Years of potential life lost


Years of potential life lost or potential years of life lost, is an estimate of the average years a person would have lived if he or she had not died prematurely. It is, therefore, a measure of premature mortality. As an alternative to death rates, it is a method that gives more weight to deaths that occur among younger people. An alternative is to consider the effects of both disability and premature death using disability adjusted life years.

Calculation

To calculate the years of potential life lost, the analyst has to set an upper reference age. The reference age should correspond roughly to the life expectancy of the population under study. In the developed world, this is commonly set at age 75, but it is essentially arbitrary. Thus, PYLL should be written with respect to the reference age used in the calculation: e.g., PYLL.
PYLL can be calculated using individual level data or using age grouped data.
Briefly, for the individual method, each person's PYLL is calculated by subtracting the person's age at death from the reference age. If a person is older than the reference age when he or she dies, that person's PYLL is set to zero. In effect, only those who die before the reference age are included in the calculation. Some examples:
  1. Reference age = 75; Age at death = 60; PYLL = 75 − 60 = 15
  2. Reference age = 75; Age at death = 6 months; PYLL = 75 − 0.5 = 74.5
  3. Reference age = 75; Age at death = 80; PYLL = 0
To calculate the PYLL for a particular population in a particular year, the analyst sums the individual PYLLs for all individuals in that population who died in that year. This can be done for all-cause mortality or for cause-specific mortality.

Significance

In the developed world, mortality counts and rates tend to emphasise the most common causes of death in older people because the risk of death increases with age. Because PYLL gives more weight to deaths among younger people, it is the favoured metric among those who wish to draw attention to those causes of death that are more common in younger people. Some researchers say that this measurement should be considered by governments when they decide how best to divide up scarce resources for research.
For example, in most of the developed world, heart disease and cancer are the leading causes of death, as measured by the number of deaths. For this reason, heart disease and cancer tend to get a lot of attention. However, one might argue that everyone has to die of something eventually, and so public health efforts should be more explicitly directed at preventing premature death. When PYLL is used as an explicit measure of premature death, then injuries and infectious diseases, become more important. While the most common cause of death of young people aged 5 to 40 is injury and poisoning in the developed world, because relatively few young people die, the principal causes of lost years remain cardiovascular disease and cancer.
Cause of premature deathPerson-years lost
Cancer8,628,000 person-years
Heart disease and strokes8,760,000 person-years
Accidents and other injuries5,873,000 person-years
All other causes13,649,000 person-years

By country

Here is a table of YPLL for all causes with the most recent available data from the OECD:
RankCountryFemale YPLLMale YPLLDate
14831132252015
26120114272016
34460123722017
4458995472017
5386396262016
6486282652016
7372992902016
8413172622016
9366065092016
10308365552017
11277657802016
12263057232015
13329250962016
14277556212015
15297253122016
16260757612016
17319750022015
18296351972016
19255854512016
20307547762015
21260647362017
22280045252015
23301940752016
24263444602016
25220747092016
26247341902016
27219843912016
28236441902015
29250839752016
30223541912017
31247638952016
32223139572016
33214440152016
34236936142016

Australia

The report of the NSW Chief Medical Officer in 2002 indicates that cardiovascular disease and malignant neoplasms are the main causes of lost years
When disability adjusted life years are considered, cancer, cardiovascular disease, mental health issues, neurological disorders, chronic respiratory disease and diabetes are the main causes of good years of expected life lost to disease or premature death. The dramatic difference is in the greater number of years of disability caused mental illness and neurological issues and by diabetes.