Insomnia symptom prevalence in England: A comparison of self-reported data and primary care records in the UK Biobank

Purpose We aimed to use a large dataset to compare self-reported and primary care measures of insomnia symptom prevalence in England and establish whether they identify participants with similar characteristics. Methods We analysed data from 163,748 UK Biobank participants in England (aged 38-71 at baseline) with linked primary care electronic health records. We compared the percentage of those self-reporting ‘usually’ having insomnia symptoms at UK Biobank baseline assessment (2006-2010) to those with a Read code for insomnia symptoms in their primary care records prior to baseline. We stratified prevalence in both groups by sociodemographic, lifestyle, sleep and health characteristics. Results We found that 29% of the sample self-reported having insomnia symptoms, whilst only 6% had a Read code for insomnia symptoms in their primary care records. Only 10% of self-reported cases had an insomnia symptom Read code, whilst 49% of primary care cases self-reported having insomnia symptoms. In both primary care and self-reported data, prevalence of insomnia symptom cases was highest in females, older participants and those with the lowest household incomes. However, whilst snorers and risk takers were more likely to be a primary care case, they were less likely to self-report insomnia symptoms than non-snorers and non-risk takers. Conclusions Only a small proportion of individuals experiencing insomnia symptoms present to primary care. However, the sociodemographic characteristics of people attending primary care with insomnia were consistent with those with self-reported insomnia, thus primary care records are a valuable data source for studying risk factors for insomnia. Key Points Plain Language Summary Around a third of the general population is thought to suffer from insomnia symptoms, but estimates are based on the responses of a small number of people and rely on them reporting their own symptoms. People’s medical records offer a more objective way of finding out how many people have insomnia, but only capture people who go to their doctor for help. In this study we compared 160,000 people’s answers to a question on insomnia symptoms to their primary care records. We found that 29% of people reported insomnia symptoms, whereas only 6% had insomnia symptoms recorded in their medical records. However, the characteristics of those reporting insomnia and those with insomnia in their medical records were similar. This means that although medical records only capture a small proportion of those suffering from insomnia, they do still provide useful information for researchers studying risk factors for insomnia. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was funded in whole, or in part, by the Wellcome Trust [grant number 226909/Z/23/Z]. For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. M.A.dL is funded by the Wellcome Trust [grant number 226909/Z/23/Z]. M.A.dL and R.C.R work in a unit that receives support from the University of Bristol and the UK Medical Research Council [grant numbers MC\_UU\_00032/1, MC/UU/00032/3, MC/UU/00032/4]. N.M.D is supported by the Norwegian Research Council [grant number 295989]. R.C.R is supported by Cancer Research UK [grant number C18281/A29019]. SVE is funded by a Diabetes UK Sir George Alberti research training fellowship [grant number: 17/0005588]. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: UK Biobank is approved by the National Health Service National Research Ethics Service (ref. 11/NW/0382; UK Biobank application number 88626). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The UK Biobank dataset used to conduct the research in this paper is available via application directly to the UK Biobank. Applications are assessed for meeting the required criteria for access, including legal and ethics standards. More information regarding data access can be found at . Full code for all analyses is available at