Labros S. Sidossis - Textbook of Lifestyle Medicine

FIGURE 3.1 Trends in insufficient physical activity for three income groups from 2001 to 2016. The shaded areas show 95% uncertainty intervals.

Source:Reprinted with permission from Guthold et al. (2018).

Inactive adults have 20–30% increased risk of all-cause mortality.

Given the severe public health effects of physical inactivity, efficient multisectoral and multidisciplinary policies need to be implemented, in order to achieve an increase in PA in the population worldwide. Under this scope, in 2013, WHO member states agreed to a target of reducing sedentariness by 10% by 2025 in the “Global Action Plan for the Prevention and Control of NCDs 2013–2020.” The WHO suggested four policy actions for achieving this PA goal:

1 Adopt and implement national guidelines on PA for health.

2 Develop policy measures to promote PA through activities of daily living, including active transport, recreation, leisure, and sport.

3 Create and preserve built and natural environments that support PA in schools, universities, workplaces, clinics, and hospitals, and in the wider community. FIGURE 3.2 (a) Country prevalence of insufficient physical activity in women in 2016. (b) Country prevalence of insufficient physical activity in men in 2016.Source: Reprinted with permission from Guthold et al. (2018).

4 Implement evidence‐informed public campaigns through mass media, social media, and at the community level to inform and motivate adults and young people to be more physically active.

The WHO has published guidelines to assist the member states and other stakeholders in the development and implementation of national PA plans and to provide guidance on policy options for effective promotion of PA at the national level. Most European and American countries have indeed integrated the promotion of PA at least to some extent in their national health and other policies. However, there is a need to continue updating the policies, both methodologically and substantially, in order to combat the current global sedentariness epidemic and promote the adoption of PA guidelines.

Most European and American countries have integrated the promotion of PA at least to some extent in their national health and other policies.

Unhealthy weight is a well‐documented risk factor for NCDs development, even in the absence of other major risk factors. Maintaining a healthy weight and refraining from smoking increases the years spent in good health, in both men and women. For obese men, the number of years spent in good health are decreased by 4.6 years, relative to men living a healthy life. For men who smoke, the number of years spent in good health are decreased by 7.8 years. The respective decreases for women are 4.5 and 6.0 years, for obese and smokers, respectively.

FIGURE 3.3 Total annual number of deaths by risk factor.

Source:Reprinted with permission from the Global Burden of Disease Collaborative Network. Global Burden of Disease Study 2017. Institute for Health Metrics and Evaluation (IHME) (2018).

FIGURE 3.4 Map of the world showing estimated gains in life expectancy with elimination of physical inactivity.

Source:Reprinted with permission from Lee et al. (2012).

In addition, in a meta‐analysis of 230 cohort studies (207 publications), overweight and obesity were associated with increased risk of all‐cause mortality, with the lowest risk observed at BMI 23–24 kg/m 2among never smokers, 22–23 kg/m 2among healthy never smokers, and 20–22 kg/m 2with longer durations of follow‐up.

As is usually the case, not all studies agree; data from the Dutch Burden of Disease study suggest that elimination of smoking or obesity does not result in absolute compression of morbidity but slightly increases the part of life lived in good health (which, by the way, is very important!).

Regarding the risk for developing T2DM, findings from the Uppsala Longitudinal Study of Adult Men (ULSAM) cohort indicated that after 20 years of follow‐up, those being overweight/obese but free of MetS had approximately 3.5 times increased risk of developing T2DM; the risk was eight times higher for overweight/obese individuals with MetS, relative to those of normal weight and free of MetS.

Contrary to the above findings suggesting that overweight/obesity is a risk factor for NCDs, other studies have shown that overweight and even grade 1 obesity (BMI = 30–35 kg/m 2) are related to decreased all‐cause mortality by 6% and 5%, respectively, compared to those of normal BMI. Still, obesity grades 2 and 3 (BMI > 35 kg/m 2) are associated with 18% and 29% increased risk of all‐cause mortality, respectively, compared to those of normal BMI.

There are many studies on BMI and mortality without uniform results. This is because many factors have been shown to confound the relationship between BMI and longevity. Possible residual confounding factors might be age, disease‐related weight loss, and individuals who smoked, had underlying diseases (e.g., cancer), or suffered early deaths.

In the elderly, mortality risk increases at BMIs lower than 22 kg/m 2, which is not seen in younger adults, while a lower risk is observed among those with overweight and mild obesity. This paradoxical finding, i.e., lower mortality at higher than “healthy” BMI levels, has been termed “the obesity paradox.” There are many possible mechanisms to explain these findings. Excess fat may act as a metabolic reserve during illness or injury. In addition, because of lower noradrenaline‐stimulated lipolytic activity in visceral fat as age increases (which leads to insulin resistance and morbidity), individuals may be less affected by excess adiposity. Moreover, physicians often prescribe more medications to those with overweight and obesity, which may indirectly contribute to the obesity paradox.

Frequent changes from normal to obese and back (yo‐yo effect) have been linked to more than twofold increased risk of all‐cause mortality, relative to stable normal BMI. However, changes from normal weight to overweight (not obesity) were not linked to elevated all‐cause mortality risk, compared to stable normal weight. These findings were similar for CVD‐ and cancer‐specific mortality.

According to the WHO, tobacco use is responsible for more than six million deaths annually. Smoking is responsible for more than five million of those fatal events, whereas secondhand smoking results in more than 600,000 deaths annually. More than 4000 chemical substances are present in tobacco smoke; more than 250 of those have been linked to negative effects for human health. Furthermore, more than 50 chemical substances in tobacco smoke have been robustly associated with increased incidence of oropharynx, esophagus, stomach, liver, cervix, and colorectal cancer. Smoking is the leading risk factor of cancer‐specific deaths; it accounts for more than 20% of the global annual cancer‐induced mortality.