Health Risks of Phthalates

Phthalates (pronounces tha-lates) are one of the most widely used types of chemical compound today. A family of more than 50 related compounds, phthalates are found in thousands of everyday products, from shower curtains to nail polish. Billions of pounds are made every year.

Unfortunately, in the last 20 years, concerns have grown over the safety of these nearly ubiquitous compounds, especially for developing fetuses and young children.

Blood and urine tests done by studies performed in the United States and Europe have found that phthalates and phthalate metabolites are present in the bodies of 90-100% of citizens in these countries. Although phthalates break down quickly in the body, they are so common in the daily lives of citizens in developed countries that low levels are maintained fairly consistently in the body.

Phthalates can be inhaled, usually on dust particles from vinyl flooring or other surfaces containing phthalates, absorbed through the skin, usually through use of cosmetics and other body care products containing phthalates, swallowed, usually from plastic food containers or cling wraps that have leached phthalates into food or drink, or injected intraveneously, usually through medical equipment such as IV bags, which may be made from vinyl containing phthalates.  

The long-term effects of this near-constant low level exposure are uncertain. The majority of studies dealing with phthalate safety have been performed on animals, who may or may not react in similar ways as humans to the same compounds. Studies dealing with the effect of phthalates on fetal and early childhood development have also concentrated primarily on animals.

Endocrine disruptors are toxins that interfere with the normal activities of the endocrine system, which regulates hormone levels in the body. A number of phthalates are known or suspected endocrine disruptors, including the most common phthalate: di-exylhethyl phthalate (DEHP).

Phthalates are generally considered to be in a class of endocrine disruptors known as "xenoestrogens," for their ability to mimic the effect of estrogen on the body.

In animal tests, phthalates have been shown to "feminize" male animals, increasing the likelihood of small or undeveloped testes, undescended testicles, and low sperm counts. A 2005 study also linked higher fetal exposure to phthalates through the mother's blood with increased risk of developmental abnormalities in male infants. Higher phthalate levels are also associated with lower testosterone production and reduced sperm count in men. 

These effects on fetal development are of particular concern because young women of childbearing age often have higher than average phthalate levels in the body thanks to their use of cosmetics, many of which contain phthalates.

One study also found that female animals exposed to higher levels of phthalates experienced increased risk of miscarriage, a common symptom of excessive estrogen levels in human women, and stillbirth. Prematurity may also be linked to phthalate exposure - a 2003 study found higher levels of phthalates and phthalate metabolites in the blood of premature human infants than full-term infants.

A Puerto Rican study linked phthalate exposurein human girls to premature breast development, a symptom of early puberty.

A recent study found a link between exposure to phthalates and increased rates of childhood obesity.

Phthalate exposure has been linked to higher risk of liver cancers in both humans and animals.

In adult human men, phthalates have been linked to greater waist circumference and higher insulin resistance, a common precursor to type 2 (adult onset) diabetes. They have been linked to thyroid irregularities, asthma, and skin allergies in both sexes. Though the exact mechanism is unclear, studies have linked higher rates of respiratory infections and other symptoms in children living in houses with vinyl floors. One possible explanation is inhalation of dust tainted by phthalates, which are used in cosmetics such as nail polishes and hand creams precisely because of their ability to bind to human tissues.

Animal studies have shown increased risks of certain birth defects (including the genital abnormalities described above and, in rats, extra ribs) and low birth rates in rats whose mothers were fed higher levels of phthalates.

Although the exact effects of phthalates on the human body are unknown, there is enough evidence to warrant further study. In the meantime, it is especially important to reduce phthalate exposure among the following groups:

• young children, especially premature infants, who are often exposed to unusually high phthalate levels through medical equipment
• women who are pregnant or who wish to become pregnant
• nursing mothers