Differences in the risk of cardiovascular disease for movers and stayers in New Zealand: a survival analysis

Objectives: To explore if risk of cardiovascular disease (CVD) for participants who moved before their first CVD event is higher than for stayers, and examine whether the relationship is moderated by ethnicity. Methods: The sample comprised of 2,068,360 New Zealand (NZ) residents enrolled in any Primary Health Organisation, aged between 30-84 years, had complete demographic information, and no prior history of CVD. Cox proportional regression was used to compare CVD risk between movers and stayers. The analysis was conducted for the whole sample and stratified by ethnicity. Results: The combined analysis suggested movers have a lower risk of CVD than stayers. This is consistent for all ethnic groups with some variation according to experience of deprivation change following residential mobility. Conclusions: Although mobile groups may have a higher risk of CVD than immobile groups overall, risk of CVD in the period following a residential mobility event is lower than for stayers. Results are indicative of a short-term healthy migrant effect comparable to that observed for international migrants.