Objectives: In older adults, sedentary behavior has been positively associated with obesity and impaired metabolic health, additional to low moderate-to-vigorous physical activity (MVPA). Further to the total time spent in sedentary behavior, the manner in which it is accumulated - number of continuous sedentary bouts of different extends - may also be relevant. The association for objectively measured uninterrupted sedentary bouts and respective patterns with abdominal obesity in older adults was examined.
Design: Cross-sectional.
Setting: Community-based older people were recruited in each region of Portugal. Data collection was performed between September, 2007 and May, 2009.
Participants: 351 older adults (230 women) mean age of 75-years.
Measurements: Sedentary time was measured by an accelerometer (counts/minute <100), worn during waking hours for four consecutive days. Continuous sedentary bouts of 5<min<10, 10< min<20, 20< min<30, 30< min<60, >60 length were treated (counts/minute <100). Abdominal obesity was defined by waist circumference (men>102 cm; women>88 cm).
Results: There were positive and escalating linear associations for the continuum of sedentary bouts' lengths with waist circumference. Logistic regression showed that for each additional sedentary bout of 10< min<20 the odds of being abdominally obese increased by 6.8% (OR=1.07, 95% CI: 1.02 - 1.13) up to 48% (OR=1.48, 95% CI: 1.07 - 2.03) for each 1-hour sedentary bout increment, after controlling for age, gender, total sedentary time, MVPA time, total wear time, movement counts within the sedentary bouts, socio-demographic and other behavioral attributes, and medical history.
Conclusion: These findings indicate positive graded associations for continuous sedentary bouts with abdominal obesity. Public health recommendations regarding breaking up sedentary time more often, potentially avoiding very prolonged bouts of sedentary time, are expected to be relevant for older adults.