A prospective ultrasound study of cigarette smoking and uterine leiomyomata incidence and growth

A Prospective Ultrasound Study of Whole Blood Metals and Incidence of Uterine Leiomyomata

BACKGROUND

Uterine leiomyomata (UL), hormone-dependent neoplasms, are a major source of gynecologic morbidity. Metals are hypothesized to influence UL risk through endocrine disruption, and their effects may vary by vitamin D status.

OBJECTIVE

We estimated associations of a metal mixture with incident UL, overall and by vitamin D status.

METHODS

We analyzed data from the Study of Environment, Lifestyle and Fibroids, a Detroit-area prospective cohort study of 1,693 black women 23-35 years of age. We measured concentrations of 17 metals/metalloids in whole blood and 25-hydroxyvitamin D [25(OH)D] in serum collected at baseline (2010-2012). Participants underwent ultrasonography at baseline and after 20 months to detect UL. We used Bayesian kernel machine regression to estimate adjusted associations (β ) of the metal mixture with probit of incident UL. We also ran Cox regression models with interaction terms to estimate incidence rate ratios (IRR) by vitamin D status.

RESULTS

Among 1,132 UL-free participants at baseline, 832 (73%) had vitamin D deficiency [25(OH)D < 20  ng / mL ] and 117 (10%) developed UL within 20 months. Increasing all metals from their 50th to 75th percentiles was weakly positively associated with UL overall [β = 0.06 ; 95% credible interval (CrI): - 0.03 , 0.16] and among vitamin D-deficient participants (β = 0.13 ; 95% CrI: 0.01, 0.24), driven by cadmium (overall and vitamin D-deficient) and mercury (vitamin D-deficient only). Increasing cadmium from its 25th to 75th percentile was positively associated with UL overall (β = 0.03 ; 95% CrI: - 0.05 , 0.11) and among vitamin D-deficient participants (β = 0.13 , 95% CrI: 0.02, 0.24). In Cox models, cadmium [IRR = 1.55 ; 95% confidence interval (CI): 1.07, 2.24, per 1-unit increase in standardized concentration] and mercury (IRR = 1.38 ; 95% CI: 0.99, 1.92) were positively associated with UL among vitamin D-deficient participants.

DISCUSSION

The metal mixture was positively associated with incident UL, but the association was weak and imprecise. We observed a stronger association among vitamin D-deficient participants that was driven by cadmium and mercury. https://doi.org/10.1289/EHP15218.

GWAS-Significant Loci and Uterine Fibroids Risk: Analysis of Associations, Gene-Gene and Gene-Environmental Interactions

BACKGROUND

Uterine fibroids (UF) is the most common benign tumour of the female reproductive system. We investigated the joint contribution of genome-wide association studies (GWAS)-significant loci and environment-associated risk factors to the UF risk, along with epistatic interactions between single nucleotide polymorphisms (SNPs).

METHODS

DNA samples from 737 hospitalised patients with UF and 451 controls were genotyped using probe-based PCR for seven common GWAS SNPs: rs117245733 LINC00598, rs547025 SIRT3, rs2456181 ZNF346, rs7907606 STN1, SLK, rs58415480 SYNE1, rs7986407 FOXO1, and rs72709458 TERT.

RESULTS

We observed an association between rs547025 SIRT3 and the decreased risk of UF in overall group (effect allele C, odds ratio (OR) = 0.61, 95% confidence interval (CI) = 0.43-0.866, p = 0.005). SNP rs547025 exhibits protective effects against UF exclusively in patients with normal fruit and vegetable intake (OR = 0.39, 95% CI = 0.21-0.75, p = 0.002), no history of spontaneous abortions (OR = 0.48, 95% CI = 0.33-0.70, p = 0.0001), no pelvic inflammatory diseases (PID) in anamnesis (OR = 0.55, 95% CI = 0.38-0.80, p = 0.0016), and in smokers (OR = 0.20, 95% CI = 0.06-0.65, p = 0.006). In addition, rs7907606 STN1, SLK was associated with the risk of UF in patients without a history of pelvic inflammatory diseases (PID) (OR = 1.34, 95% CI = 1.03-1.74, p = 0.028). SNPs rs547025 SIRT3 and rs7907606 STN1, SLK, displayed the strongest mono-effects (0.71% and 0.52% contribution to UF entropy) and were characterized by the most pronounced gene-gene (G×G) effects when interacting with each other (0.60% contribution to entropy). The interaction Medical abortion×rs547025 SIRT3 served as the base for all the best gene-environment (G×E) models. Medical abortions have the most pronounced mono-effect (1.15% contribution to the entropy of UF), exceeding the mono-effects of SNPs involved in the most significant G×E-models (0.01%-0.49% contribution to entropy) and spontaneous abortions (0.48% of UF entropy) and exceeding the effects of G×E interactions (0.05-0.46% of UF entropy).

CONCLUSIONS

Bioinformatics analysis showed that GWAS SNPs are involved in the molecular mechanisms of UF mainly through the regulation of vasculogenesis, cell proliferation, apoptosis, DNA damage, inflammation, hypoxia, steroid hormone metabolism, cell signaling, organ formation.

Higher Risk of Wound Complications but No Clinically Significant Increase in Operative Time for Smokers Receiving Myomectomy for Uterine Fibroids

Myomectomy is a common procedure to remove uterine fibroids. Smoking impacts outcomes across various surgeries; however, may limit fibroid growth. We sought to determine if smoking impacts myomectomy for uterine fibroid removal outcomes. Patients with and without a history of tobacco smoking receiving a myomectomy for uterine fibroid removal were compared. Compared to patients with no history of tobacco smoking, tobacco smokers had a significantly increased risk of wound complications. No other variables analyzed demonstrated a clinically significant difference. Future research is needed to examine how different frequency of tobacco smoking impacts outcomes.

Racial disparity in uterine leiomyoma: new insights of genetic and environmental burden in myometrial cells

Uterine leiomyoma (LM), also known as uterine fibroids, are common gynecological tumors and can reach a prevalence of 70% among women by the age of 50 years. Notably, the LM burden is much higher in Black women with earlier onset, a greater tumor number, size, and severity compared to White women. Published knowledge shows that there are genetic, environmental, and lifestyle-based risk factors associated with racial disparity for LM. Significant strides have been made on genomic, epigenomic, and transcriptomic data levels in Black and White women to elucidate the underlying pathomolecular reasons of racial disparity in LM development. However, racial disparity of LM remains a major area of concern in gynecological research. This review highlights risk factors of LM and their role in different races. Furthermore, we discuss the genetics and uterine myometrial microenvironment in LM development. Comparative findings revealed that a major racial difference in the disease is linked to myometrial oxidative burden and altered ROS pathways which is relevant to the oxidized guanine in genomic DNA and MED12 mutations that drive the LM genesis. Considering the burden and morbidity of LM, we anticipate that this review on genetic risk and myometrial microenvironment will strengthen understanding and propel the growth of research to address the racial disparity of LM burden.