Dr. David A. Alter of the University of Toronto and colleagues performed a meta-analyses a virtual method that mathematically combines results from previous studies to determine the association between prolonged sedentary time and several health outcomes, including all-cause mortality, cardiovascular disease (CVD), diabetes, and cancer. In their analyses the investigators controlled for levels of physical activity that is, they examined the effect of being sedentary per se, across differing levels of exercise or other physical activity.
The researchers used data from 47 previous investigations, used self-reported data, on how much time individuals spent in sedentary pursuits. They found significant associations between sedentary time and all-cause mortality, incidence of cancer and type 2 diabetes. In addition, they noted that the associations tended to be stronger at lower levels of physical activity.
ACSH s Dr. Ruth Kava had this to say: These data are confirmatory of earlier work in this area, and certainly suggest that extended periods of sedentary time can be deleterious. We must note she continued, that the studies included in this meta-analysis were not all run in a similar manner. This is an inherent weakness of meta-analyses, which somewhat weakens their conclusions. However, the fact that other independent investigators have reached similar conclusions supports those of this investigation.