We already know that sedentary lifestyle is associated with a greater risk of type 2 diabetes. This systematic review looked for an association with metabolic syndrome, a precursor condition of diabetes.
Is a sedentary lifestyle associated with a high risk of developing metabolic syndrome?
Metabolic syndrome is the presence of three of the following five risk factors:
- A large waistline.
- A high triglyceride level.
- A low HDL cholesterol level.
- High blood pressure.
- High fasting blood sugar.
The reviewers found ten cross-sectional studies with a total of21,393 participants. When they combined the data, the reviewers found that:
Greater time spent sedentary increased the odds of metabolic syndrome by 73% (OR 1.73, 95% CI 1.55–1.94, p<0.0001). There were no differences for subgroups of sex, sedentary behaviour measure, metabolic syndrome definition, study quality or country income.
This finding was consistent from one study to another.
- It seems likely that the search strategy would be challenging: how did they identify “sedentary behaviour” for example? Did they use appropriate synonyms?
- The studies were of variable quality.
- There was a huge variation in the baseline incidence of metabolic syndrome in the studies: from 8% to over 50%. On the one hand, this suggests that these studies must have looked at very different populations and therefore it may not be valid to combine their results. On the other hand, the consistency of the pattern of association across all of these studies implies that the link is robust.
- Note that all of the studies were cross-sectional. No prospective studies were found. Therefore we can’t be sure of the direction of causation, or whether there may be some other common factor.
- However, this evidence should add to the already substantial body of evidence in favour of encouraging people to move around a bit more.
The full text of this paper is available from PLoS One.
Edwardson CL, Gorely T, Davies MJ, Gray LJ, Khunti K, Wilmot EG, Yates T, Biddle SJ. Association of sedentary behaviour with metabolic syndrome: a meta-analysis. PLoS One. 2012;7(4):e34916. Epub 2012 Apr 13.