1. No category

Rogers LQ et al., J Food Nutr Disor 2015, 4:2
http://dx.doi.org/10.4172/2324-9323.1000166
Journal of Food &
Nutritional Disorders
Research Article
A SCITECHNOL JOURNAL
Developing Theory-Based
Measurement Tools for Improving
Diet Compliance in Head and
Neck Cancer Patients
Rogers LQ1*, Verhulst S2, Rao K3, Malone J4, Robbs R5 and
Robbins KT6
1Department
of Nutrition Sciences, University of Alabama at Birmingham, 1720
2nd Avenue North, Webb 222, Birmingham, AL 35294-3360, USA
2Statistics
and Informatics Core, Center for Clinical Research, Southern Illinois
University School of Medicine, Springfield, IL, P.O. Box 19664, Springfield, IL
62794-9664, USA
3Department of Medicine and Simmons Cancer Institute, Southern Illinois
University School of Medicine, P.O. Box 19677, Springfield, IL 62794-9677, USA
4Associated
Otolaryngologists of Pennsylvania, Inc., 34 Northeast Drive, Hershey,
PA 17033, USA
5Statistics and Informatics Core, Center for Clinical Research, Southern Illinois
University School of Medicine, Springfield, IL, P.O. Box 19664, Springfield, IL
62794-9664, USA
6Department
of Surgery and Simmons Cancer Institute, Southern Illinois
University School of Medicine, P.O. Box 19677, Springfield, IL 62794-9677, USA
*Corresponding
author: Laura Q. Rogers, University of Alabama Birmingham,
Department of Nutrition Sciences, 1720 2nd Avenue North, Webb 222,
Birmingham, AL 35294-3360,USA; Tel: (205) 975-1667; Fax: (205) 934-7049; Email: rogersl@uab.edu
Rec date: Feb 02, 2015 Acc date: Mar 30, 2015 Pub date: Apr 03, 2015
Abstract
Objectives: Increasing compliance with diet recommendations
is critical for improving health, quality of life, and survival
among head and neck cancer (HNCa) patients. The social
cognitive theory is a potentially useful behavioral theory
framework for improving compliance but measurement tools
assessing theory constructs related to diet compliance in HNCa
patients are needed. Therefore, our study aim was to pilot test
social cognitive theory construct measures, including
prevalence and preliminary associations with self-reported
compliance with physician or dietitian diet recommendations.
Methods: Cross-sectional survey completed by 33 HNCa
patients followed in an out-patient academic otolaryngology
clinic.
Results: Mean age was 59 ± 12 years with 91% being White
and 82% being men. The percent stating they intended to
improve their compliance with diet recommendations during the
past six weeks was 21% with 67% intending to improve
compliance over the next three months. The means for most
social cognitive theory constructs were near the mid-point of
the possible range with outcome expectations being the closest
to the maximum possible. Internal reliability (Cronbach’s alpha)
ranged from 0.54 to 0.96 with most being >0.70. Goal setting
and diet enjoyment were significantly associated with selfreported compliance (p=0.002 and p=0.007, respectively).
Although not statistically significant, promising associations
with self-efficacy (effect size=0.83, p=0.117) and friend social
support (effect size=0.91, p=0.093) were noted.
Conclusions: The social cognitive theory is a potentially valid
framework for improving HNCa patient adherence to diet
interventions. The measures and associations reported warrant
further study.
Keywords: Nutrition; Oncology; Supportive Care; Adherence;
Health Behavior
Introduction
Head and neck cancer (HNCa) patients may suffer significant
weight loss due to side effects such as anorexia, taste alterations,
mucositis, pain, and difficulty swallowing [1-4]. Counseling by a
dietitian can reduce weight loss, enhance quality of life, and improve
clinical outcomes [5-8] but up to 57% of HNCa patients may be
noncompliant with such counseling [9,10]. Compliance can be
improved by designing interventions based on a behavioral change
theory [11]. For example, the social cognitive theory [12] provides
principles that can be applied to assist individuals in making healthy
behavior change [13]. Self-efficacy, the most well-known construct of
the social cognitive theory, is an individual’s confidence in their ability
to engage in a specified behavior [14]. Several other important social
cognitive theory constructs include goal setting, outcome expectations
(e.g., expected effects of the behavior), perceived barriers interference
(e.g., how often barriers interfere with the behavior), environment
(e.g., social support), and emotional coping responses (e.g., enjoyment
of the behavior). Social cognitive theory constructs interact with each
other in response to behavior choices and resultant experiences
[11,13]. Although self-efficacy has a direct effect on behavior [15], it
may also be influenced by and/or change behavior through other
constructs. For example, improved self-efficacy may increase outcome
expectations and decrease barriers interference which in turn is
associated with increased adherence to the desired behavior [16]. Also,
greater social support and enjoyment of the behavior may increase
self-efficacy which is associated with greater behavior compliance [17].
Few published diet interventions have used a behavior theory
framework for improving diet compliance in HNCa patients on or off
treatment. An intervention using one face-to-face session, one
telephone counseling session, and three mailings was based on the
social learning theory (renamed the social cognitive theory in 1986)
[11,14,18]. This intervention focused on early stage HNCa patients
who were post-treatment and at risk for a second cancer [18]. Another
intervention focused on early stage post-treatment HNCa patients was
based on the transtheoretical model [19]. This intervention used one
face-to-face counseling session, weekly telephone sessions, and mailed
materials [20]. Both studies reported significant improvements in fruit
and vegetable intake in the intervention group [18,20].
Identifying social cognitive theory constructs associated with diet
compliance can be used to improve diet behavior change in future
nutritional interventions for HNCa patients. Although social cognitive
theory correlates have been studied in HNCa patients for outcomes
other than diet compliance (i.e., emotional distress [21] and exercise
[22]), no prior study has examined predictors or correlates of diet
compliance in HNCa patients using any behavior change theory. The
single study reporting patient compliance with physician provided diet
recommendations reported that anxiety was the only correlate of
All articles published in Journal of Food & Nutritional Disorders are the property of SciTechnol and is protected by
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Citation:
Rogers LQ, Verhulst S, Rao K, Malone J, Robbs R, et al. (2015) Developing Theory-Based Measurement Tools for Improving Diet Compliance in
Head and Neck Cancer Patients. J Food Nutr Disor 4:2.
doi:http://dx.doi.org/10.4172/2324-9323.1000166
compliance in 30 post-treatment HNCa patients [9]. Although anxiety
is not a specific social cognitive theory construct, it can be considered
an aspect of the emotional coping response construct [11]. Moreover,
identifying behavior change theory correlates is warranted given their
mediating role in lifestyle compliance in survivors of other cancer
types (e.g., self-efficacy mediated diet behavior among breast and
prostate cancer survivors [23] and perceived barriers interference
mediated exercise behavior among breast cancer survivors [24]).
For some HNCa patients, adhering to recommended nutritional
supplements with or without feeding tube use is an important aspect
of diet compliance. Nine of 23 HNCa patients receiving
chemoradiotherapy did not use the tube effectively and experienced
significant declines in weight, body mass index, and lean body mass
compared with those using their feeding tubes [25]. Reasons for
feeding tube noncompliance included nausea and vomiting (n=2), low
educational level or lack of awareness of nutrition importance (n=5),
and reluctance (n=2). Although not reported within a theoretical
framework, these reasons suggest useful social cognitive theory
constructs such as perceived barriers interference (e.g., nausea) and
outcome expectations (e.g., awareness of important nutrition benefits).
Also related, eating difficulties in HNCa patients may negatively
impact social interactions suggesting the potential importance of
environment (e.g., social support) [26].
Changing diet behavior in response to dietary counseling is critical
for improving health, quality of life, and survival among HNCa
patients. Interventions based on behavior change theory frameworks
are needed to improve compliance. However, the question of which
theory constructs should be targeted remains unanswered due to the
lack of information about the associations between constructs and
behavior in HNCa patients. Furthermore, no study, to date, has
published the development and testing of the measurement tools
required to optimize future diet compliance interventions for HNCa
patients using a behavior change theory. Therefore, our study aim was
to develop social cognitive theory-based measurement tools related to
diet compliance among HNCa patients. This included item reduction
and preliminary testing of reliability and associations with selfreported diet compliance.
Methods
This cross-sectional survey study took place in an academic, head
and neck oncology clinic. Study inclusion criteria were: 1) history of
HNCa, 2) currently followed in the clinic for HNCa, 3) age 18 to 89
years, and 4) able to read and complete the survey. Institutional review
board approval was obtained. Because no identifying information was
collected, a waiver of consent was approved. Potential participants
were identified by a research coordinator present in the clinical area;
the coordinator provided the individual with a survey and cover letter
explaining the study and voluntary nature of participation. Surveys
were completed in the clinic on the day of enrollment. A convenience
sample was used because it was not feasible for the coordinator to
approach all potentially eligible patients on busy clinic days. Although
the survey asked about diet and exercise behavior, only the diet-related
analyses are reported here.
Participants self-reported demographics, medical information,
compliance with diet recommendations (i.e., entered days per week
followed a physician or dietitian’s diet recommendations in the past
six weeks), and compliance with supplement recommendations (i.e.,
entered number of supplements per day recommended and ingested in
Volume 4 • Issue 2 • 1000166
the past six weeks). Similarly, participants with a feeding tube at the
time of survey completion also entered the number of supplements per
day recommended and ingested through the feeding tube in the past
six weeks.
Social cognitive theory construct measures previously used in other
populations [22,27-31] were adapted for disease outcomes and
treatment side effects experienced by HNCa patients [1-3]. For goal
setting [27], a 3-point Likert type scale asked participants their plans
for following physician or dietitian dietary advice for the past six
weeks, next six weeks, and next three months (i.e., 1=plan to follow
recommendations less, 2=about the same, or 3=more). Participants
were also asked their diet goals for the past month, next three months,
and next six months on a 6-point Likert type scale (i.e., 0=do not have
a specific diet goal, 1=do not plan to follow recommendations, 2=plan
to follow recommendations 1 to 2 days per week, 3=plan to follow
recommendations 3 to 4 days per week, 4=plan to follow
recommendations 5 to 6 days per week, 5=plan to follow
recommendations 7 days per week). Responses for the past six weeks’
time period were summed for testing the association between goal
setting and compliance.
The barriers self-efficacy scale (i.e., confidence in ability to
overcome barriers to following physician or dietitian diet
recommendations during the past six weeks) [22,28,29] included 14
common diet barriers experienced by HNCa patients [1-3].
Confidence was rated on a Likert scale from 0% to 100% (0%=not at all
confident to 100% = extremely confident) with the mean used for the
analyses. The perceived barriers interference scales [22] asked
participants to rate on a 5-point Likert scale (1=never to 5=very often)
the frequency with which barriers interfered with following diet
recommendations during the past six weeks (25 items), supplement
use (6 items) and feeding tube use (3 items). Each barriers interference
scale was summed for the analyses.
For social support [30,31], the frequency with which friends (two
items) or family (two items) encouraged or offered to help the
participant stick with or follow diet recommendations during the past
six weeks was assessed by summing the 5-point Likert scale responses
(0=none to 4=very often). The outcome expectations scale [32] asked
participants to rate their agreement on a 5-point Likert scale
(1=strongly disagree to 5=strongly agree) with the statement that
following diet recommendations would result in 15 potential benefits.
For associations with diet compliance, responses were summed. Also,
participants were asked a single item asking for their agreement (1 =
strongly disagree to 5=strongly agree) with the following: “I do not feel
that I would experience any important benefits from following the
dietitian’s recommendations”. Diet enjoyment was measured with a
single question (5-point Likert scale; 1=agree to 5=disagree) asking
participants to rate their agreement with the following: “I enjoy eating
what the physician or dietitian recommends” [22]. Responses were
reversed for the analysis so that higher scores indicated greater
enjoyment.
Descriptive statistics assessed prevalence of responses. Items with
low frequency of occurrence or overlapping concepts were removed in
an effort to shorten scales with ≥ 14 items to reduce participant burden
in future studies. Internal reliability of the scales with multiple items
(original and reduced items scales) was examined by calculating
Cronbach's alphas (coefficient representing how well the individual
items correlate with each other within the scale; values of ≥.9, ≥.8, and
≥.7 are considered excellent, good, and acceptable, respectively; values
<.5 are usually interpreted as unacceptable [33]). Associations with
• Page 2 of 9 •
Citation:
Rogers LQ, Verhulst S, Rao K, Malone J, Robbs R, et al. (2015) Developing Theory-Based Measurement Tools for Improving Diet Compliance in
Head and Neck Cancer Patients. J Food Nutr Disor 4:2.
doi:http://dx.doi.org/10.4172/2324-9323.1000166
following diet recommendations were tested by dichotomizing
responses as following recommendations seven days/week versus less
than seven days/week due to the small sample size and response
distribution (i.e., 13 reported following recommendations seven days/
week with six doing so less than seven days/week). Associations were
examined using chi-square or independent groups t-test. If available
for the construct, the reduced items scales were used when testing
associations.
Results
reported receiving diet recommendations, receiving supplement
recommendations, and/or having a feeding tube in the past six weeks
(i.e., 33 of 137 HNCa patients). Limiting the time frame for receipt of
diet recommendations to the past six weeks was done to focus the
participant’s attention on the recent past.
Sample characteristics for the 33 participants are provided in Table
1. Of note, six participants with a feeding tube failed to self-report diet
or supplement recommendations in the past six weeks but were
included in the analyses because all patients with a feeding tube receive
supplement recommendations as part of their clinical care.
The response rate for the full survey was 74% with this manuscript
reporting data from a subgroup analysis of participants who selfVariable
N (%) or mean ± standard deviation*
Age, years
59.1 ± 12.2
Gender
Men
27 (82%)
Women
6 (18%)
Ethnicity
Hispanic
0 (0%)
Not Hispanic
33 (100%)
Race
White
30 (91%)
African American
3 (9%)
Education, years
12.1 ± 2.0
Months since Diagnosis
24.8 ± 25.2 (range 4 - 109)
Cancer stage
Stage 1
0 (0%)
Stage 2
2 (6%)
Stage 3
4 (12%)
Stage 4
10 (30%)
Don’t know
15 (45%)
Missing
2 (6%)
Treatment type
Surgery only
3 (9%)
Radiation only
0 (0%)
Surgery followed by radiation
9 (28%)
Surgery followed by radiation and intravenous chemotherapy
5 (16%)
Concurrent intravenous chemotherapy and radiation
7 (21%)
Chemotherapy and/or radiation followed by surgery
6 (19%)
Other
2 (6%)
Treatment status
On treatment
1 (3%)
Off treatment
31 (97%)
Receipt of diet and/or supplement recommendations
Diet recommendations only
Volume 4 • Issue 2 • 1000166
11 (33%)
• Page 3 of 9 •
Citation:
Rogers LQ, Verhulst S, Rao K, Malone J, Robbs R, et al. (2015) Developing Theory-Based Measurement Tools for Improving Diet Compliance in
Head and Neck Cancer Patients. J Food Nutr Disor 4:2.
doi:http://dx.doi.org/10.4172/2324-9323.1000166
Supplement recommendations only
7 (21%)
Both diet and supplement recommendations
9 (27%)
Neither diet nor supplement recommendations†
6 (18%)
Number of supplements recommended per day (19 responses‡)
4.9 ± 2.4
Number of supplements ingested per day (20 responses‡)
3.9 ± 2.5
Days per week followed diet recommendations (19 responses‡)
5.8 ± 2.4 (range 0 to 7)
Feeding tube (currently) (yes) †
11 (33%)
Number of daily feeding tube supplements recommended (7 responses)
6.8 ± 2.4
Number of daily feeding tube supplements ingested (8 responses)
5.4 ± 2.0
*Categories may contain missing values. †Six of the 11 with a feeding tube did not report receiving diet or supplement recommendations in the past six weeks. ‡Several using
supplements did not report receiving recommendations in the past six weeks.
Table 1: Characteristics for head and neck cancer patients with feeding tube and/or receiving diet and/or supplement recommendations from a
physician or dietitian in the past six weeks (n=33)
To create the reduced items barriers self-efficacy scale, the most
prevalent barriers reported as interfering with following diet
recommendations were included (i.e., no appetite, sore mouth, nausea,
difficulty swallowing, painful swallowing, low on money, feel full
quickly, difficulty chewing, does not taste good, dry mouth, a lot of
phlegm in throat, heartburn or acid reflux). The outcome expectations
scale was reduced based on overlapping constructs (e.g., feel stronger
with muscle strength, have more energy with feel less tired, etc.) and
importance for HNCa patients (e.g., weight gain). As a result the
following items were retained for the reduced outcome expectations
scale: feel stronger, look better, gain weight, feel less tired, improve
body shape, reduce risk of disease, and feel better.
The reduced items barriers interference scale for compliance with
diet recommendations included barriers reported by >50% of
participants [i.e., inability to chew solid food, food does not taste good,
choking, lack of appetite, sore mouth, dry mouth, phlegm production
in mouth, difficulty swallowing, painful swallowing, cannot taste food,
do not like taste of recommended items, feel full too quickly, nausea,
Variable
heartburn or acid reflux, spouse (or other) does shopping] and
relevance to lower socioeconomic populations (i.e., recommendations
are too expensive) for 16 total items. The supplement and feeding tube
use barriers interference scales were not reduced (i.e., supplement use
items=I do not like the taste of the supplements, supplements cause
stomach upset, supplements are too expensive, I cannot get the
supplements, supplements cause diarrhea, and I cannot travel with the
supplements; feeding tube use items=using the feeding tube is
embarrassing, no one has shown me how to use my feeding tube, and I
do not know how to use the feeding tube).
Table 2 provides the descriptive statistics and Cronbach's alphas
(i.e., internal reliability) for the social cognitive theory scales related to
diet compliance. Of the nine Cronbach’s alphas reported, none were in
the unacceptable range of <.5, two were between .7 and .8 (acceptable),
two were between .8 and .9 (good), and three were ≥.9 (excellent) [33].
Only 3 (16%) felt that they would not experience any important
benefits from following diet recommendations. Goal setting is not
included in Table 2 because Cronbach’s alphas do not apply.
All original items included
Items reduce
Possible
range
Mean ±
deviation
Barriers self-efficacy
0 to 100
Barriers interference
25 to 125
standard
Cronbach’s alpha
without imputed
values
Possible range
Mean ± standard
deviation
Cronbach’s
alpha
without
imputed
values
44.7 ± 17.4 (n=16*)
0.89
0 to 100
46.7 ± 19.3 (n=16)
0.90
67.9 ± 11.0 (n=15*)
0.73
16 to 80
51.4 ± 7.1 (n=18)
0.59
0.85
N/R
N/R
N/R
7 to 35
27.4 ± 5.6 (n=18)
0.90
N/R
N/R
N/R
General diet recommendations
(n=18*)
Social support (total)
0 to 16
9.2 ± 5.3
Outcome expectations
15 to 75
61.4 ± 10.9 (n=17*)
0.96
1 to 5
2.0 ± 1.3 (n=19*)
Single item
1 to 5
3.5 ± 1.2
(n=18*)
Single item
6 to 30
12.6 ± 4.4 (n=20*)
No benefit
compliance †
Diet
expected
from
enjoyment‡
Diet supplement use Barriers
interference
Volume 4 • Issue 2 • 1000166
0.54
• Page 4 of 9 •
Citation:
Rogers LQ, Verhulst S, Rao K, Malone J, Robbs R, et al. (2015) Developing Theory-Based Measurement Tools for Improving Diet Compliance in
Head and Neck Cancer Patients. J Food Nutr Disor 4:2.
doi:http://dx.doi.org/10.4172/2324-9323.1000166
Feeding tube use
Barriers interference
6.1 ± 4.0 (n=10 §)
3 to 15
0.72
N/R
N/R
N/R
*Responses for participants reporting receiving diet or supplement recommendations (total possible n=27); n < 27 because Cronbach’s alphas calculated without imputed values.
†1=strongly disagree and 5=strongly agree with the statement “I do not feel that I would experience any important benefits from following the dietitian’s recommendations”.
‡Values reversed so that 1=disagree and 5=agree with the statement “I enjoy eating what the physician or dietitian recommends”.
§Responses for participants reporting currently having a feeding tube (total possible n=11); n < 11 because Cronbach’s alphas calculated without imputed values.
Abbreviations: N/R=Not Reduced
Table 2: Prevalence and, when appropriate, internal reliability (i.e., Cronbach’s alpha) for barriers self-efficacy, perceived barriers interference,
social support, outcome expectations, and enjoyment related to compliance with diet recommendations in head and neck cancer patients
With regard to prevalence data, the percentage of participants
planning to adhere to diet recommendations more often was 21% for
the past six weeks, 50% for the next six weeks, and 67% for the next
three months. The percent planning to follow diet recommendations 7
Social cognitive theory construct
days a week was 38% for the past six weeks, 43% for next six weeks,
and 64% for next three months. Table 3 provides associations between
social cognitive theory constructs and compliance with diet
recommendations.
Follow recommendations 7 days/week
Follow recommendations < 7 days/week
p value*
Effect size
Goal setting: summative score (n=13†)
6.0 ± 1.7
2.5 ± 0.6
0.002
2.42
Barriers self-efficacy (n=18‡)
51.2 ± 18.8
37.2 ± 13.5
0.117
0.83
Barriers interference (n=19‡)
Related to general diet recommendations
52.0 ± 8.7
52.5 ± 2.7
0.850
-0.07
(n=17‡)
5.9 ± 3.0
5.7 ± 3.2
0.880
0.08
Friend Social support (n=17‡)
4.5 ± 3.4
1.7 ± 2.7
0.093
0.91
Total Social support (n=17‡)
10.5 ± 1.8
7.3 ± 3.9
0.267
0.59
27.3 ± 6.2
29.3 ± 2.3
0.322
-0.37
1.9 ± 1.3
2.2 ± 1.3
0.714
-0.18
4.1 ± 0.9
2.5 ± 1.2
0.007
1.56
13.2 ± 4.6
11.2 ± 4.5
0.496
0.46
Family Social support
Outcome expectations
(n=19‡)
No benefit expected
compliance§ (n=19‡)
from
Diet enjoyment ǁ(n=18‡)
diet
Related to diet supplement use
Barriers interference (n=13¶)
*P
value for t-test, chi-square, or Fisher’s exact depending on the variable and number in each cell.
†Responses
for participants reporting receiving diet recommendations and completing the diet goal items (total possible=13)
‡Responses
for participants reporting receiving diet recommendations (total possible n=20)
§1=strongly
disagree and 5=strongly agree with the statement “I do not feel that I would experience any important benefits from following the dietitian’s recommendations”
(therefore, higher score reflects less perceived benefit from diet recommendations)
ǁValues
reversed so that 1=disagree and 5=agree with the statement “I enjoy eating what the physician or dietitian recommends” (therefore, higher score reflects greater enjoyment);
recommend reformatting on future surveys as noted in Table 4
¶Responses for participants reporting receiving supplement recommendations (total possible n=16).
Table 3: Prevalence [N (%) or mean ± standard deviation] of social cognitive theory construct by self-reported compliance with physician or
dietitian diet recommendations
Because associations did not differ between original and reduced
items scales, associations using the reduced items are reported. The
association for feeding tube barriers interference is not provided
because only two participants indicated receiving recommendations
Volume 4 • Issue 2 • 1000166
and completed the feeding tube barriers interference scale. Table 4
provides a listing of the final survey items recommended along with
scoring instructions.
• Page 5 of 9 •
Citation:
Rogers LQ, Verhulst S, Rao K, Malone J, Robbs R, et al. (2015) Developing Theory-Based Measurement Tools for Improving Diet Compliance in
Head and Neck Cancer Patients. J Food Nutr Disor 4:2.
doi:http://dx.doi.org/10.4172/2324-9323.1000166
Construct, response options, and scoring
Items
Barriers self-efficacy for complying with general diet recommendations; 0% to 100% in
10% increments (labeled as follows: not at all confident = 0% & 10%, slightly confident
= 20% & 30%, moderately confident = 40%, 50%, & 60%, very confident = 70% &
80%, extremely confident = 90% & 100%); mean of responses
I can follow diet recommendations if…
I do not have an appetite
My mouth is sore
I feel nauseated
I have difficulty swallowing
I have pain swallowing
I am low on money
I feel full quickly
I have difficulty chewing
It does not taste good
I have a dry mouth
I have a lot of phlegm in my throat
I have heartburn or acid reflux
Barriers interference with complying with general diet recommendations; 5-point Likert
scale (1=never, 2=rarely, 3=sometimes, 4=often, 5=very often); sum of responses
Barrier to following diet recommendations
Lack of appetite
Sore mouth
Nausea
Inability to chew solid food
Difficulty swallowing
Painful swallowing
Food does not taste good
Cannot taste food
Choking
Feeling full too quickly
Dry mouth
Phlegm production in mouth
Heartburn or acid reflux
Recommendations are too expensive
Spouse (or other) does shopping
Do not like taste of recommended items
Social support for complying with general diet recommendations*; Likert scale
(0=none, 1=rarely, 2= a few times, 3=often, 4=very often, 9=does not apply); sum of
responses after recoding “9” as “0”
During the past 6 weeks, my family (or members of my household) offered assistance
with following diet recommendations
During the past 6 weeks, my family (or members of my household) gave me
encouragement to stick with my diet recommendations
During the past 6 weeks, my friends offered assistance with following diet
recommendations
During the past 6 weeks, my friends gave me encouragement to stick with my diet
recommendations
Outcome expectations if comply with general diet recommendations; 5-point Likert
scale (1=strongly disagree, 2=somewhat disagree, 3=neutral, 4=somewhat agree,
5=strongly agree); sum of responses
If I follow the physician or dietitian’s recommendations…
I will feel stronger
I will look better
I will gain weight
I will feel less tired
I will improve my body shape
I will reduce my risk of disease
I will feel better
No benefit expected from compliance; 5-point Likert scale (1=strongly disagree,
2=somewhat disagree, 3=neutral, 4=somewhat agree, 5=strongly agree); score single
item
Volume 4 • Issue 2 • 1000166
I do not feel that I would experience any important benefits from following the
physician or dietitian’s recommendations
• Page 6 of 9 •
Citation:
Rogers LQ, Verhulst S, Rao K, Malone J, Robbs R, et al. (2015) Developing Theory-Based Measurement Tools for Improving Diet Compliance in
Head and Neck Cancer Patients. J Food Nutr Disor 4:2.
doi:http://dx.doi.org/10.4172/2324-9323.1000166
Diet enjoyment; 5-point Likert scale (1=strongly disagree, 2=somewhat disagree,
3=neutral, 4=somewhat agree, 5=strongly agree); score single item
I enjoy eating what the physician and dietitian recommends
Goal setting related to general diet recommendations†; indicate specific time period
(e.g., past six weeks, next six weeks, etc.); responses for first item: 1 = less, 2 = about
the same, or 3 = more; responses for second item: 0 = do not have a goal, 1 = do not
plan to follow recommendations, 2 = 1 to 2 days per week, 3 = 3 to 4 days per week, 4
= 5 to 6 days per week, 5 = 7 days per week; sum responses to both items for the time
period of interest
During the {time period of interest}, did you plan on following the physician or
dietitian’s recommendations to eat healthy and enough calories… less, about the same,
or more
Barriers interference with regard to supplement use; 5-point Likert scale (1=never,
2=rarely, 3=sometimes, 4=often, 5=very often); sum of responses
My diet goal for the {time period of interest}…do not have a specific diet goal, do not
plan to follow recommendations, plan to follow recommendations 1 to 2 days per week,
plan to follow recommendations 3 to 4 days per week, plan to follow recommendations
5 to 6 days per week, 5 plan to follow recommendations 7 days per week
Barrier to drinking or eating diet supplements
I cannot get the supplements
I cannot travel with the supplements
Supplements are too expensive
I do not like the taste of the supplements
Supplements cause diarrhea
Supplements cause stomach upset
Barriers interference with regard to feeding tube use; 5-point Likert scale (1=never,
2=rarely, 3=sometimes, 4=often, 5=very often); sum of responses
Barrier to using feeding tube
I do not know how to use the feeding tube
No one has shown me how to use my feeding tube
Using the feeding tube is embarrassing
*Adapted
from Sallis, et al [30; 31]
†Adapted
from Doerksen, et al [27]
Table 4: Final survey items recommended for use in future studies
Discussion
The majority of social cognitive theory measures tested in this
report demonstrated acceptable to excellent internal reliability with
goal setting, enjoyment, social support, and barriers self-efficacy
suggesting promising associations with diet recommendation
compliance. Our data supports the potential usefulness of the social
cognitive theory as a theoretical framework for improving diet
adherence in HNCa patients. Moreover, the measurement tools in this
report warrant further study and may be useful in future research
examining the role of social cognitive theory in diet compliance in this
cancer group. We acknowledge that the barriers interference scale for
diet supplement use and the reduced items barriers interference scale
for general diet recommendations demonstrated Cronbach’s alphas
between .5 and .6 (poor). The diverse nature of the items included in
these scales may have contributed, in part, to their lower internal
reliability (e.g., experiencing diarrhea as a barrier to supplement use
would not necessarily be expected to be associated with inability to pay
for supplements). Future study should refine and reevaluate these
scales including larger sample sizes and factor analyses to identify
scales and subscales with improved internal reliability. Importantly,
the scales related to barriers self-efficacy, social support, and outcome
expectations demonstrated promise as useful tools for assessing and
improving diet compliance in HNCa patients.
It is noteworthy that our study is the first to develop social cognitive
measurement tools and explore the potential role of the social
cognitive theory in diet compliance among HNCa patients.
Importantly, our preliminary study supports the need and legitimacy
of further testing these measurement tools. Also, our data generates
hypotheses related to potential social cognitive theory targets for
future interventions aimed to improve diet compliance in this cancer
Volume 4 • Issue 2 • 1000166
group. Specifically, such interventions should include behavior change
strategies addressing the constructs with ≥ large effect size associations
with compliance in our study (i.e., goal setting, barriers self-efficacy,
friend social support, and diet enjoyment). The expectation of benefit
from compliance with diet recommendations was high suggesting that
HNCa patients know why they should follow recommendations but
may require behavioral interventions addressing social cognitive
theory constructs other than outcome expectations in order to
improve diet compliance.
Also related to future intervention design, the most frequent
barriers to diet compliance in our study are consistent with HNCa
clinical characteristics and treatments (e.g., anatomic alterations,
cancer cachexia) [2,3,34,35]. Similar to our results, taste has been
reported as a major barrier to supplement use [34] and embarrassment
a potential barrier to feeding tube use [36]. Given the importance of
compliance with supplements and feeding tube use, research is needed
to determine best methods for health care professionals and dietitians
to ask about these barriers, legitimize the patient concerns, and
provide helpful solutions.
Further research is needed to determine why the percentage of
participants intending to comply with diet recommendations
increased in the future. Prospective studies are needed to determine if
intention predicts improved compliance or is simply procrastination.
Possible social cognitive theory based reasons for procrastination may
include a feeling that barriers will interfere less in the future or greater
confidence in their ability to overcome barriers in the future rather
than the present. Given the very strong association between goal
setting and diet compliance, future interventions should address and
emphasize this construct. Further research that includes details
regarding the specific diet recommendations received and diet-related
• Page 7 of 9 •
Citation:
Rogers LQ, Verhulst S, Rao K, Malone J, Robbs R, et al. (2015) Developing Theory-Based Measurement Tools for Improving Diet Compliance in
Head and Neck Cancer Patients. J Food Nutr Disor 4:2.
doi:http://dx.doi.org/10.4172/2324-9323.1000166
goals set is warranted and may improve our ability to use goal setting
as an important behavior change tool in this population.
This preliminary study’s small sample size precluded factor analysis
and limited study power for detecting statistically significant
associations between social cognitive theory constructs and diet
compliance. Although disease-related characteristics (e.g., disease
stage, treatment type) were obtained by self-report due to logistical
and budgetary constraints, such an approach resulted in missing
cancer stage data and lack of specific treatment details beyond the
general categories of chemotherapy, radiation, and/or surgery alone.
This combined with the small sample size prevented testing for
potential moderation of our findings by disease characteristics. The
primary reason for our small sample size was the low prevalence of
patients self-reporting receipt of physician or dietitian diet
recommendations in the past six weeks. This may have occurred due
to the larger percentage participants being off treatment. Alternatively,
patients may not perceive general, brief statements about diet from
their physician as diet recommendations and may not be able to
differentiate a dietitian from other clinic staff (e.g., nursing staff). Also
related, third party payers often do not cover the cost of dietitian
counseling which may reduce the frequency of dietitian counseling.
The fact that only 27% felt they had recently received diet
recommendations reinforces the value of interventions increasing
patient access to more intensive nutritional counseling.
Continued examination of social cognitive theory construct
measurement and potential contribution to diet compliance in HNCa
patients in larger studies is warranted. Reduced items scales can be
used to lessen participant burden, which is especially important given
the often overwhelming nature of HNCa diagnosis and treatment.
Test-retest reliability evaluation is needed but may be difficult in
patients on treatment given changes in clinical barriers over time.
Factor analysis may prove useful in identifying subcategories of
barriers or outcome expectations with stronger predictive properties
relative to diet compliance. Lastly, determining the moderating effects
of treatment status (on/off treatment), disease stage, treatment type,
body mass index, age, gender, education, emotional well-being,
alcohol use, and tobacco use on reliability and associations with diet
compliance would improve our ability to optimally use the social
cognitive theory to improve diet compliance and achieve resultant
benefits in HNCa patients.
Acknowledgments:
This project was supported by institutional support from the
University of Alabama at Birmingham and Southern Illinois
University (SIU) School of Medicine. In-kind support from the Center
for Clinical Research at SIU was also provided. The authors do not
have any relationships to disclose which would cause a conflict of
interest.
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