In recent years, sitting has been described as the new smoking – but does the evidence add up?
No, it doesn’t, says an international team of researchers who examined “misleading” media claims comparing the health dangers of sitting for long periods with smoking cigarettes.
Researchers from Canada, the US and Australia say that while research does suggest excessive sitting (roughly more than eight hours a day) increases the risk of premature death and some chronic diseases by 10-20%, this pales in comparison to the risks associated with smoking.
“Conflicting or distorted information about health risks related to behavioural choices and environmental exposures can lead to confusion and public doubt with respect to health recommendations,” say the authors, writing in the American Journal of Public Health.
A recent analysis of news articles found more than 300 articles which claimed sitting was the new smoking, they write.
Some even suggested smoking was safer than sitting.
Smoking increases the risk of premature death from any cause by approximately 180%, the researchers say.
“Risk estimates and absolute risk differences for smoking far outweigh those for sitting, except for type 2 diabetes,” they write.
“For example, the RR [relative risk] for all-cause mortality among smokers who smoked more than 40 cigarettes per day was 4.08 (95% CI = 3.68, 4.52) for men, and 4.41 (95% CI = 3.70, 5.25) for women.
“These RR estimates correspond to absolute risk differences of more than 2000 excess deaths from any cause per 100 000 persons per year among the heaviest smokers compared with never smokers.
“The corresponding absolute risk difference for the highest volume of sitting versus the lowest volumes is 190 excess deaths per 100,000 persons per year.
“Even when all smokers are collapsed into one group (i.e., current smokers), risk estimates far exceed those for sitting. For example, the RR of death from all causes among current smokers compared with those who have never smoked was 2.80 (95% CI = 2.72, 2.88) for men (absolute risk difference of 1554 excess deaths per 100 000 persons per year) and 2.76 for women (95% CI = 2.69, 2.84; absolute risk difference of 1099 excess deaths per 100 000 persons per year), compared with 1.22 (95% CI = 1.09, 1.41) for sitting.
“Thus, any level of smoking increases risk of dying from any cause by approximately 180% versus a 25% risk increase for sitting. Even light smoking (1–4 cigarettes per day) has been associated with a higher risk of mortality compared with sitting.
“Smoking also increases the risk of other health outcomes including depression (odds ratio = 1.62; 95% CI = 0.10, 2.40) and poor quality of life (standardised mean difference = 0.22; 95% CI = 0.09, 0.36).
“Both the magnitude of these associations and the strength of the evidence are greater than those observed for sitting time to date.”
University of South Australia epidemiologist Dr Terry Boyle, one of nine researchers involved in the evaluation, says media stories comparing sitting with smoking increased twelve-fold from 2012 to 2016, and some respected academic and clinical institutions have also spread the myth.
“The simple fact is, smoking is one of the greatest public health disasters of the past century. Sitting is not, and you can’t really compare the two,” Dr Boyle says.
“First, the risks of chronic disease and premature death associated with smoking are substantially higher than for sitting. While people who sit a lot have around a 10-20% increased risk of some cancers and cardiovascular disease, smokers have more than double the risk of dying from cancer and cardiovascular disease, and a more than 1000% increased risk of lung cancer.
“Second, the economic impact and number of deaths caused by smoking-attributable diseases far outweighs those of sitting. For example, the annual global cost of smoking-attributable diseases was estimated at US$467 billion in 2012 and smoking is expected to cause at least one billion deaths in the 21st century.
“Finally, unlike smoking, sitting is neither an addiction nor a danger to others.
“Equating the risk of sitting with smoking is clearly unwarranted and misleading, and only serves to trivialise the risks associated with smoking,” Dr Boyle says.