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Theme 4: Project 8 – Association between primary mental health outcomes with air pollution in urban populations

The Clinical Record Interactive Search (CRIS) system has been developed for use by the NIHR Maudsley Biomedical Research Centre and Dementia Biomedical Research Unit at the South London and Maudsley (SLaM) NHS Foundation Trust. CRIS provides authorised researchers with regulated access to a wide range of pseudonymised information extracted from the SLaM electronic clinical records system 2008 onwards – 250,000 cases. Mental health outcomes included in the CRIS database are antipsychotic and antidepressant usage, first episode or diagnoses of anxiety, dementia, depression, schizophrenia, schizotypal and delusional disorders, as well as linked morality and hospital outcomes.

In this project we will employ an open cohort approach including all individuals with a first diagnosis on a mental health outcome. We will define an event as a dispensed medication or adverse mental health episode at least once during follow-up.  Each cohort member will be followed up until an event occurs, loss-to-follow-up (meaning that they had no longer a registered address in the study area), death, whichever came first. Cox regression models assuming proportional hazards, with time as an underlying variable will be employed and Hazard Ratios and their 95% CIs will be provided. Exposures (PM10, PM2.5, NO2, NOx) will be analysed as continuous variables, as ratios associated with interquartile range pollutant increases. All models will be adjusted for age at the start of follow-up, sex, education level, body mass index, smoking and socio-economic indicators (e.g. Index of Multiple Deprivation).

Lead researchers

Dr Ian Mudway


King's College London