Design of the 18-year follow-up of the Danish COPSAC birth cohort.

Background: Atopic diseases, obesity and neuropsychiatric disorders are lifestyle-related and environmental-related chronic inflammatory disorders, and the incidences have increased in the last years.

Objective: To outline the design of the 18-year follow-up of the Copenhagen Prospective Study on Asthma in Childhood (COPSAC) birth cohort, where risk factors of atopic diseases, obesity and neuropsychiatric disorders are identified through extensive characterisation of the environment, along with deep clinical phenotyping and biosampling for omics profiling.

Methods: COPSAC is a Danish prospective clinical birth cohort study of 411 children born to mothers with asthma who were enrolled at 1 month of age and closely followed at the COPSAC clinical research unit through childhood for the development of atopic diseases.

The developing airway and gut microbiota in early life is influenced by age of older siblings.

Background: Growing up with siblings has been linked to numerous health outcomes and is also an important determinant for the developing microbiota. Nonetheless, research into the role of having siblings on the developing microbiota has mainly been incidental.

Results: Here, we investigate the specific effects of having siblings on the developing airway and gut microbiota using a total of 4497 hypopharyngeal and fecal samples taken from 686 children in the COPSAC cohort, starting at 1 week of age and continuing until 6 years of age.

Early life bacterial airway colonization, local immune mediator response and risk of otitis media.

Acute otitis media (AOM) is the most common bacterial infection in early childhood, but the underlying mechanisms making some children more susceptible are poorly understood. To examine the associations between bacterial airway colonization in early life and the risk of AOM and tympanostomy tube insertion (TTI), and whether such associations are modulated by an insufficient local immune mediator response to bacterial colonization. Bacterial cultures from hypopharyngeal samples were obtained at 1 week, 1 month and 3 months of age in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC) cohort comprising 700 children.