Acute respiratory illnesses in the first 18 months of life / Enfermedades respiratorias agudas en los primeros 18 meses de vida

RESUMEN

Para conocer las causas y frecuencia de las enfermedades respiratorias agudas (ERA) durante los primeros 18 meses de vida en una población chilena, se siguió, en un consultorio urbano del norte de Santiago, a una cohorte de 437 niños nacidos sanos entre mayo de 1991 y abril de 1992. La información se obtuvo de los controles médicos realizados en el consultorio, del servicio de urgencia y de médicos particulares, así como de entrevistas a las madres al incorporar a los niños en el estudio y a los 6, 12 y 18 meses del seguimiento. Completaron el seguimiento 379 niños (87%). Las ERA constituyeron 67% de los 3762 episodios de enfermedad registrados en los niños durante el período de 18 meses, 1384 (55%) de las vías altas y 1144 (45%) de las bajas. La tasa total de ERA fue de 33 episodios por 100 meses-niño de observación. Las incidencias de ERA alta y baja, y el total de episodios descendieron significativamente durante los terceros 6 meses de edad. Se encontró una asociación estadísticamente significativa entre la ERA alta (≥ 2 episodios) y la escolaridad de la madre (< 8 años), antecedentes familiares de atopia y viviendas en malas condiciones. La ERA baja (≥ 4 episodios) se asoció significativamente con esos factores y además con la existencia de uno o más hermanos, haber nacido en un mes frío, haber recibido lactancia materna menos de 4 meses y pertenecer a un bajo estrato socioeconómico. Los episodios de bronquitis obstructiva se asociaron significativamente con la mayor parte de los factores de riesgo (sexo, hermanos, mes de nacimiento, duración de la lactancia, escolaridad materna, familiares que fumaban, uso de combustibles contaminantes en el hogar y antecedentes familiares de atopia). De modo similar, hubo asociaciones significativas entre la neumonía y muchos factores de riesgo (hermanos, mes de nacimiento, duración de la lactancia, escolaridad materna, familiares que fumaban y condición socioeconómica). En general, 42 niños fueron hospitalizados durante el período de estudio por ERA bajas y 2 niños murieron de neumonía en el hogar antes de cumplir los 6 meses. La tasa de hospitalizaciones disminuyó significativamente a medida que aumentó la edad

ABSTRACT

To help assess the causes and frequency of acute respiratory illnesses (ARI) during the first 18 months of life in Chile, a cohort of 437 children born in good health between May 1991 and April 1992 was followed at an urban health clinic in northern Santiago. Information was obtained from medical checkups performed at the clinic, from emergency health care services, from private physicians, and from interviews with each child's mother when the child was enrolled in the study and when it was 6, 12, and 18 months old. Followup was completed for 379 (87%) of the children. ARI accounted for 67% of all 3762 episodes of illness recorded for these children in the 18-month study period, 1384 (55%) of the ARI episodes affecting the upper respiratory tract and the remaining 1144 (45%) affecting the lower. The overall rate of ARI observed was 33 episodes per 100 child-months of observation. The incidences of upper, lower, and total ARI episodes decreased significantly in the third six months of life. A statistically significant association was found between upper ARI (≥2 episodes) and maternal smoking (≥5 cigarettes per day), but no significant associations were found with any of the other risk factors studied. However, lower ARI (≥2 episodes) was significantly associated with maternal schooling (<8 years), a family history of atopic allergy, and substandard housing conditions; and lower ARI (≥4 episodes) was significantly associated with these factors and also with the existence of one or more siblings, birth in a cold season, limited breast-feeding (<4 months), and low socioeconomic status. Significant associations were found between obstructive bronchitis episodes and most of the risk factors studied (gender, siblings, season of birth, duration of breast-feeding, maternal schooling, smoking, use of polluting fuels in the home, and a family history of atopic allergy); similarly, significant associations were found between the occurrence of pneumonia and many risk factors (including siblings, season of birth, duration of breast-feeding, maternal schooling, smoking, and socioeconomic level). Overall, 42 of the study children were hospitalized during the study period for lower tract ARI, and two children died of pneumonia at home during their first 6 months of life. The rate of hospitalization fell significantly with increasing age