Years of potential life lost

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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.[1] 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.

Calculation[edit]

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.[2]

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:

  1. Reference age = 75; Age at death = 60; PYLL[75] = 75 - 60 = 15
  2. Reference age = 75; Age at death = 6 months; PYLL[75] = 75 - 0.5 = 74.5
  3. 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[edit]

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.[3]

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.[4]

Person-years of potential life lost in the United States in 2006[5]
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[edit]

Here is a table of YPLL for all causes (ages 0-69, per 100,000) with the most recent available data from the OECD:[1]

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  Ireland 2289 4008 2007
16  Finland 1492 2995 2009
17  France 2252 4665 2006
18  South Korea 2227 4568 2006
19  Germany 2212 4044 2006
20  Norway 2118 3710 2006
21   Switzerland 2100 3488 2006
22  Austria 2068 4143 2007
23  Greece 2017 4562 2007
24  Sweden 2011 3191 2006
25  Spain 2000 4399 2005
26  Italy 1887 3605 2006
27  Japan 1763 3287 2009
28  Netherlands 2235 3114 2009
29  Iceland 1492 2994 2009


Australia[edit]

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 years [6]

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. [7] The dramatic difference is in the greater number of years of disability caused mental illness and neurological issues and by diabetes.

References[edit]

  1. ^ Gardner JW; Sanborn JS. "Years of potential life lost (YPLL)--what does it measure?". Retrieved 2006-12-14. 
  2. ^ Association of Public Health Epidemiologists in Ontario. "Calculating Potential Years of Life Lost (PYLL)". Retrieved 2008-05-13. 
  3. ^ Burnet NG, Jefferies SJ, Benson RJ, Hunt DP, Treasure FP (January 2005). "Years of life lost (YLL) from cancer is an important measure of population burden--and should be considered when allocating research funds". Br. J. Cancer 92 (2): 241–5. doi:10.1038/sj.bjc.6602321. PMC 2361853. PMID 15655548. 
  4. ^ http://mhcs.health.nsw.gov.au/pubs/2008/pdf/chorep_summary_08.pdf Page 54 Retrieved 17 January 2009.
  5. ^ National Cancer Institute. "Person-Years of Life Lost". Cancer Trends Progress Report, 2009/2010 Update. 
  6. ^ http://mhcs.health.nsw.gov.au/public-health/chorep02/bod/bod_YLLcateg.htm Retrieved=17 January 2009
  7. ^ http://mhcs.health.nsw.gov.au/pubs/2008/pdf/chorep_summary_08.pdf Retrieved=17 January 2009 Page 53