Isolated night cough in children: how does it differ from wheeze?

Abstract Background Children with night cough but no wheeze might have a mild form of asthma (cough variant asthma), sharing risk factors with children who wheeze, and possibly developing wheeze later. Methods We compared risk factors of children with isolated night cough and children with wheeze in the Leicester Respiratory Cohort study at ages 1, 4, 6, and 9 years. We also compared prognoses of children with isolated night cough, children with wheeze, and asymptomatic children. Results Among 4,101 children at age 1 year, 2,854 at 4, 2,369 at 6, and 1,688 at 9 years, the prevalence of isolated night cough was 10% at age 1 and 18% in older children, while prevalence of wheeze decreased from 35% at 1 year to 13% at age 9. Although many risk factors were the same for cough and wheeze, day care, reflux, and family history of bronchitis were more strongly associated with cough, and male sex and family history of asthma with wheeze. Over one-third of pre-schoolers with cough continued to cough at school age, but their risk of developing wheeze was similar to that of children asymptomatic at earlier surveys. Wheeze tracked more strongly throughout childhood than cough. Conclusions Some risk factors for cough and wheeze were shared and some were not; there was little evidence that children with isolated night cough have an increased risk of future wheeze. This suggests that only a fraction of children with isolated night cough might have a variant of asthma, if at all.