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| Journal of the New Zealand Medical Association,
08-June-2012, Vol 125 No 1356
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Dietary patterns and information needs of colorectal
cancer patients post-surgery in Auckland
Ryan Cha, Melissa J Murray, John Thompson, Clare R Wall,
Andrew Hill, Mike Hulme-Moir, Arend Merrie, Michael P N Findlay
Colorectal cancer (CRC) is the third most common cancer
worldwide.1 The incidence varies greatly from
one country to another with the highest rates present in North America,
Australia, New Zealand, Western Europe and
Japan.2
In New Zealand, it is the second most common cancer in
non-Maori and the fourth most common cancer in Maori
people.3 Despite the fact that CRC incidence
and mortality within the New Zealand population is generally decreasing, the
disease is still highly prevalent and a cause of substantial morbidity to many
New Zealanders.3
There are many studies that have explored the relationship
between diet and the development of CRC.4
Studies have suggested that a “Western diet,” characterised by high
meat, fat and refined grains intake, is associated with a significantly
increased risk of colon cancer, while a “prudent diet,”
characterised by high fruit, vegetable and fish intake is non-significantly
associated with a reduced risk of developing colon
cancer.5,6
Patients diagnosed with cancer are often eager to find out
about their diet, dietary supplement use and nutritional complementary
therapies, and they are motivated to adjust their dietary patterns
accordingly.1,7
The relationship between dietary factors and development of
colon cancer is strong worldwide, particularly relating to meat
consumption.8 Whereas the global average
consumption of meat and poultry contribute 9% to the total energy of diet, in
New Zealand meat and poultry provide around 20% of the total
energy,9 indicating that NZ diet favours meat.
This could in part account for the on-going high incidence of colon cancer in
New Zealand.9
It has recently been suggested that diet not only influences
CRC incidence, but also re-occurrence rates and survival post
treatment.10 A prospective study of 1009
patients with stage III CRC treated with surgery and adjuvant chemotherapy
demonstrated that people with a high intake of a Western-type diet had worse
disease-free survival at 5 years.10
Diet can affect gut mucosa either directly from the luminal
side or indirectly through whole-body
metabolism,11 and food-derived compounds can
shift the cellular balance towards harmful outcomes via genetic and/or
epigenetic changes.11 Thus diet may not only
affect the development of CRC but also patient outcomes post diagnosis. It is
therefore very important that appropriate, accurate and easy to access dietary
information is available for CRC patients.
Along with these potential effects on patient outcomes,
accurate and accessible dietary information is inherently important to this
patient group due to the symptoms of the disease and the side-effects of
treatment, and the impacts of these on quality of life. A previous survey
investigating overall patient satisfaction in CRC patients from the Auckland
region suggested that this patient group felt that they had unmet information
needs regarding dietary advice (M Murray, personal communication).
Another study in the CRC patient population of Southern DHB
(SDHB) also found that information needs were not being met, leading to the
development of a dietary guide for optimising health after treatment for
colorectal cancer called, “Healthy Eating after Colorectal Cancer”
(Pullar, Chisholm and Jackson, University of Otago, see article in the same
issue of the NZMJ).
The aim of this study was to pilot collection of data to
describe the dietary intakes and dietary patterns of CRC patients in the
Auckland region, and to investigate what the current information resources are
for CRC patients in the Auckland region, and patient satisfaction with these
resources.
MethodsParticipants were recruited from the three district
health boards in Auckland regions: Waitemata District Health Board (WDHB),
Auckland District Health Board (ADHB) and Counties Manukau District Health Board
(CMDHB). Eligible criteria included any patient with a diagnosis of CRC who had
received surgical resection (with curative intent) of their tumour in the last
1-4 months.
Patients with stage I tumours removed by polypectomy or
who had received palliative treatment (including palliative surgery such as
ileostomy formation) were excluded. Eligible participants were identified and
approached by local clinicians, registrars, clinical nurse specialists and
patient navigators within the surgical and medical oncology departments of the
Co-Investigators at each DHB. Participants either provided written or verbal
consent form to allow their name and address details to be given to the
researchers.
A study information sheet, consent form, decline
participation form, questionnaire and a reply-paid envelope were posted to each
of the patients whose details have been provided to the researchers. The
questionnaire was a modified version of the qualitative food frequency
questionnaire (FFQ) used by the New Zealand Ministry of Health in the National
Nutritional Survey 1997. 12 Demographics such
as gender, age and ethnicity were collected. The FFQ consisted of questions on
both dietary habits and food frequency consumption.
The dietary habits questions were based on the
frequency of consumption of the MoH core food groups (fruit and vegetables,
dairy products, breads and cereals and meat). The remainder of the questionnaire
included 168 food items and inquired about average frequency of consumption of
these foods.
Participants were asked to complete these questions
based on their normal food intake prior to surgery. There were up to 9 possible
responses, which ranged from never to 6 or more times per day. Data on age,
weight and height was collected in bands, as per previous questionnaires. Three
additional questions regarding vitamin and supplement use and nutritional
information needs were added to the questionnaire.
Participants were given 3 weeks to complete the
questionnaire. A reminder letter along with another copy of the questionnaire
and reply-paid envelope were sent to all participants who had not responded one
week prior to the end of the study period. Additional clinical data on
participant co-morbidities, the extent of disease (disease stage) and treatment
received were obtained from the participants’ medical records if specific
consent was given. Data from the questionnaires and medical records were
anonymised and entered into an Access database.
Demographic and dietary data were interpreted by simple
statistics. Dietary patterns were analysed by factor analysis (principal
component) of the food frequency questions using the FACTOR PROCEDURE in SAS
with a Varimax rotation factor. Ethics approval for this research project was
obtained from New Zealand Upper South A Regional Ethics Committee
(URA/11/EXP/023).
ResultsForty patients signed the release of information form and
were sent the survey. Of these, 6 declined participation and 29 returned signed
consent forms with completed surveys. The overall response rate was 35/40 (88%),
with 29 people taking part in the study by completing the surveys (73%).
Demographics—Table 1 shows the
attributes of the 29 participants. Most of the participants were New
Zealand/European (69%). The next most prevalent ethnic group was Maori (10%).
The majority of participants were males (69%). The most commonly selected age
band selected by participants was 70+. Forty-one percent of participants were
ex-smokers and 2 participants (7%) were current smokers. Four participants (14%)
did not specify their smoking status. Thirty-one and 48% of participants
respectively reported taking either none or less than 5 standard alcoholic
drinks per week.
Vitamin and supplement
use—Participants were asked if they took any dietary supplements,
vitamins, minerals and/or herbal supplements. 11 participants (37%) reported
vitamin or supplement use, with the majority reporting daily dosing. The most
common supplements were multivitamins or minerals and fish oil (both n=4,
36%).
Information needs—Participants were
asked if they had received any information on diet post operatively. Less than
half of the participants reported that they had received dietary information
after surgery (n=13, 43%). Participants were then asked if they felt that no
information, less information, the same amount of information or more
information should be available post bowel surgery. Nearly half of the
participants (n=14, 47%) suggested that they would like to have had more
information provided to them.
A third of participants were satisfied with the amount of
information provided to them (n=10, 33%). The remainder felt that less
information that what was provided to them was required (n=6, 20%)
Table 1. Summary of characteristics of the
study participants
Dietary characteristics—Participants
were asked about their consumption of a variety of foods and drinks, including
their self-reported eating pattern pre-operation. Participants were asked
whether they included animal products in their diet. Only 1 participant (3%)
reported avoiding meats other than fish and chicken.
Specific questions were asked regarding daily fruit,
vegetable and bread servings. Sixty-seven percent of participants reported
consumption of 2 or more servings of fruit per day (n=20). Fifty percent
reported daily vegetable servings of 3 or more per day (n=15, 50%). The most
common type of bread each was wholemeal or wholegrain bread, followed by white
bread. Nearly half of participants reported consumption of 1-2 slices of bread
per day (n=14; 47%).
Dietary patterns—Participant
responses to the food frequency questions were analysed by principal component
factor analysis to investigate if any dietary patterns could be described for
this patient group. Data was missing for a minimum of one variable of the
frequency analysis in 27 of 30 completed surveys (90%).
Participants who had greater than 50% of the data missing
for these questions were excluded from the analysis (n=2, 7%). For the remaining
participants, missing data was assumed to ‘never’ for the purposes
of analysis. Four dietary patterns were suggested by the principal component
factor analysis (Table 2.)
Table 2.The four dietary patterns of patients
with CRC in Auckland
DiscussionThis was a pilot study to investigate the feasibility of
collecting data on the diet and information needs of patients with CRC in
Auckland. The food frequency questionnaire, from the National Nutritional Survey
of New Zealand in 1997, was used to investigate dietary patterns and dietary
intake of these patients. The survey was completed by 75% of patients approached
to participate in the study, suggesting that the topic is relevant and of
importance to this patient group.
It is notable that only half of the study population met the
daily vegetable requirements and two-thirds the daily fruit requirements as in
the New Zealand Food and Nutrition Guidelines (FNG –MoH).
13 The fact that a significant proportion of
the study population are not meeting these requirements suggests that awareness
of the benefits of these food types needs to be improved in this patient group.
In contrast, wholemeal/wholegrain bread was the most popular
choice for our participants. This may reflect public awareness of the suggested
benefits of wholemeal breads. It has been found that high consumption of whole
grain foods, especially hard whole grain rye bread, may reduce the risk of colon
cancer. 14 It has also been shown to reduce the
risk of other chronic diseases including coronary heart disease, and diabetes.
15
In this study, 36% of participants reported use of one or
more vitamin or dietary supplements. This is the first time vitamin or
supplement use has been reported for this patient group in New Zealand. By
comparison in America, routine use of vitamin, mineral and other
non-vitamin-non-mineral dietary supplements is common among older persons, with
an estimated 50% of persons aged 57-85 years old reported as taking a dietary
supplement regularly (at least once per week).
16
This shows that in comparison to the general population of
the United States, New Zealand colorectal patients seem to take less vitamins
and/or dietary supplements. The association between vitamins and dietary
supplements and all-cause mortality (and thus mortality in CRC patients) is not
currently known. 17
The information collected was able to be used to suggest
four different dietary patterns present in this patient cohort as per principal
component factor analysis. The diets identified are distinct from those
identified in an American study on colorectal cancer and diet by Meyerhardt,
10 which is likely to reflect the distinct
population of Auckland, being a particularly multicultural city.
As this was a pilot study, the sample size is too small to
investigate association between the dietary patterns and specific ethnic groups.
These results confirm that this type of dietary assessment is useful and
appropriate in this patient population, and that future studies can use this
analysis to determine dietary types and their associations with outcomes.
A limitation of this study was the proportion of completed
surveys that contained missing data (n = 27, 90%). The survey was 12 pages long
and comprised of 23 dietary-related questions that varied in format between
single answer, multiple selections, and food frequency counts. Missing data in
multiple answer questions tended to be related to the question design which
included a yes/no selection relating to consumption of a particular food type,
followed by multiple selections of the food frequency consumption examples of
the food type if yes was selected.
Several participants did not select yes or no but then
selected examples of the food type, and thus were considered to eat the food
type. However the most common questions to contain missing data were the food
frequency questions.
Despite having the option of selecting “never”
many food types were left with no selection. This may have been because the
participant might not have known what some of the listed foods were, or found
the concept of allocating a frequency of consumption difficult. In other cases,
two ticks had been entered into the same row followed by a blank row, suggesting
that the participant had not moved on to the next row down.
There are several suggestions that could improve these
issues. Other studies using FFQs have included pictures of the food types to
improve understanding. The method most likely to substantially reduce missing
data is through interview collection of the survey data. The primary difficulty
with conducting surveys via interview is the time required, which was not
feasible in this pilot study.
Other limitations of this study include recall bias
regarding both recollection of dietary intake prior to surgery, and of
information given. Also, the tool used was a qualitative questionnaire that does
not collect information on portion size and caloric intake.
Of interest, 5 participants completed
all of the demographics questions on the first page of the survey except for
their smoking status, which was left blank. This may be due to tobacco
“denormalisation” within our society, which influenced social norms,
related to tobacco use, targeting tobacco products the tobacco industry and
smoking itself.18
With increased stigmatization and less acceptance towards
smoking, some participants may have been found it uncomfortable to state their
smoking status. People might also have found it personal issue, which might have
led them to decide that they have the right not to indicate it on the survey.
On the other hand, every participant has specified his or
her alcohol consumption. This shows that people may be more willing to openly
talk about alcohol than tobacco use.
More than half of the participants in this study reported
that they had not received any nutritional information post their surgery.
Almost half expressed that they felt more information should be provided. This
shows a significant unmet information need in this patient group. The authors
would like to suggest the implementation of a nationally standardized
nutritional information booklet for CRC patients, such as that developed by
Pullar et al. The effect of such an implementation could be quantified in a
randomised interventional study assessing both quality of life and survival
outcomes in New Zealand CRC patients.
ConclusionsThis study has demonstrated that the assessment of dietary
intake and patterns using an FFQ in this patient group is possible. Improvements
on the current FFQ for future diet-related studies would include more
user-friendly surveys and interview administration of surveys.
Currently, not all of the Auckland CRC patient population
are meeting the daily recommended servings of fruit and vegetables, which is
suggestive of a lack of nutritional knowledge. This is further strengthened by
our findings that the information needs with respect to nutritional advice post
surgery are not being met for this patient group.
Competing interests: None
declared.
Author information: Ryan Cha, Medical
Student, School of Medicine, The University of Auckland; Melissa J Murray,
Project Manager and Clinical Research Officer, Cancer Trials New Zealand,
Faculty of Medical and Health Sciences, The University of Auckland; John
Thompson, Senior Research Fellow, Paediatrics Department, Faculty of Medical and
Health Sciences, The University of Auckland; Clare Wall, Senior Lecturer,
Nutrition Department, Faculty of Medical and Health Sciences, The University of
Auckland; Andrew Hill, Professor of Surgery, Department of Surgery, Faculty of
Medical and Health Sciences, The University of Auckland; Mike Hulme-Moir,
General Surgeon, Waitemata District Health Board, Auckland; Arend Merrie, Head
Colorectal Surgical Unit, Auckland District Health Board, Auckland; Michael P N
Findlay, Professor of Oncology, Discipline of Oncology, Faculty of Medical and
Health Sciences, The University of Auckland
Acknowledgements: We thank all the
participants of our survey as well as the staff at the hospitals that aided
recruitment to the study.
Correspondence: Melissa Murray, Cancer
Trials New Zealand, Faculty of Medical and Health Sciences, The University of
Auckland, Private Bag 92019, Auckland, New Zealand. Fax: +64 (0)9 3737927;
email: m.murray@auckland.ac.nz
References:
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