Background: Recurrent ear, nose and throat (ENT) infections and their sequelae (recurrent and chronic illness, high risk for language delay, learning and behavioural problems) are common and costly paediatric health issues caused by complex interactions among pathogenic, genetic and environmental factors. The middle ear, nose and throat may be conceptualized as a unified organ, which are susceptible viral and bacterial infection from similar pathogens. Genetic epidemiological studies (both in the BLATS sample and in Norwegian twin study) have found significant genetic correlations between susceptibility to ENT infection indicating the presence of shared genetic risk factors influencing these illnesses.

Aims: The proposed project aims to identify genetic variants influencing common ENT illnesses. We have previously conducted genome wide association (GWAS) analyses of common ENT infections within the Brisbane Longitudinal Adolescent Twin Study (BLATS) and are seeking to replicate and extend these findings through collaboration with the ALSPAC study.

Exposure Variables: NA

Outcome Variables: As minor ENT infections are very common among children we will analyse surgical interventions performed to mediate these infections to focuss on more severe and reccurent illness. As such ENT illness will be identifed using parental reprts of tonsillectomy, adenoidectomy and myringotomy (the insertion of grommets) derived from the child focused questionnaires at 103 months (8years KS questions A6 b, c and e) and 140 months (11years KW questions A3 b, c and e).

Confounding variables: There are well established sex differences in susceptibility to some ENT illnesses as such sex will be included as a covariate in all analyses.

Analyses: Univariate GWAS analyses of tonsillectomy, adenoidectomy and myringotomy will be conducted by David Evans while he is in Bristol in October 2013. The summary statistics from the analyses of the ALSPAC data will be shared with Sarah Medland and Robyn Choi to allow genome-wide meta-analysis of the BLATS and ALSPAC results.

No raw data or samples will be transfered or shared between ALSPAC and BLATS.