Associations between historical redlining, neighbourhood deprivation and chronic health in a cohort of people with a history of injection drug use.

BACKGROUND: Historical redlining, carried out by the Home Owners' Loan Corporation (HOLC), assigned US neighbourhoods grades A ('best') to D ('hazardous'), institutionalising residential segregation and leaving lasting effects on neighbourhood development and health outcomes. There is limited research examining the association between residence in historically redlined areas, present-day neighbourhood socioeconomic status and chronic disease in Baltimore, Maryland. METHODS: We used 2015-2019 data from the AIDS Linked to the IntraVenous Experience (ALIVE) cohort, an observational study of adults with a history of injection drug use living in or near Baltimore. We included 1335 participants (6568 visits), whose addresses could be assigned an HOLC grade and a 2015 Area Deprivation Index (ADI) percentile. Outcomes included eight chronic health outcomes for which we ran three logistic regression models: HOLC alone, ADI alone and both exposures with an interaction term. RESULTS: ALIVE participants were predominantly older (median age: 53.5), black (80%) and male (67%). Relative to grade D, prevalence of hypertension was 14% and 6% higher in grades A and B and prevalence of liver disease was 5-6% higher in grades B and C. Overall, ADI was not associated with any outcome. Within grade D, we saw increases of 3%-5% in prevalence of hypertension, HIV, renal disease, lung disease and multimorbidity per 25-percentile increase in ADI. CONCLUSIONS: HOLC grade, ADI and chronic conditions had at most modest relationships. Select chronic diseases had lower prevalence in grade D than in areas with higher grades, which may reflect changes in community resources since the 1930s.