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BACKGROUND: CKD of unknown etiology (CKDu) disproportionately affects young people in Central America who lack traditional CKD risk factors (diabetes and hypertension) and has instead been variably linked to heat stress, occupational and environmental exposures, nephrotoxic medications, and/or genetic susceptibility. This study aimed to estimate the prevalence of CKD and identify risk factors for traditional CKD and CKDu in Nicaragua. METHODS: Surveys and assessment for CKD markers in urine and serum were performed in 15-59 year olds in households of the León municipality of Nicaragua. The survey included questions on demographics, health behaviors, occupation, and medical history. Participants with CKD were subdivided into traditional CKD and suspected CKDu based on history of diabetes, hypertension, or other specified conditions. A multinomial logistic regression model was used to identify factors associated with traditional CKD and suspected CKDu, compared to the non-CKD reference group. RESULTS: In 1795 study participants, CKD prevalence was 8.6%. Prevalence in males was twofold higher than females (12% vs 6%). Of those with CKD, 35% had suspected CKDu. Both traditional CKD and CKDu were associated with male sex and increasing age. Traditional CKD was associated with a family history of CKD, history of urinary tract infections, and lower socioeconomic status, while CKDu was associated with drinking well water and a lower body mass index. CONCLUSIONS: Both traditional CKD and CKDu are significant burdens in this region. Our study supports previous hypotheses of CKDu etiology and emphasizes the importance of CKD screening.
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Diabetes Mellitus , Hipertensão , Insuficiência Renal Crônica , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hipertensão/epidemiologia , Hipertensão/complicações , Nicarágua/epidemiologia , Prevalência , Insuficiência Renal Crônica/epidemiologia , Fatores de Risco , Doenças Renais Crônicas Idiopáticas/epidemiologiaRESUMO
OBJECTIVE: Automated threshold audiometry (ATA) could increase access to paediatric hearing assessment in low- and middle-income countries, but few studies have evaluated test-retest repeatability of ATA in children. This study aims to analyse test-retest repeatability of ATA and to identify factors that affect the reliability of this method. DESIGN: ATA was performed twice in a cohort of Nicaraguan schoolchildren. During testing, the proportion of responses occurring in the absence of a stimulus was measured by calculating a stimulus response false positive rate (SRFP). Absolute test-retest repeatability was determined between the two trials, as well as the impact of age, gender, ambient noise, head circumference, and SRFP on these results. STUDY SAMPLE: 807 children were randomly selected from 35 schools in northern Nicaragua. RESULTS: Across all frequencies, the absolute value of the difference between measurements was 5.5 ± 7.8 dB. 89.6% of test-retest differences were within 10 dB. Intra-class correlation coefficients between the two measurements showed that lower SRFP was associated with improved repeatability. No effect of age, gender, or ambient noise was found. CONCLUSIONS: ATA produced moderate test-retest repeatability in Nicaraguan schoolchildren. Participant testing behaviours, such as delayed or otherwise inappropriate response patterns, significantly impacts the repeatability of these measurements.
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Audiometria , Ruído , Humanos , Criança , Reprodutibilidade dos Testes , Audiometria de Tons Puros/métodos , Limiar Auditivo/fisiologiaRESUMO
OBJECTIVE: To investigate the utility and effectiveness of a noise-attenuating, tablet-based mobile health system combined with asynchronous telehealth evaluations for screening rural Nicaraguan schoolchildren for hearing loss. STUDY DESIGN: Prospective population-based survey. SETTING: Rural Nicaraguan communities. PATIENTS: There were 3,398 school children 7 to 9 years of age. INTERVENTIONS: Diagnostic automated and manual audiometry, detailed asynchronous telehealth evaluations. MAIN OUTCOME MEASURES: Referral rates, ambient noise levels, and audiometric results as well as hearing loss prevalence, types, and risk factors. RESULTS: Despite high ambient noise levels during screening (46.7 dBA), no effect of noise on referral rates on automated audiometry or confirmatory manual audiometry in those who failed automated testing was seen. The overall audiometric referral rate was 2.6%. Idiopathic sensorineural hearing loss (SNHL) and cerumen impaction were the most common types of hearing loss in this population with an estimated prevalence of hearing loss (all types) of 18.3 per 1,000 children. SNHL was associated with both drug exposure during pregnancy (p = 0.04) and pesticide exposure in the home (p = 0.03). CONCLUSION: Hearing screening using a tablet-based, noise-attenuating wireless headset audiometer is feasible and effective in rural low-resource environments with moderately elevated ambient noise levels. The referral rate with noise-attenuating headsets was much lower than that previous reports on this population. In addition, manual audiometry resulted in much lower referral rates than automated audiometry. The confirmed hearing loss rate in this study is comparable to reports from other low-income countries that use some form of noise attenuation during screening. Pesticide exposure and drug exposure during pregnancy are potential causes of SNHL in this population.
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Perda Auditiva Neurossensorial , Perda Auditiva , Praguicidas , Criança , Humanos , Estudos Prospectivos , Nicarágua/epidemiologia , Audiometria/métodos , Audição , Perda Auditiva/diagnóstico , Perda Auditiva/epidemiologia , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/epidemiologia , Audiometria de Tons Puros/métodosRESUMO
INTRODUCTION: A recently recognised form of chronic kidney disease (CKD) of unknown origin (CKDu) is afflicting communities, mostly in rural areas in several regions of the world. Prevalence studies are being conducted in a number of countries, using a standardised protocol, to estimate the distribution of estimated glomerular filtration rate (eGFR), and thus identify communities with a high prevalence of reduced glomerular filtration rate (GFR). In this paper, we propose a standardised minimum protocol for cohort studies in high-risk communities aimed at investigating the incidence of, and risk factors for, early kidney dysfunction. METHODS AND ANALYSIS: This generic cohort protocol provides the information to establish a prospective population-based cohort study in low-income settings with a high prevalence of CKDu. This involves a baseline survey that included key elements from the DEGREE survey (eg, using the previously published DEGREE methodology) of a population-representative sample, and subsequent follow-up visits in young adults (without a pre-existing diagnosis of CKD (eGFR<60 mL/min/1.73m2), proteinuria or risk factors for CKD at baseline) over several years. Each visit involves a core questionnaire, and collection and storage of biological samples. Local capacity to measure serum creatinine will be required so that immediate feedback on kidney function can be provided to participants. After completion of follow-up, repeat measures of creatinine should be conducted in a central laboratory, using reference standards traceable to isotope dilution mass spectrometry (IDMS) quality control material to quantify the main outcome of eGFR decline over time, alongside a description of the early evolution of disease and risk factors for eGFR decline. ETHICS AND DISSEMINATION: Ethical approval will be obtained by local researchers, and participants will provide informed consent before the study commences. Participants will typically receive feedback and advice on their laboratory results, and referral to a local health system where appropriate.
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Taxa de Filtração Glomerular , Falência Renal Crônica , Proteinúria , Insuficiência Renal Crônica , Medição de Risco/métodos , Protocolos Clínicos , Estudos de Coortes , Progressão da Doença , Feminino , Necessidades e Demandas de Serviços de Saúde , Humanos , Cooperação Internacional , Falência Renal Crônica/etiologia , Falência Renal Crônica/mortalidade , Falência Renal Crônica/prevenção & controle , Masculino , Prevalência , Proteinúria/diagnóstico , Proteinúria/etiologia , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/epidemiologia , Projetos de Pesquisa , Fatores de Risco , População Rural , Adulto JovemRESUMO
OBJECTIVES: There is an epidemic of Mesoamerican nephropathy (MeN) in Central America, where sugarcane production is prominent. Numerous causes are proposed, but to date limited evidence supports any one hypothesis. A nested case-control study using biosamples from a rural, community-based follow-up study of 350 young adults from Northwest Nicaragua at risk of MeN was conducted with the aim of characterising the associations between urinary concentrations of metals, pesticides and mycotoxins from samples collected in the first 6 months and decline in kidney function over 2 years. METHODS: Urine samples collected at baseline (pre-sugarcane harvest) and the first 6 month follow-up (post-sugarcane harvest) visit were tested. Twelve metals and metalloids (aluminium, total arsenic, cadmium, chromium, cobalt, copper, lead, manganese, mercury, selenium, silicon and strontium) were analysed by inductively coupled plasma-mass spectrometry. Twelve pesticides or their metabolites (2,4-dichlorophenoxyacetic acid, 3-phenoxybenzoic acid, 4-fluoro-3-phenoxybenzoic acid, chloro-3,3,3-trifluoro-1-propen-1-yl-2,2-dimethylcyclopropanecarboxylic acid, cis/trans 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, ethylenethiourea, glyphosate, 4-chloro-2-methylphenoxy acetic acid, 3-hydroxy-pyrimetanil, 5-hydroxytiabendazole, hydroxy-tebuconazole and 3,5,6-trichloro-2-pyridinol) and two mycotoxins (ochratoxin A (OTA) and citrinin (CIT)) were analysed by liquid chromatography coupled-mass spectrometry. Differences in the creatinine-corrected urinary concentrations of the measured exposures between outcome groups (participants with stable vs declining kidney function) were examined. RESULTS: Elevated levels of aluminium and total arsenic as well as metabolites of several pesticides were detected across the population. No differences were identified between the declining and stable groups in the levels of metals or pesticides tested. OTA and CIT were below the limit of detection. CONCLUSIONS: The tested metals, metalloids, pesticides and mycotoxins were not associated with loss of kidney function in participants at-risk of MeN.
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Doenças dos Trabalhadores Agrícolas/induzido quimicamente , Doenças dos Trabalhadores Agrícolas/epidemiologia , Poluentes Ambientais/urina , Falência Renal Crônica/induzido quimicamente , Falência Renal Crônica/epidemiologia , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Testes de Função Renal , Masculino , Nicarágua/epidemiologia , Fatores de Risco , Saccharum , Espectrofotometria Atômica , UrináliseRESUMO
RATIONALE & OBJECTIVE: In Central America, there is a high prevalence of chronic kidney disease (CKD) of nontraditional etiology often observed among agricultural workers. Few studies have assessed CKD prevalence among workers in nonagricultural occupations, which was the objective of this investigation. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Male and female workers (n = 224) employed by artisanal brickmaking facilities in La Paz Centro, Nicaragua. PREDICTORS: Age, sex, education, smoking status, body mass index, alcohol consumption, water consumption, first-degree relative(s) with CKD, years worked, hours worked per week, job category, study visit (baseline and follow-up), and self-reported hypertension and diabetes. OUTCOMES: CKD defined as estimated glomerular filtration rate (eGFR) < 60mL/min/1.73m2 at 2 time points 4 months apart and CKD stage. ANALYTICAL APPROACH: A linear mixed-effects model with an unstructured covariance matrix was used to evaluate the association between demographics, occupational risk factors, and eGFR at baseline. The interaction between risk factors and time with change in eGFR was also evaluated. Multivariable logistic regression models were used to evaluate predictors of CKD. RESULTS: The CKD prevalence was 12.1% (n = 27), 100% of cases were male, 30% had stage 5 CKD (eGFR < 15mL/min/1.73m2), and 22% were younger than 35 years. Proportions of participants with eGFRs < 60mL/min/1.73m2 at baseline and follow-up were 13.8% and 15.2%, respectively. Linear regression analysis demonstrated significant predictors of lower kidney function at baseline including oven work, older age, lack of education, and having an immediate family member with CKD. Predictors of CKD identified using logistic regression analysis included oven work and lack of education. LIMITATIONS: Crude job classification measures, loss to follow-up, self-reported exposures. CONCLUSIONS: The prevalence of CKD is high in this population of brick workers, suggesting that the epidemic of CKD affecting Mesoamerica is not limited to agricultural workers. These results are consistent with the hypothesis that occupational heat exposure is a risk factor for kidney disease in this region.
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Indústria da Construção , Doenças Profissionais/epidemiologia , Insuficiência Renal Crônica/epidemiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nicarágua/epidemiologia , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Prevalência , Estudos Prospectivos , Insuficiência Renal Crônica/etiologia , Fatores de Risco , Adulto JovemRESUMO
BACKGROUND: After two-years of follow-up of 263 apparently healthy 18- to 30-year-old men in communities affected by Mesoamerican nephropathy (MeN), we identified three distinct case groups: a subgroup with (i) established renal dysfunction (case-group 1); individuals with (ii) a rapid decline in kidney function (case-group 2); and individuals with (iii) stable kidney function (non-cases). This paper investigates whether local tests are potentially useful for the timely identification of these case groups. METHODS: Creatinine levels were measured in local laboratories every six months for two years. Aliquots were sent to a centralized laboratory for measurements of cystatin C and creatinine levels. We investigated agreement between the locally and centrally measured creatinine-based Chronic Kidney disease Epidemiology Collaboration (CKD-EPI) equation for estimating the Glomerular Filtration Rate (eGFR). A logistic regression analysis was used to assess predictive factors for case groups 1 and 2 compared to non-cases. Predictive variables were locally measured eGFR, and urinary neutrophil gelatinase-associated lipocalin (uNGAL) levels. The discrimination performance of the model was assessed using the area under the receiver operating characteristic curve (AUC). RESULTS: Considerable variation in local eGFR measurements was observed. The prediction model for case-group 1 included baseline kidney function and with or without uNGAL (AUC = 0.98, 95% confidence interval (CI), 0.91-1.00). The prediction model for case-group 2 also required eGFRScr at six and twelve months after baseline, with or without uNGAL levels (AUC = 0.88; 95% CI 0.80-0.99). CONCLUSIONS: Established renal dysfunction was detected at a single time point using local measurements and uNGAL. For the detection of a rapid decline in kidney function over time, at least 2 more measurements at six and twelve months are needed.
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Testes de Função Renal , Rim/fisiopatologia , Insuficiência Renal Crônica/epidemiologia , Adolescente , Adulto , Albuminúria/etiologia , Albuminúria/urina , Área Sob a Curva , Creatinina/sangue , Creatinina/urina , Cistatina C/sangue , Progressão da Doença , Doenças Endêmicas , Seguimentos , Taxa de Filtração Glomerular , Humanos , Lipocalina-2/sangue , Masculino , Nicarágua/epidemiologia , Curva ROC , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/fisiopatologia , Insuficiência Renal Crônica/urina , Risco , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: The aim of this systematic review is to examine the epidemiological knowledge and gaps in understanding of the potential causes of chronic kidney disease of undetermined cause (CKDu) in Meso-America. METHODS: A systematic literature search of epidemiological studies of CKDu was conducted in PubMed, Embase and Web of Science from January 2000 to January 2017. Study quality was assessed by adapting the tool from Higgins et al. for observational studies. Where applicable, the summary prevalence odds ratio (POR) and 95% confidence interval (CI) were calculated using a random effects model. RESULTS: Twenty-five epidemiological studies were included in the analysis of risk factors for CKDu. The quality assessment of each occupational and community study was medium. The PORs for CKDu were males versus females 2.42 (95% CI 1.76-3.08), family history of CKD (versus none) 1.84 (95% CI 1.37-2.30), high water intake (versus low) 1.61 (95% CI 1.01-2.21) and low altitude (versus highland) 2.09 (95% CI 1.00-3.17). There were no significant associations between CKDu and pesticide exposure (versus no) 1.17 (95% CI 0.87-1.46), alcohol consumption (versus no) 1.34 (95% CI 0.84-1.84), non-steroidal anti-inflammatory drugs (versus no) 0.99 (95% CI 0.60-1.39) and heat stress (versus no) 1.52 (95% CI -0.91 - 3.95). CONCLUSION: Our meta-analysis showed positive associations for males (versus females) and family history of CKD, water intake, lowland altitude and CKDu. There were no significant associations with pesticide exposure, non-steroidal anti-inflammatory drugs intake, heat stress and alcohol consumption.
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Background Epidemic levels of CKD of undetermined cause, termed Mesoamerican nephropathy in Central America, have been found in low- and middle-income countries. We investigated the natural history of, and factors associated with, loss of kidney function in a population at high risk for this disease.Methods We conducted a 2-year prospective, longitudinal study with follow-up every 6 months in nine rural communities in northwestern Nicaragua and included all men (n=263) and a random sample of women (n=87) ages 18-30 years old without self-reported CKD, diabetes, or hypertension. We used growth mixture modeling to identify subgroups of eGFR trajectory and weighted multinomial logistic regression to examine associations with proposed risk factors.Results Among men, we identified three subpopulations of eGFR trajectory (mean baseline eGFR; mean eGFR change over follow-up): 81% remained stable (116 ml/min per 1.73 m2; -0.6 ml/min per 1.73 m2 per year), 9.5% experienced rapid decline despite normal baseline function (112 ml/min per 1.73 m2; -18.2 ml/min per 1.73 m2 per year), and 9.5% had baseline dysfunction (58 ml/min per 1.73 m2; -3.8 ml/min per 1.73 m2 per year). Among women: 96.6% remained stable (121 ml/min per 1.73 m2; -0.6 ml/min per 1.73 m2 per year), and 3.4% experienced rapid decline (132 ml/min per 1.73 m2; -14.6 ml/min per 1.73 m2 per year; n=3 women). Among men, outdoor and agricultural work and lack of shade availability during work breaks, reported at baseline, were associated with rapid decline.Conclusions Although Mesoamerican nephropathy is associated with agricultural work, other factors may also contribute to this disease.