Chronic interstitial nephritis of nontraditional causes in Salvadoran agricultural communities.

In El Salvador, a form of chronic kidney disease (CKD) of nontraditional causes (CKDnt) affecting farmers is being reported. Its behavior has been epidemic and is responsible for tens of thousands of deaths. This article summarizes the results obtained from a series of studies conducted to identify the epidemiology and clinical behavior of this disease, proposing a case definition and an etiopathogenic hypothesis. Methods included a survey of CKD in agricultural communities studying 2,388 people ≥ 18 years and 1,755 < 18, a descriptive clinical study followed by histopathological assessment conducted in 46 possible cases of CKDnt ≥ 18 years, and a national survey to study the prevalence of CKD and associated risk factors in 4,817 participants ≥ 20 years followed by a nested case-control study. In the agricultural communities, the prevalence of CKD in adults was 18% (men: 23.9%, women: 13.9%), 26.8% in agricultural workers (non-agricultural 13.8%), CKDnt accounted for 51.9% of cases. CKD in the population < 18 years was 3.9% (mean estimated glomerular filtration rate > 160 mL/1.73m2). The national CKD prevalence was 12.6% (urban: 11.3%; rural: 14.4%; males: 17.8%, females 8.5%), and CKDnt was only 3.8%; with associations between CKD and exposure to agrochemicals. The clinical study revealed the presence of markers of kidney damage (A3 albuminuria: 80.4%; ß2-microglobulin: 78.2%), urine electrolyte anomalies (100% hypermagnesuria, 45.7% hypernatriuria, 43.5% osmotic polyuria), abnormal osteotendinous reflexes (45.7%), sensorineural hearing loss (56.5%), and damage of the tibial arteries by Doppler imaging (66.7%). Biopsies revealed a chronic tubulointerstitial nephropathy. The etiopathogenesis of CKDnt is possibly multifactorial, including environmental contamination by agrochemicals, heat stress, and dehydration.

Epidemic of Chronic Kidney Disease of Nontraditional Etiology in El Salvador: Integrated Health Sector Action and South-South Cooperation.

In El Salvador, chronic kidney disease had reached epidemic propor-tions towards the end of this century's first decade. In 2011-2012, the Ministry of Health reported it was the leading cause of hospital deaths in men, the fifth in women, and the third overall in adult hospital fa-talities. Farming was the most common occupation among men in dialysis (50.7%). By 2017, chronic kidney disease admissions had overwhelmed hospital capacity.In 2009, El Salvador's Ministry of Health, Cuba's Ministry of Public Health and PAHO launched a cooperative effort to comprehensively tackle the epidemic. The joint investigations revealed a total prevalence of chronic kidney disease in the adult population of farming communities higher than that reported internationally (18% vs.11%-14.8%), higher in men than in women (23.9% vs 13.9%) and higher in men who were farmers/farmworkers than in men who were not (31.3% vs. 14.8%). The disease was also detected in children. An association was found between chronic kidney disease and exposure to agrochemicals (OR 1.4-2.5). In 51.9% of all chronic kidney disease cases, traditional causes (diabetes, hyperten-sion, glomerulopathies, obstructive nephropathies and cystic diseases) were ruled out and the existence of a particular form of chronic kidney disease of nontraditional etiology was confirmed (whose initial cases were reported as early as 2002). In the patients studied, functional altera-tions and histopathologic diagnosis confirmed a chronic tubulointerstitial nephritis; most presented with neurosensory hearing loss, altered tendon refiexes and tibial artery damage. The main results of this cooperation were the epidemiologic, physio-pathologic, clinical and histopathologic characterization of chronic kid-ney disease of nontraditional etiology. This characterization facilitated case definition for the epidemic and led to the hypothesis of systemic toxicity from agrochemicals (e.g., paraquat, glyphosate), which par-ticularly affect the kidneys and to which farmers/farmworkers (who may also become dehydrated in the fields) are most exposed. The research thus also laid the foundations for design of comprehensive intersectoral government actions to reduce cases and put an end to the epidemic. KEYWORDS Chronic kidney disease; chronic renal failure; tubuloint-erstitial nephritis; epidemiology; histopathology; international coopera-tion; agrochemicals; environmental pollutants, noxae, and pesticides; occupational health; PAHO; El Salvador; Cuba.