One thing is for sure. Headline writers last week must have been thrilled by the study that linked exposure to bisphenol A with sexual dysfunction in Chinese men. 鈥淪tudy a real downer.鈥� 鈥淗ard plastic has a soft side鈥� I think I could come up with some. How about 鈥淭he Rise and Fall of bisphenol A鈥� or 鈥淐hemical Unglues Chinese Glue Producers.鈥� To be sure, any study that hits men below the belt can be expected to cause concern, except perhaps among writers who see an opportunity to rise to the occasion and show off their wit. But if the results of this study are to be believed, rising to the occasion when it really matters may present a problem, at least for men with exceedingly large exposure to bisphenol A. This chemical has been in the news extensively because of various studies linking it to a range of possible health problems. Allegations have included links to breast, testicular and prostate cancers, diabetes, heart disease, shrivelled testicles, reduced sperm counts, breast growth in men, premature puberty in girls, aggression in female babies, misshaped penises, undescended testes and thwarted cancer treatments. Can one substance cause all these problems? It鈥檚 unlikely. The problem is that the supposed crimes of which bisphenol A is accused are based either on animal experiments or theoretical postulations. Nevertheless, some concern is justified given that, as evidenced by blood and urine tests, most of us harbour some bisphenol A in our bodies. This is hardly surprising since the chemical is used to make epoxy glues, resins that line food cans, carbonless paper receipts and polycarbonate plastics that show up in numerous consumer items ranging from refillable water bottles and kitchen appliances to hockey helmets and laptops. While there has been no lack of debate, much of it acrimonious, about the safety of bisphenol A, there has been a lack of data based on human studies. The Chinese study sought to remedy this situation.
Researchers compared exposure to bisphenol A among workers who were involved in the production of epoxy adhesives to that of a group of men matched for a similar lifestyle but with no direct exposure to the chemical. It came as no surprise that air samples in the epoxy factory showed the presence of bisphenol A, as did urine samples from the workers. In fact concentrations in the urine were fifty times greater than in the control group. Questionnaires revealed a link between bisphenol A exposure and an increased risk of impotence and decreased sexual satisfaction. So what does this all mean? First of all, although statistically significant, only 20% of the epoxy workers complained of sexual problems in spite of the massive exposure. And undoubtedly these workers were also exposed to a slew of other chemicals in the workplace, but these were not looked for. How about stress in the workplace? That can lead to problems at home. What about diseases such as heart disease and diabetes? These can lead to sexual dysfunction. Were they more prevalent in the factory workers? It isn鈥檛 clear. There is another curiosity here. Such sexual dysfunction is best explained by estrogenic or anti-androgenic effects. But laboratory tests have shown that contrary to the media鈥檚 constant clamouring about 鈥渆ndocrine disruptive effects,鈥� bisphenol A is an extremely weak stimulator of estrogenic activity and a very weak blocker of androgens, the male sex hormones. We are exposed to far more effective natural estrogens in our daily life. Soybeans are loaded such compounds. Chinese diets are high in soy, maybe there is some synergistic effect there. It is important to keep up with the emerging data about the possible effects of bisphenol A, but at this point the data about this chemical affecting the functioning of the male organ is pretty soft.
