Combined effects of individual and neighbourhood socioeconomic status on older adults’ mortality: a retrospective follow-up study in Hong Kong

OBJECTIVES: This study examined the interaction effects of individual and neighbourhood socioeconomic status (SES) in older adults in Hong Kong, considering all-cause and cause-specific mortality from respiratory disease, cancer, cardiovascular diseases, ischaemic heart disease, stroke, nonmedical disease and suicide. DESIGN: A retrospective follow-up study. SETTING: Hong Kong Special Administrative Region, a rapidly ageing society with 16.1% residents aged 65 years or older in 2020. PARTICIPANTS: 43 910 people aged 65 years or older were enrolled at baseline. They had participated in health check-ups during 2000–2003 in one of the Elderly Health Centres. Observation periods started on the date of the participant’s first health check-up, and ended at death, or 31 December 2011, whichever occurred first. OUTCOME MEASURES: All-cause and cause-specific mortality over the study timeframe. ANALYSIS: Cox’s proportional hazards regression models were applied to estimate the adjusted HRs of mortality, by including covariates at neighbourhood (deprivation) and individual levels (poverty, education and type of housing). RESULTS: The ‘double tragedy theory’ (ie, lower SES persons living in lower SES neighbourhoods have worst health outcomes) was more related to cancer, while the ‘psychosocial comparison theory’ (ie, lower SES persons living in higher SES neighbourhoods have poorer health outcomes) was more related to cardiovascular, ischaemic heart disease, and stroke. CONCLUSION: There were important interaction effects between neighbourhood and individual factors on mortality. Policies based on the interaction between individual and neighbourhood SES should be considered. For instance, for cancer, targeted services (ie, free consultation, relevant treatment information, health check-up, etc) could be allocated in socioeconomically deprived areas to support individuals with low SES. On the other hand, more free public services to reduce psychological stresses (ie, psychological support services, recreational services, health knowledge information, etc) could be provided for those individuals with low SES living in higher SES areas to reduce stroke, cardiovascular and ischaemic heart diseases.