Housing affordability effects on physical and mental health: household survey in a population with the world’s greatest housing affordability stress

BACKGROUND: We examined the association of housing affordability with physical and mental health in Hong Kong, where there is a lack of related research despite having the worst housing affordability problem in the world, considering potential mediating effect of deprivation. METHODS: A stratified random sample of 1978 Hong Kong adults were surveyed. Housing affordability was defined using the residual-income (after housing costs) approach. Health-related quality of life was assessed by the Short-Form Health Survey version 2 (SF-12v2), from which the physical component summary (PCS) and mental component summary (MCS) measures were derived. Multivariable linear regressions were performed to assess associations of housing affordability with PCS and MCS scores, adjusting for sociodemographic, socioeconomic and lifestyle factors. Mediation analyses were also conducted to assess the mediating role of deprivation on the effect of housing affordability on PCS or MCS. RESULTS: Dose–response relationships were observed between housing affordability and mean PCS score (β (95% CI) compared with the highest affordable fourth quartile: −2.53 (−4.05 to −1.01), −2.23 (−3.54 to −0.92), −0.64 (−1.80 to 0.51) for the first, second and third quartiles, respectively) and mean MCS score (β (95% CI): −3.87 (−5.30 to –2.45), −2.35 (−3.59 to −1.11), −1.28 (−2.40 to –0.17) for the first, second and third quartiles, respectively). Deprivation mediated 34.3% of the impact of housing unaffordability on PCS and 15.8% of that on MCS. CONCLUSIONS: Housing affordability affects physical and mental health, partially through deprivation, suggesting that housing policies targeting deprived individuals may help reduce health inequality in addition to targeting the housing affordability problem.