-Yu Tai et al. reported that personal hair dye use increased risk of prostate cancer with a dose-response effect. Although hair dyes were identified as carcinogenic in animals and increased risk of some cancers among hairdressers, the existing epidemiological data did not support that personal hair dye use increased risk of cancers, even for bladder cancer. Given that Tai et al.’s report of a potential hazard of personal hair dye use on risk of prostate cancer was particular, the methodology of the study was scrutinized and some flaws were found including the issue of external validity.

Hair product use and breast cancer risk among African American and White women

Exposures to carcinogens in hair products have been explored as breast cancer risk factors, yielding equivocal findings. We examined hair product use (hair dyes, chemical relaxers and cholesterol or placenta-containing conditioners) among African American (AA) and White women, and explored associations with breast cancer. Multivariable-adjusted models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to describe the associations of interest among 2280 cases (1508 AA and 772 White) and 2005 controls (1290 AA and 715 White). Among controls, hair dye use was more common among Whites than AAs (58 versus 30%), while relaxer (88 versus 5%) and deep conditioner use (59 versus 6%) was more common among AAs. Among AAs, use of dark hair dye shades was associated with increased breast cancer risk (OR = 1.51, 95% CI: 1.20-1.90) and use of dark shades (OR = 1.72, 95% CI: 1.30-2.26) and higher frequency of use (OR = 1.36, 95% CI: 1.01-1.84) were associated with ER+ disease. Among Whites, relaxer use (OR = 1.74, 95% CI: 1.11-2.74) and dual use of relaxers and hair dyes (OR = 2.40, 95% CI: 1.35-4.27) was associated with breast cancer; use of dark hair dyes was associated with increased ER+ disease (OR = 1.54, 95% CI: 1.01-2.33), and relaxer use was associated with increased ER- disease (OR = 2.56, 95% CI: 1.06-6.16). These novel findings provide support a relationship between the use of some hair products and breast cancer. Further examinations of hair products as important exposures contributing to breast cancer carcinogenesis are necessary.

Association of N-acetyltransferase 1 polymorphism and bladder cancer risk: an updated meta-analysis and trial sequential analysis

BACKGROUND

Individual studies of the association between N-acetyltransferase 1 (NAT1)*10 allele and bladder cancer susceptibility have shown inconclusive results. To derive a more precise estimation of any such relationship, we performed this systemic review and updated meta-analysis based on 17 publications.

METHODS

A total of 17 studies were investigated with 4,322 bladder cancer cases and 4,944 controls. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. Subgroup analyses were conducted based on ethnicity, sex, source of controls and detecting methods. Then trial sequential analysis was performed to evaluate whether the evidence of the results was sufficient and reduce the risk of type I error.

RESULTS

There was no association between NAT1*10 allele and bladder cancer risk in a random-effects model (OR = 0.96, 95% CI, 0.84-1.10) or in a fixed-effects model (OR = 0.95, 95% CI, 0.87-1.03). In addition, no significantly increased risk of bladder cancer was found in any other subgroup analysis. Then, trial sequential analyses demonstrated that the results of our study need to be further verified.

CONCLUSIONS

Despite its limitations, the results of the present meta-analysis suggested that there was no association between NAT1*10 allele and bladder cancer risk. More importantly, our findings need to be further validated regarding whether being without the NAT1*10 allele could in the future be shown to be a potential marker for the risk of bladder cancer.

para-Phenylenediamine induces apoptosis through activation of reactive oxygen species-mediated mitochondrial pathway, and inhibition of the NF-κB, mTOR, and Wnt pathways in human urothelial cells

para-Phenylenediamine (PPD) has long been used in two-thirds of permanent oxidative hair dye formulations. Epidemiological studies and in vivo studies have shown that hair dye is a suspected carcinogen of bladder cancer. However, the toxicity effects of PPD to human bladder remains elusive. In this study, the effects of PPD and its involvement in the apoptosis pathways in human urothelial cells (UROtsa) was investigated. It was demonstrated that PPD decreased cell viability and increased the number of sub-G₁ hypodiploid cells in UROtsa cells. Cell death due to apoptosis was detected using Annexin V binding assay. Further analysis showed PPD generated reactive oxygen species (ROS), induced mitochondrial dysfunction through the loss of mitochondrial membrane potential and increased caspase-3 level in UROtsa cells. Western blot analysis of PPD-treated UROtsa cells showed down-regulation of phosphorylated proteins from NF-κB, mTOR, and Wnt pathways. In conclusion, PPD induced apoptosis via activation of ROS-mediated mitochondrial pathway, and possibly through inhibition of NF-κB, mTOR, and Wnt pathways. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 265-277, 2017.

Female with bladder cancer: what and why is there a difference?

While men are at a considerable higher risk of developing urothelial carcinoma of the bladder (UCB), women present with more advanced disease stages and seem to experience unfavorable outcomes. Evaluating specific differences in the UCB incidence and outcomes between both genders in the non-muscle invasive, muscle-invasive or locally advanced and metastatic setting, as well as determining the underlying causes of disease, may allow optimizing treatment and improving the quality of urological care among both genders. In this review we summarize the best evidence and most recent findings on gender-specific differences in UCB incidence and outcomes. In addition, we present a comprehensive overview on established and potential reasons for differences in gender-specific UCB outcomes, including disparities in the pelvic anatomy, the diagnostic work-up, the modality and quality of treatment, the exposure to risk factors, the degradation of carcinogens as well as the sex-hormone signaling.

Hair dye use, regular exercise, and the risk and prognosis of prostate cancer: multicenter case-control and case-only studies

Background

This study investigated the effects that hair dye use and regular exercise exert on the risk and prognosis of prostate cancer.

Methods

We studied 296 cases of histologically confirmed prostate cancer and 296 age- (in 2-y bands), ethnicity-, and hospital-matched controls in Taiwan between August 2000 and December 2008. To determine the rate of prostate cancer survival, another 608 incident prostate cancer cases occurring between August 2000 and December 2007 were investigated. Information on hair dye use and regular exercise was obtained using a standardized questionnaire.

Results

The use of hair dyes was associated with a significant 2.15-fold odds of developing prostate cancer (adjusted odds ratio = 2.15, 95 % confidence interval [CI] = 1.32–3.57), but was not associated with prostate cancer survival, compared with no use. The significant risks were more prominent in users aged < 60 years who had used hair dyes for > 10 years, > 6 times per year, and started using hair dyes before 1980. By contrast, regular exercise significantly reduced the number of prostate-cancer-specific death (adjusted hazard ratio = 0.37, 95 % CI = 0.16–0.83); the protective effect of exercise was more prominent among cancer patients who exercised daily (≥7 times/week). However, exercise could not prevent the development of prostate cancer.

Conclusions

Hair dye use increased the risk of prostate cancer, whereas regular exercise reduced the number of prostate-cancer-specific deaths.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2280-7) contains supplementary material, which is available to authorized users.

Occupation, smoking, opium, and bladder cancer: A case-control study

PURPOSE

The aim of this study was to investigate occupational risk factors associated with bladder cancer.

MATERIALS AND METHODS

In this case-control study, control group included patients who referred to a specialized clinic in the same city and hospitals where patients had been registered. Data were entered into SPSS software. Odds ratios (OR) were calculated for occupational variables and other characteristics. Then, using logistic regression, the association between cancer and drugs was studied while smoking was controlled.

RESULTS

Cigarette smoking, even after quitting, was also associated with bladder cancer (OR = 2.549). Considering the classification of occupations, the OR of working in metal industry in patients was 10.629. Multivariate analysis showed that use of the drug by itself can be a risk factor for bladder cancer. Drug abuse together with the control of smoking increased the risk of bladder cancer by 4.959.

CONCLUSION

According to the findings of this study, contact with metal industries such as welding, and working with tin was found as a risk factor for bladder cancer. In addition, cigarette smoking and opium abuse individually were associated with bladder cancer.

GSTT1 Null Genotype Significantly Increases the Susceptibility to Urinary System Cancer: Evidences from 63,876 Subjects

GSTT1 gene plays an important role in detoxification and clearance of reactive oxygen species(ROS). A null variant in this gene has been demonstrated to confer cancer susceptibility. Although many studies have demonstrated the association between GSTT1 null polymorphism and urinary system cancer susceptibility, several publications reported opposite conclusions. For better understanding the effects of this polymorphism on the risk of urinary system cancer, a updated meta-analysis was performed with a total of 26,666 cases and 37,210 controls extracted from 117 studies, by following the latest meta-analysis guidelines (PRISMA). The results suggested that the GSTT1 null genotype was significantly associated with an increased risk of urinary system cancer (OR=1.13, 95%CI=1.05-1.22). Furthermore, stratified analyses by the type of cancer, ethnicity, source of control and quality score presented a significantly increased risk associated with GSTT1 null genotype in bladder and prostate cancer subgroup, Caucasians and Indians subgroup, population-based(PB) subgroup, medium quality and low quality subgroup. Overall, our meta-analysis suggested that GSTT1 null genotype is a potential cancer susceptibility variant. Well-designed and large-cohort studies are needed to confirm the association between GSTT1 null genotype and urinary system cancer risk.

Gender and Bladder Cancer: A Collaborative Review of Etiology, Biology, and Outcomes

CONTEXT

The incidence of bladder cancer is three to four times greater in men than in women. However, women are diagnosed with more advanced disease at presentation and have less favorable outcomes after treatment.

OBJECTIVE

To review the literature on potential biologic mechanisms underlying differential gender risk for bladder cancer, and evidence regarding gender disparities in bladder cancer presentation, management, and outcomes.

EVIDENCE ACQUISITION

A literature search of English-language publications that included an analysis of the association of gender with bladder cancer was performed using Pubmed. Ninety-seven articles were selected for analysis with the consensus of all authors.

EVIDENCE SYNTHESIS

It has been shown that the gender difference in bladder cancer incidence is independent of differences in exposure risk, including smoking status. Potential molecular mechanisms include disparate metabolism of carcinogens by hepatic enzymes between men and women, resulting in differential exposure of the urothelium to carcinogens. In addition, the activity of the sex steroid hormone pathway may play a role in bladder cancer development, with demonstration that both androgens and estrogens have biologic effects in bladder cancer in vitro and in vivo. Importantly, gender differences exist in the timeliness and completeness of hematuria evaluation, with women experiencing a significantly greater delay in urologic referral and undergoing guideline-concordant imaging less frequently. Correspondingly, women have more advanced tumors at the time of bladder cancer diagnosis. Interestingly, higher cancer-specific mortality has been noted among women even after adjusting for tumor stage and treatment modality.

CONCLUSIONS

Numerous potential biologic and epidemiologic factors probably underlie the gender differences observed for bladder cancer incidence, stage at diagnosis, and outcomes. Continued evaluation to define clinical applications for manipulation of the sex steroid pathway and to improve the standardization of hematuria evaluation in women may improve future patient outcomes and reduce these disparities.

PATIENT SUMMARY

We describe the scientific basis and clinical evidence to explain the greater incidence of bladder cancer in men and the adverse presentation and outcomes for this disease in women. We identify goals for improving patient survival and reducing gender disparities in bladder cancer.

NAT1 polymorphisms and cancer risk: a systematic review and meta-analysis

PURPOSE

To investigate the association between the N-acetyltransferase 1 (NAT1) slow and rapid acetylation phenotypes with cancer risk based on a meta-analysis.

METHODS

Previously published case-control studies were retrieved from PubMed, Embase, and Web of Science. Odds ratios (ORs) with 95% confidence intervals (CIs) were determined to assess the relationship between NAT1 polymorphisms and cancer risk.

RESULTS

A total of 73 studies (24874 cases and 30226 controls) were included in this meta-analysis. No significant association was identified between NAT1 polymorphisms (slow acetylation versus rapid acetylation genotypes: OR = 0.978, 95% CI = 0.927-1.030, P < 0.001 for heterogeneity, I(2) = 45.5%) and cancer risk, whereas a significantly reduced risk of pancreatic cancer was identified in individuals with NAT1 slow acetylation genotype (OR = 0.856, 95% CI = 0.733-0.999, P =0.509 for heterogeneity, I(2) = 0). When the NAT1 slow acetylation genotype was analysed on the basis of stratified analyses of ethnicity, a significantly reduced risk of head and neck cancers was found among Asian (OR=0.281, 95% CI = 0.127-0.622). When the NAT1 slow acetylation genotype was analysed on the basis of stratified analyses of source of control, only significantly reduced risks of colorectal cancer (OR = 0.882, 95% CI = 0.798- 0.974, P = 0.212 for heterogeneity, I(2) = 22.9) and pancreatic cancer (OR=0.856, 95% CI = 0.733-0.999, P = 0.509 for heterogeneity, I(2) = 0) were found among hospital-based studies.

CONCLUSIONS

No significant association between the NAT1 polymorphisms and the risk of cancer was found except for pancreatic cancer.

Bladder carcinoma data with clinical risk factors and molecular markers: a cluster analysis

Bladder cancer occurs in the epithelial lining of the urinary bladder and is amongst the most common types of cancer in humans, killing thousands of people a year. This paper is based on the hypothesis that the use of clinical and histopathological data together with information about the concentration of various molecular markers in patients is useful for the prediction of outcomes and the design of treatments of nonmuscle invasive bladder carcinoma (NMIBC). A population of 45 patients with a new diagnosis of NMIBC was selected. Patients with benign prostatic hyperplasia (BPH), muscle invasive bladder carcinoma (MIBC), carcinoma in situ (CIS), and NMIBC recurrent tumors were not included due to their different clinical behavior. Clinical history was obtained by means of anamnesis and physical examination, and preoperative imaging and urine cytology were carried out for all patients. Then, patients underwent conventional transurethral resection (TURBT) and some proteomic analyses quantified the biomarkers (p53, neu, and EGFR). A postoperative follow-up was performed to detect relapse and progression. Clusterings were performed to find groups with clinical, molecular markers, histopathological prognostic factors, and statistics about recurrence, progression, and overall survival of patients with NMIBC. Four groups were found according to tumor sizes, risk of relapse or progression, and biological behavior. Outlier patients were also detected and categorized according to their clinical characters and biological behavior.

Pioglitazone has a dubious bladder cancer risk but an undoubted cardiovascular benefit

On 8 April 2014, a US jury ordered Takeda and Eli Lilly to pay $9 bn in punitive damages after finding that they had concealed the cancer risks associated with pioglitazone. By contrast, on 28 August 2014, the long-awaited outcome of the 10-year Kaiser Permanente Northern California study was announced. That study was specifically designed to investigate whether patients exposed to pioglitazone were at an increased risk of bladder cancer and found no association; thus, at last, the controversial issue has been resolved. A review, in retrospect, of the story of the proposed link between pioglitazone and bladder cancer reveals flaws at every stage. In 2012, a BMJ editorial, in keeping with some other contemporary reports, stated 'it can confidently be assumed that pioglitazone increases the risk of bladder cancer'. Examination of the information which led to such a statement shows that: 1) the pre-clinical findings of bladder cancer in male rats is not indicative of human risk; 2) there is no association between bladder cancer and pioglitazone in randomized controlled trials, once cases that could not plausibly be related to treatment are removed; and 3) the observational studies that have suggested a link have over-extrapolated from the data: pioglitazone-treated patients had more risk factors for bladder cancer than those not treated with pioglitazone. Meanwhile careful study of randomized controlled trials shows evidence of cardiovascular benefit from pioglitazone in Type 2 diabetes, a condition which results, more than anything, in premature cardiovascular death and morbidity.

Exposure of hairdressers to ortho- and meta-toluidine in hair dyes

BACKGROUND

Carcinogenic aromatic amines derived from hair dyes have recently received new attention. One of these is ortho (o)-toluidine, which is classified as carcinogenic to humans.

OBJECTIVES

To clarify exposure of hairdressers to potentially carcinogenic aromatic amines, including o-toluidine.

METHODS

We measured eight potentially carcinogenic aromatic amines in the blood of 295 hairdressers, 32 users of hair dyes and 60 controls. The study was restricted to female non-smokers. Lifestyle data were collected for all participants using self-administered questionnaires. Blood samples were taken for analysis of ortho-, meta (m)- and para (p)-toluidine; 2-, 3- and 4-ethylaniline, 2,3- and 3,4-dimethylaniline as haemoglobin adducts. The samples were analysed with gas chromatography-tandem mass spectrometry.

RESULTS

Generally, adduct concentrations were in the range of 0-200 pg/g haemoglobin. A comparison of the adduct concentrations found in hairdressers, consumers and controls showed no statistically significant differences. However, for hairdressers, o- and m-toluidine concentrations increased significantly with the weekly number of hair waving (p=0.020) and permanent hair dyeing treatments (p=0.026), respectively. o-Toluidine and m-Toluidine concentrations also tended (p=0.076 and 0.080, respectively) to increase with the frequency of light-colour permanent hair dye treatments.

CONCLUSIONS

Hairdressers who use light-colour permanent hair dyes, other permanent hair dyes and hair waving treatments seem to be exposed to o- and m-toluidine as indicated by associations with the number of treatments performed. Analyses of hair waving and hair dye products should be performed to identify the possible sources of exposure to o- and m-toluidine.

Metabonomic profiling of bladder cancer

Early diagnosis and life-long surveillance are clinically important to improve the long-term survival of bladder cancer patients. Currently, a noninvasive biomarker that is as sensitive and specific as cystoscopy in detecting bladder tumors is lacking. Metabonomics is a complementary approach for identifying perturbed metabolic pathways in bladder cancer. Significant progress has been made using modern metabonomic techniques to characterize and distinguish bladder cancer patients from control subjects, identify marker metabolites, and shed insights on the disease biology and potential therapeutic targets. With its rapid development, metabonomics has the potential to impact the clinical management of bladder cancer patients in the future by revolutionizing the diagnosis and life-long surveillance strategies and stratifying patients for diagnostic, surgical, and therapeutic clinical trials. An introduction to metabonomics, typical metabonomic workflow, and critical evaluation of metabonomic investigations in identifying biomarkers for the diagnosis of bladder cancer are presented.

Genome-wide interaction study of smoking and bladder cancer risk

Bladder cancer is a complex disease with known environmental and genetic risk factors. We performed a genome-wide interaction study (GWAS) of smoking and bladder cancer risk based on primary scan data from 3002 cases and 4411 controls from the National Cancer Institute Bladder Cancer GWAS. Alternative methods were used to evaluate both additive and multiplicative interactions between individual single nucleotide polymorphisms (SNPs) and smoking exposure. SNPs with interaction P values < 5 × 10(-) (5) were evaluated further in an independent dataset of 2422 bladder cancer cases and 5751 controls. We identified 10 SNPs that showed association in a consistent manner with the initial dataset and in the combined dataset, providing evidence of interaction with tobacco use. Further, two of these novel SNPs showed strong evidence of association with bladder cancer in tobacco use subgroups that approached genome-wide significance. Specifically, rs1711973 (FOXF2) on 6p25.3 was a susceptibility SNP for never smokers [combined odds ratio (OR) = 1.34, 95% confidence interval (CI) = 1.20-1.50, P value = 5.18 × 10(-) (7)]; and rs12216499 (RSPH3-TAGAP-EZR) on 6q25.3 was a susceptibility SNP for ever smokers (combined OR = 0.75, 95% CI = 0.67-0.84, P value = 6.35 × 10(-) (7)). In our analysis of smoking and bladder cancer, the tests for multiplicative interaction seemed to more commonly identify susceptibility loci with associations in never smokers, whereas the additive interaction analysis identified more loci with associations among smokers-including the known smoking and NAT2 acetylation interaction. Our findings provide additional evidence of gene-environment interactions for tobacco and bladder cancer.

Toxicogenetic profile and cancer risk in Lebanese

An increasing number of genetic polymorphisms in drug-metabolizing enzymes (DME) were identified among different ethnic groups. Some of these polymorphisms are associated with an increased cancer risk, while others remain equivocal. However, there is sufficient evidence that these associations become significant in populations overexposed to environmental carcinogens. Hence, genetic differences in expression activity of both Phase I and Phase II enzymes may affect cancer risk in exposed populations. In Lebanon, there has been a marked rise in reported cancer incidence since the 1990s. There are also indicators of exposure to unusually high levels of environmental pollutants and carcinogens in the country. This review considers this high cancer incidence by exploring a potential gene-environment model based on available DME polymorphism prevalence, and their impact on bladder, colorectal, prostate, breast, and lung cancer in the Lebanese population. The examined DME include glutathione S-transferases (GST), N-acetyltransferases (NAT), and cytochromes P-450 (CYP). Data suggest that these DME influence bladder cancer risk in the Lebanese population. Evidence indicates that identification of a gene-environment interaction model may help in defining future research priorities and preventive cancer control strategies in this country, particularly for breast and lung cancer.

Epidemiology and risk factors of urothelial bladder cancer

CONTEXT

Urothelial bladder cancer (UBC) is a disease of significant morbidity and mortality. It is important to understand the risk factors of this disease.

OBJECTIVE

To describe the incidence, prevalence, and mortality of UBC and to review and interpret the current evidence on and impact of the related risk factors.

EVIDENCE ACQUISITION

A literature search in English was performed using PubMed. Relevant papers on the epidemiology of UBC were selected.

EVIDENCE SYNTHESIS

UBC is the 7th most common cancer worldwide in men and the 17th most common cancer worldwide in women. Approximately 75% of newly diagnosed UBCs are noninvasive. Each year, approximately 110 500 men and 70 000 women are diagnosed with new cases and 38 200 patients in the European Union and 17 000 US patients die from UBC. Smoking is the most common risk factor and accounts for approximately half of all UBCs. Occupational exposure to aromatic amines and polycyclic aromatic hydrocarbons are other important risk factors. The impact of diet and environmental pollution is less evident. Increasing evidence suggests a significant influence of genetic predisposition on incidence.

CONCLUSIONS

UBC is a frequently occurring malignancy with a significant impact on public health and will remain so because of the high prevalence of smoking. The importance of primary prevention must be stressed, and smoking cessation programs need to be encouraged and supported.

Personal hair dye use and the risk of bladder cancer: a case-control study from The Netherlands

BACKGROUND

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.

OBJECTIVE

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).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Nonsteroidal anti-inflammatory drugs and other analgesic use and bladder cancer in northern New England

A few epidemiologic studies have found that use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with reduced risk of bladder cancer. However, the effects of specific NSAID use and individual variability in risk have not been well studied. We examined the association between NSAIDs use and bladder cancer risk, and its modification by 39 candidate genes related to NSAID metabolism. A population-based case-control study was conducted in northern New England, enrolling 1,171 newly diagnosed cases and 1,418 controls. Regular use of nonaspirin, nonselective NSAIDs was associated with reduced bladder cancer risk, with a statistically significant inverse trend in risk with duration of use (ORs of 1.0, 0.8, 0.6 and 0.6 for <5, 5-9, 10-19 and 20+ years, respectively; p(trend) = 0.015). This association was driven mainly by ibuprofen; significant inverse trends in risk with increasing duration and dose of ibuprofen were observed (p(trend) = 0.009 and 0.054, respectively). The reduced risk from ibuprofen use was limited to individuals carrying the T allele of a single nucleotide polymorphism (rs4646450) compared to those who did not use ibuprofen and did not carry the T allele in the CYP3A locus, providing new evidence that this association might be modified by polymorphisms in genes that metabolize ibuprofen. Significant positive trends in risk with increasing duration and cumulative dose of selective cyclooxygenase (COX-2) inhibitors were observed. Our results are consistent with those from previous studies linking use of NSAIDs, particularly ibuprofen, with reduced risk. We observed a previously unrecognized risk associated with use of COX-2 inhibitors, which merits further evaluation.