MedWire News: Physical inactivity accounted for an estimated 5.3 million of the 57 million deaths in 2008, a report shows.
This equated to 9% of premature mortality worldwide when the four major noncommunicable diseases - coronary heart disease (CHD), Type 2 diabetes mellitus, breast cancer, and colorectal cancer (CRC) - were taken into account.
Reporting in The Lancet, authors I-Min Lee (Harvard Medical School, Boston, Massachusetts, USA) and colleagues say: "These findings make inactivity similar to the established risk factors of smoking and obesity."
Further analysis showed that eliminating physical inactivity would increase the worldwide average life expectancy by 0.68 years, and likely by more in physically inactive groups.
Using estimates of relative risk from meta-analyses and worldwide measures of inactivity from World Health Organization (WHO) studies, the researchers showed that eradicating inactivity would have the largest effect on CRC and breast cancer deaths, which could be reduced by 10% compared with 6% of CHD and 7% of Type 2 diabetes deaths. However, because of the prevalence of CHD, this is where the largest number of deaths could be prevented in absolute terms.
The authors acknowledge that completely overcoming physical inactivity worldwide is likely to be an unrealistic goal. Nevertheless, they show that even reductions of inactivity by 10% or 25% would save 533,000 and 1.3 million lives per year, respectively.
The impact of eliminating physical inactivity was also greatest in countries with the highest incomes. For example, the authors estimate that 98,000 deaths from CHD could be prevented in high-income countries compared with 15,000 in low-income countries. Preventable deaths from CRC were estimated at 37,000 in high-income countries compared with just 1000 in low-income countries.
The WHO currently recommends that adults take 30 minutes of moderate physical activity, 5 days a week. In another study taken from the same series in The Lancet on physical activity, by Pedro Hallal et al (Universidade Federal de Pelotas, Brazil), it was found that roughly three in 10 adults do not reach these recommendations.
"The role of physical inactivity continues to be undervalued despite robust evidence of its protective effects being available for more than 60 years," says Harold Kohl (University of Texas, Austin, USA), in a press release.
Providing updated information on these effects, the authors say: "We must explore all avenues and support all efforts to reduce physical inactivity worldwide."
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