Simple Analysis for Women With Diabetes, Aged 40 Years or More

The researchers have found that higher concentrations of per- and polyfluoroalkyl substances (PFAS) used in a variety of products, particularly cosmetics, were most clearly associated with an increased risk of diabetes, particularly among women aged 40 to 60 years. This study was performed by Dr. Sung Kyun Park and colleagues at the Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA and was published in the journal Diabetologia.

The Use and Misuse of Cosmetics

PFAS are a group of more than 4,700 synthetic chemicals and are widely used in the field of cosmetics and also in industry as well as in consumer products such as non-stick cookware, stain-repellent coatings, and so on. Their molecular structure is based on the linked chain of carbon atoms with one or more fluorine atoms attached, and the extreme stability of those carbon and fluorine bonds makes PFAS highly resistant to being broken down. This durability causes PFAS to persist and accumulate in the environment as well as in the bodies of humans and animals where they can remain for years, hence referred to as “forever chemicals.”

The use of cosmetics has led PFAS exposure to a serious public health concern, resulting in restrictions on their use. Almost every American blood sample tested by the US Biomonitoring Program contains at least one type of PFAS, and they have been found in the drinking water supply of more than 200 million people in the United States. A recent review of the potential health effects of these chemicals suggests that exposure to some may be associated with pre-eclampsia, altered levels of liver enzymes, elevated blood fats, decreased antibody response to vaccines, and low birth weight, although causal relationships have yet to be established.

Many PFAS have molecular structures that are similar to naturally occurring fatty acids, resulting in similar chemical properties and effects on the human body. Fatty acids act on a class of protein molecules found in cells called peroxisome proliferator-activated receptors (PPARs), which act as fat and insulin sensors and are important regulators for the formation and growth of new adipocytes (fat cells). Structurally and chemically similar PFAS compounds may interact with the same PPARs, suggesting a possible mechanism for these substances to interfere with their regulatory behavior and affect the risk of diabetes, particularly in women aged 40 to 60 years.

Experimental studies with cell cultures suggest that high levels of PFAS in some humans may disturb PPAR function resulting in increased production of fat cells, changes to fat and sugar metabolism, and abnormal inflammatory responses.

Sample Study and its Results

The sample group for this study was selected from the Study of Women’s Health Across the Nation (SWAN), an ongoing multisite, multiethnic, and community-based prospective study of midlife women referring to menopause. A total of 3,302 menopausal participants aged 42 to 52 years who met the selection criteria for SWAN at seven locations in the United States from 1996 to 1997 were recruited, and the basic clinical trial was repeated annually.

The SWAN-Multi-Pollutant Study (SWAN-MPS) was launched in 2016 to assess the role of environmental pollutants in chronic diseases during and after menopause. It analyzed the stored blood and urine samples from 1,400 study participants, which had been collected by SWAN since the third follow-up (1999–2000). These were tested for the presence of environmental chemicals, including seven PFAS.

After excluding women with diabetics, the authors were left with the final sample of 1,237 women with an average age of 49.4 years who were monitored from 1999 until 2017. There were 102 cases of diabetes during the 17,005 person-year follow-up which had a rate of 6 cases per 1,000 person-years. Compared with disease-free participants, those who developed diabetes were black, were from Southeastern Michigan (a more socio-economically backward area), with lower literacy, lower physical activity, higher energy intake, and higher BMI at baseline.

Advertisement

The authors observed, “Higher serum concentrations of certain PFAS were associated with a higher risk of incident diabetes in midlife women.” They also note, “The joint effects of PFAS mixtures were greater than those for individual PFAS, suggesting a potential additive or synergistic effect of multiple PFAS on diabetes risk.”

Serum concentrations of PFAS were categorized into high/middle/low exposure groups (tertiles), and a hazard ratio (HR) for incident diabetes was calculated by comparing the incidence rate in the "high" or "middle" tertiles to that in the lowest tertile (reference group). The team found that combined exposure to the seven different PFAS had a stronger association with diabetes risk than was seen with individual compounds. Women in the high tertile for all seven were 2.62 times more likely to develop diabetes than those in the low category, while increased risk associated with each PFAS ranged from 36% to 85%, suggesting a potential additive or synergistic effect of multiple PFAS on diabetes risk.

Advertisement

The strength of the association between combined exposure and incident diabetes rates also suggests that PFAS in cosmetics may have substantial clinical impacts on diabetes risk. They say, “Given the widespread exposure to PFAS in the general population, the expected benefit of reducing exposure to these ubiquitous chemicals might be considerable.”

This prospective cohort study supports the hypothesis that exposure to PFAS, individually and as mixtures, may increase the risk of incident diabetes in midlife women. Although the effect sizes in men and other populations not included in their study are unknown, if these results are also applicable to men as well as to individuals of all ages and ethnicities regardless of location, then approximately 370,000 cases (around 25%) out of the 1.5 million Americans newly diagnosed with diabetes each year could be attributable to PFAS exposure. These findings suggest that PFAS may be an important risk factor for diabetes and have a substantial public health impact.

The authors conclude it by saying, “Reduced exposure to these ‘forever and everywhere chemicals’ even before entering midlife may be a key preventative approach to lowering the risk of diabetes. Policy changes around the drinking water and consumer products could prevent population-wide exposure.”

They suggest that regulation focusing on certain compounds in cosmetics may be ineffective and persistent PFAS may need to be regulated as a "class." Finally, they point out that clinicians should be aware of PFAS as an undiagnosed risk factor for diabetes and be prepared to advise patients on sources of exposure and their potential health risks.

Source-Medindia