Chronic interstitial nephritis in agricultural communities: a worldwide epidemic with social, occupational and environmental determinants

Abstract

Increase in the prevalence of chronic kidney disease (CKD) is observed in Central America, Sri Lanka and other tropical countries. It is named chronic interstitial nephritis in agricultural communities (CINAC). CINAC is defined as a form of CKD that affects mainly young men, occasionally women. Its aetiology is not linked to diabetes, hypertension, glomerulopathies or other known causes. CINAC patients live and work in poor agricultural communities located in CINAC endemic areas with a hot tropical climate, and are exposed to toxic agrochemicals through work, by ingestion of contaminated food and water, or by inhalation. The disease is characterized by low or absent proteinuria, small kidneys with irregular contours in CKD stages 3–4 presenting tubulo-interstitial lesions and glomerulosclerosis at renal biopsy. Although the aetiology of CINAC is unclear, it appears to be multifactorial. Two hypotheses emphasizing different primary triggers have been proposed: one related to toxic exposures in the agricultural communities, the other related to heat stress with repeated episodes of dehydration heath stress and dehydration. Existing evidence supports occupational and environmental toxins as the primary trigger. The heat stress and dehydration hypothesis, however, cannot explain: why the incidence of CINAC went up along with increasing mechanization of paddy farming in the 1990s; the non-existence of CINAC in hotter northern Sri Lanka, Cuba and Myanmar where agrochemicals are sparsely used; the mosaic geographical pattern in CINAC endemic areas; the presence of CINAC among women, children and adolescents who are not exposed to the harsh working conditions; and the observed extra renal manifestations of CINAC. This indicates that heat stress and dehydration may be a contributory or even a necessary risk factor, but which is not able to cause CINAC by itself.

Leptospirosis Renal Disease: Emerging Culprit of Chronic Kidney Disease Unknown Etiology

“…Existing evidence supports occupational and environmental toxins are the primary triggers and the similarity of CKDu between Mesoamerican nephropathy and Sri Lanka narrow down to a common single caustic agent that ubiquitously persists in these 2 regions, that is, leptospirosis (Table 1). This indicates that heat stress and dehydration may be a contributory or a necessary risk factor, but which may not cause CKDu by itself [43].…”

Role of Organochlorine Pesticides in Chronic Kidney Diseases of Unknown Etiology

“…According to them, more than 4000 cases have already been diagnosed among paddy and coconut farmers of this area. The source of this information is through a personal communication with Dr. Gangadhar, Nephrologist, Nizam's Institute of Medical Sciences, Hyderabad, India [13]. No significant data of CKDu particularly among CKD patients in general population of urban or rural area are available so far.…”

“…[33]. In a recent study, Jayasumana et al [13] proposed a well-researched theory of renal tubular damage by heavy metals which absorbed into the body as a lattice structure formed by chelation of metal ions with glyphosate, a widely used herbicides by the farmers of the endemic area. This theory, though attractive has yet to be proven by bench research and many academic chemists do not support this view.…”

“…This theory, though attractive has yet to be proven by bench research and many academic chemists do not support this view. The high prevalence of CKD in the villages located downstream [34], and among consumers of water from shallow wells [16,35] strongly indicates the possibility of entry of toxins through contaminated drinking water [13]. Genetic susceptibility is another possible risk factor according to some studies [36].…”

Survey of Heavy Metal Contamination in Water Sources in the Municipality of Torola, El Salvador, through In Situ Sorbent Extraction

“…The disease cannot be explained by traditional causes, such as diabetes mellitus or hypertension [15] and it has also been identified in other Central American countries, as well as in Asian countries, such as Sri Lanka and Vietnam. This type of disease is described as chronic interstitial nephritis related to both environmental conditions and to the farmers' hard labour conditions [16,17]. However, in Sri Lanka researchers have identified risk factors, such as exposure to pesticides and heavy metals together with the intake of hard water [18].…”