How A Healthy Lifestyle Affects Life Expectancy Free of Comorbidities – Diabetes In Control

As we continue to age, maintaining a healthy lifestyle plays a big part in how chronic diseases develop and impact daily life.  

People around the world have been living longer over the past few decades. However, this longer life expectancy comes with the uneasy fact that this population of people often lives with disabilities and chronic diseases. Included in such are diabetes, cardiovascular disease, and cancer. Individuals in this population have a shorter life expectancy compared to others who are not affected by these comorbidities. It is estimated that there are 7.5 to 20 years of life lost due to these chronic conditions. Previously, it has been studied that modifiable lifestyle factors and diet quality affect both total life expectancy and incidence of chronic diseases. Smoking, inactivity, poor diet quality, and heavy alcohol consumption have all been shown to account for 60% of premature deaths and 7.4 to 17.9 years in loss of life expectancy. Little research has given insight into how a combination of certain lifestyle factors relates to life expectancy. 

The purpose of this study was to examine how a healthy lifestyle correlates to a life expectancy that is free from diabetes, cardiovascular complications, and cancer. This was a prospective cohort study that utilized The Nurses‘ Health Study and the Health Professionals Follow-Up Study. In both groups, self-administered questionnaires were sent every two years to update pertinent information such as newly identified diagnosed cases of various diseases. Researchers used 1980 as a baseline for the Nurses‘ Health Study and 1986 for the Health Professionals Follow-Up Study. 111,562 participants were included in this study for analysis. Participants were excluded if they were already diagnosed with having any of the three outcomes (cancer, cardiovascular disease, and diabetes), implausible energy intakes, and those with missing values for body mass index, physical activity, alcohol, or smoking at baseline. The Nurses‘ Health Study and the Health Professionals Follow-Up Study were assessed using questionnaires on diet, exercise, smoking status, and other factors.  

A population-based multistate life table was used to calculate the differences in life expectancy and years lived with and without major chronic diseases for each lifestyle factor and the total lifestyle factor score. Four multistate life tables were constructed, one that included a combination of cancer, cardiovascular disease, and type 2 diabetes, and three for individual diseases. Using three states (disease-free, presence of disease, and death) and three transitions between states (from non-disease to incident disease, from non-disease to mortality among participants free of significant chronic disease, and from disease diagnosis to mortality among those with the disease) the association between the number of low-risk factors and life expectancy free of cancer, cardiovascular disease and type 2 diabetes was assessed. Since potential bias was identified regarding changes in diet after the diagnosis of certain diseases, a sensitivity analysis was implemented that ceased the updates on lifestyle factors at the beginning of the interval in which the participant was diagnosed as having cancer, cardiovascular disease, or diabetes. Statistical significance was considered at a p-value of less than 0.05.  

After this study, researchers found that total life expectancy at age 50 increased with an increasing number of low-risk lifestyle factors. Specifically, life expectancy free of diabetes, cardiovascular diseases, and cancer at age 50 was 23.7 years with 95% confidence interval for those with no low-risk lifestyle factors, compared to 34.4 years for women who had four or five low-risk factors. Absent from any of these diseases at age 50, the life expectancy was 23.5 years among men with no low-risk lifestyle factors and 31.1 years in men with four or five low-risk lifestyle factors.  

Researchers were able to observe and quantify that a healthier lifestyle was indeed related to a lower risk of cancer, cardiovascular disease, and diabetes as well as mortality, with an increased total life expectancy and the number of years lived free of these diseases. Additionally, researchers believe that promoting a healthy lifestyle will help reduce healthcare burdens by simultaneously lowering the risk of developing multiple chronic diseases. Contrarily, limitations exist that relied heavily upon self-reported lifestyle factors leaving room for errors. This warrants further study of this topic to eliminate this gray area.  

Practice Pearls: 

• A longer life expectancy has been associated with cancer, cardiovascular disease, and diabetes. 
• People who practice a healthy lifestyle have a higher life expectancy free from additional comorbidities. 
• Limitations exist that could confound results. 

Li Yanping, Schoufour Josje, Wang Dong D, Dhana Klodian, Pan An, Liu Xiaoran, et al. Healthy lifestyle and life expectancy free of cancer, cardiovascular disease, and type 2 diabetes: prospective cohort study BMJ 2020; 368:l6669 

Deonna Andrews, PharmD Candidate 2020 of Florida Agricultural & Mechanical University College of Pharmacy and Pharmaceutical Sciences

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