There have been reports of associations between cesarean section delivery and the risk of childhood asthma, potentially mediated through changes in the gut microbiota. We followed 700 children in the Copenhagen Prospective Studies on Asthma in Childhood2010 (COPSAC2010) cohort prospectively from birth. We examined the effects of cesarean section delivery on gut microbial composition by 16S rRNA gene amplicon sequencing during the first year of life. We then explored whether gut microbial perturbations due to delivery mode were associated with a risk of developing asthma in the first 6 years of life. Delivery by cesarean section was accompanied by marked changes in gut microbiota composition at one week and one month of age, but by one year of age only minor differences persisted compared to vaginal delivery. Increased asthma risk was found in children born by cesarean section only if their gut microbiota composition at 1 year of age still retained a cesarean section microbial signature, suggesting that appropriate maturation of the gut microbiota could mitigate against the increased asthma risk associated with gut microbial changes due to cesarean section delivery.

A few months delay before final treatment of a non-small-cell lung cancer seems to have an impact on the perioperative stage of the cancer, and thereby on the patients prognosis. A screening of asymptomatic risk-group patients will result in recognition of early lung cancer.

WHAT'S KNOWN ON THIS SUBJECT:The World Health Organization recommends using vaccination contacts to deliver high-dose vitamin A supplementation (VAS) to children aged 6 to 59 months. The effect of this policy on overall child mortality has not been assessed. WHAT THIS STUDY ADDS:In this first randomized controlled trial of VAS at routine vaccination contacts after 6 months, VAS had no overall effect on mortality but was associated with reduced mortality in girls and increased mortality in boys.abstract BACKGROUND: The World Health Organization recommends vitamin A supplementation (VAS) at routine vaccination contacts after 6 months of age based on the assumption that it reduces mortality by 24%. The policy has never been evaluated in randomized controlled trials for its effect on overall mortality. We conducted a randomized double-blind trial to evaluate the effect of VAS with vaccines. METHODS:We randomized children aged 6 to 23 months 1:1 to VAS (100 000 IU if aged 6-11 months, 200 000 IU if aged 12-23 months) or placebo at vaccination contacts in Guinea-Bissau. Mortality rates were compared in Cox proportional-hazards models overall, and by gender and vaccine. CONCLUSIONS: This is the first randomized controlled trial to assess the effect of the policy on overall mortality. VAS had no overall effect, but the effect differed significantly by gender. More trials to ensure an optimal evidence-based vitamin A policy are warranted.