American journal of epidemiology
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Studies have indicated that children delivered by cesarean section are at an increased risk of developing wheezing and asthma. This could be the result of an altered immune system development due to delayed gut colonization or of increased neonatal respiratory morbidity. The authors examined the associations between delivery by cesarean section and the development of wheezing, asthma, and recurrent lower respiratory tract infections in children up to 36 months of age among 37,171 children in the Norwegian Mother and Child Cohort Study. ⋯ Findings were similar among children delivered by acute and elective cesarean section. In conclusion, children delivered by cesarean section may have an increased risk of current asthma at 36 months, but residual confounding cannot be excluded. In future prospective studies, investigators should reexamine this association in different age groups.
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In this article, the authors demonstrate a time-series analysis based on a hierarchical Bayesian model of a Poisson outcome with an excessive number of zeroes. The motivating example for this analysis comes from the intensive care unit (ICU) of an urban university teaching hospital (New Haven, Connecticut, 2002-2004). Studies of medication use among older patients in the ICU are complicated by statistical factors such as an excessive number of zero doses, periodicity, and within-person autocorrelation. ⋯ By applying elements of time-series analysis within both frequentist and Bayesian frameworks, the authors evaluate differences in shift-based dosing of medication in a medical ICU. From a small sample and with adjustment for excess zeroes, linear trend, autocorrelation, and clinical covariates, both frequentist and Bayesian models provide evidence of a significant association between a specific nursing shift and dosing level of a sedative medication. Furthermore, the posterior distributions from a Bayesian random-effects Poisson model permit posterior predictive simulations of related results that are potentially difficult to model.
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In 1949, Alexander Langmuir became the first chief epidemiologist at the Communicable Disease Center (CDC) in Atlanta, Georgia. Among his many contributions to the agency and to public health, 2 of the most important--the Epidemic Intelligence Service (EIS) and his particular brand of epidemic-assistance investigation (the Epi-Aid)--are highlighted in this supplement to the American Journal of Epidemiology. ⋯ Support to state and local health departments has been instrumental to CDC's success during its first 60 years, and the articles describing Epi-Aids in this supplement capture this partnership elegantly. They also reflect the evolution of CDC from an agency focused almost entirely on communicable diseases to one engaged in a broad array of global public health challenges.