Fanny Janssen, Sergi Trias-Llimós and Anton Kunst
Smoking, alcohol misuse and behaviours that result in obesity (such as an unhealthy diet and insufficient physical activity) have strong negative effects on individual health. Because these health behaviours are very common among people in Europe, smoking, alcohol and obesity also largely influence mortality rates and life expectancy in Europe.
However, the impact of these three lifestyle factors on life expectancy is likely changing over time. Smoking, obesity and alcohol misuse, like true epidemics, tend to first become more common in a population, followed (eventually) by a decline in their prevalence and associated mortality.
This raises the question of how changes in smoking, obesity and alcohol use have influenced improvements in life expectancy over time. Answering this question is particularly relevant because of the recently observed stagnation in life expectancy improvements in some European countries.
In our study recently published in the IJE, we examined, for the first time, the combined effects of smoking, obesity and alcohol on both life expectancy and secular trends in life expectancy for 30 European countries.
We found that, in these countries in 2014, the average combined impact of smoking, obesity and alcohol on life expectancy at birth was 5.8 years among men (3.4 years for smoking, 1.8 years for alcohol and 1.3 years for obesity). Among women, the impact was much lower, at 2.3 years (0.8 years for smoking, 0.5 years for alcohol, and 1.2 years for obesity). In other words, without these three lifestyle factors, life expectancy at birth in Europe would have been 5.8 years longer for men (currently 75 years) and 2.3 years longer for women (currently 82 years).
The impact of the three lifestyle factors on life expectancy is, however, not stable over time. Among men in the 30 European countries studied, the average combined impact of smoking, obesity and alcohol on life expectancy at birth declined from 6.6 years in 1990 to 5.8 years in 2014. This was mostly due to a decline in smoking-attributable mortality. Among women, the average combined impact of smoking, obesity and alcohol on life expectancy at birth actually showed an increase, from 1.9 to 2.3 years during the same period, due to, on average, increases in all three lifestyle factors.
The three lifestyle factors combined also affected improvements in life expectancy at birth over time. Across the 30 European countries, the observed average increase in life expectancy at birth between 1990 and 2014 was 5 years for men (from 69.3 to 74.3 years) and 4 years for women (from 77.3 to 81.2 years). Without the impact of smoking, obesity and alcohol, this increase would have been 4.2 to 4.3 years for both men and women. The resulting stable and more uniform increase in life expectancy – without the impact of the lifestyle factors – likely captures the underlying gradual increase in life expectancy in Europe, which was postulated as part of the epidemiological transition theory, and which is a result of overall socioeconomic growth and medical progress.
Our results indicate that lifestyle ‘epidemics’ have the tendency to distort this general gradual increase in life expectancy, albeit differently so by sex, by country and by time period. In Europe – particularly in the United Kingdom, but also in France, Germany, Sweden and the Netherlands – slowdowns in life expectancy increases have been observed since 2011. Increases in both obesity prevalence and alcohol misuse among adults have been mentioned as potential causes. For women, the rapid recent increases in smoking-attributable mortality, particularly in the abovementioned countries, are likely also a contributor.
The importance of lifestyle factors in determining past trends in life expectancy also has implications for future trends. In the coming years, projected further increases in smoking-attributable mortality for women in most European countries, coupled with expected further increases in obesity-attributable mortality, would likely result in less favourable life expectancy trends, particularly for women. Once declines in smoking-attributable mortality among women become more widespread, and the hypothesised declines in obesity-attributable mortality and alcohol-attributable mortality among selected Eastern European countries eventually also set in, more positive developments in life expectancy can be expected again. Achieving such declines in mortality requires dedicated efforts across Europe to combat the epidemics of smoking, obesity and alcohol misuse.
Janssen F, Trias-Llimós S, Kunst AE. The combined impact of smoking, obesity, and alcohol on life-expectancy trends in Europe. Int J Epidemiol 2021; 11 January. doi: 10.1093/ije/dyaa273.
This work was supported by the Netherlands Organisation for Scientific Research (NWO) in relation to the research program ‘Smoking, alcohol, and obesity, ingredients for improved and robust mortality projections’, under grant no. 452-13-001.
Fanny Janssen is a senior researcher at the Netherlands Interdisciplinary Demographic Institute (NIDI-KNAW) in The Hague and honorary professor in “Mortality and Longevity” at the Population Research Centre, University of Groningen, the Netherlands. Her research focuses on the role of health-related lifestyle factors (smoking, alcohol, obesity) in shaping mortality differences and mortality trends, and on improving the estimation of future mortality and life expectancy.
Sergi Trias-Llimós is a postdoctoral researcher in the Centre for Demographic Studies (CED-UAB) in Barcelona, Spain. He is interested in a wide range of population health issues, particularly lifestyle-related health outcomes, causes of death, COVID-19 and inequalities therein.
Anton Kunst is a professor in social epidemiology at Amsterdam UMC, University of Amsterdam. His research centres on two key problems in public health: socioeconomic inequalities in health and the health burden of tobacco. On both topics, he has coordinated national and European projects.