Male Reproductive Problems Top Health Concerns
Pollution in People Report - Chapter 1 - Phthalates: Male Reproductive Problems Top Health Concerns
For years, evidence that exposure to phthalates may be leading to health problems has been accumulating. Animal tests have revealed a wide array of phthalate-related health effects, most of them reproductive: small or otherwise abnormal testes, hypospadias (abnormal urinary openings), and undescended testes (Gray 2000). These effects occur at exposure levels higher than those expected for people today; however, some of the most highly exposed people have phthalate levels greater than the no-effect, or safe, level in animal tests. For example, some children in neonatal intensive care have DEHP doses greater than levels considered safe by the FDA or EPA. In humans, phthalates cross the placenta to reach the growing fetus. They’re also present in breastmilk.
Researchers believe that the phthalate forms that have these reproductive effects, such as DEHP and DBP, act by reducing levels of testosterone and important growth factors in young males. Damage occurs when males are exposed in utero—that is, when mothers come into contact with phthalates during pregnancy. Phthalates are not all equally toxic in this regard, but CDC testing indicates that exposure patterns are of concern. In particular, women have higher exposure to DBP, the harmful phthalate form found in nail polish and other cosmetics, than do men. These women are also exposed to other phthalates, with similar effects, creating the potential that a significant segment of the population may have total phthalate levels high enough to cause harm.
A 2005 study that looked at mothers’ phthalate exposure and reproductive organs in their baby boys provides evidence that current exposure levels may indeed be having an impact on boys’ health. University of Rochester researcher Shana Swan and colleagues found that baby boys whose mothers had greater exposure to phthalates were more likely to have altered genital development. These boys had a changed penis location and a smaller average penis size and were more likely to have undescended testicles (Swan 2005). These effects are consistent with a “phthalate syndrome” observed in male rodents with phthalate-induced feminized traits. Future studies will shed more light on the extent to which phthalates are already affecting baby boys’ reproductive development.
Phthalate exposure has also been linked to lower sperm counts, reduced sperm motility, and damaged sperm in men (Duty 2003). The plasticizers may also affect women’s fertility; animal studies show that females exposed to the chemicals experience more difficulty becoming pregnant (Hauser 2005).
Other phthalate-related health concerns include liver and kidney damage as well as asthma (ATSDR 2002). Researchers have found that children in homes with greater levels of phthalates are more likely to have asthma (Bornehag 2004). In adults, phthalate exposure has been associated with reduced lung capacity, with the magnitude of effects similar to that of tobacco smoke (Hoppin 2004).