Serum metabolomic profile of hair dye use.

The International Agency for Research on Cancer reported that some chemicals in hair dyes are probably carcinogenic to those exposed to them occupationally. Biological mechanisms through which hair dye use may be related to human metabolism and cancer risk are not well-established. We conducted the first serum metabolomic examination comparing hair dye users and nonusers in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Metabolite assays were conducted using ultrahigh performance liquid chromatography-tandem mass spectrometry. The association between metabolite levels and hair dye use was estimated using linear regression, adjusting for age, body mass index, smoking, and multiple comparisons. Among the 1,401 detected metabolites, 11 compounds differed significantly between the two groups, including four amino acids and three xenobiotics. Redox-related glutathione metabolism was heavily represented, with L-cysteinylglycine disulfide showing the strongest association with hair dye (effect size (ß) = - 0.263; FDR adjusted p-value = 0.0311), along with cysteineglutathione disulfide (ß = - 0.685; FDR adjusted p-value = 0.0312). 5alpha-Androstan-3alpha,17beta-diol disulfate was reduced in hair dye users (ß = - 0.492; FDR adjusted p-value = 0.077). Several compounds related to antioxidation/ROS and other pathways differed significantly between hair dye users and nonusers, including metabolites previously associated with prostate cancer. Our findings suggest possible biological mechanisms through which the use of hair dye could be associated with human metabolism and cancer risk.

A 28-year prospective analysis of serum vitamin E, vitamin E-related genetic variation and risk of prostate cancer.

OBJECTIVE: Investigate the relationship between serum α-tocopherol concentration and long-term risk of prostate cancer, and evaluate the interaction with vitamin E-related genetic variants and their polygenic risk score (PRS). METHODS: We conducted a biochemical analysis of 29,102 male Finnish smokers in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Serum α-tocopherol was measured at baseline using high-performance liquid chromatography, and 2724 prostate cancer cases were identified during 28 years of follow-up. Cox proportional hazards models examined whether serum α-tocopherol concentrations were associated with prostate cancer risk. Among 8383 participants, three SNPs related to vitamin E status (rs964184, rs2108622, and rs11057830) were examined to determine whether they modified the relationship between serum α-tocopherol concentrations and prostate cancer risk, both individually and as a PRS using logistic regression models. RESULTS: No association was observed between serum α-tocopherol and prostate cancer risk (fifth quintile (Q5) vs. Q1 hazard ratio (HR) = 0.87, 95% confidence interval (95% CI) 0.75, 1.02; P-trend = 0.57). Though no interactions were seen by population characteristics, high α-tocopherol concentration was associated with reduced prostate cancer risk among the trial α-tocopherol supplementation group (Q5 quintile vs. Q1 HR = 0.79, 95% CI 0.64, 0.99). Finally, no associated interaction between the three SNPs or their PRS and prostate cancer risk was observed. CONCLUSION: Although there was a weak inverse association between α-tocopherol concentration and prostate cancer risk over nearly three decades, our findings suggest that men receiving the trial α-tocopherol supplementation who had higher baseline serum α-tocopherol concentration experienced reduced prostate cancer risk. Vitamin E-related genotypes did not modify the serum α-tocopherol-prostate cancer risk association.

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.