10 Calculating Potential Years of Life Lost (PYLL)

The PYLL is an indicator of premature mortality. It represents the total number of years NOT lived by an individual who died before age 75.

  • This indicator gives more importance to the causes of death that occurred at younger ages than those occurred at older ages.
  • The upper age limit of 75 is used to approximate the life expectancy of Canadians for both sexes combined. For example, an individual in good health is expected to live up to age 75 in Canada.
  • Deaths occurring in individuals age 75 or older are NOT included in the calculation.
  • Infant deaths, deaths among infants under 1 year of age, are included in the calculation due to their very small numbers. Other methods exclude these deaths since they are often due to causes that have different etiology from deaths at later ages.

PYLL can be calculated in two ways. The Core Indicators for Public Health in Ontario uses Method A.


Method A (Individual):

The PYLL due to death is calculated for each person who died before age 75. For example, a person who died at age 20 would contribute 55 potential years of life lost. Deaths occurring in individuals age 75 or older are NOT included in the calculation. Potential years of life lost correspond to the sum of the PYLL contributed for each individual. The rate is obtained by dividing total potential years of life lost by the total population less than 75 years of age.

Method of Calculation:
 

Individual  Age at Death (in years) PYLL Contributed(75 – age at death)
1 6 months 75 – 0.5 = 74.5
2 55 75 – 55 = 20
3 15 75 – 15 = 60
4 85 * 0
5 60 75 – 60 = 15

SUM of PYLL

  169.5

Note: * refers to deaths that DO NOT contribute to PYLL as deaths occurred to individuals 75 years of age or older.


Method B (Age Group):

The PYLL due to death is calculated for each age group (< 1, 1-4, 5-9, …, and 70-74) by multiplying the number of deaths by the difference between age 75 and the mean age at death in each age group. Potential years of life lost correspond to the sum of the products obtained for each age group. The rate is obtained by dividing total potential years of life lost by the total population under 75 years old.

Method of Calculation:

Age # of Deaths (1) Mean Age at Death (2) 75 – Mean Age at Death (3) PYLL(1) x (3)
 < 1  0.5  74.5  298.0
1-4  28 3.0  72.0  2,016.0
5-9  52 7.5  67.5  3,510.0
10-14   64 12.5 62.5 4,000.0
15-19 315 17.5 57.5 18,112.5
20-24 410 22.5 52.5 21,525.0
25-29 308 27.5 47.5 14,630.0
30-34 243 32.5 42.5 10,327.5
35-39  171 37.5 37.5 6,412.5
40-44  131 42.5 32.5 4,257.5
45-49  116 47.5 27.5 3,190.0
50-54  85 52.5 22.5 1,912.5
55-59  85 57.5 17.5 1,487.5
60-64  86 62.5 12.5 1,075.0
65-69  64 67.5 7.5 480.0
70-74  70  72.5 2.5 175.0
SUM of PYLL        93,409.0

 
(1) Calculate the mean age for each age group (column 2) and subtract from the selected age, 75 (column 3)
(2) Calculate the potential years of life lost for each age group by multiplying the number of deaths (column 1) by the remaining years of life lost (column 3)
(3) Calculate the PYLL rate by dividing the sum of the potential years of life lost by age group (93,409) by the total population for the ages selected (12,975,615).

Rate per 1,000 persons
= Total PYLL divided by Population under age 75
= 93,409.0/12,975,615
= 7.2 per 1,000

Source: Working Group on Community Health Information Systems, Community Health Indicators – Definitions and Interpretations, Ottawa, Ontario: Canadian Institute for Health Information.

This page last updated: June 1, 2006