‘Forever chemicals’ up type 2 diabetes risk in midlife White women
Levels of 12 phthalate metabolites
Previously, the researchers reported how another class of “forever chemicals,” PFAS, were associated with risk of hypertension in a 17-year follow-up of middle-aged women in the SWAN study.
In the current study, they analyzed data from 1,308 women in SWAN-MPS who had been recruited at five study sites (Oakland, Calif; Los Angeles; Detroit; Pittsburgh; and Boston).
The women were between ages 42 and 52 years in 1996-1997 and self-identified as White, Black, Chinese, or Japanese.
They did not have diabetes in 1999-2000 and had sufficient urine samples for phthalate assessment then and midway through a 6-year follow-up.
The women were a median age of 49 years in 1999-2000. About half were White, 20% were Black, 13% were Chinese, and 15% were Japanese.
Researchers analyzed levels of 12 metabolites, chosen because their parent phthalates have been widely used in industry and commerce, and exposure to these phthalates is a national biomonitoring priority.
The measured phthalates were:
Three metabolites of low-molecular-weight phthalates:
- mono-ethyl phthalate (MEP)
- mono-n-butyl phthalate (MnBP)
- mono-isobutyl phthalate (MiBP)
Four metabolites of the high-molecular-weight phthalate di(2-ethylhexyl) phthalate (DEHP), which is of particular public health interest:
- mono(2-ethylhexyl) phthalate (MEHP)
- mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP)
- mono(2-ethyl-5-oxohexyl) phthalate (MEOHP)
- mono(2-ethyl-5-carboxypentyl) phthalate (MECPP)
Five metabolites of other high-molecular-weight phthalates:
- monobenzyl phthalate (MBzP)
- monoisononyl phthalate (MiNP)
- mono-carboxyoctyl phthalate (MCOP)
- mono-carboxy-isononyl phthalate (MCNP)
- mono(3-carboxypropyl) phthalate (MCPP)
The researchers excluded MiNP from all analyses because it was detected in less than 1% of urine samples.
The different phthalate metabolites were detected in 84.8% of samples (MEHP) to 100% of samples (MnBP and MECPP).
Women who were younger, Black, current smokers, or obese generally had higher concentrations of phthalate metabolites.
Over 6 years, 61 women developed diabetes (an incidence rate of 8.1 per 1000 person-years).
Compared with other women, those with incident diabetes had significantly higher concentrations of all phthalate metabolites except DEHP metabolites and MCPP.
Phthalates were not associated with incident diabetes in Black or Asian women.
However, among White women, each doubling of the concentrations of MiBP, MBzP, MCOP, MCNP, and MCCP was associated with a 30% to 63% higher incidence of diabetes (HR 1.30 for MCNP; HR 1.63 for MiBP).
The SWAN study was supported by the National Institutes of Health, Department of Health & Human Services, National Institute on Aging, National Institute of Nursing Research, NIH Office of Research on Women’s Health, and SWAN Repository. The current study was supported by the National Center for Research Resources, National Center for Advancing Translational Sciences, NIH, National Institute of Environmental Health, and Centers for Disease Control and Prevention/National Institute for Occupational Safety and Health. Dr. Peng was supported by an Interdisciplinary Research Training on Health and Aging grant from the NIA. The authors have reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.
