Which measurable influence does a healthy lifestyle have of American adults? And which factors are part of a healthy lifestyle? These are the questions that Harvard researchers examined by using the enormous amount of data about the associations between different lifestyle factors and causes of mortality from two big observational studies that have already been running for the last three decades: 800,000 participants in the Nurses’ Health Study and 45,000 men in the Health Professionals Follow-Up study.
The data from these two studies showed five healthy lifestyle factors:
- Individuals who have never smoked,
- Individuals who have a normal body weight (BMI…)
- Individuals who exercise moderately at least 30 minutes a day;
- Individuals who eat a healthy diet;
- And individuals who consume alcoholic beverages moderately.
Moderate consumption was defined as follows:
- for women 5-15 g of alcohol/day or the equivalent of 50 to 150 ml of wine, and
- for men, 5-30 g of alcohol/day or the equivalent of 50 to 300 ml of wine.
The results showed only 8% of US citizens follow the healthy lifestyle factors listed above. It was therefore clear from the beginning that a healthy lifestyle would increase the life expectancy, however, the researchers were surprised at how big the benefits of all these five lifestyle factors are:
- 50-year-old women who would practice ALL these healthy lifestyle factors could potentially live 14 additional years (93 instead of 79 years); and
- 50-year-old men would benefit by living 12 additional years (87 instead of 75 years).
The reference group consisted of individuals who followed none of these lifestyle factors.
- Compared to this group, the mortality risk was 74% lower when all 5 factors would be followed, the cancer risk was 65% lower and the risk of cardiovascular disease was 82% lower.
The so-called J-curve* was also confirmed when assessing the association of alcoholic beverages with various health parameters. Those consuming moderately (5-30 g of alcohol/day) had the lowest risk to die from any cause. A higher consumption as well as abstinence was related to a higher risk (27% higher in teetotalers and 25% higher when consuming more than 30 g of alcohol/day).
* Moderate wine drinkers have a lower mortality rate than those who abstain or drink heavily. This widely accepted association is known as the J-curve. (ref.: Wine Information Council)
Li Y et al, Impact of healthy lifestyle factors on life expectancies in the US population, Circulation. 2018;137:00–00. DOI: 10.1161/CIRCULATIONAHA.117.032047