“Forever Chemicals” Strongly Linked to Gestational Diabetes, Major Review Finds
A comprehensive review of nearly 130 studies reveals the strongest evidence to date connecting exposure to per- and polyfluoroalkyl substances (PFAS) – often called “forever chemicals” – with an increased risk of gestational diabetes. The research, published in eClinicalMedicine, underscores the need for further investigation into the broader impact of these ubiquitous chemicals on various diabetes outcomes.
Diabetes mellitus (DM) is a growing global health crisis, currently affecting over 828 million individuals worldwide. Beyond well-established risk factors like lifestyle and genetics, emerging research points to environmental chemicals as potential contributors to the disease’s rising prevalence. PFAS, known for their persistence in the environment and the human body, have increasingly come under scrutiny for their potential health effects.
What are PFAS and Why are They a Concern?
PFAS are a group of man-made chemicals used in a wide range of consumer and industrial products, from non-stick cookware to firefighting foam. Their widespread use and chemical stability have led to their presence in virtually all environmental media and human blood samples. These chemicals interfere with the endocrine system and have been linked to metabolic syndrome, insulin resistance, cellular stress, inflammation, and disruptions in pancreatic function. “The pervasiveness and long half-lives of PFAS are what earn them the moniker ‘forever chemicals’,” explained one analyst.
Examining the Link Between PFAS and Diabetes
Researchers conducted a systematic review and meta-analyses, analyzing data from 129 observational studies identified through searches of the Medline and Embase databases. The studies examined associations between PFAS exposure and key markers of diabetes risk, including glycemic control, pancreatic β-cell function, insulin resistance, and overall diabetes incidence. The majority of studies were conducted in the United States (54) and China (30), with a significant proportion (70) employing a cross-sectional design.
Across the studies, 45 different PFAS were measured, with perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorodecanoic acid (PFDA), and perfluorononanoic acid (PFNA) being the most commonly assessed. Exposure timing varied, with studies examining adulthood (75), the gestational/prenatal period (42), adolescence (22), and childhood (16).
Gestational Diabetes: The Strongest Association
The meta-analyses revealed a clear and consistent association between PFAS exposure and gestational diabetes (GDM). Specifically, each doubling of PFOS and perfluorobutanesulfonic acid (PFBS) levels was linked to an increased risk of GDM in prospective studies. Nested case-control studies further supported this finding, showing positive associations for several long-chain and emerging PFAS, including PFOA, PFNA, PFDA, PFBS, perfluoroheptanesulfonic acid (PFHpS), and 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2 Cl-PFESA).
Mixed Results for Type 2 Diabetes and Other Markers
While the link to GDM was robust, associations between PFAS exposure and type 2 diabetes (T2D) were largely insignificant. However, prospective studies did suggest a positive trend for PFNA, PFOA, and PFOS. Researchers also observed significant associations between PFAS levels and measures of insulin resistance and β-cell function. Specifically, higher insulin resistance (HOMA-IR) was positively associated with PFOS and PFNA, while β-cell function (HOMA-β) showed associations with PFOA, PFOS, and PFNA.
Associations with fasting glucose were inconsistent, and there were generally no significant findings related to glycated hemoglobin (HbA1c), although sensitivity analyses suggested a potential link between PFOS and HbA1c in cross-sectional studies. .
Mixture Effects and Research Quality
Sixty studies examined the effects of multiple PFAS or PFAS in combination with other chemicals. Most of these mixture studies assessing GDM or T2D reported positive associations, suggesting a potential synergistic effect. The overall quality of the evidence was considered moderate for some long-chain PFAS and selected outcomes, but low for short-chain PFAS and outcomes like T2D, fasting glucose, and HbA1c.
Implications and Future Research
The findings highlight the potential for PFAS exposure to contribute to the development of gestational diabetes and suggest modest metabolic effects on insulin sensitivity and secretion. However, the researchers emphasize the need for more prospective studies to confirm these associations and to better understand the underlying mechanisms. “Effect sizes were generally small, and many findings were derived from cross-sectional studies, limiting our ability to establish causality,” a senior official stated.
The ongoing research into the health effects of PFAS underscores the importance of reducing exposure to these “forever chemicals” and developing strategies to mitigate their impact on public health.
