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Exploring Physical Activity Outcomes from a Pediatric Obesity Intervention:
Does Season of the Year Matter?
1,2
MA ,
1,2,
1,2
MA ,
Kelsey Borner
Katrina M Poppert
Cathleen Odar Stough
Kelsey Dean MS RD
Meredith Dreyer Gillette PhD1,3 Susana Patton PhD1,4 Ann M Davis PhD MPH ABPP1,4
1
LD ,
1 Center
for Children’s Healthy Lifestyles & Nutrition, Kansas City, Missouri
2 University of Kansas, Clinical Child Psychology Program, Lawrence, Kansas
3 Children’s Mercy Hospitals and Clinics, Kansas City, Missouri
4Department of Pediatrics, The University of Kansas Medical Center
Background
• Physical activity (PA) promotion is a critical component of physical obesity
interventions, but studies show inconsistent changes to PA post-intervention (Cliff et
al., 2010).
• One reason for this may be due to seasonal changes in PA, since youth are naturally
less active during the winter versus spring and summer months (e.g., Rowlands et al.,
2009; Belanger et al., 2009).
• However, the science examining a seasonal impact on PA within pediatric obesity
interventions is lacking.
• The current study examines moderate-to-vigorous PA (MVPA) levels and changes in
MVPA according to season of start date (i.e., Winter, Spring, Summer, Fall) using PA
data gathered from youths participating in a 12-week family-based behavioral group
(FBBG) pediatric obesity intervention.
Methods
Participants
• 142 children between the ages of 5 and 18 (M=10.36; SD=2.81 years)
• Baseline BMI Percentile=97.58, SD=3.05; Baseline BMI z-score=2.19, SD=0.46
• Participants were 51% female and represented a variety of races (46.30% African
American, 28.40% Caucasian, 22.22% Latino, 3.09% other).
Measures
• Physical Activity. The ActiGraph Actometer (Actigraph LLC, Pensacola, FL) measured
MVPA with 60-second epochs. Participants wore the monitors on the non-dominant hip
for 7 days; valid days included at least 6 hours of wear time. The two weekdays and
one weekend day with the greatest amount of valid wear time were used for analyses.
Minutes of moderate, vigorous, and very vigorous activity were combined to create
MVPA as a single variable; minutes of MVPA were adjusted for wear time.
Intervention and Procedures
• Healthy Hawks (Davis et al., 2013) is a 12-week FBBG with concurrent parent and
child weekly sessions (conducted in English or Spanish), which include behavioral,
nutrition, and exercise education, as well as supervised physical activity. 20 Healthy
Hawks groups were conducted between April 2006 and January 2013. Participants
were recruited at health fairs and community events; eligible children had a BMI over
the 85th percentile.
Results
Results Continued
Baseline and Post-Intervention MVPA values by Season
Within-Group Differences in MVPA from Baseline to Post-Intervention
Baseline
Season
N
Post
Mean (SD)
N
N
Mean (SD)
Baseline
Mean (SD)
N
Post
Mean (SD)
Paired Samples Test
Mean (SD)
t
df p
Spring
18 55.426 (46.96) 18 36.907 (34.51) 18.52 (27.52) 2.855 17 .011
Fall
8
Winter
12 30.53 (22.24) 12 38.83 (37.03) -8.31 (31.12) -.925 11 .375
MVPA Spring 54 55.28 (42.39) 22 50.92 (64.23)
MVPA Fall
59.71 (24.19)
8
40.63 (23.65) 19.08 (27.98) 1.929 7 .095
16 51.27 (27.18) 11 36.67 (25.06)
MVPA Winter 38 35.77 (27.40) 18 41.35 (34.56)
Summer 16 57.35 (49.58) 16 55.71 (35.83)
Table 1. Descriptive statistics of MVPA levels. N = Number of participants in each seasonal
category of groups. Mean (SD) = Number of minutes engaged in MVPA.
1.67 (21.64)
.308 15 .762
Table 3. Results of within-group difference testing. N = Number of participants in each seasonal category of
groups. Mean (SD) = number of minutes engaged in MVPA.
• ANOVA revealed significant between-group differences for baseline MVPA (F (3, 148) =
2.85, p<.05), but not post-intervention (F (3, 63) = 0.52, p<.05).
•
Most seasonal groups decreased MVPA levels from baseline to post-intervention and
Spring groups significantly decreased MVPA following intervention (t (17) = 2.86;
p < .01). Winter groups increased MVPA over course of intervention (n.s.).
Between-Group Differences in MVPA: Baseline and Post-Intervention
Baseline
t
df
Winter vs. Spring
-2.679
90
Winter vs. Summer
-2.827
Winter vs. Fall
Post
p
t
df
p
.009 -.568
38
.574
65
.006 -1.188
32
.243
-1.902
52
.063
.390
27
.699
Spring vs. Summer
-.691
96
.491 -.268
36
.790
Spring vs. Fall
.357
68
.723
.705
31
.486
Summer vs. Fall
1.013
51
.316 1.521
25
.141
Table 2. Between-group differences testing. Results of between-group t-tests at baseline and postintervention. Negative t values represent lower mean MVPA values of first seasonal group. Higher t values
represent higher mean MVPA values of second group.
• Winter groups were significantly less active at baseline than Spring (t (90) = -2.68,
p<.01) and Summer groups ( t (80) = -2.83, p <.01).
Data Analysis
References
•
Between group differences were analyzed by one-way ANOVAs and independent
samples t-tests. Within-group changes (from baseline to post-intervention) were
analyzed by paired-samples t-tests.
•
Four seasons (Spring, Summer, Fall, Winter) were determined by groups’ baseline
start date according to calendar cut-offs for appropriate years.
Cliff, D. P., Okely, A. D., Morgan, P. J., Jones, R. A., & Steele, J. R. (2010). The impact of child and adolescent
obesity treatment interventions on physical activity: a systematic review. Obesity reviews, 11(7), 516-530.
Rowlands, A. V., Pilgrim, E. L., & Eston, R. G. (2009). Seasonal changes in children's physical activity: an
examination of group changes, intra-individual variability and consistency in activity pattern across season.
Annals of human biology, 36(4), 363-378.
Bélanger, M., Gray-Donald, K., O'loughlin, J., Paradis, G., & Hanley, J. (2009). Influence of weather conditions
and season on physical activity in adolescents. Annals of epidemiology, 19(3), 180-186.
Davis, A. M., Daldalian, M C., Mayfield, C. A, Dean, K., Black, W. R., Sampilo, M. L., Gonzalez-Mijares, M., &
Suminski, R. (2013). Outcomes from an Urban Pediatric Obesity Program Targeting Minority Youth: The
Healthy Hawks Program. Childhood Obesity, 9(6), 492-500.
Conclusions
• There may be a seasonal impact on patterns of PA among youths participating in
pediatric obesity interventions, indicating that interventions should consider describing
PA outcomes by season, echoing the call of Cliff and colleagues (2010) for more
evidenced-based approaches to PA.
• Given the relationship between time spent outside and PA, future interventions should
modify PA promotion strategies to account for seasonal differences.
• As we continue to build this literature toward evidenced-based PA, future interventions
should consider: 1) Utilizing modern techniques for accounting for missing data to
account for participant attrition, and 2) Analyzing changes in MVPA levels dependent
on levels discretionary time to account for differences in availability of discretionary
time for PA (i.e., in school versus out of school).
Acknowledgments
The authors wish to thank the parents and children who participated in our interventions
and contributed the data for the current analyses. We would also like to acknowledge
funding from the Health Care Foundation of Greater Kansas City, the Kansas City
YMCA, and the The Junior League of Kansas City, Missouri.
For more information contact: Kelsey Borner, M.A.; 2020 Dole Human Development
Center, 1000 Sunnyside Avenue Lawrence, KS 66045; [email protected]