Is it the place or the people in the places? Exploration of why young people in deprived coastal communities of England have worse mental health than their peers inland

Previous research has shown that English adolescents who lived in the most deprived coastal neighbourhoods had worse mental health outcomes up to 11 years later than if they had lived in equivalent inland neighbourhoods. We used the same twelve waves (2009-2022) of Understanding Society, to examine whether environmental characteristics during adolescence, or their socio-demographics, explained this association. All analyses were adjusted for probability of selection into the study via survey weights, clustering of individuals within areas, and attrition over time. During adolescence, coastal youth (n=764) were exposed to worse average levels of sixteen environmental measures and better average levels for five environmental measures, than their peers inland (n=4,157). The concentration of area deprivation was also greater for coastal youth compared with their inland peers. When longitudinal models were fitted between environmental measures and SF-12 mental functioning scores (MCS) during adulthood (age 16+), and adjustments made for individual age, gender, ethnicity, household income and tenure, only local crime and higher education participation were independently associated with MCS scores [Top 20% vs Bottom 20% (95% Confidence interval (CI): -1.20 (-2.38,-0.03) and Middle 20% vs Worse 20%: 1.07 (0.09,2.05)]. However, the amplified effect of area deprivation on MCS scores in coastal, compared to inland, areas was reduced the most by adjustment for individual socio-demographics [interaction term coastal*Top20% deprived area: -5.1 (-8.1,-2.2) to -4.3 (-7.0,-1.6)], then the two environmental measures [further reduced to -3.9 (-6.7,-1.1)]. Interventions to improve the mental health of coastal youth should focus on young peoples socioeconomic circumstances in these areas.