A Decomposition of Life Expectancy and Life Disparity: Comparison Between Hong Kong and Japan

Abstract

Background: Life expectancy and life disparity are 2 useful indicators to assess the health condition of a society. Both Hong Kong and Japan have one of the longest life expectancies in the world. Recently, Hong Kong has overtaken Japan and topped the life expectancy rankings. However, whether Hong Kong has also outperformed Japan in life disparity is still unknown. Methods: Decomposition analyses have been conducted to evaluate age-specific contributions to the changes in life expectancy and life disparity for each of the populations. Furthermore, the differences between the 2 populations were examined over the period 1977-2016. Results: Reduction in mortality of the adult and the old age groups contributes most to the increase in life expectancy for the study period. Hong Kong has a higher life disparity than Japan, and due to the great improvement in reducing premature deaths, the Hong Kong-Japan gap has been narrowing. However, in recent years, further reduction in mortality of the oldest elderly in Hong Kong has actually contributed to the increase in its disparity, thus widening its gap with Japan again. Conclusion: Increasing dominant influence of "saving lives at late ages" is very likely to cause the reemergence of increasing life disparity in these 2 long-lived populations.

What can lifespan variation reveal that life expectancy hides? Comparison of five high-income countries

“…In Hong Kong, life disparity increased alongside increased threshold age with no apparent slowdown in e0 gains. 8 By contrast, we show that in the USA, life disparity increased alongside slowdown and decreases in e0. Thus, it may be that the threshold age in the USA also fell, in contrast to the increase in Hong Kong, and a rising life disparity in the context of stalling or falling threshold age may also indicate population health challenges.…”

“…A study of two populations with increasing longevity, Japan and Hong Kong, showed that life disparity can increase where no adverse trends in mortality are occurring at any age, and while e0 continues to increase. 8 Conversely, analysis of the burden of COVID-19 on mortality in the UK found lifespan inequality decreased during the first year of the pandemic, while e0 also decreased. 3 In both examples, the utility of life disparity is as complementary to e0 -a rising life disparity in the context of stagnating or falling e0 may indicate emerging public health challenges in a given population but a decreasing life disparity in isolation does not indicate a healthy population.…”

“…The negative correlation between increasing e0 and reducing life disparity is typically due to progress in reducing premature mortality -reducing deaths at older ages can increase life disparity, 6 as demonstrated in the Hong Kong example. 8 Zhang and Vaupel classified the different effects of 'early' deaths from 'late' deaths on life disparity, separated by the calculation of a 'threshold age' -averting deaths before that age reduces life disparity, while averting deaths after increases life disparity. 18 Vaupel et al show the 'threshold age' classifies deaths at late ages as premature or early: for example, in Japanese females, deaths up to the age of 85 years were considered premature.…”

“…6 Some have argued that life disparity has a 'crucial' public health interpretation, not least because life disparity can differ between societies with similar life expectancies. 8,9 One example is research by van Raalte et al, which showed that in the USA, where e0 increased by approximately 10% for men and 5% for women over 1980-2014, lifespan variation (measured as standard deviation) fluctuated then increased. 10 e0 in the USA then declined every year since 2015 11 driven by what have been termed 'deaths of despair', 12,13 from alcohol, other drugs and suicide.…”

The age and cause decomposition of inequality in life expectancy between Iranian provinces: application of Arriaga method

“…Life expectancy (LE) at birth indicates the mortality pattern in all age groups, which estimates the average number of years that a newborn is expected to live, provided that the current pattern of mortality does not change [ 1 ]. Globally, this indicator is frequently used as a tool for measuring the progress and backwardness of countries.…”