Background Limited international research suggests sexual minority individuals, in particular sexual minority women, may experience worse asthma outcomes than their heterosexual peers. However, little research has explored if a similar disparity is present in the UK. This project aims to address this gap by exploring differences in asthma by sexual minority status using UK longitudinal population studies. This project will also explore how asthma disparities vary by sex and specific sexual identity, and cohort and age effects.

Methods Using data from five UK longitudinal studies (Millennium Cohort Study (MCS), Next Steps, the British Cohort Study (BCS70), Understanding Society: the UK Household Longitudinal Study (UKHLS), and the English Longitudinal Study of Ageing (ELSA)), we used pooled data from all studies to examine whether asthma diagnosis reporting varies by sexual minority status. We examined differences by sex, sexual identity, and by study. Finally, to explore the impact of aging effects we compared asthma diagnosis reports by sexual minority status at the most recent sweep and the sweep approximately ten years prior in each study.

Results In four of the five datasets and in the pooled analysis, sexual minority respondents are more likely to report a diagnosis of asthma. Sexual minority women and respondents who identified as bisexual were most likely to report a diagnosis of asthma compared to their heterosexual counterparts. Reports of asthma did not vary by sexual minority status in the youngest respondents, supporting the hypothesis that disparities emerge over the lifecourse.

Conclusion This analysis adds substantially to our understanding of asthma disparities by sexual minority status in the UK and responds to calls from the National Advisor for LGBT Health at NHS England to expand the evidence base for LGBTQ+ health disparities.This study also addresses key methodological challenges when exploring sexual minority disparities such as insufficient power and highlights the role of physical health disparities in sexual minority wellbeing.