Thursday, September 13, 2018

Lifestyle Factors And Life Expectancy


A new study was recently published that is so compelling that it deserves its very own feature article. The study is titled “Impact of healthy lifestyle factors on life expectancies in the US population” and it was published in the journal Circulation. The authors of this investigation are the very best of the Harvard School of Public Health’s Department of Nutrition faculty, which includes Dr. Walter Willett, Dr. Frank Hu and Dr. Meir Stampfer (Reference 1).

Most nutrition research focuses on a very specific aspect of lifestyle and its impact on health. For example, “eating red meat increases incidence of colon cancer” or “eating oatmeal decreases serum cholesterol”. What makes this study so interesting is that several lifestyle behaviors are combined so we can see their cumulative impact on health.

The Article
This investigation used subjects from both The Nurses’ Health Study and The Health Professional Follow-up Study for a total of 123,219 men and women. The researchers created 5 lifestyle factors and scored each subject on how well they followed the behavior. Here is the scoring system:

1) Smoking: If the subject never smoked they received a score of 1. If they were a current smoker or had smoked in the past, they received a score of 0.

2) Physical Activity: If the subject engaged in 30 minutes or more of moderate to vigorous physical activity each day they received a score of 1. If they did less than this, they received a score of 0.

3) Alcohol Consumption: Low risk was considered an alcohol consumption of 5 to 15 grams per day for women (which equals 2.5-7.5 drinks per week) and 5 to 30 grams per day for men (which equals 2.5-14 drinks per week). If the subject’s alcohol consumption was in this range, they received a score of 1, if not they received a score of 0.

4) Body Mass Index: Low risk was considered a BMI between 18.5-24.9. If the subject’s BMI was in this range, they received a score of 1, if not they received a score of 0.

5) Diet: Subjects received a score of 1 for this variable if their diet was in the top 40% of the cohort distribution for the Alternate Healthy Eating Index. This diet score is based on a high consumption of vegetables, fruits, nuts, whole grains, polyunsaturated fats and long chain omega 3 fatty acids and a low intake of red and processed meats, sugar sweetened beverages, trans fat and sodium.

Each subject was given a score for the 5 lifestyle factors. A perfect lifestyle would be a score of “5”, while adhering to none of the lifestyle factors would yield a score of “0”.  Subjects were followed for up to 34 years.

Results
When comparing subjects who followed all 5 factors to subjects following none:

-Risk of all-cause mortality was 74% lower in subjects that followed all 5 factors.

-Risk of death from cancer was 65% lower in subjects that followed all 5 factors.

-Risk of death from cardiovascular disease was 82% lower in subjects that followed all 5 factors.

Starting at age 50, women following all 5 factors could expect to live another 43.1 years, while women following none of the factors could expect to live another 29 years.

Starting at age 50, men following all 5 factors could expect to live another 37.6 years, while men following none of the factors could expect to live another 25.5 years

The researchers ran an additional analysis with a stricter criterion for the lifestyle score.

Body mass index: A score of 1 was given to those with a BMI between 18.5 and 22.9.

Physical Activity: A score of 1 was given to those exercising more than 52 minutes per day.

Diet: A score of 5 was given to those in the top 20% of the distribution for the Alternate Healthy Eating Index.

The scoring for smoking and alcohol consumption were kept the same.

Women who followed this expanded score lived 20.5 years longer than those that followed none of the lifestyle factors. For men, the number was 19.6 years.

Conclusions And Recommendations
These results are truly remarkable. To think that by living a healthy lifestyle you could add up to 20 years to your life is amazing. The coolest part is that this study does not take into account quality of life, which is much higher if you follow these habits. If you are able to hit all 5 of these behaviors consistently, you will notice significant and positive changes in your energy, mood, immune system, confidence, mental focus/performance and how you handle stress. 

The take home message on this is one is simple. Go through each of the 5 lifestyle factors and give yourself a score. If you are at 5, you are all set and keep up the good work. If you are hitting less than 5, do your best to work towards a perfect score. Will it be easy to attain all 5 of these? Probably not. However, the effort you put into a healthy lifestyle is paid back to you many times over. It all begins with making your health a priority.

References
1) Li Y, et al. Impact of healthy lifestyle factors on life expectancies in the U.S. population Circulation 2018 DOI: 10.1161/CIRCULATIONAHA.117.032047.

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