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Volume
2:
No. 2, April 2005
ORIGINAL RESEARCH
Anthropometric Changes Using a Walking Intervention in African
American Breast Cancer Survivors: A Pilot Study
Diane B. Wilson, EdD, MS, RD, Jerlym S. Porter, MS, Gwen
Parker, MS, James Kilpatrick, PhD
Suggested citation for this article: Wilson DB, Porter
JS, Parker G, Kilpatrick J. Anthropometric changes using a
walking intervention in African American breast cancer survivors:
a pilot study. Prev Chronic Dis [serial online] 2005
Apr [date cited]. Available from: URL: http://www.cdc.gov/pcd/issues/2005/ apr/04_0112.htm.
PEER REVIEWED
Abstract
Introduction
African American women exhibit a higher mortality rate from
breast cancer than do white women. African American women are
more likely to gain weight at diagnosis, which may increase their
risk of cancer recurrence and comorbidities. Physical activity
has been shown to decrease body mass index and improve quality of
life in cancer survivors. This study was designed to evaluate the
feasibility and impact of a community-based exercise intervention
in African American breast cancer survivors.
Methods
A theory-based eight-week community intervention using
pedometers with scheduling, goal setting, and self-assessment was
tested in a convenience sample of African American breast cancer
survivors (n = 24). Data were collected at three time points to
examine changes in steps walked per day, body mass index, and other
anthropometric measures, attitudes, and demographic
variables.
Results
Statistically significant increases in steps walked per day and
attitude toward exercise as well as significant decreases in body
mass index, body weight, percentage of body fat, and waist, hip,
and forearm circumferences, as well as blood pressure, were reported from baseline to
immediate post-intervention. Positive changes were retained or
improved further at three-month follow-up except for
attitude toward exercise. Participant retention rate during
eight-week intervention was 92%.
Conclusion
Increasing walking for exercise, without making other changes,
can improve body mass index, anthropometric measures, and
attitudes, which are associated with improved quality of life and
reduced risk of cancer recurrence. The high participant retention
rate, along with significant study outcomes, demonstrate that
among this sample of African American breast cancer survivors,
participants were motivated to improve their exercise habits.
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Introduction
African American women exhibit a higher rate of breast cancer
mortality when compared with white women (1,2). Being diagnosed
later, variation in treatment response, and larger tumor size
have all been identified as factors that may contribute to
differences in breast cancer survival time (3). Obesity is also
more prevalent among African American women. Although the
majority of women report weight gain after breast cancer
diagnosis, African American women are at greater risk for this
pattern (4). Being overweight is not only associated with
increased risk of cancer recurrence but also with comorbid
conditions such as heart disease, stroke, diabetes, and
depression, all of which may contribute to decreased quality of
life and shorter survival time (5-10). By contrast, being more
physically active is associated with improved quality of life and
decreased body mass index (BMI) in cancer survivors, which in
turn may contribute to longer survival time (11,12).
Until recently, women who have completed cancer therapy have
been offered little to improve survival or decrease risk of new
disease. Yet studies show that as a group, breast cancer
survivors are interested in improving their health behaviors and
quality of life (4,7). Two randomized trials (13,14) are
currently testing healthy lifestyle interventions for cancer
survivors. However, very few interventions have been developed
and tested specifically among African American women with breast
cancer, even though they are a population at high risk for
recurrence and comorbid disease.
To address weight gain in African American breast cancer
survivors, we designed a theory-based cognitive-behavioral
walking program to test its feasibility and impact on steps per day
and BMI. The study was pilot tested among African American breast
cancer survivors, using a community education model in an urban inner-city
setting.
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Methods
We pilot tested an eight-week community-based walking program in a
convenience sample of African American breast cancer survivors (n = 24) to
investigate feasibility and impact on outcome measures over three time points:
1) baseline, 2) immediate post-intervention, and 3) three-month follow-up.
African American women who 1) had been diagnosed with breast
cancer, 2) had completed treatment at least three months before
recruitment, 3) were mobile, and 4) were less than 70 years of age were
eligible for the study.
Participant recruitment
Using a broad, organized effort, participants were recruited
from Massey Cancer Center clinics, outreach sites, contacts with
local churches, community leaders, and breast cancer
organizations including breast cancer support groups. A city
council member, along with other breast cancer survivors, was
also instrumental in communicating study information throughout
the community. Flyers, television announcements, and personal
communication were used during the three-month recruitment
effort. We contacted approximately 230 potentially eligible
women. Recruitment rate was approximately 10%. Reasons for
nonparticipation included having cancer treatment within the
prior three months, not being able to attend community meetings
because of work or family commitments, or having comorbid
conditions that decreased mobility.
Intervention
The theory-driven intervention was designed with the primary
study goal of integrating walking into one’s daily routine.
The Health Belief Model was used as the theoretical framework for
the intervention (15). This well-known model is based on
perceived seriousness and perceived susceptibility as the
strongest predictors for the implementation of health behaviors.
Thus, the intervention was designed on the basis that breast
cancer survivors are a population who have experienced a serious
disease and perceive their susceptibility toward a cancer
recurrence. Eight 75-minute weekly sessions were held at a
community center (evening) and at a local church (noontime).
Sessions were presented by the same instructor and staff, using
a curriculum that described benefits and barriers to exercise, its
relationship to health and cancer risk, and personal
assessment/problem-solving sessions for motivation. Didactic,
interactive, and small-group processes were used during each
session. Steps-only pedometers were tested, and progressive step
goals were provided. Participants scheduled walking times for the
upcoming week and reported steps walked per day for the previous week
using scheduler/tracker forms. Patients served as their own
controls.
Study variables
Study variables were assessed at three time points: baseline,
immediate post-intervention, and at three-month follow-up. The study goal was the integration of walking into
the participant’s daily routine. The primary study outcomes
were changes in number of steps and BMI. Steps per day were measured
using a steps-only pedometer. Participants were instructed to
wear the pedometer upon rising in the morning until bedtime and
to record the number of steps walked. BMI was calculated from
weight and height using a calibrated scale. Waist, hip, and
upper arm circumferences were measured using a tape measure, and
blood pressure was measured with a standard blood pressure cuff.
Body-fat percentage was measured using Futrex, a portable
near-infrared sensor system (16). All clinical measures were
taken by a clinical nurse practitioner.
Participant demographic information, cancer history, and
attitudinal measures were assessed using standardized survey
items from other study instruments. The instrument was pilot
tested in a comparable age group of African American women.
Attitudes toward exercise were measured using the Exercise
Decisional Balance instrument (17), a 16-item questionnaire
focused on avoidance of exercise (cons) and positive perceptions
of exercise (pros). Cancer anxiety was measured using the Cancer
Anxiety Scale (18), and participants’ concern about
cancer recurrence was assessed.
Data collection and statistical analysis
Data were entered into a database using SPSS statistical
software (SPSS Inc, Chicago, Ill). Descriptive statistics were
determined for all study variables. Analysis of variance
was performed to test for differences in measures collected at
baseline, immediately after intervention, and at three-month follow-up. Paired t tests were used to determine
differences in mean anthropometric and attitudinal measures
between the three time points. In addition, based on frequency
distribution of time since diagnosis, all study variables were
tested among those diagnosed three years or less prior to start
of the intervention (1999–2002) (n = 10) and those
diagnosed earlier (1978–1998) (n = 12), using independent
samples t tests.
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Results
Twenty-four women were enrolled in the intervention study.
One participant dropped out because of scheduling conflicts. One
experienced a cancer recurrence, resulting in 22 eligible women
completing the intervention.
Table 1 shows the characteristics of the study sample. Mean
age was 55 years (range 47–66 years). The majority of
the women had post-high school education. The sample was
approximately 50% married and 50% divorced, widowed, or single.
Receiving both chemotherapy and radiation therapy was most
prevalent among participants (46%), with 18% receiving radiation
alone, chemotherapy alone, or neither treatment; 23% were
currently taking tamoxifen. Forty-five percent of participants
(10/22) had been diagnosed with breast cancer in or since 1999, and 55%
(12/22) were diagnosed before 1999. For most participants (91%),
this was their first cancer diagnosis.
Feasibility
Feasibility was determined by examining attendance at weekly
sessions, study retention, and receptivity to pedometer use.
Attendance at weekly sessions was excellent, with 70% of the
participants attending seven or more intervention sessions. Study
retention to the eight-week study was also excellent, with 22 of 24
women completing the intervention and immediate post-assessment.
Participants had positive experiences using the pedometers and
recording steps per day. Broken or lost pedometers were reported by
approximately 25% of the study sample, and they were replaced to
ensure continuous data collection. Additional data showed that
95% responded “about right” to a survey item asking
whether number of study sessions were too many, too few, or about
right.
Impact on study outcomes
Results of ANOVA analyses of repeated measures (baseline,
immediate post-intervention, and at three-month follow-up)
showed statistically significant differences in steps per day
(P < .001), hip circumference (P = .009),
forearm circumference (P < .001), systolic blood
pressure (P = .002), diastolic blood pressure (P = .001), and attitude toward exercise (P
=
.005).
Table 2 shows the difference in mean study measures using
paired t tests, from baseline to immediate
post-intervention. Mean steps per day significantly increased from
4791 to 8297 (P < .001). Other significant decreases
included the following: BMI (P = .004), body weight
(P = .005), percentage body fat (P = .003), and
forearm circumference (P = .007). Increased positive
perception of exercise was also reported (P = .03).
Table 3 shows study results among women who completed
the three-month follow-up assessment (n = 17). From immediate
post-intervention to the three-month follow-up, mean steps per day did
not significantly change. There were
statistically significant improvements in hip circumference
(P = .04), forearm circumference (P = .04), and
diastolic blood pressure (P = .02). Thus, all
anthropometric measures either stayed the same or showed further
improvement by further reduction in measures from immediate
post-intervention to three-month follow-up. Of all study
variables, only attitude toward exercise significantly changed
direction (P < .001), with women showing a more negative
opinion of exercise by three-month follow-up compared with immediate post-intervention. There were
no differences in mean study outcomes in the participants who did
not attend three-month follow-up assessment sessions (n = 5)
compared with participants who did attend and had measurements (n =
17).
Time since diagnosis
More recently diagnosed women tended to have higher body
measures at all three time points, but only diastolic blood
pressure was significantly higher at baseline (P = .02)
when compared to earlier diagnosed women. The same effect was
true at immediate post-intervention for both diastolic blood
pressure (P = .02) and systolic blood pressure (P =
.003). At three-month follow-up, recently diagnosed women
were significantly more likely to have higher waist measures
(P = .048), with trends toward larger hip (P = .06)
and body fat (P = .05) measures than earlier diagnosed women.
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Discussion
We found statistically significant changes in the main study
outcomes of steps per day, BMI, and virtually all of the
anthropometric changes measured in the study population after an
eight-week intervention, with most results remaining at three-month follow-up. The breast cancer survivor participants were motivated and compliant
with the intervention, which likely enhanced their success.
Having had cancer and understanding their risk of recurrence may account
for the strong motivation we found in this population, as suggested by the
constructs of the Health Belief Model. It
is also important to note that the sample participants all had
more than a high school education, which may also have
contributed to their success.
Although we found only a few statistically significant
differences in mean body measures in relationship to time since
diagnosis, we may have detected more evidence of this pattern had
we had a larger study sample. While not significant, the more
recently diagnosed women had larger body measures and lower mean
steps per day than earlier diagnosed women at both immediately post
and at three-month follow-up.
The goal of the study was to have women integrate walking into
their daily routines on their own. They attended sessions for
education, motivation, and self-assessment; walking did not take
place during the study sessions. This was an important feature of
the study design because research shows that compliance is likely
to decline significantly after an intervention is completed
(19). Thus, our results showing that mean steps per day stayed
relatively steady even at three-month follow-up was encouraging.
Anthropometric and clinical measures
The mean change in body weight was modest but significantly
less than baseline. This level of weight loss supports what
similar interventions have reported (20). We were encouraged to
see weight loss occur among participants using an exercise-only intervention.
Nearly every participant posted decreases in at least one
anthropometric measure, so that even among women who did not show
weight loss, decreases were noted in body circumferences or blood
pressure. We were also encouraged to see that anthropometric
improvements did not fall off at three-month follow-up, and some improved
further. It is possible that adding dietary modifications
to the exercise intervention would contribute to more substantial
anthropometric changes.
Attitudinal factors
Women in the study improved their attitude toward exercise
from baseline to post-intervention by reporting fewer barriers to
exercise over the study period. This was not surprising given the
focus of the intervention sessions on overcoming personal
obstacles to exercise. However, the attitudinal improvement did
not hold at three-month follow-up. Although steps per day did not
significantly change at three-month follow-up, one might wonder if the
decline in exercise attitude might eventually negatively
influence exercise behavior after a longer time interval. Cancer
stress scores did not change significantly over the course of the
intervention. However, scores for this variable were not
particularly high even at the start of the intervention. This
could be related to the fact that only 18% of participants were
diagnosed during the 12 months prior to the start of the study.
Cancer stress may subside as time passes after a woman’s
diagnosis. Had we studied a group of more recently
diagnosed women, we may have found more evidence of cancer
stress at baseline and potential for impact after the exercise intervention than we did the
with this study population.
Limitations
This study was limited by the study size and lack of control
group. For a pilot study, however, the sample size was adequate
to study feasibility and study outcomes. In addition, the study
reflects the common limitations for relying on self-report data.
Anthropometric variables were included in the study in addition
to self-reported data to provide measured data for evaluating
results. The intervention tested exercise only; thus, even more
significant changes among this population are possible if both
energy balance components — food intake and physical activity — are modified. Overall, the study objectives
were realized, and the study provides interesting pilot data for
testing a more comprehensive lifestyle intervention in a similar
population. However, the sample does not constitute a
representative sample, and the study findings may not be
applicable to other breast cancer survivors.
Summary and conclusions
Steps walked per day, BMI, body circumferences, blood pressure,
and attitudinal variables all showed improved mean statistically
significant changes in this population of African American breast
cancer survivors after a theory-based cognitive-behavioral
community intervention. The study showed strong feasibility
measures in positive response to using pedometers, high
participant retention, social support, and excellent compliance
after eight weeks. Given data indicating obesity is associated
with shorter breast cancer survival time, these study results may
position breast cancer survivors to have both improved quality of
life and reduced risk of cancer recurrence. Further study is
needed to test a randomized comprehensive diet and exercise
intervention in African American breast cancer survivors against
controls in a longer, larger randomized trial with additional
study variables.
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Acknowledgments
This study was funded through a competitive peer-reviewed grant
initiative by the Massey Cancer Center at Virginia Commonwealth
University.
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Author Information
Corresponding Author: Diane B. Wilson, EdD, MS, RD, Department
of Internal Medicine and Massey Cancer Center, PO Box 980306,
Virginia Commonwealth University, School of Medicine, Richmond, VA
23298-0306. Telephone: 804-828-9891. E-mail: dbwilson@vcu.edu.
Author Affiliations: Jerlym S. Porter, MS, Department of
Psychology, Virginia Commonwealth University, Richmond, Va; Gwen
Parker, MS, Massey Cancer Center, Virginia Commonwealth
University, Richmond, Va; James Kilpatrick, PhD, Department of
Biostatistics, Virginia Commonwealth University, Richmond,
Va.
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