A chemical used in BPA-free products may have a connection to diabetes control

Researchers measured bisphenol exposure alongside diet and medication adherence in adults with type 2 diabetes, uncovering a more complex relationship between environmental chemicals and blood sugar control. Study: Beyond medication adherence: bisphenol exposure and its relationship with good glycemic control in type 2 diabetes. Image Credit: Konektus Photo In a recent study published in the journal Acta Diabetologica, researchers evaluated the relationship between exposure to bisphenol chemicals, including bisphenol A (BPA) and its common substitute, bisphenol S (BPS), and glycemic control in adults with type 2 diabetes (T2D). The study cohort comprised 307 participants with T2D who were prescribed oral antihyperglycemic medication, and the analysis examined the associations between bisphenol exposure, medication adherence, and diet and glycated hemoglobin (HbA1c) levels. Study findings revealed that higher plasma BPS concentrations were positively associated with higher HbA1c levels in unadjusted analyses and in a model accounting for age, sex, race, medication adherence, and diet. BPA concentrations were not associated with HbA1c. These findings add to questions about the metabolic effects of BPA substitutes such as BPS. The authors proposed that reducing BPS exposure may complement medication and diet, but the observational study did not test whether reducing exposure improves glycemic control. Background Type 2 diabetes accounts for more than 95% of diabetes cases; about 830 million adults worldwide were living with diabetes in 2022. The condition is characterized by chronic hyperglycemia, which contributes to diabetes-related complications and poorer long-term health outcomes. Clinical guidelines emphasize medication adherence, while dietary and other lifestyle approaches can complement pharmacological treatment. The paper notes that poor medication adherence is common among people with T2D and can contribute to the progression of diabetes complications. Research has identified food as a major route of exposure to endocrine-disrupting chemicals (EDCs), including bisphenols that can leach from food packaging and beverage containers. Experimental studies have linked BPA and BPS to obesity, insulin resistance, and disturbances in glucose metabolism, while human epidemiological findings remain inconsistent. Concerns about BPA toxicity have increased the use of BPA-free products, and BPS is one of the structural analogs used as a replacement for BPA. Few studies have examined whether BPA or BPS exposure is associated with T2D progression, particularly while accounting for medication adherence. The researchers also noted that no dietary questionnaire had been shown to estimate bisphenol exposure effectively in people with T2D. About the study The present study aimed to test whether the Connor dietary survey could estimate BPA and BPS exposure and to evaluate associations between plasma bisphenols, HbA1c, and medication adherence. This secondary analysis included 307 participants with a mean age of about 64 years using baseline samples and data from the Diabetes Comorbidity Study at the University of Pittsburgh Medical Center (UPMC). Participants were at least 40 years old, had physician-confirmed T2D for at least one year, and also had hypertension, hyperlipidemia, or both. The study’s methodology evaluated four primary components: 1. Medication adherence tracked for about a month using electronic Drug Exposure Monitors (eDEM); 2. Dietary habits quantified through the Connor Diet Habit Survey; 3. Physical fitness measured using the six-minute walk test (6MWT), and 4. Fasting plasma concentrations of total BPA and BPS, which were quantified using enzyme-linked immunosorbent assay (ELISA) kits. Medication adherence was assessed using three measures covering correct daily doses, correctly timed doses, and total doses taken. Statistical modeling used multivariable linear regression to evaluate associations with HbA1c. BPS, medication adherence, and the cholesterol and saturated-fat diet score were entered as independent variables; models accounted for age, sex, and race, then added BPA, BMI, and physical fitness. Study findings The study revealed that participants demonstrated an average baseline HbA1c of 7.43% and medication adherence of approximately 80% across the three measures. Laboratory biochemical assays measured both BPA and BPS in fasting plasma. The Connor survey did not effectively estimate BPA or BPS levels. No tested dietary category was associated with BPS, while beverage and restaurant scores were associated with BPA. The survey question covering canned, bottled, and packaged foods also showed no association with plasma BPS. These findings indicate that the self-reported dietary measures used in the study did not reliably identify sources of BPS exposure. After accounting for demographic factors, medication adherence, and diet, higher BPS remained associated with higher HbA1c. When BPA, BMI, and physical fitness were also considered, the BPS association was no longer statistically significant, while better medication adherence and healthier cholesterol and saturated-fat dietary behavior remained associated with lower HbA1c. Biochemical plasma assays revealed that BPA correlated with participants’ circulating triglyceride levels. BPS correlated with HbA1c; BPA did not. Conclusions The present study found a modest association between higher plasma BPS and higher HbA1c in adults with T2D, while BPA was not associated with HbA1c. The BPS association did not remain statistically significant when BPA, BMI, and physical fitness were also considered, and the observational design cannot establish that BPS causes poorer glycemic control. The findings add to questions about the metabolic effects of BPA substitutes such as BPS, but they do not show that BPS counteracts the benefits of medication adherence. Larger studies are needed to clarify whether low-level BPS exposure contributes to glycemic dysregulation over time. The study is limited by its cross-sectional design, the modest BPS association, and the difficulty of estimating bisphenol exposure from self-reported dietary surveys. The authors also advised caution when interpreting the cholesterol and saturated-fat diet score because that survey category contained more questions than other dietary components, which may have increased the chance of detecting an association. Better dietary tools are needed to estimate bisphenol exposure, along with studies testing whether reducing BPS exposure can improve glycemic control. The paper suggests that strategies addressing BPS exposure and dietary behavior may complement pharmacological treatment, but this study did not show that avoiding plastic packaging improves diabetes outcomes.