Exposure to one of the world’s most widely used chemicals is associated with an increased risk of heart disease - the leading cause of death globally – research from Exeter Professors Tamara Galloway and David Melzer has found.
This research has been instrumental in providing evidence which questions the safety of this environmental pollutant in humans and has led to regulatory authorities across the world committing to reducing bisphenol A (BPA) in food and drinks.
More than 95 per cent of the population is exposed to BPA - a synthetic oestrogen used in the creation of polycarbonate plastics, such as plastic bottles and food containers, and the epoxy resins used to line cans. Exposure to BPA occurs mainly when people eat or drink BPA-contaminated food and drinks with additional exposure coming from dental sealants, BPA-coated paper and household dusts.
After examining data from the US Health and Nutrition Examination Survey (NHANES), Professor David Melzer, Professor of Epidemiology and Public Health and Professor Galloway, a Professor of Ecotoxicology, discovered that exposure to BPA, shown by the presence of BPA metabolites in urine, was significantly associated with the incidence of heart disease, type 2 diabetes, hormonal imbalance and with increased concentrations of key liver enzymes.
The 25 per cent of the population with the highest exposure to BPA were three times more likely to develop heart disease. Since then, the results for heart disease have been replicated in a separate population and the team has been able to show that exposure to the chemical predates the development of heart disease by up to ten years.
The team have also found that exposure to BPA is associated with changes in testosterone levels in men with BPA, which is a synthetic oestrogen, acting as an endocrine disruptor.
Professors Galloway and Melzer presented their findings to the Food and Drug Administration (FDA) in the USA in 2008 and in 2014 the European Food Standards Agency announced its intention to reduce the recommended tolerable daily limit for BPA for the general population.
Countries including the USA, Germany, Canada plus the European Union have published policy papers discussing the results of the study and its impact on legislation. The FDA has said it has ‘some concern’ over BPAs safety particularly for infants and young children. Canada, France, and Denmark have declared BPA a toxin and banned it from baby bottles. While the USA and EU have prohibited its use in infant feeding containers.
Professor Galloway said "We now need to investigate what causes these health risk associations in more detail and to clarify whether they are caused by BPA itself or by some other factor linked to BPA exposure. The risks associated with exposure to BPA may be small, but they are relevant to very large numbers of people."
The suggestion that there may be health risks associated with everyday exposure to this common chemical is controversial. Animal and laboratory studies of BPA exposure consistently reported adverse health effects at concentrations well below the recommended tolerable daily intake, but data on human health had previously been lacking.
Now work by Exeter’s Environmental Biology group and College of Medicine and Health has addressed this lack of human health-related data. This research has prompted an increased public awareness of the risks associated with common environmental chemicals and has led to increased industrial interest in finding safer alternatives.