Risk factors for upper respiratory infection in the first year of life in a birth cohort

Abstract

ObjectivesDespite being one of the commonest causes of morbidity among infants, there are no reliable data on the incidence and risk factors of upper respiratory infection among Indian infants. Accordingly, we aimed to study the incidence and age related prevalence, socio-demographic risk factors and association between upper respiratory infection and nasopharyngeal colonization with Streptococcus pneumoniae in the first year of life among rural Indian infants. MethodsA birth cohort of 210 babies was evaluated monthly with nasopharyngeal swabbing to note the frequency of upper respiratory infection and carriage rate with S. pneumoniae. Data on 11 potential risk factors were noted and subjected to statistical analysis. ResultsUpper respiratory infection episodes commenced within a few weeks of life and increased in frequency with age, peaking at 72% in the 9th month. There were 747 episodes of upper respiratory infection overall (6.1 episodes per child-year follow up). The prevalence was maximum in the winter months (65%). There were 3 significant risk factors for upper respiratory infection in the first year of life, i.e., winter season (OR=1.86; 95% CI=1.4–3.5), nasopharyngeal colonization with S. pneumoniae (OR=1.34; 95% CI=1.1–1.7) and parental occupation (OR=1.37; 95% CI=1.1–1.8). The OR were adjusted for other covariates like sex of the child, parents’ education, type of house, birth weight, number of family members, passive smoking, use of firewood for cooking and water source. ConclusionsSeasonal predilection in winter, nasopharyngeal colonization with S. pneumoniae and parental occupation (poor socioeconomic status) are the most important risk factors for upper respiratory infection among rural Indian infants.