Background Sustainable Development Goal #8 refers to decent work and economic growth. In the context of climate change and global resource depletion, it is important to understand whether low economic growth is compatible with positive population health in rich countries, particularly because the past decade of austerity in the UK and USA is associated with stagnating life expectancy. Japan provides a natural experiment in that it has experienced low economic growth since 1992, and life expectancy continued to improve. However, the trend in health inequality in good self-rated health is unknown.

Methods We examined trends in health and health inequalities using ten triennial waves of a nationally representative survey in Japan, 1986–2013 (n=731,647). Change in age-standardized self-rated good health was calculated, and health inequalities and their time trends were calculated using Slope and Relative Indices of Inequality (SII and RII respectively) in relation to net household income. Analyses were stratified by sex and age, for children (6–18 years), working-age adults (20–59 years), younger old (60–69 years) and older old (70–79 years), given age differences in relation to the economy and labour market. Time trends of SII and RII were tested during the period of economic stagnation 1992–2013.

Results Overall, age-standardised self-rated good health was high among children (70%) and low among the older old (30%). In all age groups, prevalence of good health declined slightly from its peak in 1995 but increased after 2007. In 1992 among children, working-age adults and younger old, health inequality based on SII for net household income was small (approximately 10% lower prevalence of good health in those with lowest compared to highest income). Among working-age adults, time trends of health inequalities between 1992 and 2013 were curvilinear. The SII narrowed and then widened after 2002 (quadratic trends in men and women p<0.05), resulting in the magnitude of health inequality returning to its level at the beginning of economic stagnation in 1992 but not exceeding it. Time trends in relative inequality (RII) were qualitatively similar to those in absolute inequality (SII). Health inequality narrowed and then widened, and the RIIs in 2013 was no larger than those in 1992.

Conclusion The long-term low-growth Japanese economy appears compatible with maintaining and improving population health and holding health inequalities at current levels. This evidence is of great significance for sustainable development and the health of current and future generations.