Bonny Rockette-Wagner

Measuring Physical Activity and Sedentary Behavior in Youth with Type 2 Diabetes

BACKGROUND Lifestyle interventions that encourage increasing physical activity (PA) and losing weight are critical for overweight and obese youth with comorbid conditions. Assessing PA within such lifestyle intervention efforts requires measurement tool(s) that are both accurate and appropriate for these youth. This research compares PA levels and sedentary behavior in an ethnically diverse cohort of overweight/obese youth with type 2 diabetes using both accelerometry and a questionnaire previously validated in the general youth population. METHODS Spearmans correlations were used to compare time spent sedentary and in different PA intensities between a questionnaire, the three-day PA recall (3DPAR), and an objective PA measure, the ActiGraph accelerometer, in 236 overweight/obese youth with diabetes. RESULTS Spearman correlations between 3DPAR and accelerometer results for total PA were small and not significant (rho = 0.11, p > 0.05 for males and females). Correlations for specific PA intensities (moderate/vigorous and light) were also small and not significant. Sedentary time between instruments was significant, but weakly correlated in females (rho = 0.19, p < 0.05), but not in males (rho = 0.07, p = 0.48). CONCLUSIONS Subjective PA measures validated in the general youth population may not be the best method for differentiating levels of movement in overweight/obese youth with type 2 diabetes, who spend most of their time in light-intensity activity and sedentary pursuits with little or no time spent in moderate/vigorous-intensity activities. Objective measures such as accelerometers that can capture the lower end of the movement scale are likely the more appropriate measures under these conditions.

Activity Levels for Four Years in a Cohort of Urban-Dwelling Adolescent Females

Purpose Evidence suggests that female adolescents and those living in urban environments may have lower physical activity (PA) levels compared with their peers. Yet few studies report PA for urban adolescent females, and there is no consensus regarding potential causes for low PA in this subgroup. We examined PA levels, in a large, diverse cohort of 14- to 17-yr-old urban-dwelling females and assessed the effect of socioeconomic, personal, and neighborhood/environmental factors on PA. Methods One week of time-stamped step count data were collected on 926 girls from the Pittsburgh Girls Study at four annual visits. Valid recordings (worn at least 10 h on 3+ d) were examined and compared with normalized step count values from a U.S. population-representative sample. Relationships between important covariates and average steps per day were examined with regression models. Results Adjusted mean ± SD step counts per day at baseline were 5614 ± 2434 after controlling for important covariates with less than 6% of girls achieving at least 10,000 steps per day. The girls from the Pittsburgh Girls Study accrued ~45% of their steps during school hours. Age-specific median step counts per day for study participants were similar to the 25th percentile of U.S. population normalized values and did not significantly change during follow-up. Non-Hispanic African American race/ethnicity was associated with higher average step counts per day; obesity and a recent childbirth were associated with lower average step counts per day. Conclusions Step counts in this cohort of urban adolescent girls were considerably lower than expected for U.S. adolescent females. Targeted efforts to improve PA levels in urban youth should consider the importance of school-based activity while increasing PA opportunities outside of school.

Racial/Ethnic Differences in the Associations between Physical Activity and Sleep Duration: A Population-Based Study.

BACKGROUND This study examined associations between physical activity (recreational, nonrecreational) and sleep duration among a nationally representative diverse sample of U.S. adults. METHODS We used cross-sectional data from 9,205 National Health and Nutrition Examination Survey 2007 to 2012 participants aged 20 to 65 years who identified as White, Black, or Hispanic. Activity (ie, recreation, occupation, and transportation activity) was categorized into quartiles. Sleep duration was categorized as short (≤6 hours/night) or normal (>6 to ≤9 hours/night). Logistic regression was used to estimate associations of activity with sleep duration. RESULTS Recommended levels of recreation activity and moderate levels of transportation activity were associated with normal sleep duration [Odds Ratio (OR): = 1.33, 95% Confidence Interval (CI) = 1.08, 1.65; OR = 1.28, 95% CI = 1.02, 1.62, respectively]. High occupation physical activity was associated with shorter sleep duration (OR = 0.59, 95% CI = 0.49, 0.71). Differences were observed by race/ethnicity in associations of recreation and occupation activity with sleep duration. CONCLUSIONS White individuals who engaged in some recreation activity, relative to being inactive, had more favorable sleep duration; whereas, high levels of occupation activity were associated with worse sleep duration among White and Black individuals. Physical activity was not associated with sleep duration among Hispanics.

Activity and Sedentary Time 10 Years After a Successful Lifestyle Intervention: The Diabetes Prevention Program

INTRODUCTION This study aims to determine if evidence exists for a lasting effect of the Diabetes Prevention Program (DPP) lifestyle intervention on activity levels by comparing objectively collected activity data between the DPP Outcome Study (DPPOS) cohort and adults from the National Health and Nutrition Examination Survey (NHANES; 2003-2006). METHODS Average minutes/day of light and moderate to vigorous physical activity (MVPA) and sedentary behavior from ActiGraph accelerometers (collected 2010-2012) were examined (2013-2014) for comparable DPPOS and NHANES subgroups by age, sex, and diabetes status. Longitudinal questionnaire data on leisure activity, collected yearly from DPP baseline to the time of accelerometer measurement (1996-2010; 11.9-year mean follow-up), were also examined to provide support for a long-term intervention effect. RESULTS Average minutes/day of accelerometer-derived MVPA was higher in all DPPOS subgroups versus NHANES subgroups of similar age/sex/diabetes status; with values as much as twice as high in some DPPOS subgroups. Longitudinal questionnaire data from DPP/DPPOS showed a maintained increase of 1.24 MET hours/week (p=0.026) of leisure activity in DPPOS participants from all original study arms between DPP baseline and accelerometer recording. There were no consistent differences between comparable DPPOS and NHANES subgroups for accelerometer-derived sedentary or light-intensity activity minutes/day. CONCLUSIONS More than 10 years after the start of DPP, DPPOS participants performed more accelerometer-measured MVPA than similar adults from NHANES. Longitudinal questionnaire data support the accelerometer-based findings by suggesting that leisure activity levels at the time of accelerometer recording remained higher than DPP baseline levels.

Bidirectional Relationships Between Weight Change and Sleep Apnea in a Behavioral Weight Loss Intervention

Objective: To examine the bidirectional relationship between weight change and obstructive sleep apnea (OSA) in the context of a behavioral weight loss intervention. Patients and Methods: Adults who were overweight or obese (N=114) participated in a 12‐month behavioral weight loss intervention from April 17, 2012, through February 9, 2015. The apnea‐hypopnea index (AHI), a marker of the presence and severity of OSA, was assessed at baseline, 6 months, and 12 months. Linear mixed models evaluated the effect of weight change on the AHI and the effect of OSA (AHI ≥5) on subsequent weight loss. Secondary analyses evaluated the effect of OSA on intervention attendance, meeting daily calorie goals, and accelerometer‐measured physical activity. Results: At baseline, 51.8% of the sample (n=59) had OSA. Adults who achieved at least 5% weight loss had an AHI reduction that was 2.1±0.9 (adjusted mean ± SE) events/h greater than those with less than 5% weight loss (P<.05). Adults with OSA lost a mean ± SE of 2.2%±0.9% less weight during the subsequent 6‐month interval compared with those without OSA (P=.02). Those with OSA were less adherent to daily calorie goals (mean ± SE: 25.2%±3.3% vs 34.8%±3.4% of days; P=.006) and had a smaller increase in daily activity (mean ± SE: 378.3±353.7 vs 1060.1±377.8 steps/d; P<.05) over 12 months than those without OSA. Conclusion: Behaviorally induced weight loss in overweight/obese adults was associated with significant AHI reduction. However, the presence of OSA was associated with blunted weight loss, potentially via reduced adherence to behaviors supporting weight loss. These results suggest that OSA screening before attempting weight loss may be helpful to identify who may benefit from additional behavioral counseling.

Design of a randomized controlled trial to decrease depression and improve insulin sensitivity in adolescents: Mood and INsulin sensitivity to prevent Diabetes (MIND)

BACKGROUND Depressive symptoms often manifest in adolescence and predict worsening insulin sensitivity, a key precursor in the path to β-cell failure and type 2 diabetes (T2D). OBJECTIVE To assess the efficacy of a six-week cognitive-behavioral group versus six-week health education group for improving insulin sensitivity and preserving β-cell function in adolescent girls at-risk for T2D with depressive symptoms and evaluate mechanisms underlying the association between depression and insulin dynamics. DESIGN Randomized controlled trial of N = 150 12-17-year-old girls with overweight/obesity (body mass index [BMI; kg/m2] ≥85th percentile), elevated depressive symptoms (Center for Epidemiologic Studies-Depression Scale [CES-D] total score > 20), and diabetes family history. METHODS Girls at-risk for T2D with elevated depressive symptoms are recruited from the Denver-metropolitan area and randomized to participate in one of two six-week interventions. The cognitive-behavioral group is a depression prevention program involving psycho-education, restructuring negative thoughts, and behavioral activation. The health education group is a didactic control that provides knowledge about healthy living. Participants are assessed at baseline, immediate post-intervention, and one-year follow-up. Primary outcomes are insulin sensitivity and β-cell function from oral glucose tolerance tests. Secondary outcomes are disinhibited eating, physical activity, sleep, and cortisol. SUMMARY Results from this adequately powered randomized controlled trial will determine whether decreasing depressive symptoms with a behavioral health program preventatively alters insulin sensitivity and β-cell function trajectories in adolescents at-risk for T2D. Results from the MIND Project will add to knowledge of the contribution of depressive symptoms to T2D risk.

Sedentary behavior patterns in non-pregnant and pregnant women

Sedentary behavior has been associated with adverse health outcomes among pregnant women; however, few studies have characterized sedentary behavior patterns in this population. We described patterns of accelerometer-determined indicators of sedentary behavior among a national sample of US pregnant (n = 234) women and non-pregnant (n = 1146) women participating in the NHANES 2003-06 cycles. We included women with ≥ 4 days of accelerometer wear of ≥ 10 h/day. A count threshold of < 100 cpm was used to describe sedentary behavior as: 1) total accumulated sedentary time by bout length categories; 2) accumulated sedentary time within discrete bout length categories; 3) mean, median, and usual bout length; and 4) and bout frequency. Both non-pregnant and pregnant women spent up to 60% of their accelerometer wear time in sedentary behavior depending on the minimum bout threshold applied. Sedentary time was higher among pregnant women compared to non-pregnant women when lower bout thresholds (i.e. 10 min or less) were applied. The majority of total sedentary time was accumulated in bouts lasting < 10 min. The women averaged less than two prolonged sedentary bouts (i.e., ≥ 30 min) per day, which accounted for nearly 20% of total accumulated sedentary time. When applying a minimum threshold of at least 15 min, sedentary time increased across pregnancy trimesters, while sedentary time was similar across trimesters when using lower thresholds. These findings provide the first characterization of accelerometer-determined indicators of sedentary behavior in pregnant women. The minimum bout threshold applied influenced estimates of sedentary time and patterns sedentary time accumulation across pregnancy trimesters.