Lifestyle habits are the key to improving healthy life expectancy

The development of many antibiotics, vaccines, drugs, surgical procedures and other medical feats that have marked the last century have made it possible to reduce the burden imposed by several diseases (in particular infectious diseases) and to considerably increase life expectancy. In Canada, for example, as in all industrialized countries, the life expectancy of a child born today is around 80 years, almost double that of 150 years ago.

This dramatic increase in life expectancy, however, masks a darker reality: we may be living longer, but a significant proportion of those extra years are often marked by illness, suffering and loss of autonomy. In Canada and Quebec, for example, the high incidence of many of the chronic diseases that occur during aging (cardiovascular disease, diabetes, cancer and dementia, in particular) means that a person will lose almost ten years of healthy life, i.e., just over 12% of their total life if they reach age 80 (Figure 1). It goes without saying that the decrease in quality of life caused by these years in poor health considerably reduces the benefits that a longer life could provide.

Figure 1. Life expectancy at birth and healthy life expectancy measured in Canada and Quebec. Data are from Statistics Canada (2022) (life expectancy) and Statistics Canada (2019) (healthy life expectancy).

Healthy life expectancy
In terms of aging, the primary objective should therefore not only be to live longer, but above all to improve the quality of these additional years of life by delaying the onset of chronic diseases for as long as possible.

According to a recent study, adopting a series of measures that optimize cardiovascular health would be an excellent way to achieve this. In this study, carried out among 135,199 participants in the UK Biobank study, researchers examined the association between the level of cardiovascular health, measured using the Life’s essential 8 (LE8) score which combines 8 parameters known to optimize cardiovascular health (Figure 2), and life expectancy without the four main chronic diseases associated with aging, namely cardiovascular disease, diabetes, cancer and dementia.

Figure 2. The 8 essential parameters for optimizing cardiovascular health, as defined by the American Heart Association. Note that for food, the AHA recommends a high intake of vegetables, a moderate consumption of lean meats, a reduced intake of sodium as well as added sugars and refined flours, which roughly corresponds to the DASH diet.

This approach made it possible to classify the study population into 3 main categories according to their levels of cardiovascular health: 1) Low level (LE8 score < 50/100); 2) Moderate level (LE8 score between 50 and 80/100); and 3) High level (LE8 score > 80/100). By examining the life expectancy at age 50 that corresponds to each of these categories, the researchers first found that better cardiovascular health was associated with a significant increase in total life expectancy, from about 86 to 92 years old (Figure 3). However, the most interesting point of the study is that these extra years of life are mainly in the absence of chronic diseases, with an average gain of around 10 years of healthy life among people with the best levels of cardiovascular health. (Figure 3).

Figure 3. Life expectancy at age 50 according to the level of cardiovascular health. Note the increase in years of life in good health (dark blue) and the decrease in those with chronic diseases (light blue) in the population with the highest levels of cardiovascular health. Adapted from Wang et al. (2023).

In other words, good cardiovascular health not only increases life expectancy, but simultaneously reduces the number of those extra years lived with one or more chronic diseases. A similar phenomenon is observed in people with a lower socioeconomic status, an important risk factor for premature mortality. Improving the cardiovascular health of disadvantaged populations could therefore represent a concrete way to reduce health and longevity inequalities in our society.