Epidemiology of chronic kidney disease of undetermined aetiology in Taiwanese farmers: a cross-sectional study from Changhua Community-based Integrated Screening programme.

Objectives: Chronic kidney disease of undetermined or non-traditional aetiology (CKDu or CKDnT) has been reported in Mesoamerica among farmers under heat stress. Epidemiological evidence was lacking in Asian countries with similar climatic conditions. The objective of this study was to investigate the prevalence of CKDu and possible risk factors.

Methods: We used the data from the Changhua Community-based Integrated Screening programme from 2005 to 2014, which is the annual screening for chronic diseases in Taiwan's largest rice-farming county since 2005. Our study population included farmers and non-farmers aged 15-60 years. CKDu was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m at age under 60 years without hypertension, diabetes, proteinuria, haematuria or using Chinese herbal medicine. We estimated the adjusted prevalence OR (POR) of CKDu by farmers, age, sex, education, urbanisation, smoking, body mass index, hyperuricaemia, hyperlipidaemia, heart disease and chronic liver disease.

Results: 5555 farmers and 35 761 non-farmers were included in this study. CKDu accounted for 48.9% of all CKD cases. The prevalence of CKDu was 2.3% in the farmers and 0.9% in the non-farmers. The crude POR of CKDu in farmers compared with non-farmers was 2.73 (2.13-3.50), and the adjusted POR was 1.45 (1.10-1.90). Dehydration (blood urea nitrogen-to-creatinine ratio >20) was found in 22% of the farmers and 14% of the non-farmers.

Conclusions: Farmers in subtropical Asian countries are at increased risk of CKDu. Governments should take the CKDu epidemics seriously and provide farmers with occupational health education programmes on thermal hazards.