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Sofiya Alhassan and Thomas N. Robinson

Background:

Receiver operating characteristic (ROC) analysis is a common method used in diagnostic and screening tests to define thresholds levels of a factor that discriminates between 2 levels of another factor. The purpose of this analysis was to use ROC analysis to determine the optimal accelerometer-measured physical activity (PA) thresholds for predicting selective cardiovascular disease (CVD) risk factors.

Methods:

ROC was performed using data from Stanford Girls Health Enrichment Multisite Studies trial. PA was assessed for multiple days using accelerometers. CVD variables were overweight, elevated triglyceride, reduced HDL-C, hypertension, impaired fasting glucose, fasting insulin, and clustering of multiple CVD risk factors.

Results:

A sample of 261 girls participated, of which 208 had complete CVD risk measures (mean ± SD age = 9.4 ± 0.9yrs, BMI = 20.7 ± 4.8kg/m2). An average of ≥11.1 minutes/day at ≥2,600 counts/min was the maximally sensitive and specific threshold for discriminating girls who were overweight, ≥16.6 minutes/day at ≥2,000 counts/min for hyperinsulinemia or with ≥2 CVD risk factors. The Area Under the Curve for overweight, hyperinsulinemia, and ≥2 CVD risk factors was of 0.66, 0.58, and 0.60, respectively. The sensitivity and specificity associated with overweight, hyperinsulinemia, and ≥2 CVD risk factors were 60.3% and 72.9%, 53.3% and 83.9%, 44.0% and 84.7%, respectively.

Conclusion:

Empirically-derived thresholds of PA to optimally discriminate between girls with and without CVD risk were lower in this sample than generally recommended. This ROC approach should be repeated in other populations to determine optimal PA thresholds with clinical validity for research, surveillance and program evaluation.

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Cory J. Greever, John Sirard and Sofiya Alhassan

Background:

The purpose of this study was to examine the temporal patterns of preschoolers’ physical activity (PA) levels during a typical outdoor free playtime.

Methods:

Baseline playtime accelerometer counts (4.3 ± 0.8 days) from 3 preschool PA intervention studies were used (n = 326 children, age = 4.0 ± 0.8 years). Data were collected using 15-second epochs and classified into sedentary, light, or moderate-tovigorous physical activity (MVPA). Patterns of change during playtime were analyzed using orthogonal polynomial comparisons.

Results:

For all ages, there was a U-shaped pattern of change for the percent of epochs classified as sedentary [F(1, 323) = 47.12, P < .001) and an inverted U-shaped pattern of change for the percent of epochs classified as MVPA [F(1,323) = 32.15, P < .001]. Age-stratified analyses indicated that the 3-year-olds maintained the decrease in sedentary time [F(2,323) = 6.408, P = .002] and the increase in MVPA [F(2,323) = 3.2, P = .04] to a greater extent than the 4- and 5-year-olds.

Conclusions:

Preschool children gradually became more active during the first 10 to 15 minutes of outdoor gross motor playtime and less active over the final 10 to 15 minutes of playtime. During the second half of playtime 3-year-olds maintained these changes to a greater degree than 4- and 5-year-olds.

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Sarah Burkart, Jasmin Roberts, Matthew C. Davidson and Sofiya Alhassan

Background: Poor adaptive learning behaviors (ie, distractibility, inattention, and disruption) are associated with behavior problems and underachievement in school, as well as indicating potential attention-deficit hyperactivity disorder. Strategies are needed to limit these behaviors. Physical activity (PA) has been suggested to improve behavior in school-aged children, but little is known about this relationship in preschoolers. This study examined the effects of a PA intervention on classroom behaviors in preschool-aged children. Methods:Eight preschool classrooms (n = 71 children; age = 3.8 ± 0.7 y) with children from low socioeconomic environments were randomized to a locomotor-based PA (LB-PA) or unstructured free playtime (UF-PA) group. Both interventions were implemented by classroom teachers and delivered for 30 minutes per day, 5 days per week for 6 months. Classroom behavior was measured in both groups at 3 time points, whereas PA was assessed at 2 time points over a 6-month period and analyzed with hierarchical linear modeling. Results:Linear growth models showed significant decreases in hyperactivity (LB-PA: −2.58 points, P = .001; UF-PA: 2.33 points, P = .03), aggression (LB-PA: −2.87 points, P = .01; UF-PA: 0.97 points, P = .38) and inattention (LB-PA: 1.59 points, P < .001; UF-PA: 3.91 points, P < .001). Conclusions: This research provides promising evidence for the efficacy of LB-PA as a strategy to improve classroom behavior in preschoolers.

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Sofiya Alhassan, Christine W. St. Laurent and Sarah Burkart

The purpose of this review was to assess the effectiveness of physical activity (PA) interventions in African American and Latino/Hispanic preschool children. A systematic search was conducted for English-language printed research articles published between January 1980 and December 2017. The inclusion criteria for studies in this review were that they were experimental PA studies conducted in the preschool setting in the United States that targeted African American/Black or Latino/Hispanic children between the ages of 2.9 and 5 years. A total of 1,533 articles were located, of which 10 met the inclusion criteria. Overall, studies reported positive changes in preschool-day PA levels, yet only 2 reported significant improvements in total daily PA. Limited scientific literature suggests that preschool-based interventions are effective in improving aspects of PA during the preschool day for children of color. However, minimal evidence exists on the effectiveness of these interventions in changing total daily PA.

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Eric P. Plaisance, J. Kyle Taylor, Sofiya Alhassan, Asheber Abebe, Michael L. Mestek and Peter W. Grandjean

Inflammatory markers such as C-reactive protein (CRP), fibrinogen, and white-blood-cell (WBC) count are strongly associated with cardiovascular disease. The authors’ purpose was to compare the inflammatory response to a single aerobic-exercise session between individuals of high and moderate fitness. Ten apparently healthy highly ft and 11 moderately ft men expended 500 kcal at 70% of VO2peak. Fasting blood samples were obtained on 2 consecutive days before and again at 24, 72, and 120 h post exercise. Blood samples were analyzed for CRP, fibrinogen, and WBC count. CRP was 76% lower at baseline in the highly ft group than in the moderately ft group (P = 0.03). CRP, fibrinogen, and WBC count remained unaltered, however, in the days after exercise (P > 0.05 for all). These findings suggest that markers of inflammation are stable in the days after a single session of moderate-intensity aerobic exercise in apparently healthy men of at least average fitness.

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Kate Lyden, Sarah Kozey Keadle, John Staudenmayer, Patty Freedson and Sofiya Alhassan

Background:

The Compendium of Energy Expenditures for Youth assigns MET values to a wide range of activities. However, only 35% of activity MET values were derived from energy cost data measured in youth; the remaining activities were estimated from adult values.

Purpose:

To determine the energy cost of common activities performed by children and adolescents and compare these data to similar activities reported in the compendium.

Methods:

Thirty-two children (8−11 years old) and 28 adolescents (12−16 years) completed 4 locomotion activities on a treadmill (TRD) and 5 age-specific activities of daily living (ADL). Oxygen consumption was measured using a portable metabolic analyzer.

Results:

In children, measured METs were significantly lower than compendium METs for 3 activities [basketball, bike riding, and Wii tennis (1.1−3.5 METs lower)]. In adolescents, measured METs were significantly lower than compendium METs for 4 ADLs [basketball, bike riding, board games, and Wii tennis (0.3−2.5 METs lower)] and 3 TRDs [2.24 m·s-1, 1.56 m·s-1, and 1.34 m·s-1 (0.4−0.8 METs lower)].

Conclusion:

The Compendium of Energy Expenditures for Youth is an invaluable resource to applied researchers. Inclusion of empirically derived data would improve the validity of the Compendium of Energy Expenditures for Youth.

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Sofiya Alhassan, Christine W. St. Laurent, Sarah Burkart, Cory J. Greever and Matthew N. Ahmadi

Background: For a health behavior intervention to be sustainable within preschool centers, the intervention should be implemented by classroom teachers. Unfortunately, teachers are constrained by demands such as meeting early childhood education standards. Therefore, the purpose of this pilot study was to examine the feasibility and preliminary efficacy of integrating a health behavior intervention into early education learning standards on physical activity (PA), diet, and sleep (PADS) behavior of preschoolers. Methods: Two preschool centers were randomized to either the PADS (children, n = 60) or the control (CON; children, n = 54) group. The PADS intervention consisted of PADS lesson plans and activities embedded into Massachusetts early learning standards and were implemented for 4 days per week for 12 weeks. The CON preschool participated in their usual curriculum. PA was assessed using accelerometers for 7 consecutive days at baseline, 6 weeks, and 12 weeks. Other outcome variables were assessed with parental surveys at baseline and 12 weeks. Results: Significant group by time interactions were observed for moderate to vigorous PA (percentage of time) during the preschool day (PADS: baseline = 10.6% (4.2%), 12 wk = 13.2% (2.3%); CON: baseline = 12.4% (3.9%), 12 wk = 11.2% (3.6%); P = .02). Conclusion: This pilot study provides preliminary evidence that integrating health behaviors into learning standards is feasible and potentially an effective way for increasing preschoolers’ PA levels.

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Sofiya Alhassan, Ogechi Nwaokelemeh, Manneh Ghazarian, Jasmin Roberts, Albert Mendoza and Sanyog Shitole

This pilot study examined the effects of a teacher-taught, locomotor skill (LMS)- based physical activity (PA) program on the LMS and PA levels of minority preschooler-aged children. Eight low-socioeconomic status preschool classrooms were randomized into LMS-PA (LMS-oriented lesson plans) or control group (supervised free playtime). Interventions were delivered for 30 min/day, five days/week for six months. Changes in PA (accelerometer) and LMS variables were assessed with MANCOVA. LMS-PA group exhibited a significant reduction in during-preschool (F (1,16) = 6.34, p = .02, d = 0.02) and total daily (F (1,16) = 9.78, p = .01, d = 0.30) percent time spent in sedentary activity. LMS-PA group also exhibited significant improvement in leaping skills, F (1, 51) = 7.18, p = .01, d = 0.80). No other, significant changes were observed. The implementation of a teacher-taught, LMS-based PA program could potentially improve LMS and reduce sedentary time of minority preschoolers.

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Sofiya Alhassan, Kate Lyden, Cheryl Howe, Sarah Kozey Keadle, Ogechi Nwaokelemeh and Patty S. Freedson

This study examined the validity of commonly used regression equations for the Actigraph and Actical accelerometers in predicting energy expenditure (EE) in children and adolescents. Sixty healthy (8–16 yrs) participants completed four treadmill (TM) and five self-paced activities of daily living (ADL). Four Actigraph (AG) and three Actical (AC) regression equations were used to estimate EE. Bias (±95% CI) and root mean squared errors were used to assess the validity of the regression equations compared with indirect calorimetry. For children, the Freedson (AG) model accurately predicted EE for all activities combined and the Treuth (AG) model accurately predicted EE for TM activities. For adolescents, the Freedson model accurately predicted EE for TM activities and the Treuth model accurately predicted EE for all activities and for TM activities. No other equation accurately estimated EE. The percent agreement for the AG and AC equations were better for light and vigorous compared with moderate intensity activities. The Trost (AG) equation most accurately classified all activity intensity categories. Overall, equations yield inconsistent point estimates of EE.

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Sofiya Alhassan, John R. Sirard, Tirzah R. Spencer, Ann Varady and Thomas N. Robinson

Background:

The purpose of this study was to develop a data-driven approach for analyzing incomplete accelerometer data from field-base studies.

Methods:

Multiple days of accelerometer data from the Stanford Girls health Enrichment Multi-site Studies (N = 294 African American girls) were summed across each minute of each day to produce a composite weekday and weekend day. Composite method estimates of physical activity were compared with those derived from methods typically described in the literature (comparison methods).

Results:

The composite method retained 99.7% and 100% of participants in weekday and weekend-day analysis, respectively, versus 84.7% to 94.2% and 28.6% to 99.0% for the comparison methods. Average wearing times for the composite method for weekday and weekend day were 99.6% and 98.6%, respectively, 91.7% to 93.9% and 82.3% to 95.4% for the comparison methods. Composite-method physical activity estimates were similar to comparison-methods estimates.

Conclusion:

The composite method used more available accelerometer data than standard approaches, reducing the need to exclude periods within a day, entire days, and participants from analysis.