Life span has been steadily increasing these past three decades, a trend made clear in the paper I'll point out today. Yet when it comes to the scope of history, the state of the present, and the future ahead, most people are quite pessimistic. Millennialism never really goes away. The past is seen in rose-tinted hues, the present is experienced against a backdrop of media emphasis on the fearful and the terrible, and the future is commonly painted as a descent into the pit. Yet in truth we live in an age of tremendous positive progress, in which wealth, access to medicine, security, comfort, and healthy longevity are on average increasing year by year. This has been true for more than two centuries in some parts of the world, those first into the industrial revolution, and certainly for at least a lifetime elsewhere. When it comes to biotechnology and medicine, there is a massive shift underway, a gathering of forces for even greater progress. Computing, materials science, and the life sciences are all accelerating, and nowadays researchers are turning their attention towards the treatment of the causes of aging rather than merely patching over and slightly slowing its consequences. The future of human health will be far more than a simple continuation of the gentle upward trend of the past. Great leaps lie ahead.
We're all aware that the past few decades have seen improved health and longevity across most of the world. This is as much a matter of growing wealth as it is a combination of new medicine made better and old medicine made cheap. Many regions are far wealthier today than even a generation ago, and that makes a sizable difference in the statistics of health and mortality: better control over infectious disease, better nutrition, greater awareness of common health practices, less exposure to pollution, and so on and so forth, a longer list than simply greater access to modern medical technology throughout life. Where do the statistics of life and death come from, however? As it happens, there is a fair-sized industry of researchers who mine and manage human mortality data from around the world. It is a massive undertaking, made challenging by the poor nature of much of that data on mortality, and especially mortality due to age-related disease, in many parts of the world. Even in wealthier countries, until fairly recently data on the oldest people was notably inaccurate, characterized by a tendency for medical staff to enter "old age" or similar general category as a cause of death rather than something more specific. Cleaning up large-scale databases and obtaining good statistical results with a high confidence of correctness and utility is a specialized business.
The open access paper linked below gives some idea of the sort of toil that goes into pulling together mortality data from countless reporting bodies into a useful set of working data. You should certainly click through and take a look at the full text, particularly the explanations (complete with diagrams and flow charts) of how researchers go about building the analysis from raw data. Given the doom-laden zeitgeist of this age of ours, as much of the blurb is concerned with inequality, healthcare costs, and regional declines as it is with simply presenting the data. It is unarguably the case, however, that the state of medicine and health has greatly improved over the past three decades, and that process of improvement continues. Progress is the true spirit of the age, for all that many do not want to see it. That progress is both good and necessary, as there is much left to be accomplished in the quest to end suffering; the tools to achieve an end to disease, step by step, are both foreseeable and in some cases already under development. The more of that, the better.
Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015: a systematic analysis for the Global Burden of Disease Study 2015
Comparable information about deaths and mortality rates broken down by age, sex, cause, year, and geography provides a starting point for informed health policy debate. However, generating meaningful comparisons of mortality involves addressing many data and estimation challenges, which include reconciling marked discrepancies in cause of death classifications over time and across populations; adjusting for vital registration system data with coverage and quality issues; appropriately synthesising mortality data from cause-specific sources, such as cancer registries, and alternative cause of death identification tools, such as verbal autopsies; and developing robust analytical strategies to estimate cause-specific mortality amid sparse data. The annual Global Burden of Disease (GBD) analysis provides a standardised approach to addressing these problems, thereby enhancing the capacity to make meaningful comparisons across age, sex, cause, time, and place.
Global life expectancy at birth increased by 10.2 years, rising from 61.7 years in 1980 to 71.8 years in 2015, equating to an average gain of 0.29 years per year. By 2015, male life expectancy had risen by 9.4 years, increasing from 59.6 years in 1980 to 69.0 years, whereas female life expectancy improved by 11.1 years, climbing from 63.7 years to 74.8 years. On average, an additional 0.27 and 0.32 years of life were gained per year for males and females, respectively, since 1980. Global gains in life expectancy were generally gradual but steady, although catastrophic events, including the Rwandan genocide and North Korean famines, and escalating mortality due to HIV/AIDS, had worldwide effects on longevity. Slower gains were achieved for life expectancy at 50 years, or the average number of additional years of life 50 year olds can anticipate at a given point in time. On average, 50-year-old females saw an increase of 4.5 additional years of life since 1980, and 50-year-old males experienced an increase of 3.5 years. Total deaths increased by 4.1% from 2005 to 2015, rising to 55.8 million in 2015, but age-standardised death rates fell by 17.0% during this time, underscoring changes in population growth and shifts in global age structures. The result was similar for non-communicable diseases (NCDs), with total deaths from these causes increasing by 14.1% to 39.8 million in 2015, whereas age-standardised rates decreased by 13.1%. Globally, this mortality pattern emerged for several NCDs, including several types of cancer, ischaemic heart disease, cirrhosis, and Alzheimer's disease and other dementias.
At the global scale, age-specific mortality has steadily improved over the past 35 years; this pattern of general progress continued in the past decade. Progress has been faster in most countries than expected. Against this background of progress, some countries have seen falls in life expectancy, and age-standardised death rates for some causes are increasing. Despite progress in reducing age-standardised death rates, population growth and ageing mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems.