A breakthrough study claims to have demonstrated for the first time that bisphenol A (BPA) can cause changes in male human sex hormones.
An international group of researchers, led by the Peninsula Medical School and the University of Exeter, in the UK, said it has found a correlation between higher BPA exposure and a small increase in levels of testosterone in the blood. The findings justify the need for human safety studies to gauge its effect on the population, they added.
The team came to its conclusions after analysing data from the Italian population sample, InCHIANTI and measuring the amount of BPA excreted per day in urine samples. Some 715 adults aged between 20 and 74 years were studied and any “statistical associations” between the amount of BPA exposure and serum oestrogen and testosterone concentrations were measured.
The researcher found that the average BPA daily exposure level in this European study population – at over 5 micrograms per day - was slightly higher than recent comparable estimates for the US population. The study found that higher BPA exposure was statistically associated with endocrine changes in men, specifically small increases in levels of testosterone in the blood.
The scientists stated that BPA has a similar molecular structure to oestrogen and said it has been proved that the chemical does cause some disruption of sex hormone signalling in laboratory animals. The significance of theses findings is that this is the first large human study to suggest that it may have similar effects in adults at 'background' exposure levels, they added.
"This is the first big study of BPA from a European country and confirms that 'routine' exposures in the population are not negligible,” said David Melzer, Professor of Epidemiology and Public Health at the Peninsula Medical School.
“It also shows that higher exposure to BPA is statistically associated with modest changes in levels of testosterone in men. This finding is consistent with the evidence from laboratory experiments. However, this is just the first step in proving that at 'ordinary' exposure levels, BPA might be active in the human body. This new evidence does justify proper human safety studies to clarify the effects of BPA in people," he added.