Background The association between socioeconomic  status (SES) and incidence of out-of-hospital cardiac arrest  (OHCA) is not fully understood. The aim of this study was  to see if area-level socioeconomic differences, measured  in terms of area-level income and education, are  associated with the incidence of OHCA, and if this  relationship is dependent on age. 

Methods We included OHCAs that occurred in  Stockholm County between the 1st of January 2006 and  the 31st of December 2017, the victims being confirmed  residents (n=10 574). We linked the home address to  a matching neighbourhood (base unit) via available  socioeconomic and demographic information.  Socioeconomic variables and incidence rates were  assessed by using cross-sectional values at the end of  each year. We used zero-inflated negative binomial  regression to calculate incidence rate ratios (IRRs). 

Results Among 1349 areas with complete SES  information, 10 503 OHCAs occurred between 2006 and  2017. The IRR in the highest versus the lowest SES area  was 0.61 (0.50–0.75) among persons in the 0–44 age  group. Among patients in the 45–64 age group, the  corresponding IRR was 0.55 (0.47–0.65). The highest SES  areas versus the lowest showed an IRR of 0.59  (0.50–0.70) in the 65–74 age group. In the two highest  age groups, no significant association was seen (75–84  age group: 0.93 (0.80–1.08); 85+ age group: 1.05  (0.84–1.23)). Similar crude patterns were seen among  both men and women. 

Conclusions Areas characterised by high SES showed  a significantly lower incidence of OHCA. This relationship  was seen up to the age of 75, after which the relationship  disappeared, suggesting a levelling effect.