Presentation Abstract

Session: 08-A-Technology to Promote/Measure Health Behavior
Thursday, Mar 24, 2011, 3:30 PM - 5:00 PM
Presentation: 028 - Methods of Self-Monitoring and their Effect on Adherence to Physical Activity Self-Monitoring and Goals: 24-Month Results from the SMART Trial
Location: A601
Pres. Time: Thursday, Mar 24, 2011, 4:30 PM - 4:45 PM
Category: +NPAM - Physical Activity/Fitness
Keywords: Physical activity; Behavior modification; Clinical trials
Author(s): Molly B Conroy, Lei Ye, Mindi Styn, Jing Wang, Edvin Music, Susan M Sereika, Lora E Burke, Univ of Pittsburgh, Pittsburgh, PA
Abstract: BACKGROUND: Weight loss has been associated with higher physical activity (PA) levels and frequent dietary self-monitoring. Less is known about how self-monitoring (SM) affects adherence to PA goals, PA levels and weight, particularly over an extended period of follow-up. The purpose of this analysis is to examine associations among SM methods, PA self-monitoring, adherence to PA goals, PA levels, and weight loss over 24 months of follow-up.
METHODS: The SMART Trial is a clinical weight loss trial in which 210 overweight adults were randomized equally to one of three SM methods: 1) paper diary (PD); 2) personal digital assistant with a dietary and PA software (PDA); and 3) PDA with daily tailored feedback message (PDA+FB). Participants were asked to record daily minutes of PA in their diary. SM data were based on the submission of diaries. Adherence to PA goals was defined as recorded minutes divided by weekly PA goals (50 minutes until week 6 and 150 minutes thereafter). PA levels were measured via self-report by the Modifiable Activity Questionnaire. PA levels and weight were measured at baseline, 6, 12, 18, and 24 months. Analysis was done using logistic mixed model, Poisson mixed model, linear mixed model, and the likelihood ratio test was used.
RESULTS: Participants were 85% (178 0f 210) female and 78% (164 of 210)White with mean (SD) age of 46.8 (9.0) years and mean baseline BMI of 34.0 (4.5) kg/m2. Median PA level (MET-hr/wk) was 7.4 (IQR: 2.1, 16.3) at baseline, 13.4 (5.4, 24.8) at 6 months, 11.5 (5.2, 22.0) at 12 months, and 7.5 (2.6, 15.8) at 24 months with no differences by SM method at any time point. After 6 months, SM declined in all 3 groups; however, participants in PDA and PDA +FB groups recorded on more days than those in PD group (p=.002). PDA and PDA+FB participants also had higher odds of meeting PA goals over time (OR=3.2 and OR=4.5, respectively; p=.003) than PD participants. Higher levels of SM were associated with both greater increases in PA level and greater weight loss over 24 months. An increase of one day in SM per week was associated with 1.1 MET-hr/wk increase in PA (p=.01) and a 0.97% decrease in weight (p<.0001) compared to baseline. Higher adherence to PA goals was also associated with both greater increases in PA level and greater weight loss over 24 months. An increase of 1% in goal achievement was associated with 0.067 MET-hr/wk increase in PA (p=.01) and a 0.06% decrease in weight (p<.0001) compared to baseline.
CONCLUSIONS: Better patterns of PA self-monitoring and higher odds of adherence to PA goals were more likely to occur over time in participants in the PDA and PDA+FB groups and were associated with greater increases in PA levels and decreases in weight. However, declines in SM and adherence to PA goals were common in all SM groups. Future studies should address ways to keep participants engaged with PA self-monitoring over time.
Disclosures:  M.B. Conroy: None. L. Ye: None. M. Styn: None. J. Wang: None. E. Music: None. S.M. Sereika: None. L.E. Burke: None.