Joe Feinglass, Jungwha Lee, Pamela Semanik, Jing Song, Dorothy Dunlop and Rowland Chang
This study analyzes Chicago-area weather effects on objectively measured physical activity over a 3-year period among a cohort of 241 participants in an on-going arthritis physical activity trial.
Uniaxial accelerometer counts and interview data were analyzed for up to 6 weekly study waves involving 4823 days of wear. The effects of temperature, rainfall, snowfall and daylight hours were analyzed after controlling for participant characteristics, day of the week, and daily accelerometer wear hours in a mixed effects linear regression model.
Daylight hours, mean daily temperature < 20 or ≥ 75 degrees, and light or heavy rainfall (but not snowfall) were all significantly associated with lower physical activity after controlling for the significant effects of weekends, accelerometer wear hours, age, sex, type of arthritis, employment, Hispanic ethnicity, obesity, and SF36 physical and mental health scores.
The cumulative effects of weather are reflected in a 38.3% mean monthly difference in daily counts between November and June, reflecting over 3 additional hours of sedentary time. Physical activity promotion programs for older persons with chronic conditions need lifestyle physical activity plans adapted to weather extremes.
Abigail L. Gilbert, Jungwha Lee, Madeleine Ma, Pamela A. Semanik, Loretta DiPietro, Dorothy D. Dunlop and Rowland W. Chang
Sedentary behavior is associated with increased risk of functional decline and disability. Individuals with rheumatoid arthritis (RA) spend more time sedentary than healthy adults. Self-reported assessment of sedentary behavior has not been well-developed in this patient population.
172 adults with RA wore an accelerometer for 7 days and completed a modified version of the Yale Physical Activity Survey (YPAS). YPAS-derived sedentary estimates included 1) daily sitting categories (<3, 3 to 6, 6 to 8, >8 hours/day), 2) continuous daily sedentary time calculated by subtracting hours spent sleeping or in physical activity from a 24-hour day, and 3) rank order of YPAS-derived continuous daily sedentary time. Each estimate was compared with objective accelerometer-derived sedentary time using linear regression and Bland-Altman analysis.
A significant relationship was observed between accelerometer-derived sedentary time and all 3 estimates. Bland-Altman plot demonstrated systematic bias, however Bland-Altman plot of rank-order demonstrated that the ranked YPAS-derived continuous estimate was an unbiased predictor of ranked accelerometer sedentary time though limits of agreement were wide.
This patient-reported approach using the YPAS shows promise to be a useful tool to identify the most sedentary patients. Providing a practical and accurate tool may increase the frequency sedentary behavior is assessed by clinicians.
Dorothy D. Dunlop, Jing Song, Emily K. Arntson, Pamela A. Semanik, Jungwha Lee, Rowland W. Chang and Jennifer M. Hootman
The harmful relationship of sedentary behavior to health may reflect an exchange of sedentary activity for moderateto- vigorous physical activity (MVPA), or sedentary behavior may be a separate risk factor. We examined whether time spent in sedentary behavior is related to disability in activities of daily living (ADL), independent of time spent in MVPA in older adults.
The nationally representative 2003−2006 National Health and Nutrition Examinations Surveys (NHANES) included 2286 adults aged 60 years and older in whom physical activity was assessed by accelerometer. The association between ADL task disability and the daily percentage of sedentary time was evaluated by multiple logistic regression.
These adults on average spent 9h/d being sedentary during waking hours and 4.5% reported ADL disability. The odds of ADL disability were 46% greater (odds ratio, 1.46; 95% confidence interval, 1.07−1.98) for each daily hour spent in sedentary behavior, adjusted for MVPA and socioeconomic and health factors.
These US national data show a strong relationship between greater time spent in sedentary behavior and the presence of ADL disability, independent of time spent in moderate or vigorous activity. These findings support programs encouraging older adults to decrease sedentary behavior regardless of their engagement in moderate or vigorous activity.
Christine A. Pellegrini, Jing Song, Rowland W. Chang, Pamela A. Semanik, Jungwha Lee, Linda Ehrlich-Jones, Daniel Pinto and Dorothy D. Dunlop
We examined if changes in moderate-to-vigorous physical activity (MVPA), light activity, and sedentary behavior are related to weight change over a 2-year period in obese adults with/elevated risk for knee osteoarthritis.
Weight, physical activity, and sedentary time at baseline and 2 years were obtained from 459 obese participants from the Osteoarthritis Initiative. Weight change was categorized as ≥ 10 lbs, 5.0 to 9.9 lbs, 4.9 to –4.9 lbs, –5.0 to –9.9 lbs, and ≤ –10 lbs. We examined the association between 2-year weight change categories and changes in activity/sedentary time from accelerometer monitoring by multiple linear regression adjusted for baseline weight, demographic, and health factors.
Across the 5 weight categories (loss to gain), average 2-year change ranged from -7.4 to 28.0 sedentary minutes/day, 4.2 to –23.1 light activity minutes/day, and 3.2 to –4.9 MVPA minutes/day, respectively. Higher weight loss categories were separately associated with increased MVPA (P for trend < 0.001) and less sedentary gain (P for trend = 0.01). Weight loss categories had a strong trend with light activity gain but not statistically significant (P for trend = 0.06).
Small increases in MVPA and decreases in sedentary time over 2 years were associated with weight loss among adults with obesity and with or at elevated risk for knee osteoarthritis.