[Blood and urine lead levels in children with attention deficit hyperactivity disorder]. / Niveles de plomo en niños con diagnóstico de trastorno por déficit de atención e hiperactividad.

BACKGROUND: Attention deficit hyperactivity disorder is the most common neuropsychiatric disorder in children; symptoms can persist into adult life by 60 %. Our objective was to quantify the levels of lead in blood and urine in pediatric patients with attention deficit hyperactivity disorder. METHODS: We did an observational study which included a captive population of children diagnosed with attention deficit hyperactivity disorder in the mental health service of Hospital General, from Centro Médico Nacional La Raza. Lead levels were determined in blood and urine by atomic absorption technique. RESULTS: We included 39 patients, 932 % male, with a mean age of 9.2 ± 2.16 years. The deficit and hyperactivity disorder combined type was the most frequent (69.2 %); 49 % of patients were found with toxic lead levels in blood (above 10 mg/dL); 17.9 % with stage III and 5.12 % with stage IV, according to the Mexican Official Standard (NOM-199-SSA-2000). Significant association was found between blood lead levels and the clinical expression of attention deficit hyperactivity disorder. CONCLUSIONS: Levels of lead exposure during early childhood have been shown to be inversely proportional to neurological development in the first seven years of life. Data results are insufficient to relate them with causality.

INTRODUCCIÓN: los síntomas del trastorno por déficit de atención e hiperactividad pueden persistir hasta la vida adulta en 60 % de quienes la padecieron en la niñez. Nuestro objetivo fue cuantificar los niveles de plomo en la sangre y la orina en niños con diagnóstico de trastorno por déficit de atención e hiperactividad para identificar si existe alguna relación. MÉTODOS: estudio observacional que incluyó a una muestra cautiva del Servicio de Higiene Mental del Hospital General del Centro Médico Nacional La Raza, con diagnóstico de trastorno por déficit de atención e hiperactividad. Se cuantificaron los niveles séricos y urinarios del plomo mediante la técnica de absorción atómica. RESULTADOS: se incluyeron 39 pacientes, 92.3 % del sexo masculino, con una edad promedio de 9.2 ± 2.16 años. El trastorno por déficit de atención e hiperactividad combinado fue el más frecuente (69.2 %). En 49 % de los pacientes se encontraron niveles de plomo en sangre superiores a 10 ?g/dL. Conforme los parámetros establecidos en la NOM-199-SSA1-2000, 17.9 % clasificaba en estadio III y 5.12 % en estadio IV. Se encontró relación significativa entre los niveles de plomo y la expresión clínica del trastorno por déficit de atención e hiperactividad. CONCLUSIONES: los niveles de exposición al plomo durante la infancia temprana han demostrado ser inversamente proporcionales al desarrollo neurológico en los primeros siete años de vida. Los datos son insuficientes para inferir la causalidad.

Father's occupational exposure to carcinogenic agents and childhood acute leukemia: a new method to assess exposure (a case-control study).

BACKGROUND: Medical research has not been able to establish whether a father's occupational exposures are associated with the development of acute leukemia (AL) in their offspring. The studies conducted have weaknesses that have generated a misclassification of such exposure. Occupations and exposures to substances associated with childhood cancer are not very frequently encountered in the general population; thus, the reported risks are both inconsistent and inaccurate. In this study, to assess exposure we used a new method, an exposure index, which took into consideration the industrial branch, specific position, use of protective equipment, substances at work, degree of contact with such substances, and time of exposure. This index allowed us to obtain a grade, which permitted the identification of individuals according to their level of exposure to known or potentially carcinogenic agents that are not necessarily specifically identified as risk factors for leukemia. The aim of this study was to determine the association between a father's occupational exposure to carcinogenic agents and the presence of AL in their offspring. METHODS: From 1999 to 2000, a case-control study was performed with 193 children who reside in Mexico City and had been diagnosed with AL. The initial sample-size calculation was 150 children per group, assessed with an expected odds ratio (OR) of three and a minimum exposure frequency of 15.8%. These children were matched by age, sex, and institution with 193 pediatric surgical patients at secondary-care hospitals. A questionnaire was used to determine each child's background and the characteristics of the father's occupation(s). In order to determine the level of exposure to carcinogenic agents, a previously validated exposure index (occupational exposure index, OEI) was used. The consistency and validity of the index were assessed by a questionnaire comparison, the sensory recognition of the work area, and an expert's opinion. RESULTS: The adjusted ORs and 95% confidence intervals (CI) were 1.69 (0.98, 2.92) during the preconception period; 1.98 (1.13, 3.45) during the index pregnancy; 2.11 (1.17, 3.78) during breastfeeding period; 2.17 (1.28, 3.66) after birth; and 2.06 (1.24, 3.42) for global exposure. CONCLUSION: This is the first study in which an OEI was used to assess a father's occupational exposure to carcinogenic agents as a risk factor for the development of childhood AL in his offspring. From our results, we conclude that children whose fathers have been exposed to a high level of carcinogenic agents seem to have a greater risk of developing acute leukemia. However, confounding factors cannot be disregarded due to an incomplete control for confounding.