Cadmium, Age at Menarche, and Early Puberty in Girls
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Non-technical overview of the research topic and relevance to breast cancer: 
 
 
 
 Women who experience their first menstrual period (i.e., menarche) before the age of 12 years have an increased risk of breast cancer. This association is consistent with the hypothesis that women who experience menarche at an earlier age experience a longer period during which susceptible breast cells are exposed to carcinogens, which may induce these cells to become cancerous. Over the past two decades the average age at menarche has been declining in the US and Europe. While the causes of early menarche and puberty are largely unknown, emerging evidence from animal studies suggest that increasing exposures to environmental chemicals that act as estrogens in the body may be contributing to this trend. Cadmium (Cd), a trace metal released into air and soil as a byproduct of industrial processes, is perhaps the most potent of these estrogenic chemicals. While the major sources of non-occupational exposure to Cd in adults include cigarette smoke, diet, and inhalation of air contaminated by industrial processes and combustion of fossil fuels, recent discoveries of Cd in children’s toys and jewelry have led to public concern about potential children’s exposure from ingestion and hand-to-mouth activity. Having a higher level of Cd in the body has been previously associated with breast cancer risk. It is possible that early-life exposure to this estrogenic metal may contribute to earlier age at menarche and pubertal development and thus also contribute to the risk of breast cancer.
 
 
 
 
 
 The question(s) or central hypotheses of the research: 
 
 
 
 The primary hypothesis of this proposal is that the measured concentration of Cd in urine, an indicator of lifetime exposure to this metal, is associated with an earlier age at menarche and early onset of pubertal development.
 
 
 
 
 
 The general methodology: 
 
 
 
 This proposed study will utilize existing data and urine specimens from the GRowth and LifeStyle Study (GRLS), a prospective cohort study of girls. A total of 214 girls, aged 10-13 years at the start of the study, provided overnight urine specimens that will be used to measure urinary Cd levels, completed an interview, provided a self-assessment of breast development and public hair growth based on standard pictorial depictions and verbal descriptions, and had their height and weight measured. A total of 87 girls had their first menstrual period prior to the start of the study, while 134 girls had not yet attained menarche at the start of the study and followed for up to two years using monthly questionnaires to ascertain the onset of menarche and pubertal development and an additional urine specimen was collected. Laboratory assays will measure urinary levels of Cd in the urine specimens. These indicators of Cd exposure will be compared with girls’ age at menarche and stage of breast and pubic hair development.
 
 
 
 
 
 Innovative elements of the project:
 
 
 
 Given the estrogenic potential of Cd, this proposed study would be one of the first evaluations of Cd and its role in the timing of menarche and pubertal development. One of the innovative aspects of this project is the fact that urine specimens were collected at the start of study from 134 girls who had not yet attained of menarche. Thus, we will be able to evaluate prospectively whether measured Cd levels from the beginning of follow-up predict the timing of menarche.
 
 
 
 
 
 Advocacy involvement and relevance to the human issues associated with breast cancer:
 
 
 
 As Cd exposures are potentially modifiable, this proposed study offers tremendous potential to contribute to our knowledge about the prevention of early menarche, a known risk factor for breast cancer. This project has high potential for meaningful translation into the reduction of children’s exposures to this estrogenic metal. If this study finds an association between early pubertal development and cadmium exposure, it could provide a major impetus for further regulatory actions to reduce the use of cadmium in industrial processes and the development of public health strategies to reduce exposures. To ensure our results are translated into actions aimed at mitigating the burden of exposure, we will disseminate our results to the scientific and lay communities, as well as to policy makers, using both a scientific manuscripts and lay-friendly fact sheet. Breast cancer and environmental advocacy organizations will play a critical role in the translation of findings from our study into meaningful and measurable interventions.