by Richard Aiken MD, PhD @rcaiken

Years of Life Lost due to Death: World

Heart disease is well-known as the leading cause of death in the United States as in other developed countries of the western world.   The impact of this might be best understood by examining the years of life lost (YLL) to this disease.

YLL due to premature mortality is calculated by multiplying the number of deaths at each age by a reference life expectancy at that age. The table below indicates a total of about two billion years of life lost globally to disease states. The diseases and injuries with the largest number of YLLs in 2015 were cardiovascular disease, lower respiratory infections, stroke, preterm birth complications, and diarrheal disease, shown in the following table[1].

Years of Life Lost due to Death: United States

In the United States, by far the leading cause of YLL is cardiovascular disease, followed by lung cancer, stroke, chronic obstructive pulmonary disease (COPD), road injury, and self-harm, as shown in the following table[2].  The reason why road injury and self-harm (suicide)  are so high on the list is that the cause of death occurs across the age spectrum – not just in older age.

Despite declines over the past ten years, 15.9% of YLLs were related to cardiovascular disease and 4.3% were related to stroke – cerebrovascular – highlighting the continued dominance of vascular diseases in premature death.

Years of Life Lost to Disability: World

While the goal is to increase years in our lives, an associated need is to have life in our years.

Non-fatal health outcomes from diseases are a crucial consideration in the promotion and monitoring of individual and population health. The Global Burden of Disease (GBD) studies done in 1990 and 2000 have been the only studies to quantify non-fatal health outcomes across an exhaustive set of disorders at the global and regional level[3]. This information has raised awareness about a range of disorders that primarily cause ill health but not death, such as unipolar major depression, bipolar disorder, asthma, and osteoarthritis.

A measure of this is “years lost to disability” (YLD) calculated by multiplying prevalence (based on systematic reviews) by the disability weight (based on population-based surveys) for each sequela; “disability” refers to any significant short- or long-term loss of health and function.

The following shows the leading global YLD[4].

Note that over three-quarters of a billion years are lost annually due to disabilities. Of these, mental disorders are the major cause of disability in the world, accounting for 22·7% of all YLDs. YLDs for this category as a whole have increased by 37% from 1990 to 2010. If one includes neurological and cerebrovascular diseases, directly related to mental, cognitive, and behavioral disorders – psychoneurological disorders – the importance of this category is further magnified.

Cardiovascular diseases did not contribute more than 5% of global YLDs, mental disorders being 20 times as important and neurological disorders about 5 times as important when considering years lost to disability.

Years of Life Lost to Disability: United States

YLD in the United States is similar to the global trend except COPD and diabetes outranks cancer and cardiovascular disease., as indicated in the following table[5]  Again mental or neuropsychiatric disorders, most prominently clinical depression, are the largest cause of years lost to disability.

References

[1] Global Health Estimates 2015: Disease burden by Cause, Age, Sex, by Country and by Region, 2000-2015. Geneva, World Health Organization; 2016.

[2] Murray, C. J. (2013). The State of US Health, 1990-2010. Jama, 310(6), 591. doi:10.1001/jama.2013.13805.

[3] Murray CJ, Ezzati M, Flaxman AD, et al. GBD 2010: design, definitions, and metrics. Lancet. 2012;380(9859):2063-2066.

[4] Voss, T. et al.,  Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010

[5] Murray ibid