NATAP: Exercise Reduces Diseases/Mortality-new Lancet Studies

StephenW

Subject: NATAP: Exercise Reduces Diseases/Mortality-new Lancet Studies


Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy

"Worldwide, we estimated that physical inactivity causes 6–10% of the major non-communicable diseases of coronary heart disease, type 2 diabetes, and breast and colon cancers. Furthermore, this unhealthy behaviour causes 9% of premature mortality, or more than 5·3 of the 57 million deaths in 2008.18 With elimination of physical inactivity, life expectancy of the world’s population might be expected to increase by 0·68 years"




Physical inactivity causes around 1 in 10 deaths worldwide, comparable to the impact of smoking


**Embargo: 00:01H UK time Wednesday 18 July**



A lack of physical activity, or people’s failure to spend 150 minutes a week doing moderate physical activity (eg, brisk walking for 30 minutes, 5 days a week), causes around 6–10% of four major non-communicable diseases (coronary heart disease [CHD], type 2 diabetes, and breast and colon cancer) worldwide, andwas responsible for around 5.3 million of the 57 million deaths globally in 2008. The new estimates published Online First in The Lancet, indicate that physical inactivity has become a contributor to the burden of disease and shortening of life expectancy similar to tobacco smoking or obesity.

I-Min Lee from Brigham and Women’s Hospital and Harvard Medical School, Boston, USA and colleagues estimated the global impact of physical inactivity on CHD, type 2 diabetes, and breast and colon cancer by calculating population attributable fractions (PAF)—how much of these diseases could theoretically be prevented in the population if all inactive people were to become sufficiently active—by country and region.



The estimates suggest that worldwide some 6% of CHD cases are linked to physical inactivity, ranging from 3.2% in southeast Asia to 7.8% in the eastern Mediterranean region. A lack of physical activity is responsible for about 7% of type 2 diabetes cases (ranging from 3.9% to 9.6%), and 10% of breast (5.6%–14.1%) and colon cancer cases (5.7%–13.8%).


The researchers say, “Removal of physical inactivity had the largest effect on colon cancer, and the smallest on coronary heart disease, in terms of percentage reduction. However, with respect to the number of cases that can potentially be averted, coronary heart disease would have a far larger effect than would colon cancer because of its higher incidence. Although the worldwide incidence of coronary heart disease is not readily available, deaths from coronary heart disease can be viewed against colorectal cancer deaths to provide some perspective.”


For example, of the 7.25 million deaths from CHD in 2008, physical inactivity accounted for 15 000 preventable deaths in Africa, 60 000 in the Americas, 44 000 in the eastern Mediterranean region, 121 000 in Europe, 59 000 in southeast Asia, and 100 000 in the western Pacific region.


In contrast, of the 647 000 colorectal cancer deaths in 2008, 1000 deaths could have been avoided in Africa by eliminating physical inactivity, 14 000 in the Americas, 2000 in the eastern Mediterranean region, 24 000 in Europe, 4 000 in southeast Asia, and 24 000 in the western Pacific region.


Because physical inactivity is unlikely to be completely eliminated, the researchers also calculated the number of theoretically preventable deaths if inactivity decreased by 10% or 25%, translating to some 533 000 and 1.3 million deaths potentially averted worldwide every year.


What is more, say the authors, life expectancy of the world’s population would rise by around 0.68 years* if physical inactivity were eliminated.This is similar to the effect of eradicating smoking or obesity.


According to Lee, “This summer, we will admire the breathtaking feats of athletes competing in the 2012 Olympic Games. Although only the smallest fraction of the population will attain these heights, the overwhelming majority of us are able to be physically active at very modest levels – e.g. 15–30 min a day of brisk walking – which bring substantial health benefits.”



Notes to Editors:
*This figure seems low because it represents gains in the population as a whole (including inactive and active people), rather than just in inactive people who become active. The increase in life expectancy in the inactive group would be much greater.


Series 1
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A third of adults and 4 out of 5 adolescents are at high risk of disease from failing to do recommended amounts of physical activity


**Embargo: 00:01H UK time Wednesday 18 July**



Worldwide, around a third of adults (about 1.5 billion people) and 4 out of 5 adolescents are failing to do the recommended amounts of physical activity, placing them at 20–30% greater risk of heart disease, diabetes, and some types of cancer. The first global estimates of physical activity levels are described in the first paper in The Lancet Series on physical activity.

The global picture shows that inactivity varies widely between regions, from 17% of adults in southeast Asia to 43% in the Americas, and between countries from 5% of individuals in Bangladesh to 71% in Malta.

Using self-reported data, Pedro C Hallal from Universidade Federal de Pelotas in Brazil and colleagues compared global patterns of physical activity in adults (aged 15 years or older) from 122 countries (representing 89% of the world’s population) and in adolescents (aged 13–15 years) from 105 countries. Standardised physical activity questionnaires were used to measure total physical activity during leisure-time, housework, at work, and transport-related activity (eg, cycling or walking to work).

The estimates suggest that roughly three out of every ten adults worldwide do not meet the recommended amounts of activity, defined by moderate-intensity activities, such as brisk walking for at least 30 minutes or more five times a week, or more vigorous exercise for 20 minutes three times a week.

Within Europe, countries with the greatest prevalence of inactive adults were Malta (71%); Serbia (68%); the UK (63%); Turkey (56%); Cyprus (55%); and Italy (55%). Adults in Greece (16%); Estonia (17%); and the Netherlands (18%) reported the least inactivity. In comparison, around 41% of adults in the USA and 34% in Canada were found to be inactive or underactive.

“In most countries, inactivity rises with age and is higher in women than in men [34% vs 28%]. Inactivity is also increased in high-income countries”*, says Hallal.

Guidelines recommend that adolescents are moderately physically active for at least an hour a day. But according to the findings, over 80% of 13 to 15 year-olds are not managing the recommended weekly amounts, with boys reporting more activity than girls.

According to Hallal, “Although the technological revolution has been of great benefit to many populations throughout the world, it has come at a major cost in terms of the contribution of physical inactivity to the worldwide epidemic of noncommunicable diseases.  Societal trends are leading to less not more activity than previously, [and] with few exceptions, health professionals have been unable to mobilise governments and populations to take physical inactivity sufficiently seriously as a public health issue.”

Of particular importance, he notes, are the large gaps in existing surveillance, with no data available for about a third of countries, particularly in Africa and the poorest parts of Latin America and central Asia, where the greatest burden of non-communicable diseases is located.






Series 2
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Why are some people more physically active than others?


**Embargo: 00:01H UK time Wednesday 18 July**


In the second paper in The Lancet Series on physical activity, an international team of researchers examine our current understanding of why some people are more physically active than others. They argue that while significant progress has been made in the past two decades, research has mainly focused on individual-level factors (eg, age, sex, socioeconomic status) in high-income countries, and important fundamental questions about factors that cause inactivity, particularly in low and middle income countries where about 80% of the burden of non-communicable diseases lies, remain unanswered.

“Targeting factors known to cause inactivity is key to improving and designing effective interventions to increase activity levels”, explains Adrian Bauman from the University of Sydney in Australia who led the research. “However, most studies of physical activity have assessed correlates (factors associated with activity) in small, non-representative samples rather than providing longitudinal evidence that could identify factors with a stronger causal relationship.”*

The review identifies a small number of consistent correlates that appear to influence whether people are regularly active or not. For instance: health status and intention to exercise in adults; being male, young, or wealthy, self-efficacy (confidence in the ability to be physically active in specific situations) and previous history of physical activity at all ages; and family and social support in adolescents.

New evidence also suggests that some people might be genetically predisposed to being physically active while evolutionary factors and obesity might also add to the propensity to be inactive.

But despite these apparent advances, Bauman and colleagues point out that, “Research has been heavily concentrated in a few developed countries, most of which have stable or falling rates of non-communicable diseases, rather than in low-income countries where understanding of evidence-based strategies for increasing physical activity is poor.”*

“Future research needs to have a stronger focus on causal determinants rather than just repetition of cross-sectional correlates studies, especially in low and middle income countries”, they say, adding that, “this improved understanding will be vital to reducing the effect of future epidemics of inactivity and contribute to effective global prevention of non-communicable diseases.”*




Series 3
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Study identifies the most effective interventions to promote physical activity from around the world


**Embargo: 00:01H UK time Wednesday 18 July**


The third paper in The Lancet Series on physical activity identifies a range of successful and promising interventions from around the world that could be used to improve opportunities for regular physical activity and encourage more people to be physically active.

“Because even moderate physical activity such as walking and cycling can have substantial health benefits, understanding strategies that can increase these behaviours in different regions and cultures has become a public health priority”*, explains Gregory Heath from the University of Tennessee, USA, lead author of the study.

By analysing 100 reviews of clinical and community-based physical activity interventions published between 2001 and 2011, the authors identified a number of effective ways of promoting exercise in people of different ages, social groups, and countries worldwide, through communication and information strategies, social and behavioural support initiatives, and modifications to environmental design and transport policies.

Successful examples included promoting exercise and community events through mass media campaigns  as well as decision prompts and signage to motivate people, for instance to use stairs instead of lifts.

Social support networks such as buddy systems and walking clubs were also important, as were free exercise classes in public places such as parks that targeted populations who are less likely to manage recommended levels of activity, including women, those on lower incomes, and older adults.

The authors also recommend creating environments conducive to walking or biking (eg, bike lanes and trails), improving access to sport and recreational activities, as well as shaping policies for community and neighbourhood design, land use (eg, increasing green space), and travel choice (improving public transport).

For example, evidence from studies in the USA, Australia, Belgium, Canada, England, and Germany indicates that street-level strategies such as improved lighting and aesthetics can boost activity levels by as much as 50%.

Another potentially effective intervention that originated in Bogotá, Columbia, and has now spread to almost half of countries (100 cities) in the Americas, is known as Ciclovía. The programme closes city streets to motorised vehicles for the use of walkers, runners, skaters, and cyclists on Sunday mornings and public holidays. The Ciclovía attracts about a million users every week, mostly people on lower incomes, and provides about 14% of the weekly recommended population requirement for weekly minutes of physical activity for Bogotá.

“Overall, our findings showed the interventions to have consistent and significant effects on physical activity behaviours. Even though in some instances the effect sizes of these interventions were rather modest, they  were large enough to translate into real population-level benefits if  rolled out on a larger scale”,* concludes Heath.




Series 4
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Mobile phone technology could encourage much greater numbers of people to become physically active


**Embargo: 00:01H UK time Wednesday 18 July**


Information and communication technologies, especially mobile phones, could be an effective way of encouraging millions of people worldwide to become more physically active, according to a new simulation model reported in the fourth paper in The Lancet Series on physical activity.

“The findings indicate that the potential effects of web and mobile phone technology are roughly the same size as the average effects of targeted physical activity interventions, suggesting that the greatest potential to increase population level physical activity might be through the creation of supportive policies outside the realms of health in sectors such as communication”*, explains Michael Pratt from the Centers for Disease Control and Prevention in the USA who led the research.

With an estimated four billion users worldwide, text messaging is a promising delivery mechanism for interventions to promote physical activity and could create new opportunities for implementing behavioural change in large numbers of inactive and underactive individuals because of its widespread use in less affluent and less healthy populations at high risk of inactivity.

Pratt and colleagues developed simulation models to project the probable effects of global megatrends (defined as major forces in societal development that are likely to shape people’s lives during the next 10–15 years) in the internet, mobile phones, and car ownership on levels of physical activity in countries of low, middle, and high income.

They estimated that the potential overall positive effect of the internet-based interventions on physical activity for middle-income countries to be double that of high-income (3.44 min vs 1.46 min per week), a finding attributable to middle-income countries accounting for a much greater proportion (71%) of the global population.

Because access to mobile phone technology is similar in countries of middle and high income, the potential effect weighted by income country population distribution of mobile phone interventions on physical activity are also estimated to be far greater in middle-income countries (7.91 min vs 2.27 min per week).

“With the high prevalence of both physical inactivity and the rapid growth of the mobile phone sector in low-income and middle-income countries, there is the potential for population-level effects that could truly affect global health”*, says Pratt.

But he warns, “Technology-based physical activity interventions and policies are unlikely to be optimised when 90% of the evidence and experience comes from high-income countries, while 84% of the world lives in the very different context of low-income and middle-income countries. If we are to truly take advantage of promising technologies and intervention strategies we must build the research and public health practice capacity required to effectively deploy and evaluate these strategies in low and middle income countries. This is a big challenge, but marked progress in countries such as Colombia and Brazil suggests that it is also an achievable challenge.”*


Series 5
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The pandemic of physical inactivity—a call for global action


**Embargo: 00:01H UK time Wednesday 18 July**


The high prevalence, global reach, and colossal harms of physical inactivity mean it should be recognised as pandemic, according to the fifth and final paper in The Lancet Series on physical inactivity.

“The role of physical inactivity continues to be undervalued despite robust evidence of its protective effects being available for more than 60 years and the evident cost burden posed by present levels of physical inactivity globally”*, says Harold W Kohl, III from The University of Texas Health School of Public Health , lead author of the paper.

Worse still, he adds, “The response to physical inactivity has been incomplete, unfocused, and most certainly understaffed and underfunded, particularly compared with other risk factors for non-communicable diseases.  The effect of this tardiness has been to put physical activity in reverse gear compared with population trends and advances in tobacco and alcohol control and diet.”

Currently, national programmes to move people from sedentary lifestyles to meeting recommended levels of exercise remain very limited both in developed and developing countries. Although nearly three quarters of WHO member states have a plan to tackle physical inactivity, only 55% of these plans are operational, and just 42% are both funded and operational.

Much work needs to be done to address physical inactivity as a true public health issue, say Kohl and colleagues. “Substantial improvements in the infrastructure of planning and policy, leadership and advocacy, workforce training and surveillance must be realised.”

“Traditional public health approaches, where responsibility for change has resided with the health sector, will not be sufficient”*, they add. Physical inactivity is an issue that crosses many sectors and will require collaboration, coordination, and communication with multiple partners (eg, city and community planners, transport engineers, school authorities, recreation and parks officials, and the media).

They argue for capacity building to be prioritised across multiple sectors of influence including health, transport, sport, education, and business, adding that “this is of particular importance in countries with low-to-middle incomes, where rapid economic and social changes are likely to reduce the domestic, work, and transport-related physical activity demands of daily life. Improved understanding of what works best in these nations will be key to developing national policies and action plans.”*

Finally, the authors say that a systems-based approach** to address the population-level causes of inactivity rather than efforts focused on individual health will be key to increasing physical activity worldwide.