At-a-glance – Impact of drug overdose-related deaths on life expectancy at birth in British Columbia
Correspondence: Xibiao Ye, Office of the Provincial Health Officer, British Columbia Ministry of Health, 4th floor, 1515 Blanshard Street, Victoria, BC V8W 3C8; Tel: 250-952-2026; Email: email@example.com
We quantified the contributions of leading causes of death and drug overdose to changes in life expectancy at birth over time and inequalities by sex and socioeconomic status in British Columbia. From 2014 to 2016, life expectancy at birth declined by 0.38 years and drug overdose deaths (mainly opioid-involved) contributed a loss of 0.12 years of the decrease. The analysis also demonstrated that the higher drug overdose mortality among males and among those in lower socioeconomic status communities contributed to a differential decrease in life expectancy at birth for males and for those in the latter category.
Keywords: opioid overdose death, life expectancy at birth, inequality
- Life expectancy at birth (LE0) in BC decreased by 0.38 years from 2014 to 2016, and fatal drug overdoses (the majority involving opioids) accounted for 32% of the decrease.
- In 2016, LE0 for males was 4.59 years lower than that for females, and drug overdose mortality accounted for 9% of this gap.
- In 2016, LE0 for those in communities with the highest deprivation index (quintile 5 or lowest socio-economic status) was 5.58 years lower compared to people who live in communities with the lowest deprivation index (quintile 1 or highest socio-economic status), and drug overdose mortality accounted for 7% of this gap.
The number of illicit drug overdose deaths has dramatically increased in British Columbia (BC) since 2014, from 369 deaths in 2014 to 1208 deaths (including suspected cases) as of October 31, 2017.Reference 1 Fentanyl or its analogues, in combination with other drugs, accounted for the majority of illicit drug overdose deaths.Reference 2 In response to the increasing drug overdose crisis, a public health emergency was declared on April 14, 2016 in BC.Reference 3
The contribution of drug overdose deaths to life expectancy change has rarely been quantified. Between 2000 and 2014, unintentional poisonings (mostly drug and alcohol overdoses) contributed a loss of 0.338 years in life expectancy at birth (LE0) for the non-Hispanic white population in the United States of America (USA), the greatest negative impact by cause of death.Reference 4 Specifically, opioid-involved overdose deaths contributed to a loss of 0.21 years in LE0 for the entire USA population between 2000 and 2015.Reference 5 In this article, we sought to adapt the analysis to the BC setting and to further expand the analysis by quantifying the contribution of opioid and other drug overdose deaths to life expectancy inequalities by sex and socioeconomic status (SES).
We obtained data on deaths recorded by the BC Vital Statistics Agency during 2001-2016. We used the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) to classify causes of deaths. We identified deaths involved opioids (T40.0, T40.1, T40.2, T40.3, T40.4, T40.6), cocaine (T40.5) and other drugs (T40.7, T40.8, T40.9). Those classified as unintentional injuries (X40-X44) or undetermined intent (Y10-Y14) were included in the analysis. We calculated mortality using the insured population in the province and used the 2001 population as the reference to standardize mortality rates.
We used the Chiang methodReference 6 to construct period life tables and calculated LE0 gaps between 2001 and 2016 and between 2014 and 2016. We examined LE0 inequalities by sex and by deprivation index. Deprivation index, an area-based SES measurement including material deprivation (a composite of household income, unemployment and high school graduation) and social deprivation (a composite of marital status, living alone and residential stability), was constructed using the 2011 Canadian Census according to the method described by Pampalon et al.Reference 7 A lower score for this index indicates a better SES (less deprivation). We partitioned the gaps into age and leading cause of death including drug overdose using Arriaga's decomposition method.Reference 8 Analyses were undertaken using SAS version 9.3 (SAS Institute Inc., Cary, NC, USA).
LE0 in BC increased from 80.27 years (95% confidence interval [CI] 80.12-80.42) in 2001 to 83.02 years (95% CI 82.88-83.16) in 2014. However, from 2014 to 2016, LE0 decreased by 0.38 years to 82.64 years (95% CI 82.50-82.77) (Table 1). Reduced mortality rates for cancers, heart diseases, cerebrovascular diseases and accidents contributed to the majority of the 2.37-year increase in LE0 during 2001 and 2016. However, deaths involving any type of drugs caused a loss of 0.15 years to LE0 during this period. Opioid-involved deaths accounted for nearly 80% of overall drug overdose deaths in 2001, but this increased to 90% in 2016. The increase in opioid-involved deaths contributed a loss of 0.16 years to LE0 in 2016, compared to 2001. Drug overdose deaths contributed a loss of 0.12 years in 2016 compared to 2014, accounting for 32% of the total decline during this period.
|Category/cause of death||Year 2001||Year 2014||Year 2016||Change and contributions (in years) by selected causes of death to the life expectancy at birth change in 2016|
|Number||Rate||Number||Rate||Number||Rate||Change from 2001||Contributiontable 1 note a||Change from 2014||Contributiontable 1 note a|
|Life expectancy (in years)||-||80.27||-||83.02||-||82.64||2.37||-||−0.38||-|
|Number of deaths and age-standardized mortality rate (per 100 000 population) by cause of death|
|Chronic lower respiratory diseases||1299||32.7||1590||26.1||1801||27.5||−16.1%||0.08||5.1%||−0.03|
|Alzheimer's disease and other dementia||1041||26.2||2487||36.3||2726||37.2||41.8%||−0.15||2.5%||−0.02|
|Chronic liver disease and cirrhosis||269||6.8||463||8.1||480||8.1||20.2%||−0.03||0.7%||0.00|
|Primary hypertension and renal diseases||110||2.8||279||4.3||301||4.2||51.6%||−0.02||−1.2%||0.00|
Opioid and cocaine
Opioid w/o other drugs except cocaine
Cocaine w/o other drugs except opioid
Other drugs without opioid or cocaine
|Other diseases (including undetermined causes)||4716||118.8||5486||92.5||7095||116.7||−1.7%||−0.14||26.2%||−0.63|
Abbreviation: S, suppressed due to the number of death is less than 5.
Table 1 Notes
In 2001, LE0 for males was 5.01 years lower than that for females (Table 2). The higher drug overdose mortality in males contributed 0.20 years to the gap, but the majority were attributed to cancer, heart disease and injury (accidents and suicide) deaths. While the sex difference in LE0 declined to 4.59 years in 2016, the contribution by drug overdose deaths doubled to 0.42 years (accounting for 9% of the gap). Drug overdose mortality rates were inversely associated with both material and social deprivation index. In 2011, LE0 for the population living in the highest total deprivation level (quintile 5 or the lowest SES) communities was 5.50 years lower than that for the population living in the lowest total deprivation level (quintile 1 or the highest SES). Of this, 0.31 years were attributed to drug overdose deaths. The contribution by drug overdose increased to 0.39 years in 2016 (accounting for 7% of the gap). The inequalities by social deprivation were greater than that by material deprivation in both years.
|Factor||2001 or 2011table 2 note a||2016|
|Life expectancy difference||Contribution by drug overdose||Life expectancy difference||Contribution by drug overdose|
|Sex (male vs. female)table 2 note b||−5.01||−0.20||−4.59||−0.42|
|Deprivation level (quintiles 5 vs. 1)table 2 note c|
Table 2 Notes
In this analysis, we found a 2.37-year increase in LE0 from 2001 and 2016, but a 0.38-year decline from 2014 to 2016 (with 0.12 years attributed to drug overdose deaths). While the sex difference in LE0 slightly narrowed between 2001 and 2016, the contribution by drug overdose deaths to the inequality doubled. During 2011 and 2016, LE0 inequalities by deprivation level (between quintiles 1 and 5) were relatively stable, but the contribution by drug overdose deaths increased.
Between 2000 and 2015, drug overdoses contributed to 0.28 years lost in LE0 in the USA. Of this, 0.21 years were attributed to opioid-involved overdose deaths.Reference 5 In this analysis, we demonstrated that drug overdose deaths, specifically opioid overdose deaths, contributed to a considerable loss to LE0 in BC. However, the contribution was smaller than in the USA due to the lower age-standardized morality rates (e.g. opioid overdose mortality rate in both sexes was 16.3 per 100 000 in the USA in 20155 and 11.9 per 100 000 in BC in 2016). LE0 has improved over past decades in the USA, reaching the highest at 78.9 years in 2014, but slightly declined to 78.8 years in 2015 and to 78.6 years in 2016. The decline was largely due to the increased deaths in younger ages and deaths from unintentional injuries including drug overdose.Reference 4,Reference 9 Similarly, we have found a LE0 decline since 2014 in BC and the decline was partially attributed to increased drug overdose deaths, in particular in males. Other provinces have also experienced increasing drug overdose deaths,Reference 10,Reference 11,Reference 12 but it is unclear how this will impact life expectancy at the national level.
Sex and socioeconomic inequalities in life expectancy at birth have been reported at different geographic levels.Reference 13,Reference 14,Reference 15,Reference 16 While studies clearly showed the differences in life expectancy, little is known about the contributions of cause of death and risk factors associated with sex and SES. In this analysis, we showed that drug overdose deaths alone explained approximately 9% of LE0 loss in males in 2016, compared to females. The contribution has doubled during the last 15 years due to the significantly increased drug overdose deaths in males. Drug overdose mortality rate for those in the lowest SES communities was 3 times higher than that in the highest SES communities (data not shown), accounting for 7% of LE0 loss. These findings show the important impact that drug overdose deaths have had on the entire population of BC, and in particular, the differential negative impact on males and those who live in the most socioeconomically deprived areas of the province. This should further our resolve to address this largely preventable cause of death.
The contribution by drug overdose deaths may have been underestimated as only confirmed cases were included and coroners' cause of death can take up to two years or longer to determine. For 2016, BC Coroners Service reported 985 drug overdose deaths,Reference 1 but by using vital statistics data, we identified 528 drug overdose deaths and over 1200 cases with undetermined causes of deaths. A significant proportion of these unspecified cases will likely be determined as opioid related, driving the contribution of opioid overdose deaths higher (likely greater than 50%). A recent study showed that 30% of drug-related deaths registered in the forensic toxicology registry in Sweden had not been recorded in the country's vital statistics database, resulting in an approximately 20% underreporting of drug-related mortality.Reference 17 Including other data sources, e.g. forensic toxicological registry to identify additional drug-related deaths would further improve the estimation.
The life expectancy at birth for people in BC increased by 3 years between 2001 and 2014, but decreased by 0.38 years from 2014 to 2016. The opioid overdose crisis was an important contributor to this loss. The higher death rate from opioid overdoses was also a major contributor to a shorter life expectancy among males compared to females and to a shorter life expectancy for people from the most socioeconomically disadvantaged communities compared to those from the least disadvantaged communities.
The authors thank Mr. Kim Reimer for his comments on the manuscript.
Conflicts of interest
The authors have no conflicts of interest to disclose.
Authors' contributions and statement
XY conceptualized the design of the study and wrote the initial draft. JS led data analysis. PK, BH and MT provided input to study design, analysis and interpretation of the data, and drafting and revising the paper. All authors have seen and approved the final manuscript.
The content and views expressed in this article are those of the authors and do not necessarily reflect those of the Government of Canada.
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