How does socioeconomic development affect risk of mortality? An age-period-cohort analysis from the recently transitioned population of Hong Kong

Presenter: Roger Chung, University of Hong Kong

Abstract

Objective: The Hong Kong Chinese population uniquely experienced two sudden macro-environmental changes in the 20th century brought about by mass migration and very rapid socioeconomic development. In the mid 20th century a largely migrant population experienced rapid transition from essentially pre-industrial living conditions, followed about 20 years later by the emergence of the infant and childhood obesity epidemic in the 1960s. We aimed to delineate the effects of these two aspects of economic development on mortality, thus providing a sentinel for other rapidly developing economies.

Methods: We used sex-specific Poisson models to decompose Hong Kong adult mortality from 1976 to 2005 into the effects of age, period (calendar time) and cohort. We considered all-cause mortality and mortality grouped into ischemic heart disease (IHD), cardiovascular disease excluding IHD, cancer, respiratory disease, accidents and all others.

Results: Age-standardized all-cause mortality in men and women decreased from 1976 to 2005, although this was less marked for IHD and cancer. There was no obvious beneficial change in adult mortality with economic transition by birth cohort, i.e. for those born from the late 1940s onwards; instead there was increased mortality risk from IHD in men and from cancer in women. There was also increased CVD and cancer mortality risk in both sexes with birth after the start of the infant and childhood obesity epidemic in the 1960s. There were no obvious changes in adult mortality with calendar time.

Conclusions: Economic transition was not clearly associated with a lower risk of adult mortality, but growing up in generally better living conditions had sex-specific effects, namely increased IHD in men and increased cancer, probably from hormonally driven cancers, in women. On the other hand, the emergence of the epidemic of infant and childhood obesity was assocaited with increased risk of CVD and cancer mortality in both sexes. The macro-enviromental changes assocaited with economic development have specific effects which extend over the life course probably originating with early life exposures. Thus we are unlikely to see the full population health consequences of economic transition and the epidemic of childhood obesity until those who have spent their early lives in such environments reach an age to become vulnerable to non-communicable chronic diseases, i.e. possibly 50 or 60 years after the original macro-environmental changes took place.