Decreased kidney function and agricultural work: a cross-sectional study in middle-aged adults from Tierra Blanca, Mexico.

BACKGROUND: We aimed to determine the prevalence of decreased kidney function in a potential chronic kidney disease (KD) of unknown aetiology hotspot in Mexico, assess its distribution across occupations and examine the associated risk factors. METHODS: A cross-sectional study collected sociodemographic, occupational, medical and biometric data from 616 men and women aged 20-60 years who were residents of three communities within the Tierra Blanca region in Mexico. Kidney function was assessed by standardized serum creatinine and estimated glomerular filtration rate (eGFR) and semi-quantitative albumin-to-creatinine ratio (ACR). To examine the distribution of decreased kidney function within the population, age- and sex-adjusted prevalence of low eGFR (≤60 mL/min/1.73 m2) was estimated for all participants and across occupations. Multivariable logistic regression was used to assess the association of occupation with having low eGFR. RESULTS: Of the 579 participants analysed (37 excluded due to missing data), the age- and sex-adjusted prevalence of low eGFR was 3.5%. Agriculture was the occupation associated with the highest adjusted prevalence of low eGFR (8.8%), with 1 in every 11 agricultural workers having low eGFR. Working in agriculture was independently associated with more than a 5-fold risk of having low eGFR [odds ratio 5.2 (95% confidence interval 1.1-24.3), P = 0.032], after adjustment for age, sex, diabetes, hypertension, body mass index, ACR and family history of KD. Additionally, a quarter of the population (25%) had either low eGFR or an ACR >30 mg/g, mostly due to albuminuria. CONCLUSIONS: Our work suggests that there is a high prevalence of decreased kidney function in Tierra Blanca, particularly amongst agricultural workers.