To the Editor:
Continued increases in life expectancy have been observed for most high-income countries for the past 100 years.1,2 However, vanguard groups—variously defined, e.g., in terms of higher education,3–6 a combination of high education and marriage,7 or membership of an elite academic institution8—have enjoyed higher life expectancy. Evidence about vanguard life expectancy informs us about the further potential for mortality gains for the total population.6,7 In this letter, we estimate long-term changes in life expectancy for men and women with doctoral degrees, as we are not aware of such estimates published elsewhere. We use register-based data for the total population of Finland for a period from 1971 to 2015.
The data consist of eight subsets. The first subset is based on all 1970 Finnish census records linked to death certificates in 1971–1975 by Statistics Finland. The others were constructed by linking the 1975, 1980,…, 2010 census records to death certificates for 1976–1980, 1981–1985, …, 2011–2015 periods, respectively. Education was measured as the highest educational degree at the time of each census: (1) doctorate or licentiate, (2) other tertiary education lasting for 13+ years, (3) secondary education lasting for 10–12 years, and (4) basic education lasting for 9 years or less.
Life expectancy is the hypothetical average age at death, given age-specific death rates in a specific period and is one of the most common measures of survival. We calculated abridged period life expectancies in each of the periods by education and sex at age 40, and their 95% confidence intervals (see eTable for details; http://links.lww.com/EDE/B561).
The proportion of Finnish men with a doctoral degree more than tripled from the early 1970s to the early 2010s (eTable; http://links.lww.com/EDE/B561). This compositional change went together with increasing overall life expectancy, which benefitted those with doctorate degrees in particular.
Among men (Figure 1A), those with a doctoral degree consistently held an advantageous position, even when compared with other tertiary-educated men. No sign of convergence was observed. In 1971–1975, the life expectancy at age 40 among men with a tertiary education was 1.2 years lower than that among men with a doctoral degree. In 2011–2015, the difference was 2.1 years.
Due to the small number of women with a doctorate, we present the results in 10-year intervals in 1971–2010, and a final interval of 2011–2015 (Figure 1B). Starting from the 1990s, the advantage of women with a doctoral degree against the other tertiary-educated has also become visible. During the period 2011–2015, the gap between these two stood at 2.1 years, the same as among men. Among women, the increase in proportion with doctorates was stronger than among men.
Overall, the study established the vanguard position of those with doctoral degrees by showing increasing life expectancy advantage against other educational groups. Despite relatively high overall levels of life expectancy, those with doctoral degrees continued to enjoy robust gains at a pace that shows little signs of slowing down. This indicates a large potential for further longevity gains for the other educational groups.6
Life expectancy improvements among vanguard women were somewhat slower than among vanguard men. This may be because women had much higher initial life expectancy levels and additional life expectancy gains were dependent on much more difficult to achieve mortality reductions at older ages. However, in the last period, 2010–2015, the educational advantage in life expectancy among those with a doctorate was similar among men and women at 2.1 years. In the 1970s and 1980s, this difference was negligible among women, possibly because women aiming at doctorates had to make a conscious choice between following a career in research at the expense of family life.
This observational study does not provide direct evidence on the causal role of factors behind the life expectancy differentials. However, the importance of selection should have decreased over time due to more equitable education policies and the increased size of the doctorate group. These changes should have led to a deceleration of longevity improvements and a gradual disappearance of the mortality advantage of those with doctorates. Our study did not find systematic evidence supporting this selection assumption.
We also found persisting life expectancy advantages of doctorates in comparison with other tertiary-educated people. These differences were observed despite relatively similar physical working conditions and both groups being generally high-income and high-status groups with good access to services.4 However, the finding that life expectancy advantages can be detected even at the highest level of definition is consistent with the idea that those in ever-higher social positions continue to enjoy many incremental advantages of life while avoiding disadvantage. Future research should examine whether health behaviors and psychosocial characteristics known to be important for the educational gap in mortality more broadly also explain the 2-year life expectancy gap between those with doctorates and those with other tertiary education.
The authors thank Vladimir M. Shkolnikov (Max Planck Institute for Demographic Research, Germany) for useful insights on mortality in vanguard groups.
Population Research Unit, Faculty of Social Sciences, University of Helsinki, Helsinki, Finland, Centre for Health Equity Studies (CHESS), Stockholm University and Karolinska Institutet, Stockholm, Sweden, The Max Planck Institute for Demographic Research, Rostock, Germany, firstname.lastname@example.org
The Max Planck Institute for Demographic Research, Rostock, Germany
Population Research Unit, Faculty of Social Sciences, University of Helsinki, Helsinki, Finland
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