Serum levels of glycosylated hemoglobin, insulin, total protein and their association with somatoform disorder in environmentally exposed populations in Kazakhstan

Biochemical blood parameters may serve as biomarkers of environmental pollution, with somatoform disorder (SD) being of interest. This study examined serum glycosylated hemoglobin (HbA1C), insulin, total protein, and SD prevalence in populations from polluted areas in Kazakhstan. It assessed the predictive value of these parameters for SD, along with other risk factors. A cross-sectional study of 1881 individuals (ages 18–52) in Kazakhstan used the PHQ-15 questionnaire to assess SD. HbA1C was measured via immunoturbidimetry, insulin via immunoassay, and total protein via colorimetry. HbA1C levels > 6.5 % identified undiagnosed diabetes in 2.4 % of control residents, with higher rates in Ust-Kamenogorsk (10.6 %), Berezovka/Aksay (4.8 %), and Borodulikha/Abay (3.7 %). Pollutant-exposed populations had higher rates of hyperinsulinemia. Moderate to severe SD was more common in Ust-Kamenogorsk (26.6 %) and Berezovka/Aksay (27.2 %) than in controls, with lower rates in Borodulikha/Abay (16.7 %). Age, HbA1c levels, and residence near the condensate gas extraction plant significantly increased the odds of having moderate to severe SD, while being male and of Kazakh ethnicity significantly decreased the odds. The study links environmental exposure to increased rates of SD, diabetes, and insulin resistance.