Exogenous hormone use and cutaneous melanoma risk in women: The European Prospective Investigation into Cancer and Nutrition

Evidence suggests an influence of sex hormones on cutaneous melanoma risk, but epidemiologic findings are conflicting. We examined the associations between use of oral contraceptives (OCs) and menopausal hormone therapy (MHT) and melanoma risk in women participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). EPIC is a prospective cohort study initiated in 1992 in 10 European countries. Information on exogenous hormone use at baseline was derived from country-specific self-administered questionnaires. We used Cox proportional hazards regression models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Over 1992–2015, 1,696 melanoma cases were identified among 334,483 women, whereof 770 cases among 134,758 postmenopausal women. There was a positive, borderline-significant association between OC use and melanoma risk (HR = 1.12, 95% CI = 1.00–1.26), with no detected heterogeneity across countries (p_homogeneity = 0.42). This risk increased linearly with duration of use (p_trend = 0.01). Among postmenopausal women, ever use of MHT was associated with a nonsignificant increase in melanoma risk overall (HR = 1.14, 95% CI = 0.97–1.43), which was heterogeneous across countries (p_homogeneity = 0.05). Our findings do not support a strong and direct association between exogenous hormone use and melanoma risk. In order to better understand these relations, further research should be performed using prospectively collected data including detailed information on types of hormone, and on sun exposure, which may act as an important confounder or effect modifier on these relations.     

Theoretical potential for endometrial cancer prevention through primary risk factor modification: Estimates from the EPIC cohort

Endometrial cancer (EC) incidence rates vary ~10-fold worldwide, in part due to variation in EC risk factor profiles. Using an EC risk model previously developed in the European EPIC cohort, we evaluated the prevention potential of modified EC risk factor patterns and whether differences in EC incidence between a European population and low-risk countries can be explained by differences in these patterns. Predicted EC incidence rates were estimated over 10 years of follow-up for the cohort before and after modifying risk factor profiles. Risk factors considered were: body mass index (BMI, kg/m²), use of postmenopausal hormone therapy (HT) and oral contraceptives (OC) (potentially modifiable); and, parity, ages at first birth, menarche and menopause (environmentally conditioned, but not readily modifiable). Modeled alterations in BMI (to all ≤23 kg/m²) and HT use (to all non-HT users) profiles resulted in a 30% reduction in predicted EC incidence rates; individually, longer duration of OC use (to all ≥10 years) resulted in a 42.5% reduction. Modeled changes in not readily modifiable exposures (i.e., those not contributing to prevention potential) resulted in ≤24.6% reduction in predicted EC incidence. Women in the lowest decile of a risk score based on the evaluated exposures had risk similar to a low risk countries; however, this was driven by relatively long use of OCs (median = 23 years). Our findings support avoidance of overweight BMI and of HT use as prevention strategies for EC in a European population; OC use must be considered in the context of benefits and risks.     

The association between adverse childhood experiences and adult traumatic brain injury/concussion: a scoping review

Background: Adverse childhood experiences are significant risk factors for physical and mental illnesses in adulthood. Traumatic brain injury/concussion is a challenging condition where pre-injury factors may affect recovery. The association between childhood adversity and traumatic brain injury/concussion has not been previously reviewed. The research question addressed is: What is known from the existing literature about the association between adverse childhood experiences and traumatic brain injury/concussion in adults?

Methods: All original studies of any type published in English since 2007 on adverse childhood experiences and traumatic brain injury/concussion outcomes were included. The literature search was conducted in multiple electronic databases. Arksey and O’Malley and Levac et al.’s scoping review frameworks were used. Two reviewers independently completed screening and data abstraction.

Results: The review yielded six observational studies. Included studies were limited to incarcerated or homeless samples, and individuals at high-risk of or with mental illnesses. Across studies, methods for childhood adversity and traumatic brain injury/concussion assessment were heterogeneous.

Discussion: A positive association between adverse childhood experiences and traumatic brain injury occurrence was identified. The review highlights the importance of screening and treatment of adverse childhood experiences. Future research should extend to the general population and implications on injury recovery.

• Implications for rehabilitation

• Exposure to adverse childhood experiences is associated with increased risk of traumatic brain injury.

• Specific types of adverse childhood experiences associated with risk of traumatic brain injury include childhood physical abuse, psychological abuse, household member incarceration, and household member drug abuse.

• Clinicians and researchers should inquire about adverse childhood experiences in all people with traumatic brain injury as pre-injury health conditions can affect recovery.

     

Use of a new model of transgenic mice to clarify the respective functions of thyroid hormone receptors in vivo

3,5,3′-Triido-l-thyronine (T3) exerts pleiotropic actions on development and homeostasis mostly via its nuclear receptors, TRα1, TRβ1, and TRβ2, encoded by the THRA and THRB genes. Μouse genetics data outline the contrasting functions of THRA and THRB, and suggest that these are dictated by both the respective abundance of the receptor isoforms in a given cell type and the differences in the intrinsic properties of the receptors. The diversity of consequences of either hypothyroidism or THRA/THRB mutation is astonishing, suggesting that TR controls a large number of genes and that the repertoire of target gene differs from one tissue to another. In order to distinguish between the direct and indirect actions of TH in vivo, we use the CRE/LoxP recombination system to control the expression of a mutant TRα1 receptor with dominant negative properties. Ubiquitous expression of this mutation in heterozygous mice recapitulates many consequences of TH deficiency, except in tissues where TRβ is highly expressed.