Exposure to per- and polyfluoroalkyl substances and glycemic control in older US adults with type 2 diabetes mellitus

Perfluoroalkyl substances (PFAS) have been associated with impaired glucose homeostasis. We aimed to examine associations of serum concentrations of PFAS with poor glycemic control (PGC) in US adults aged ≥65 years with type 2 diabetes mellitus (T2DM).We abstracted data from the 1999 to 2018 NHANES examination. In main analyses, we defined PGC as glycated haemoglobin A1C ≥ 8.0% in adults aged ≥75 years and A1C ≥ 7.0% (in main analyses) or A1C ≥ 7.5% (in sensitivity analyses) in those aged 65-74 years. We considered PFAS detected in >80% of the US population: perfluorodecanoic acid (PFDeA), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS). We estimated the adjusted odds ratio (aOR) and 95% confidence intervals (95% CI) of PGC across quartiles of PFAS concentrations using generalized linear mixed models, with the logit link.Of the 4575 adults included, 42.2% were ≥75 years of age and men represented 53.2%. Compared to adults in the bottom quartile, the odds of PGC was lower in the third quartile of PFDeA (aOR = 0.46, 95% CI: 0.29-0.77; P = 0.0026) and PFHxS (aOR = 0.56, 95% CI: 0.32-0.96; P = 0.0368), the second quartile of PFNA (aOR = 0.41, 95% CI: 0.23-0.71), the upper quartile of PFOA (aOR = 0.29, 95% CI: 0.12-0.73; P = 0.0017), and higher in the second quartile of ΣPFAS (aOR = 1.85, 95% CI: 1.16-2.95; P = 0.0102). In sensitivity analyses, likelihood for PGC was higher in the upper quartile of PFNA (aOR = 2.30, 95% CI: 1.25-4.21; P = 0.0071) and PFHxS (aOR = 2.87, 95% CI: 1.56-5.30; P = 0.0007), the second quartile of PFOS (aOR = 2.81, 95% CI: 1.11-7.14; P = 0.0297), PFHxS (aOR = 1.90, 95% CI: 1.09-3.32; P = 0.0240) and ΣPFAS (aOR = 2.29, 95% CI: 1.40-3.77; P = 0.0010).In US adults aged ≥65 years with known T2DM, PGC is more likely to be observed in those with high serum levels of PFNA and PFHxS (independent of sex) and PFDeA (in men), after controlling for confounders.