MLHU - Health Status Resource

Potential Years of Life Lost

Potential Years of Life Lost

Key Findings: 

Potential years of life lost (PYLL) is a summary measure of premature mortality that assesses the relative impact of various diseases on the health of the population and emphasizes those affecting younger people. It estimates the additional time a person would have lived had he or she not died prematurely (before age 75). Deaths at younger ages are often preventable and can be reduced by public health interventions. PYLL from preventable causes is a subset of PYLL and focuses on the years of life lost to preventable causes. Preventable PYLL can be directly reduced through public health interventions and a focus on addressing health inequities.

Overall, the health of the residents of Middlesex-London improved from 2006 to 2015 as indicated by a decrease in the rate of PYLL once population growth and changes in age structure were taken into consideration. Males lost more years of life compared to females. Rural residents and those that lived in more material deprived neighbourhoods also lost more years of life. Most preventable years of lost life were due to injuries, cancer and cardiovascular disease.

PYLL Time Trends Preventable PYLL by Cause Groups
PYLL Subgroups Preventable PYLL inequities

PYLL Time Trends

There has been a general decrease in the rate of potential years of life lost (PYLL) from 2006 (53.0/ 1,000 population) to 2015 (46.2/ 1,000) in Middlesex-London after population growth and age structure are taken into consideration (Figure 3.6.1).

There was a significant increase and peak in the rate of PYLL for one year in 2009 in Middlesex-London which corresponded with the beginning of the economic recession (Figure 3.6.1).

The rate of PYLL in Middlesex-London was slightly higher, but significantly different, than the rate in Ontario for each year from 2006 and 2015 (Figure 3.6.1).

The decrease in the potential years of life lost (PYLL) age-standardized rate may indicate improvements in prevention and treatment specifically for younger populations. However, in comparison to Ontario, there is still room for improvement in this general health indicator.

PYLL Subgroups

Females consistently had a significantly lower PYLL rate compared to males in Middlesex-London from 2006 to 2015, once population growth and age structure are taken into consideration (Figure 3.6.2).

Sex-specific time trends indicate that the overall increase in potential years of life lost in 2009 for Middlesex-London was almost completely due to an increase in PYLL in males in 2009 (Figure 3.6.2).

Rural residents had a significantly higher rate of PYLL compared to urban residents in Middlesex-London for each of the three years between 2013 to 2015 (Figure 3.6.3).

The rate of potential years of life lost varied significantly by the two subgroups that were assessed: sex and region. The higher rates of PYLL in males compared to females generally corresponds to higher rates of death in males at younger ages, more preventable deaths and lower life expectancies. This has generally been attributed with more risk-taking behaviours in younger males.

Preventable PYLL by Cause Group

Injuries, followed by cancer and cardiovascular disease, had the highest preventable potential years of life lost (PYLL) rates on average from 2013 to 2015, for all three jurisdictions: Middlesex-London, Ontario and the Peer Group (Figure 3.6.4).

Males, more so than females, contributed to high rates of injury related PYLL. Much of the higher burden of preventable PYLL in males compared to females is related to the substantially higher rates of PYLL due to injury and to a smaller degree to cardiovascular disease in males compared to females (Figure 3.6.5).

The top causes of potential years of life lost varies considerably by age. The top two by age group were exactly the same as were found for preventable mortality. Injuries by far contributed the greatest burden to PYLL for those aged 0-19 followed by infection from 2013 to 2015. For those aged 20-44, injuries also contributed the greatest burden of PYLL followed by alcohol and drugs. In those aged 45-64, injury slipped to second place behind cancer and in those 65-74, cancer and cardiovascular disease contributed the greatest burden of PYLL (Figure 3.6.6).

The relative burden of cause-specific PYLL is greater in the older age groups for all causes except injuries, which peaks in the 20 to 44 year olds (Figure 3.6.7).

Preventable PYLL are those years of life lost due to preventable causes only. This is different than preventable mortality. For example, injury is the leading cause of preventable PYLL whereas cancer is the leading cause of preventable mortality. This underscores the utility of this indicator to emphasize the causes that affect younger people.

Preventable PYLL inequities

The age standardized rate of PYLL significantly increased with each material deprivation quintile on average from 2011 to 2015 in Middlesex-London. The rate for those that lived in the most well-off neighbourhoods was almost a third (Q1; 12.4/1,000 population) that of the most material deprived neighbourhoods (Q5: 36.1/1,000 population). This is a rate difference of 23.7 PYLL per 1,000 population (Figure 3.6.8).

Most cause-specific rates were incrementally higher by deprivation quintile. However, some causes, such as injury, were much higher in residents living in the most material deprived neighbourhoods (Figure 3.6.9).

Health inequities are evident in global population health indicators such as the age standardized rate of preventable potential years of life lost. Greater inequities in specific causes such as injury point to areas were greater preventive efforts could be focused.

Interpretive Notes

Potential years of life lost (PYLL) is an indicator of premature mortality.  It reflects the number of deaths which occur before the age of 75 and weights those who die younger more heavily. The younger a person is when they die, the greater the number of PYLL that are lost. For instance, a 73-year-old who dies of ischemic heart disease would count for two PYLL. A 20-year-old who dies in a motor vehicle collision would count as 55 potential years of life lost.

How this Indicator was Calculated: 
Ontario Public Health Standard: 

Population Health Assessment and Surveillance Protocol, 2018

Last modified on: June 24, 2019

Jargon Explained

Potential years of life lost
The sum of the total years of life lost relative to age 75. PYLL is calculated by adding together, for all deaths, the number of years remaining until age 75, and then dividing this by the population under the age of 75 years.