Chronic Kidney Disease of Unknown Aetiology Among Agricultural Labour Communities: A Community-Based Cross-Sectional Study with Occupational and Biomarker Phenotyping

Chronic kidney disease of unknown aetiology (CKDu) has emerged as a distinct occupational kidney syndrome among agricultural labour communities in Central America, South Asia, and parts of Africa. Patients are typically young to middle-aged men engaged in heat-exposed agricultural work, present without conventional risk factors of diabetes or hypertension, and progress to end-stage kidney disease at younger ages than in conventional CKD populations. We conducted a community-based cross-sectional study in 295 adults across four occupational strata: sugarcane and paddy harvest workers (n=88), mixed farming smallholders (n=76), casual agricultural labourers (n=72), and non-agricultural village residents serving as controls (n=59). Any-stage CKD prevalence was 24.5% in sugarcane and paddy workers compared with 4.1% in non-agricultural controls. Heat exposure index, daily working water intake below 2 litres, NSAID use, and recurrent dehydration episodes were independently associated with CKDu in multivariable analysis. Urinary NGAL a sensitive marker of tubular injury was elevated in high-exposure occupational strata even among individuals with normal eGFR, suggesting that subclinical tubular injury precedes detectable glomerular decline. The findings strengthen the case for occupational health interventions centred on heat mitigation, work-rest cycles, and hydration in this population.