Prestin and otolin-1 proteins in the hearing loss of adults chronically exposed to lead.

BACKGROUND: Some studies in animal models and humans suggest that exposure to lead is associated with hearing loss. Lead can reach the inner ear through the blood circulation; evidence suggests that lead could accumulate in the inner ear, causing inner ear damage. AIM: To evaluate prestin and otolin-1 protein levels and their relationship with an increased hearing threshold in participants exposed to lead. METHODS: We conducted a cross-sectional study with 315 participants from Tlaxcala, Mexico. Blood lead levels (BPb) were evaluated by graphite furnace atomic absorption spectrometry. Serum prestin and otolin-1 were quantified using ELISA. Auditory function at frequencies of 0.125 to 8 kHz was evaluated in a soundproof chamber. RESULTS: Participants were classified according to BPb: group I (<10 µg/dL) had a median BPb of 6 µg/dL and prestin levels of 11.06 ng/mL. While participants in group II (≥10 µg/dL) had a median of BPb 20.7 µg/dL (p < 0.05) and prestin levels of 0.15 ng/mL (p < 0.001). Participants in both groups showed a normal hearing. Otolin-1 levels were higher for participants with normal hearing and lower for participants with hearing loss in both groups, p > 0.05. Multiple linear regression models predict an average decrease of 0.17 to 0.26 ng/mL in prestin levels per decibel increase for the frequencies evaluated. CONCLUSIONS: Participants with high BPb showed an increase in hearing threshold, and prestin levels decreased proportionally to the hearing threshold increase. This is the first study to evaluate prestin as a potential biomarker for hearing damage, evaluated by audiometry, in participants with lead exposure.

Commute times and audiometric findings among adult population in Mexico City.

INTRODUCTION: Long commute times are common in big cities. OBJECTIVE: To determine hearing thresholds and their association with commute time in Mexico City. METHODS: Cross-sectional study that included 177 healthy adults from 2009 to 2011. Demographic information and commute times were recorded. Hearing was assessed by audiometry. Regression models were constructed to determine the predictors of hearing thresholds. RESULTS: There were 101 men (53%) and 76 women (43%). Mean commute time was 43 minutes (1-150 minutes). A hearing threshold drop was observed at 4000 Hz, with recovery at 8000 Hz in both ears when patients were stratified by gender and age groups. A commute time > 40 min/day increased the hearing threshold at 4000 Hz (ß = 2.96 dB HL, p < 0.01). Men had higher thresholds (ß = 2.6 dB HL), as older subjects also did: 25-34 years, ß = 2.2 dB HL; 35-44 years, ß = 5.2 dB HL; and ≥ 45 years, ß = 8.3 dB HL. CONCLUSION: The hearing pattern, although normal, resembled that of noise-induced hearing loss, associated with long commute times.

INTRODUCCIÓN: Los tiempos prolongados de traslado son comunes en las ciudades grandes. OBJETIVO: Determinar los umbrales auditivos y su asociación con el tiempo de traslado al trabajo en la Ciudad de México. MÉTODOS: Estudio transversal que incluyó a 177 adultos sanos de 2009 a 2011. Se registró información demográfica y tiempo de traslado al trabajo. La audición se evaluó mediante audiometría. Se realizaron modelos de regresión para determinar los predictores de los umbrales auditivos. RESULTADOS: Se trató de 101 hombres (53 %) y 76 mujeres (43 %). El tiempo promedio de traslado fue 43 minutos (1 a 150 minutos). Se observó una caída del umbral auditivo en 4000 Hz, con recuperación en 8000 Hz en ambos oídos al estratificar por sexo y grupos de edad. Un tiempo de traslado > 40 minutos/día incrementó el umbral auditivo en 4000 Hz (b = 2.96 dB HL, p < 0.01). Los hombres presentaron umbrales mayores (b = 2.6 dB HL), al igual que los sujetos de edad más avanzada: 25 a 34 años, b = 2.2 dB HL; 35 a 44 años, b = 5.2 dB HL y ≥ 45 años, b = 8.3 dB HL. CONCLUSIÓN: El patrón auditivo, aunque normal, se asemejó a la pérdida auditiva por ruido asociada a tiempo prolongado de traslado al trabajo.

Occupational predictors of urinary dialkyl phosphate concentrations in Mexican flower growers.

Background Flower growers have high potential for exposures to pesticides. Occupational factors, such as tasks performed, the production method (organic or conventional), the use of personal protective equipment (PPE), and workplace characteristics influence the intensity of pesticide exposure. Objective To evaluate occupational characteristics affecting urinary concentration of dialkylphosphate (DAP) metabolites of organophosphate pesticides among a group of Mexican floricultural workers. Methods A questionnaire was administered to 117 workers who also provided a first morning urine sample. According to tasks performed and the production methods, pesticide contact was defined as low, medium, or high. PPE use was categorized as acceptable, fairly acceptable, and unacceptable. Urinary concentration of DAP metabolites were determined using gas-liquid chromatography. Association between occupational characteristics and DAP urinary concentrations was assessed by means of linear regression models. Results After adjusting for potential confounders, the workers in the medium and high contact categories had significantly higher DAP concentrations than those in the low contact category (ß: 0.3, CI 95%: 0.1-0.5). Greenhouse workers had greater DAP concentrations than outdoors workers (ß: 0.3, CI 95%: 0.1-0.5). Compared with non-acceptable use of PPE, acceptable use of PPE was associated with lower DAP concentrations (ß: -0.4, CI 95% -0.6 to -0.1). Conclusion Improved safety training is needed for correct PPE usage, especially among flower growers who use conventional pest control methods and who work in a greenhouse environment.

La equidad y la salud en el trabajo: explorando un área emergente / Inequity and health in the workplace: exploring an emergent area

El trabajo, bajo condiciones de empleo justo y decente, reduce las inequidades en salud; sin embargo, en la actualidad parece prevalecer la obtención y desempeño de este sin los atributos referidos, con exposición tanto a accidentes como a padecer enfermedades causadas por diversos agentes, y a riesgos ergonómicos y psicosociales presentes en el trabajo, y los relacionados con el modo de trabajar impuesto por el wildmarket y sin prestaciones en materia de seguridad social. Las políticas que en salud y seguridad en el trabajo deberían instituir los países miembros de la Organización Internacional del Trabajo (OIT) acortarían las inequidades mencionadas, no obstante, el Estado, quien garantizaría esas políticas, parece haberse convertido en intermediador a favor de los grandes corporativos. Es fundamental que se definan y fortalezcan acciones para constituir empleos con condiciones apropiadas y decorosas, a fin de generar equidad, igualdad y bienestar social.

Work, under fair employment and decent work, reduces inequities in health. Nowadays it seems, however, that obtaining and carrying out a job and worker performance take precedence over the aforementioned attributes. Workers are not only exposed to accidents, diseases caused by various agents, ergonomic and psychosocial risks but also affected by work modes imposed by the “wildmarket”, such as the lack of social security benefits. Member countries of the International Labour Organization (ILO) should institute occupational health and safety policies in order to reduce the above mentioned inequities. Nonetheless, governments, which would guarantee such policies, seem to have become intermediaries in favor of large corporations. It is essential to define and strengthen actions that create jobsin decent and appropriate conditions with a view to generating equity, equality, and social well-being.

[Inequity and health in the workplace: exploring an emergent area]. / La equidad y la salud en el trabajo: explorando un área emergente.

Work, under fair employment and decent work, reduces inequities in health. Nowadays it seems, however, that obtaining and carrying out a job and worker performance take precedence over the aforementioned attributes. Workers are not only exposed to accidents, diseases caused by various agents, ergonomic and psychosocial risks but also affected by work modes imposed by the "wildmarket", such as the lack of social security benefits. Member countries of the International Labour Organization (ILO) should institute occupational health and safety policies in order to reduce the above mentioned inequities. Nonetheless, governments, which would guarantee such policies, seem to have become intermediaries in favor of large corporations. It is essential to define and strengthen actions that create jobs in decent and appropriate conditions with a view to generating equity, equality, and social well-being.

Estimation of health-care costs for work-related injuries in the Mexican Institute of Social Security.

BACKGROUND: Data on the economic consequences of occupational injuries is scarce in developing countries which prevents the recognition of their economic and social consequences. This study assess the direct heath care costs of work-related accidents in the Mexican Institute of Social Security, the largest health care institution in Latin America, which covered 12,735,856 workers and their families in 2005. METHODS: We estimated the cost of treatment for 295,594 officially reported occupational injuries nation wide. A group of medical experts devised treatment algorithms to quantify resource utilization for occupational injuries to which unit costs were applied. Total costs were estimated as the product of the cost per illness and the severity weighted incidence of occupational accidents. RESULTS: Occupational injury rate was 2.9 per 100 workers. Average medical care cost per case was $2,059 USD. The total cost of the health care of officially recognized injured workers was $753,420,222 USD. If injury rate is corrected for underreporting, the cost for formal injured workers is 791,216,460. If the same costs are applied for informal workers, approximately half of the working population in Mexico, the cost of healthcare for occupational injuries is about 1% of the gross domestic product. CONCLUSIONS: Health care costs of occupational accidents are similar to the economic direct expenditures to compensate death and disability in the social security system in Mexico. However, indirect costs might be as important as direct costs.

Globalization and the transfer of hazardous industry: asbestos in Mexico, 1979-2000.

This study quantified asbestos use in Mexico in the past decade and evaluated available data on mortality due to malignant mesothelioma in Mexico between 1979 and 2000. Mortality data were analyzed from secondary databases of the Mexican Social Security System and the Ministry of Health. Data on the import and export of asbestos in Mexico were obtained from the Ministry of Trade and Industrial Development of Mexico. Deaths due to pleural mesothelioma significantly increased in this period. Although the import of asbestos declined, the number of Mexican products that contain asbestos tripled. Export of Mexican asbestos-containing products to Central America grew rapidly in the last ten years of the study. Mexico continues the appreciable use of asbestos and has experienced a significant increase in the occurrence of the sentinel asbestos-related disease, malignant mesothelioma. Given the many limitations to the control of hazardous work exposures in Mexico, a ban on asbestos is advocated as the most feasible means of limiting an epidemic of asbestos-related disease.