Previous studies of determinants of mortality have identified various risk factors across disciplines. A recent study published in Proceedings of the National Academy of Sciences found that alcohol abuse, divorce, and smoking are behavioral and social factors that are most closely connected to death.
The team used nationally representative data from 13,611 adults in the US Health and Retirement Study between 1992 and 2008. Participants ranged from 50 to 104 years old with an average age of 69.3. The researchers then identified which behavioral and social factors applied to those who died between 2008 and 2014.
Lifespan approach in understanding mortality and health
University of British Columbia School of Kinesiology’s assistant professor Eli Puterman said via Medical Xpress that a lifespan approach, a framework for understanding human development from conception to death, is needed to understand mortality and health. For instance, rather than asking whether a person is unemployed, the researchers looked at their history of unemployment for the last 16 years. If a person is unemployed at a certain time during that period, would it be considered a predictor of mortality? Puterman believes it’s more than just a single time snapshot in a person’s life where something could be missed because it did not happen.
The team’s approach focused on the potential long-term impacts of the behavioral and social factors through a lifespan year. In the US, life expectancy has stagnated for three decades compared to other industrialized nations, raising questions as to what factors may have contributed to it. Medical conditions and biological factors are always on top of the list, which is why Puterman and the team intentionally excluded those in favor of behavioral, economic, psychological, and social factors.
10 factors most closely associated with mortality
The 10 factors that have the closest connection to death out of the 57 behavioral and social factors analyzed by the team are the following, in order of significance: (1) current smoker, (2) history of divorce, (3) history of alcohol abuse, (4) recent financial difficulties, (5) history of unemployment, (6) previous history as a smoker, (7) lower life satisfaction, (8) never married, (9) history of food stamps, and (10) negative affectivity.
These top predictors of mortality spanned all investigated domains and they open up opportunities for hypothesis generation in clinical and observational studies as well as identification of potential new targets for policy and screening.
The survey data from US Health and Retirement Study may not have captured every possible adversity and neither domestic abuse nor food insecurity was addressed, but the findings offered an indication of where several factors stand in connection with each other.
Puterman, who is the lead author of the study, said that if they are going to put effort and money into policy changes or interventions, those areas mentioned could lead to the greatest return on investment. For instance, it has been recognized for 40 years that smoking is one of the greatest predictors of mortality. However, by determining a factor, like negative affectivity (NA), we could see the need to also target it with interventions. NA is a personality variable that involves the experience of negative emotions and poor self-concept that a person tends to feel and see more negative things in their life.
The lead author wondered if the shift in such factors has an impact on mortality rates and if we can focus on interventions for people experiencing financial difficulties and the unemployed to lessen the risk.
Differences in life expectancy across the world
Life expectancy refers to the number of years a person is expected to live based on the statistical average and it varies by era and geographical area. Often, richest countries have life expectancies of over 80 years. Life expectancy in Australia, Italy, Switzerland, and Spain in 2019, for instance, was over 83 years. The country with the highest life expectancy was Japan with close to 85 years, according to Our World in Data, a scientific online publication that focuses on large global problems.
Countries with the highest life expectancy include Japan (84.6 years), New Zealand (82.3 years), France (82.7 years), Spain (83.6 years), Canada (82.4 years), Sweden (82.8 years), UK (81.3 years), Iceland (83 years), and Austria (81.5 years), among others. On the other hand, countries with the lowest life expectancy in 2019 include the Central African Republic (53.3 years), Nigeria (54.7 years), Sierra Leone (54.7 years), Chad (54.2 years), and Cameroon (59.3 years).
In the last few centuries, there has been a dramatic increase in life expectancy as people in all countries achieved progress in health that helped increased life expectancy globally. South Korea is among the countries that improved later but achieved faster progress than Japan and the UK. From 23.5 years of life expectancy in 1908, South Korea's life expectancy is 2015 stood at 82.1 years.
How to increase life expectancy
Behavior change expert Mark Stibich, Ph.D., FIDSA, who has helped individuals make lasting lifestyle improvements, said that life expectancy can be increased with simple changes and steps. The easiest way is to go outside and allow your skin to get exposed to healthy sunlight. Such exposure triggers the cells in the skin to produce vitamin D, which is essential for bone health and lessens the risk of heart disease, diabetes, and depression.
Life expectancy can also be increased by spending time with family and friends. The more connected a person is, the better their overall health. This is especially true if they are maintaining positive relationships with their spouse, family, and friends. Because of this connection, people take care of themselves, and having people around them reduces the impact of stress. Daily exercise likewise improves life expectancy. A study has established that people who exercise vigorously for 3 hours a week had cells and DNA that were 9 years younger than people who don’t exercise. Health screenings and medical tests will also extend one’s life expectancy. Since watching TV makes a person inactive and antisocial, turning off the TV will also improve people’s health and therefore increase their life expectancy.
Health authorities can make extensive use of the recent findings in monitoring the health of the public, exploring other variations in health, comparing them with other health authorities, and reducing local inequalities in health.