Influence of environmental and metabolic factors on kidney function in people with metabolically healthy obesity in the Southern Aral Sea region: results of a clinical and functional study

Abstract

Aim. The Southern Aral Sea region is one of the most ecologically vulnerable regions of Central Asia, characterized by a harsh continental climate, high levels of atmospheric pollution (PM2.5), water scarcity, and dietary patterns with excessive consumption of carbohydrates and flour products. Against this background, there is a significant prevalence of obesity, including the phenotype of metabolically healthy obesity (MHO)—a condition in which there are no signs of metabolic syndrome, but overweight remains. Despite the apparent ‘‘metabolic norm”, such patients are susceptible to latent renal dysfunction with prolonged exposure to environmental factors. The aim of the study was to conduct a comprehensive assessment of the impact of environmental (PM2.5, water salinity, soil salinity) and metabolic factors on kidney function in patients with MHO in the Southern Aral Sea region, using the estimated glomerular filtration rate (eGFR) and functional renal reserve (FRR) before and after a 6-month intervention.

Materials and methods. The study included 133 participants (25–50 years old), divided into three groups: 1st—grade I MHO (BMI 30–34.9 kg/m²), 2nd—grade II MHO (BMI 35–39.9 kg/m²), and a control group of clinically healthy individuals. The main group received azilsartan 10 mg/day and structured physical activity (walking ≥60 minutes a day, ≥5 times a week). Renal function was assessed using CKD-EPI 2021 and the FRR test (0.5% NaCl salt load, 0.5% of body weight). The follow-up lasted 6 months.

Results. In patients from the Southern Aral Sea region, eGFR and FRR values were significantly lower than in the control group (eGFR—126.1 ± 1.7 and 123.7 ± 2.0 ml/min/1.73 m² vs. 131.1 ± 2.2 ml/min/1.73 m²; FRR—28.3 ± 3.5% and 24.3 ± 3.6% vs. 34.1 ± 2.2%, p < 0.05). After the 6-month intervention, patients with grade I MHO showed a 12% increase in FRR (p < 0.01), while those with grade II MHO demonstrated less pronounced improvements.

Conclusion. Patients with MHO living under environmental stress are at risk of early subclinical renal dysfunction, even if the metabolic profile remains preserved. Assessment of functional renal reserve makes it possible to detect disorders at the preclinical stage and can serve as an effective tool for early screening of chronic kidney disease. The results confirm the feasibility of using azilsartan and structured physical activity as a nephroprotective strategy in MHO populations.