Christensen et al. showed that the recent increase in life expectancies in developed countries was due to improvement of old-age mortality. During this time, the prevalence of disease in the elderly population has generally increased. This might be a result of improved medical knowledge and better treatment. The disability prevalence has been falling. For people age younger than 85 years, there is a postponement of limitations and disabilities. But for people age older than 85 years, the situation is less clear. I am curious about the situation in other countries. With less advanced medical knowledge and treatment, is the older population in these countries will have increased disease and disability. Or are they experiencing the postponements of physical and cognitive disability as their counterpart in the developed countries?
Preston et al. estimated the effects of changes in smoking and obesity are likely to result in an improvement in US life expectancy over the next 30 years. Preston et al. reported that smoking accounts for stagnation of mortality improvement in the US between 1980s and 1990s. And the reductions in smoking could lead to a much faster decrease of mortality. And beyond the year of 2020, the effect of declining of smoking on life expectancy strongly outpace the effect of increase of obesity. Besides its effect on mortality, obesity is also widely discussed because it is related to many poor health outcomes, including disability. Besides their effects on life expectancy, I think it would be interesting to study the effect of changes in smoking and obesity on disease-free health expectancy or disability-free life expectancy.