A Job–Exposure Matrix for Potential Endocrine-disrupting Chemicals Developed for a Study into the Association between Maternal Occupational Exposure and Hypospadias

A study to assess the association between the prevalence of hypospadias and maternal occupational exposure to potential endocrine-disrupting chemicals was carried out using data from the congenital anomaly register of the Office for National Statistics. The occupation of the mother is recorded in this register and to facilitate the assessment of maternal occupational exposure, a specific job–exposure matrix for potential endocrine-disrupting chemicals was developed. Seven categories of contaminants were evaluated (pesticides, polychlorinated organic compounds, phthalates, alkylphenolic compounds, bi-phenolic compounds, heavy metals and other substances). Maternal occupations were all coded using the 1980 version of Categories of Occupations. Three occupational hygienists assessed the likelihood of exposure (unlikely, possible, probable) to these seven substance groups for all 348 possible job titles independently. Almost 30% of the job titles were classified as exposed to at least one substance category (possible or probable), with ∼16% of the job titles being probably exposed to at least one substance category. Some examples of occupations with probable exposure to potential endocrine-disrupting chemicals include: farm workers, electricians, workers in the plastics industry, painters, printers, hairdressers, dental practitioners, laboratory workers, textile workers and cleaners. It is recognized that there are a lot of limitations to the use of job–exposure matrices in general and with the matrix presented in this paper in particular. However, the matrix forms the basis on which further developments on occupational exposure assessment of potential endocrine-disrupting chemicals could be founded. In addition, the job–exposure matrix has identified areas where more exposure information is required. For example, exposure to potential endocrine-disrupting chemicals can occur in occupations such as hairdressing and workers in beauty salons, where the working population is more likely to be female and for which little data exist on levels of exposure.