ABSTRACT
The contamination of the Sonora River with 40,000 m3 of toxic leachate released from a copper mine on August 6, 2014, was considered the worst environmental disaster of the mining industry in Mexico, exceeding safety levels in the concentrations of heavy metals and arsenic. To explore the potential association of the toxic release with subfecundity, by comparing time to pregnancy (TTP) of women with different levels of exposure at municipalities located along the Sonora River watershed, just 35 km south of the Arizona-Mexico border. Data from 235 pregnancies were included in a retrospective cohort study. Exposure was measured whether pregnancy occurred before or after the disaster and included a non-exposed community outside the watershed. Pregnancies were also compared between communities according to the concentration-level gradient of water pollutants found in the river. Fecundability odds ratios (fORs) were calculated using discrete time analogue of Cox's proportional hazard models. Multiple analysis included all pregnancies with TTP of no more than 12 months, only first-time pregnancy, or excluding women with TTP = 1. The probability for pregnancy decreased after the disaster (fOR 0.55, 95% CI 0.31, 0.97), when the residency was located mid-or-downstream the watershed (fOR 0.37, 95% CI 0.15, 0.91), when reported chicken consumption, when mining was the father's occupation, and when surface water was reported to be used for crop irrigation and for animal consumption. There was a decrease in fecundity on women exposed to the contaminated river. There is a need for more studies to prove these findings and to broaden the knowledge of other possible adverse health effects associated with this environmental disaster.
Subject(s)
Disasters , Environmental Exposure/analysis , Mining , Rivers/chemistry , Water Pollutants, Chemical/analysis , Adult , Copper/analysis , Copper/toxicity , Female , Fertility/drug effects , Humans , Metals, Heavy/analysis , Metals, Heavy/toxicity , Mexico , Odds Ratio , Pregnancy , Retrospective Studies , Time-to-Pregnancy/drug effects , Water Pollutants, Chemical/toxicityABSTRACT
Introducción: El tiempo para quedar en embarazo (TPE) es una medida clínica de la fecundidad útil en la evaluación de efectos reproductivos relacionados con exposiciones ambientales u ocupacionales. Estudios con mujeres europeas evidencian que su uso tiene una adecuada recordación y reproducibilidad; sin embargo, estas propiedades no han sido evaluadas en Latinoamérica. Objetivos: Evaluar la reproducibilidad de la medida TPE en una población de mujeres colombianas como una aproximación clínica de la fecundidad. Metodología: Estudio de reproducibilidad prueba-reprueba de un cuestionario para determinar el tiempo al primer embarazo en una sub-muestra de 27 mujeres, anidado en una cohorte retrospectiva de evaluación de los efectos reproductivos de la exposición al mercurio metálico en la minería artesanal de oro. El cuestionario fue administrado de forma repetida por un evaluador entrenado, en el primer momento en una entrevista presencial y 12 meses después en una entrevista telefónica. La reproducibilidad del cuestionario fue evaluada usando el coeficiente de correlación intraclase (CCI). Resultados: La mediana de tiempo al embarazo fue de 4 meses (rango intercuartil 1-12). El rango de tiempo transcurrido desde el primer embarazo estuvo entre 1 y 15 años. El CCI (2,k) fue 0.726 (IC 95% 0.39, 0.88), demostrando una buena reproducibilidad de la variable después de un año de separación entre la primera y segunda entrevista. Conclusiones: El TPE para el primer embarazo mostró ser una medida clínica de fecundidad sencilla y reproducible, con un tiempo de recordación de hasta 15 años y en evaluación presencial o telefónica en una población de mujeres colombianas.
Introduction: Time to pregnancy (TTP) is a clinical measurement of fecundity that has been used in occupational and environmental epidemiological research. Previous studies conducted in European women have shown an adequate reliability and reproducibility. However, these characteristics have not been yet evaluated in Latin American women. Objective: To assess the reproducibility of TTP for the first pregnancy as clinical measurement of couple's fecundity in a population of Colombian women. Methods: A test-retest study of TTP in 27 Colombian women was nested in a retrospective cohort study assessing the effect of mercury exposure on reproductive effects. The questionnaire was applied twice by the same trained interviewer (by person at baseline and by phone 12 months later). The TTP's reproducibility was evaluated using the intraclass correlation coefficient (ICC 2,k). Results: The median TTP was 4 months (Interquartile range 1-12). The range of time from the first pregnancy to the first interview was between 1 and 15 years. The ICC (2,k) was 0.726, (CI 95% 0.39 - 0.88), indicating good reproducibility between both measures. Conclusions: Our results suggest that TTP is a useful and reproducible measurement, with a remembrance time up to 15 years. Results were similar when assessed by phone and face-to face interview in a population of Colombian women.