A Genetic Epidemiological Mega Analysis of Smoking Initiation in Adolescents.

Introduction: Previous studies in adolescents were not adequately powered to accurately disentangle genetic and environmental influences on smoking initiation (SI) across adolescence.

Methods: Mega-analysis of pooled genetically informative data on SI was performed, with structural equation modeling, to test equality of prevalence and correlations across cultural backgrounds, and to estimate the significance and effect size of genetic and environmental effects according to the classical twin study, in adolescent male and female twins from same-sex and opposite-sex twin pairs (N = 19 313 pairs) between ages 10 and 19, with 76 358 longitudinal assessments between 1983 and 2007, from 11 population-based twin samples from the United States, Europe, and Australia.

Results: Although prevalences differed between samples, twin correlations did not, suggesting similar etiology of SI across developed countries.

Hoarseness as the initial clinical presentation of anomalous left coronary artery from the pulmonary artery.

Anomalous origin of the left coronary artery from the pulmonary artery is a rare congenital anomaly that, if left untreated, will most often result in severe myocardial ischemia and significant morbidity and mortality. We report an unusual presentation of this defect in a 2-month-old infant who had an initial complaint of a "hoarse cry." We theorize that impingement of the recurrent laryngeal nerve due to dilatation of the pulmonary artery was the most likely etiology of the patient's symptoms.