Years of potential life lost
Encyclopedia
Years of potential life lost (YPLL) or potential years of life lost (PYLL), 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 a method, it is an alternative to death rates
that gives more weight to deaths that occur among younger people. Another alternative is to consider the effects of both disability and premature death using disability adjusted life years.
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 (i.e., there are no "negative" PYLLs). In effect, only those who die before the reference age are included in the calculation. Some examples:
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.
For example, in most of the developed world, heart disease and cancer are the leading causes of death, as measured by the number (or rate) of deaths. For this reason, heart disease and cancer tend to get a lot of attention (and research funding). 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.
When disability adjusted life years are considered, cancer
(25.1/1,000), cardiovascular disease
(23.8/1,000), mental health
issues (17.6/1,000), neurological disorders (15.7/1,000), chronic respiratory disease
(9.4/1,000) and diabetes (7.2/1,000) 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.
Average
In mathematics, an average, or central tendency of a data set is a measure of the "middle" value of the data set. Average is one form of central tendency. Not all central tendencies should be considered definitions of average....
years a person would have lived if he or she had not died prematurely. It is, therefore, a measure of premature mortality
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
. As a method, it is an alternative to death rates
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...
that gives more weight to deaths that occur among younger people. Another 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[75].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 (i.e., there are no "negative" PYLLs). In effect, only those who die before the reference age are included in the calculation. Some examples:
- Reference age = 75; Age at death = 60; PYLL[75] = 75 - 60 = 15
- Reference age = 75; Age at death = 6 months; PYLL[75] = 75 - 0.5 = 74.5
- Reference age = 75; Age at death = 80; PYLL[75] = 0 (age at death greater than reference age)
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 emphasize 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 individuals, 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 (or rate) of deaths. For this reason, heart disease and cancer tend to get a lot of attention (and research funding). 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 death | Person-years lost |
|---|---|
| Cancer | 8,628,000 person-years |
| Heart disease and strokes | 8,760,000 person-years |
| Accidents and other injuries | 5,873,000 person-years |
| All other causes | 13,649,000 person-years |
By country
Here is a table of YPLL for all causes (ages 0-69, per 100,000) with the most recent available data from the OECD:http://www.irdes.fr/EcoSante/DownLoad/OECDHealthData_FrequentlyRequestedData.xlshttp://www.oecd.org/document/30/0,3343,en_2649_34631_12968734_1_1_1_1,00.html| Rank | Country | Female YPLL | Male YPLL | Date |
|---|---|---|---|---|
| 1 |  Mexico |
5027 | 8528 | 2006 |
| 2 |  Hungary |
4032 | 9235 | 2005 |
| 3 |  United States |
3633 | 6291 | 2005 |
| 4 |  Slovakia |
3343 | 7732 | 2005 |
| 5 |  Poland |
3211 | 7962 | 2006 |
| 6 |  Portugal |
2858 | 6024 | 2003 |
| 7 |  Belgium |
2848 | 5471 | 1999 |
| 8 |  New Zealand |
2747 | 4540 | 2005 |
| 9 |  United Kingdom |
2564 | 4220 | 2007 |
| 10 |  Canada |
2554 | 4168 | 2004 |
| 11 |  Denmark |
2493 | 4311 | 2006 |
| 12 |  Czech Republic |
2430 | 5486 | 2007 |
| 13 |  Luxembourg |
2378 | 4080 | 2005 |
| 14 |  Australia |
2289 | 3946 | 2004 |
| 15 |  Republic of Ireland |
2289 | 4008 | 2007 |
| 16 |  Netherlands |
2266 | 3259 | 2007 |
| 17 |  Finland |
2255 | 5094 | 2007 |
| 18 |  Early Modern France |
2252 | 4665 | 2006 |
| 19 |  South Korea |
2227 | 4568 | 2006 |
| 20 |  Germany |
2212 | 4044 | 2006 |
| 21 |  Norway |
2118 | 3710 | 2006 |
| 22 |  Switzerland |
2100 | 3488 | 2006 |
| 23 |  Austria |
2068 | 4143 | 2007 |
| 24 |  Greece |
2017 | 4562 | 2007 |
| 25 |  Sweden |
2011 | 3191 | 2006 |
| 26 |  Spain |
2000 | 4399 | 2005 |
| 27 |  Italy |
1887 | 3605 | 2006 |
| 28 |  Japan |
1831 | 3397 | 2007 |
| 29 |  Iceland |
1744 | 3118 | 2007 |
Australia
The report of the NSW Chief Medical Officer in 2002 indicates that cardiovascular disease (32.7% (of total Males Years of Life Lost due to premature mortality) and 36.6% of females YLL) and malignant neoplasms (27.5% of Males YLL and 31.2% of Females YLL) are the main causes of lost yearsWhen disability adjusted life years are considered, cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
(25.1/1,000), cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
(23.8/1,000), mental health
Mental health
Mental health describes either a level of cognitive or emotional well-being or an absence of a mental disorder. From perspectives of the discipline of positive psychology or holism mental health may include an individual's ability to enjoy life and procure a balance between life activities and...
issues (17.6/1,000), neurological disorders (15.7/1,000), chronic respiratory disease
Respiratory disease
Respiratory disease is a medical term that encompasses pathological conditions affecting the organs and tissues that make gas exchange possible in higher organisms, and includes conditions of the upper respiratory tract, trachea, bronchi, bronchioles, alveoli, pleura and pleural cavity, and the...
(9.4/1,000) and diabetes (7.2/1,000) 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
Mental illness
A mental disorder or mental illness is a psychological or behavioral pattern generally associated with subjective distress or disability that occurs in an individual, and which is not a part of normal development or culture. Such a disorder may consist of a combination of affective, behavioural,...
and neurological issues and by diabetes.