Phthalate exposure linked to diabetes in elderly
MedWire News: Exposure to phthalates may promote development of diabetes as well as obesity, report researchers.
They found that high levels of several phthalate metabolites were associated with an increased prevalence of diabetes, poor insulin secretion, and insulin resistance in an elderly population.
Phthalates are industrial chemicals that are commonly used as plasticizers and are found in numerous household products such as food packaging, furniture, and toys, as well as in personal care products such as cosmetics.
It has been known for several years that phthalates can bind to members of the nuclear peroxisome proliferator-activated receptors (PPARs) involved in adipose tissue and lipid homeostasis, say the researchers.
"As it has been reported that phthalate levels in humans are associated with obesity, a well-known effect of PPAR-γ receptor activation, and because obesity is an important risk factor for diabetes development, we hypothesized that high levels of phthalates in humans also might be associated with diabetes," explain Lind et al.
The team measured the serum levels of ten phthalate metabolites in 1016 participants, all aged 70 years, from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) Study.
As reported in Diabetes Care, 116 of the participants had diabetes.
Of the ten metabolites measured, only monomethyl phthalate (MMP), monoisobutyl phthalate (MiBP), monoethyl phthalate (MEP), and mono (2-ethylhexyl) phthalate (MEHP) were detectable, in 96% of the participants.
The researchers report that there was a significantly higher prevalence of diabetes among patients with MEP, MiBP, and MMP levels in the highest quintile versus lowest quintile, at odds ratios of 2.27, 2.00, and 2.54, respectively, whereas no such association was observed for MEHP levels.
Furthermore, the authors found that MiBP levels were inversely related to a marker of poor insulin secretion (proinsulin-to-insulin ratio), while MEP and MMP were related to insulin resistance, as assessed by the homeostasis model assessment-insulin resistance index.
Interestingly, "the common feature of the metabolites MEP, MiBP, and MMP is that all these three metabolites are derived from degradation of associated phthalate parent compounds used as solvents/carriers of fragrances used in personal products," note the authors.
The findings support the view that these commonly used chemicals might influence glucose metabolism in humans at the level of exposure seen in the general elderly population, they conclude.
By Sally Robertson