Writing in The Lancet, researchers quantify for the first time the global impact of physical inactivity on the world’€™s major non-communicable diseases (NCDs) with detailed data by country.

The findings are published in a new series on physical activity, which examines how unlike other NCD risk factors – such as tobacco, diet, and alcohol – physical activity is a neglected dimension of prevention and intervention worldwide, especially in low-income and middle-income countries. The series also reviews current knowledge and latest thinking on how we tackle physical inactivity, and why it needs to be taken more seriously as a public health issue.

Physical inactivity kills as many as smoking

Physical inactivity kills as many people as tobacco smoking or obesity, according to new estimates published in The Lancet.

A lack of physical activity – or people’€™s failure to spend 150 minutes a week doing moderate physical activity (such as brisk walking for 30 minutes, five days a week) – causes between six and 10 percent of major non-communicable diseases worldwide, and was responsible for around 5,3 million in 2008.

Researchers estimated the global impact of physical inactivity on coronary heart disease (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 percent of CHD cases are linked to physical inactivity, ranging from 3,2 percent in southeast Asia to 7,8 percent in the eastern Mediterranean region. A lack of physical activity is responsible for about 7 percent of type 2 diabetes cases (ranging from 3.9 percent to 9.6 percent), and 10 percent of breast (5.6 percent’€“14.1 percent) and colon cancer cases (5.7 percent’€“13.8 percent).

‘€œRemoval of physical inactivity had the largest effect on colon cancer, and the smallest on coronary heart disease, in terms of percentage reduction,’€ said the team of researchers from Harvard Medical School, Boston (United States). ‘€œHowever, 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, 1 000 deaths could have been avoided in Africa by eliminating physical inactivity, 14 000 in the Americas, 2 000 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 percent or 25 percent, 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 Dr I-Min Lee, who led the study, ‘€œThis 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 ‘€“ for example 15 to 30 minutes a day of brisk walking ‘€“ which bring substantial health benefits.’€

Source: The Lancet

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