Researchers from the Harvard T.H. Chan School of Public Health conducted a massive 34-year-long study of the impact of health habits on life expectancy, and identified 5 areas that could substantially reduce premature mortality and prolong life expectancy in US adults.
Adopting a healthy lifestyle could substantially reduce premature mortality in US adults
Americans have a shorter life expectancy compared with residents of almost all other high-income countries, yet spend the most money on healthcare. A team of researchers from Harvard conducted a massive 34-year-long study to estimate the impact of lifestyle factors on premature mortality and life expectancy in the US population, using data from the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). The researchers looked at NHS and HPFS data on diet, physical activity, body weight, smoking, and alcohol consumption. These five areas were chosen because prior studies have shown them to have a large impact on risk of premature death. Here we look at how these healthy habits were defined and measured.
5 key lifestyle areas identified to prolong life expectancy
The United States is one of the wealthiest nations worldwide, but Americans have a shorter life expectancy compared with residents of almost all other high-income countries, ranking 31st in the world for life expectancy at birth in 2015.
In 2014, with a total health expenditure per capita of $9402, the United States was ranked first in the world for health expenditure as a percent of gross domestic product (17.1%).
However, the US healthcare system has focused primarily on drug discoveries and disease treatment rather than prevention. Chronic diseases such as cardiovascular disease (CVD) and cancer are the most common and costly of all health problems but are largely preventable. It has been widely acknowledged that unhealthy lifestyles are major risk factors for various chronic diseases and premature death.
Researchers from the Harvard T.H. Chan School of Public Health conducted a massive study of the impact of health habits on life expectancy, using data from the well-known Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). This meant that they had data on a huge number of people over a very long period of time.
The NHS included over 78,000 women and followed them from 1980 to 2014. The HPFS included over 40,000 men and followed them from 1986 to 2014. This is over 120,000 participants, 34 years of data for women, and 28 years of data for men.
The researchers looked at NHS and HPFS data on diet, physical activity, body weight (BMI), smoking, and alcohol consumption that had been collected from regularly administered, validated questionnaires. These five areas were chosen because prior studies have shown them to have a large impact on risk of premature death.
For each low-risk factor, the participant received a score of 1 if he or she met the criterion for low risk. If the participant did not meet the criterion, he or she was classified as high risk for that factor and received a score of 0. The sum of these 5 scores provided a total number of low-risk factors of 0, 1, 2, 3, 4, or 5, with higher scores indicating a healthier lifestyle.
According to this analysis, those who met criteria for all five habits enjoyed significantly longer lives than those who did not.
The researchers estimated that adherence to 5 low-risk lifestyle-related factors could prolong life expectancy at age 50 years by 14.0 and 12.2 years for female and male US adults, respectively, compared with individuals who adopted zero low-risk lifestyle factors. These estimates suggest that Americans could narrow the life-expectancy gap between the United States and other industrialised countries by adopting a healthier lifestyle. (Scroll down to see how these healthy habits were defined and measured)
Researchers estimate that adherence to a low-risk lifestyle could prolong life expectancy at age 50 years by 14.0 and 12.2 years in female and male US adults compared with individuals without any of the low-risk lifestyle factors. Their findings suggest that the gap in life expectancy between the United States and other developed countries could be narrowed by improving lifestyle factors.