Journal

Environmental Research

Papers (7)

Hair relaxer use and risk of uterine cancer in the Black Women's Health Study

Chemical hair relaxers, use of which is highly prevalent among Black women in the US, have been inconsistently linked to risk of estrogen-dependent cancers, such as breast cancer, and other reproductive health conditions. Whether hair relaxer use increases risk of uterine cancer is unknown. In the Black Women's Health Study, 44,798 women with an intact uterus who self-identified as Black were followed from 1997, when chemical hair relaxer use was queried, until 2019. Over follow-up, 347 incident uterine cancers were diagnosed. We used multivariable Cox proportional hazards regression models, adjusted for age and other potential confounders, to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of hair relaxer use with risk of uterine cancer. Compared to women who never used hair relaxers or used them infrequently (<4 years and ≤1-2 times/year), the HR for uterine cancer associated with heavy use (≥15 years and at least 5 times/year) was 1.18 (95% CI: 0.81, 1.71). However, among postmenopausal women, compared to never/light use, the HR for moderate use was 1.60 (95% CI: 1.01, 2.53), the HR for heavy use was 1.64 (1.01, 2.64), and the HR for ≥20 years of use regardless of frequency was 1.71 (1.08, 2.72). Results among premenopausal women were null. In this large cohort of Black women, long-term use of chemical hair relaxers was associated with increased risk of uterine cancer among postmenopausal women, but not among premenopausal women. These findings suggest that hair relaxer use may be a potentially modifiable risk factor for uterine cancer.

Plastic-related endocrine disrupting chemicals significantly related to the increased risk of estrogen-dependent diseases in women

To evaluate the association between exposure to plastic-related endocrine-disrupting chemicals (EDCs), specifically Bisphenol A (BPA), Phthalates, Cadmium, and Lead, and the risk of estrogen-dependent diseases (EDDs) such as polycystic ovary syndrome (PCOS), endometriosis, or endometrial cancer by conducting a meta-analysis of relevant studies. PubMed, Web of Science, and Cochrane Library databases were used for literature retrieval of articles published until the 21st of April 2023. Literature that evaluated the association between BPA, phthalates, cadmium, and/or lead exposure and the risk of PCOS, endometriosis, or endometrial cancer development or exacerbation were included in our analysis. STATA/MP 17.0 was used for all statistical analyses. Overall, 22 articles were included in our meta-analysis with a total of 83,641 subjects all of whom were females aged between 18 and 83 years old. The overall effect size of each study was as follows: endometriosis risk in relation to BPA exposure ES 1.82 (95% CI; 1.50, 2.20). BPA and PCOS risk ES 1.61 (95% CI; 1.39, 1.85). Phthalate metabolites and endometriosis risk; MBP ES 1.07 (95% CI; 0.86, 1.33), MEP ES 1.05 (95% CI; 0.87, 1.28), MEHP ES 1.15 (95% CI; 0.67, 1.98), MBzP ES 0.97 (95% CI; 0.63, 1.49), MEOHP ES 1.87 (95% CI; 1.21, 2.87), and MEHHP ES 1.98 (95% CI; 1.32, 2.98). Cadmium exposure and endometrial cancer risk ES 1.14 (95% CI; 0.92, 1.41). Cadmium exposure and the risk of endometriosis ES 2.54 (95% CI; 1.71, 3.77). Lead exposure and the risk of endometriosis ES 1.74 (95% CI; 1.13, 2.69). Increased serum, urinary, or dietary concentration of MBzP and MEHP in women is significantly associated with endometriosis risk. Increased cadmium concentration is associated with endometrial cancer risk.

Solid fuel use for heating and risks of breast and cervical cancer mortality in China

Carcinogens released from indoor burning of solid fuels are believed to enter the bloodstream and to be metabolized in breast and cervical tissues. Little evidence exists about the relationship of solid fuel use from heating with breast and cervical cancer. To examine the association of solid heating fuel use with breast and cervical cancer mortality. This study included female participants aged 30-79 years who were enrolled in the China Kadoorie Biobank during 2004-2008 from 10 diverse regions across China. During a 10.2-year median follow-up, 177 breast cancer deaths and 113 cervical cancer deaths were documented. Multivariable Cox regression models yielded adjusted hazard ratios (HRs) for the associations of self-reported long-term heating fuel exposure with two cancer deaths. Stratified analyses were used to assess effect modification. We included 236,116 participants for breast cancer analyses and 228,795 for cervical cancer analyses. Compared with non-solid fuel use, the fully adjusted HRs of cervical cancer deaths were 1.75 (0.91-3.38) for wood use, 2.23 (1.09-4.59) for mixed fuel (coal and wood) use. No evident relationship was observed for breast cancer deaths. Cervical cancer risk increased with the duration of solid fuel use (P for trend = 0.041). Elevated cervical cancer risk was observed in post-menopausal women (HR 2.01, 1.01-4.03), not in pre-menopausal women (HR 0.77, 0.56-2.31) (P for heterogeneity = 0.004); and in those aged ≥50 years (HR 2.56, 1.17-5.86), not in those aged < 50 years (HR 0.69, 0.26-1.84) (P < 0.001). Indoor solid fuel combustion for heating may be associated with a higher risk for cervical cancer death, but not for breast cancer. The strength of the association increased with the duration of exposure and was modified by age and menopause status.

Publisher

Elsevier BV

ISSN

0013-9351