Background Income has seldom been used to study social differences in disability-free life expectancy (DFLE). This study investigates income inequalities in life expectancy and DFLE at age 50 and 65 and estimates the contributions from the mortality and disability effects on the differences between income groups.
Methods Life tables by income quintile were constructed using Danish register data on equivalised disposable household income and mortality. Data on activity limitations from the Danish part of the Survey of Health, Ageing and Retirement in Europe (SHARE) was linked to register data on income. For each income quintile, life table data and prevalence data of no activity limitations from SHARE were combined to estimate DFLE. Differences between income quintiles in DFLE were decomposed into contributions from mortality and disability effects.
Results A clear social gradient was seen for life expectancy as well as DFLE. Life expectancy at age 50 differed between the highest and lowest income quintiles by 8.6 years for men and 5.5 years for women. The difference in DFLE was 12.8 and 11.0 years for men and women, respectively. The mortality effect from the decomposition contributed equally for men and slightly more for women to the difference in expected lifetime without than with activity limitations. The disability effect contributed by 8.5 years for men and 8.0 years for women.
Conclusion The income inequality gradient was steeper for DFLE than life expectancy. Since income inequality increases, DFLE by income is an important indicator for monitoring social inequality in the growing share of elderly people.
- Functioning and disability
- Social inequalities
- Health expectancy
- Health inequalities
- Quality of life
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Contributors HB-H planed and designed the study. EF processed the SHARE data. HB-H conducted the analysis and drafted the work. All authors contributed to interpretation of the results and revision of the manuscript.
Funding The study was financed by grants from Helsefonden (The Health Foundation), Grant number 17-B-0281.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The use of microdata from the national registers accessed from Statistics Denmark follows the rules and regulations of the General Data Protection Regulation and is not subject to authorisation from the National Committee on Health Research Ethics, as the investigations do not involve personal contact and informed consent is not required for register-based studies in Denmark. However, the processing and linking of data was approved by the Danish Data Protection Agency. In Denmark, the National Committee on Health Research Ethics does not require ethical approval to use SHARE Wave 5 as it is solely based on survey data and does not include any samples of biological materials from humans (http://en.nvk.dk/how-to-notify/what-to-notify). However, the SHARE project is submitted to continuous ethics reviews. From wave 4 and onwards, SHARE has received ethical approval from the Ethics Council of the Max Planck Society. The last ethics approval was granted on March 4, 2016 (http://www.share-project.org/organisation/dates-facts.html).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.
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