Sitting Less Trims Diabetes Risk

  • by
    Staff Writer, MedPage Today

Action Points

  • Note that there has been an increased focus on sedentary behavior as a risk factor for chronic disease independent of vigorous physical activity. This study was designed to evaluate these relationships in a population with known risk factors for type 2 diabetes mellitus.
  • The study found that the time spent sedentary, as opposed to the vigor of physical activity, was significantly and negatively correlated with a number of metabolic risk factors.






But previous research into sedentary behavior and health outcomes has relied on self-reports and has not considered factors such as age and specific disease risk factors.

Earlier studies also have not examined the effects of taking breaks from sedentary behavior, when individuals simply get up from sitting or lying down and move around.

Therefore, Henson's group analyzed data from two diabetes prevention trials, the Walking Away from Type 2 Diabetes Study, a lifestyle intervention among middle-age and older adults, and Project STAND, an educational and monitoring study of young at-risk adults.

Participants wore triaxial accelerometers that measured activity, translating acceleration data into activity counts per 15-second intervals.

Counts below 25 per 15 seconds were considered sedentary, between 25 and 488 were light-intensity activity, and more than 488 were moderate-to-vigorous activity.

The data analysis also included total physical activity and counts of breaks in sedentary times, which were 15-second periods when activity counts shifted from below to above 25.

The study incuded 153 participants from Project STAND, whose mean age was 33 and who were predominantly female, and 725 from Walking Away, whose mean age was 64 and who were mostly male.

The analysis identified inverse associations between total physical activity and numerous factors relating to cardiovascular and metabolic health, including 2-hour glucose (β = −0.164, P<0.001), triglycerides (β = −0.173, P<0.001), HDL cholesterol (β = 0.160, P<0.001), and total cholesterol to HDL ratio (β = −0.126, P<0.001).

Total physical activity also correlated with BMI (β = −0.281, P<0.001) and waist circumference (β = −0.270, P<0.001), but after adjustment for sedentary time, the only significant association remaining for total activity was with HDL cholesterol.

Breaks in sedentary time had an inverse correlation with 2-hour glucose (β = −0.111, P=0.046), BMI (β = −0.151, P=0.003), and waist circumference (β = −0.215, P<0.001), but the association of breaks with 2-hour glucose was lost after additional adjustment for BMI.

Further analysis also found stronger associations in the older cohort for moderate-to-vigorous activity, total physical activity, and breaks in sedentary time with BMI and and waist circumference.

The findings of this study are in accord with some other investigations of the effects of sedentary behavior and "provide preliminary evidence that sedentary behavior may be a more effective paradigm to target in the prevention of type 2 diabetes mellitus, rather than solely focusing on [moderate-to-vigorous physical activity]," observed Henson and colleagues.

Encouraging patients at risk for diabetes would be "an innovative approach that requires a paradigm shift, so that individuals think about the balance of sedentary behavior and activity in all aspects of daily life," they wrote.

The study was limited by being cross-sectional, so reverse causality cannot be ruled out. In addition, accelerometers may underestimate certain types of movement.

This work was funded by the Medical Research Council and the Collaboration for Leadership in Applied Health Research and Care.

The authors reported no conflicts of interest.