Epidemic of chronic kidney disease of unknown causes in Nicaragua: epidemiology, causal hypotheses, and public health interventions
- Autores: Oriana Ramirez Rubio
- Directores de la Tesis: Daniel R. Brooks (dir. tes.), Ángel Otero Puime (dir. tes.)
- Lectura: En la Universidad Autónoma de Madrid ( España ) en 2013
- Idioma: inglés
- Tribunal Calificador de la Tesis: Fernando Rodríguez Artalejo (presid.), Julia del Amo Valero (secret.), Rafael Selgas Gutiérrez (voc.), George L. Delclós Clanchet (voc.), Francisco Bolúmar Montrull (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: Biblos-e Archivo
- Resumen
Introduction There is a long time neglected epidemic of CKD of unknown causes (CKDu), recently named Mesoamerican Nephropathy (MeN), which probably extends from South Mexico to Panama. The author of this thesis document has been studying with researchers from Boston University this disease since 2009, as part of a mediation process between a sugar cane company and sick ex-workers and their families.
Research Objectives 1. Describe the epidemiology of CKDu/MeN, and causal hypotheses proposed to date.
2. Gain a better understanding of the CKDu/MeN causal web, based on Nicaraguan health professionals¿ perceptions.
3. Assess kidney damage through urine biomarkers among Nicaraguan adolescents from different schools.
Methods In order to address the 3 research objectives proposed, a systematic review of the literature published to date, a qualitative study of semi-structured in person interviews with Nicaraguan physicians and pharmacists (n=19), and a cross-sectional study of 200 school children from different regions of Nicaragua, were conducted.
Results Regarding Objective 1: -Mortality rates and prevalence studies have confirmed that communities where agriculture, mining and port-related occupations are prevalent, and particularly those in lowlands of the Pacific coast are the ones most affected. Contrary to the typical distribution of a chronic [renal] disease, it affects primarily men in their 20-40s (relatively young). Women, although less affected, follow also the same distribution as men (e.g. higher prevalence¿s in low altitude).
-Risk factors (susceptibility, initiation and/or progression) associated with CKDu in the different prevalence and case control studies to date, as well as well known environmental causes of CKD thought to play a role in this epidemic, have brought researchers to think that etiology is presumably multifactorial. The variety of hypothesized causes include: heat and heavy physical work load (chronic volume depletion), exposure to heavy metals such as arsenic or cadmium, agrichemicals, systemic infectious diseases such as leptospirosis, and chronic intake of potential nephrotoxic medications such as non-steroidal anti-inflammatory drugs (NSAIDs), analgesics or aminoglycoside antibiotics.
Regarding Objective 2: -Physicians and pharmacists interviewed working in the front line of the disease described it in a way consistent with results from the studies conducted so far in the region.
-Our analysis articulated perceptions of physicians and pharmacists in a causal framework where heat stress and subsequent volume depletion experienced by manual laborers may play a role in the frequent occurrence of dysuria-like symptoms (locally called ¿chistata¿), which are often treated with non-steroidal anti-inflammatory drugs, diuretics and antibiotics that may be further nephrotoxic.
Regarding Objective 3: - Adolescents from four schools in three different regions of Nicaragua showed biomarkers of kidney tubulo-interstitial damage ranked by mortality rates in the general population by region. For example, the results for NAG were most consistent in this regard, with the relative concentrations rank ordered by school according to the mortality rate risk profile in both boys and girls. On the other hand, Albumin-Creatinine Ratio, which is primarily associated with glomerular damage, did not demonstrate these patterns, and macroalbuminuria measured with dipstick, was virtually absent.
-An unusual finding is that girls had higher levels than boys for all biomarkers, with particularly large differences for ACR and IL-18. Conclusions The epidemiological information on MeN/CKDu is still very narrow and presents several limitations, but has helped to describe the distribution of the disease and propose some risks factors.
Dehydration during hard work, and nephrotoxic medications (such as NSAIDs and antibiotics) appear as a plausible causal hypothesis that needs to be the focus of further research. Also, early risk factors for CKD in the region may be present even during teenage, prior to other additionally exposures.
Multi-level public health responses to the epidemic cannot wait until efforts to identify the causes are completed, especially because treatment is not widely available, and poverty and premature death are key elements that have turned this disease into a real public health crisis of regional dimensions.
