Wellbeing recovery inequity following the 2010/2011 Canterbury earthquake sequence: repeated cross-sectional studies

To track population mental wellbeing following the 2010/2011 Christchurch earthquakes and after-shocks.

The Canterbury Wellbeing Survey, a cross-sectional survey of randomly selected adults aged ≥18 years resident in Christchurch, was repeated biannually from April 2013 until June 2017 and annually thereafter. The self-reported 5-item World Health Organization Well-Being Index (WHO-5) has been elicited from April 2013. Regression analysis was employed to model WHO-5 score patterns over time and between important socio-demographic groups.

Between 1,137 and 1,482 adults participated in each survey, totalling 14,100 overall. The mean WHO-5 significantly increased (p<0.001) from 52.4 (95% confidence interval [CI]: 51.1, 53.8) in the April 2013 survey to 60.8 (95%CI: 59.7, 61.9) in the June 2019 survey. A significant and sustained household income group disparity existed (p<0.001), even when adjusting for age, gender and ethnic differences.

The disaster appeared to affect the mental wellbeing of all, and recovery was incremental and prolonged, taking a number of years. Those within the lowest household income group had lower mean WHO-5 scores than their wealthier counterparts at every measured time point. Implications for public health: Recovery takes time, and pre-existing inequities persist despite the implementation of recovery processes aimed at mitigating these risks.