Researchers have found that phthalates, which are commonly found in cosmetics and plastics, can increase the risk of developing diabetes among elderly.
Even at a modest increase in circulating phthalate levels, the risk of diabetes is doubled, a study by researchers at Uppsala University found.
"Although our results need to be confirmed in more studies, they do support the hypothesis that certain environmental chemicals can contribute to the development of diabetes," said Monica Lind, associate professor of environmental medicine at the Section for Occupational and Environmental Medicine, Uppsala University.
Together with Lars Lind, professor of medicine at Uppsala University, she has analyzed new information from the so-called PIVUS study, which covers more than 1 000 70-year-old women and men in Uppsala.
In a physical examination participants were examined for fasting blood sugar and various insulin measures. They submitted blood samples for analysis of various environmental toxins, including several substances formed when the body breaks down so-called phthalates.
Most people come into daily contact with phthalates as they are used a softening agents in plastics and as carriers of perfumes in cosmetics and self-care products.
As expected, diabetes was more common among participants who were overweight and had high blood lipids. But the researchers also found a connection between blood levels of some of the phthalates and increased prevalence of diabetes, even after adjusting for obesity, blood lipids, smoking, and exercise habits.
Individuals with elevated phthalate levels had roughly twice the risk of developing diabetes compared with those with lower levels. They also found that certain phthalates were associated with disrupted insulin production in the pancreas.
"However, to find out whether phthalates truly are risk factors for diabetes, further studies are needed that show similar associations. Today, besides the present study, there is only one small study of Mexican women. But experimental studies on animals and cells are also needed regarding what biological mechanisms might underlie these connections," said Lind.
The results were published in the journal Diabetes Care.