Risk of diagnosed and undiagnosed mental distress in coastal and inland English residents: A pooled cross-sectional analysis of adult UKHLS respondents

Recent research in the United Kingdom (UK) has highlighted a potential ‘coastal effect’, whereby residents of coastal areas may be subject to poorer health outcomes, including mental health. This study sought to investigate the coastal effect by comparing the risk of experiencing diagnosed and undiagnosed mental distress in both coastal and inland English adult residents. Data from waves 10–13 (2018–2023) of Understanding Society, a nationally representative population study, were extracted for analysis. Respondents were categorised by residential area (coastal or inland), mental health status (no mental distress, diagnosed mental distress, and undiagnosed mental distress), and age category (young adult (16–24 years) (n = 3,615), working age adult (25–65 years) (n = 18,011) and older adult (66+ years) (n = 6,923)). The results of multinomial regression revealed that after adjusting for sex, ethnicity, tenure and household income, young adults residing in the most deprived coastal areas had three times the risk of experiencing undiagnosed mental distress compared to young adults from equally deprived inland areas (RRR: 3.42, 95%CI: 1.24, 9.36). In contrast, older adults in the most deprived coastal areas had approximately one-third of the risk of experiencing undiagnosed mental distress compared with their inland peers (RRR: 0.13, 95%CI: 0.13, 0.95). This research highlights the striking mental health inequality in coastal young adults and calls for investment in both short-term interventions to support mental health and long-term investment in coastal infrastructure and youth mental health services to prevent future generations from experiencing similar mental health disparities.