1. Level of Dietary Adherence to WCRF/AICR
Recommendations among 75,131 Adventist
Health Study-2 Participants
Lap T. Le, DrPH(s)
Loma Linda University School of Public Health
3. Objectives
» Rationales: WCRF/AIRC Index, AHS-2 cohort
» Aims of study
» Methods: Operationalization of
WCRF/AIRC Index
» Results
» Discussion
» Conclusion
4. Rationale: WCRF/IACR » Most common
chronic diseases,
including cancers
are preventable
through modifiable
risk factors.
5. Rationale: WCRF/AICR
» The relationship between modifiable risk
factors and the major chronic diseases of
lifestyle, including cancer is complex and
intricate, and therefore requires a
comprehensive approach to assess risk
behaviors which encompass diets, physical
activity, and other intermediate risk factors.
6. Rationale:
Significance to Public Health
» The need to explore alternative measurements
to assess and effectively prescribe overall
dietary and lifestyle behavior recommendations
to the public for cancer prevention is warranted.
7. WCRF / AICR
» World Cancer Research Fund & American
Institute of Cancer Research (WCRF/AICR)
issued 8 recommendations (+2 special
recommendations) for cancer prevention.
~ Diet
~ Alcohol consumption
~ Physical activity
~ Weight management
8. WCRF/AICR Index-Based
Recommendations
1. Body fatness. Be as lean as possible without becoming underweight.
2. Physical activity. Be physically active as part of your everyday life.
3. Foods and drinks that promote weight gain. Limit consumption of
energy-dense foods; avoid sugary drinks.
4. Plant foods. Eat mostly foods of plant origin.
5. Animal foods. Limit intake of red meat and avoid processed meat.
6. Alcoholic drinks. Limit alcoholic drinks.
7. Preservation, processing, preparation. Limit consumption of salt.
Avoid moldy cereals (grains) or pulses (legumes).
8. Dietary Supplements. Aim to meet nutritional needs through diet alone.
9. Breastfeeding. Aim to breastfeed infants exclusively up to six months
and continue with complementary feeding thereafter.
10. Cancer survivors.* All cancer survivors to receive nutritional care from
an appropriately trained professional.
9. Rationale: WCRF/AICR
» Popular dietary index scores only dietary components
» Characterized at the level of nutrients, individual foods,
food groups, and 5 dietary patterns (non-veg, semi-,
pesco-, lacto-ovo, and vegan)
» WCRF/AICR Index assesses both diets and lifestyle
components (+ special recommendations)
~ Allows AHS-2 to generate a composite index score to
assess both dietary and lifestyle behaviors.
10. Why focus on AHS-2 cohort?
» Large cohort of ~96,000 Adventists in North America, with
unique & wide range of dietary patterns
~ 35% male; 65% female
~ 48% non-veg, 5% semi-, 10% pesco-, 29% lacto-ovo, and
8% vegan.
» Relatively small percentage of alcohol consumption and
cigarette smoking.
» Dietary, lifestyle, and breastfeeding variables.
11. Aims of Study
» To assess the degree of dietary adherence to
the WCRF/AICR recommendations among the
Adventist Health Study-2 (AHS-2) population.
» Compare the WCRF/AICR scores among
vegetarians and non-vegetarians.
12. Methods
» Constructed from the operationalization of
multiple dietary and lifestyle components, using
data from AHS-2 comprehensive questionnaires
including:
~ Quantitative FFQ
~ Lifestyle assessment questionnaires
» SAS 9.4 was used.
13. EXAMPLE:
WCRF/AICR
recommendations
Personal
Recommendations
Operationalization for
AHS-2 Cohort Score
3) Foods and drinks
that promote weight
gain. Limit
consumption of
energy-dense foods;
avoid sugary drinks.
3a) Consume energy-
dense foods sparingly
Consumed energy dense food less
than 150 kcals per 100 grams per day
1
Consumed energy dense food more
than 150 but less than 225 kcals per
100 grams per day
0.5
Consumed energy dense food more
than 225 kcals per grams per day
0
3b) Avoid sugary
drinks
Consumed sugary drinks equal to
zero gram per day
1
Consumed sugary drinks greater than
zero but less than 250 grams per day
0.5
Consumed sugary drinks greater than
250 grams per day
0
3c) Consume fast
foods sparingly, if at
all
Never or rarely consumed fast food or
consumed 1-3 times per month
1
Consumed fast food 1-3 per month or
once a week
0.5
Consumed fast food 4 times or more
per week
0
14. Methods
» Computed WCRF/AICR composite scores
~ Total score = ∑ score of each individual recommendations
» Higher scores indicate greater concordance with
recommendations.
~ 0 = poor diet/lifestyle quality
~ 16 = high diet/lifestyle quality (for AHS-2)
» Assumption of WCRF/AICR: Each major recommendation
should contribute equally to the total composite score.
17. Average
WCRF/AICR
Score for
Selected
Characteristics
among 75,131
AHS-2
Participants
Participant Characteristics Mean SD
Age, yrs
<50 8.97 1.86
50-64 9.14 1.82
>64 9.18 1.69
Educational level
High school or less 8.80 1.83
Trade school, associate degree, or some college 9.04 1.82
College graduates or higher 9.30 1.73
Smoking status
Never 9.22 1.75
Past 8.64 1.84
Current 7.13 1.88
Marital status
Never married 8.68 1.86
First marriage, remarried, Common Law marriage 9.12 1.78
Separated, divorced, widowed 9.14 1.82
Household income, $ per year
Less than 10,000 8.82 1.83
10,000 to 75,000 9.03 1.79
>75,000 to 200,000 9.18 1.77
More than 200,000 9.49 1.78
22. Summary
» The average composite score is 9.09, ranging from 2 to 16.
» There is a step-wise increase in the average WCRF/AICR
score moving toward a plant-based diet.
» Overall, non-black female vegans have better dietary and
lifestyle quality than their black non-vegetarian male
counterparts, with the average score being higher with
increased age, increased level of education, being married,
higher household income, and those who never smoked
cigarettes.
23. Discussion
» EPIC cohort:
score range 0-6 for males; 0-7 for females
~ Difference in operationalization for each
component among different studies
~ Not all studies have available data to satisfy all
10 recommendations outlined by the WCRF/AICR.
» Further improvements to better operationalize
individual components.
24. Conclusion
» Data collected from AHS-2 cohort were applicable to
9 out of 10 recommendations
~ Applying WCRF/AICR index to this cohort is appropriate
in assessing overall dietary and lifestyle behaviors
» Vegan dietary pattern may be a good surrogate measure for
healthy lifestyle
» WCRF/AICR scoring index could be used an exposure
variable relating to other outcomes.
Dr. Karen Jaceldo, my advisor and researcher faculty at Loma Linda University School of public health.
Rawiwan Sirirat is a fellow doctoral student, working on this research project.
The current burden from chronic diseases reflects the cumulative effects of unhealthy lifestyles and health behaviors including the consumption of diets excess in sugars, saturated fats, and salt, typical of "fast foods" diets, smoking, alcohol use, and the lack of physical activity.* These common dietary and lifestyle behaviors are expressed through intermediate risk factors such as raised fasting blood glucose, abnormal serum lipids, high blood pressure, and overweight/obesity. As a result, various chronic disease processes culminate in high incidence including heart disease, stroke, diabetes, and *cancers*, and many others contributing to morbidity and mortality. The key point is that most chronic diseases including cancer are preventable through modifiable risk factors including: nutritious diet, maintaining a healthy weight and regular physical activity.
We see that the relationships between modifiable risk factors and the major chronic diseases of lifestyle, including cancer is complex and intricate, and therefore requires a comprehensive approach to assess risk behaviors which encompass diets, physical activity, and other intermediate risk factors.
In addition, the need to explore alternative measurements to assess and effectively prescribe overall dietary and lifestyle behavior recommendations to the public for cancer prevention is warranted.
In 2007, the WCRF/AICR issued 8 recommendations (+2 special recommendations) which overall entails: diets, alcohol intake, physical activity, and weight management for cancer prevention.
More specifically, the WCRF/AICR recommendations entail:
Body fatness.
Physical activity.
Foods and drinks that promote weight gain.
Plant foods.
Animal foods.
Alcoholic drinks.
Preservation, processing, preparation.
Dietary Supplements.
Breastfeeding.
Cancer survivors.
Most popular dietary index scores (e.g., HEI, Diet Quality Index, and Recommended Food Score) used only dietary components. In AHS-2 study, diets have been characterized at the level of nutrients, individual foods, food groups, and 5 dietary patterns (non-veg, semi-, pesco-, lacto-ovo, and vegan). The WCRF/AICR Index assesses both diets and lifestyle components (including special recommendations). This give thes opportunity to use AHS-2 data to generate a composite index score to assess both dietary and lifestyle behaviors.
This is a large cohort of more than 96,000 Adventists in North America, with unique and wide range of dietary patterns, where 48% are non-veg, 5% semi-, 10% pesco-, 29% lacto-ovo, and 8% vegan. Of the total, 35% are males and 65% are females. In addition, this population has a relatively small percentage of alcohol users (6.6% current drinker) and cigarette smokers (1% current smoker), thus this reduces possible confounders due to non-dietary factors. More importantly, our data contains dietary, lifestyle, and breastfeeding variables applicable to the WCRF/AICR recommendations.
The aim of this study is to assess the degree of dietary adherence to the WCRF/AICR recommendations among the Adventist Health Study-2 (AHS-2) cohort, and to compare the index scores among vegetarians and non-vegetarians.
The score is constructed from the operationalization of multiple dietary and lifestyle components recommended by the WCRF/AICR, using data from AHS-2 comprehensive questionnaires including the quantitative food frequency questionnaires (FFQ) and lifestyle assessment questionnaires. In addition, SAS 9.4 was used in the analysis.
In order to compute an overall composite score, each of the components and subcomponents of the WCRF/AICR recommendations were coded to specified cut-off points. For our population, individuals were assigned a score according to their degree of adherence to the recommendations. For example*, individuals who consumed sugary drinks equal to zero gram per day were assigned 1. Individuals who consumed sugary drinks greater than zero but less than 250 grams per day were assigned 0.5. Those who consumed sugary drinks greater than 250 grams per day were assigned 0.
A composite score was computed from the sum score of each individual recommendations. For our population, 0 is the lowest score; and 16 is the highest possible total score. Higher scores indicates greater concordance with the WCRF/AICR recommendations.
An assumption of the WCRF/AICR is that each major recommendation should contribute equally to the total composite score.
This table shows the WCRF/AICR mean scores and range for the composite score, gender, race, and dietary patterns. For our study population, the average composite score is 9.1, with the range of 2 to 16. By gender, females have higher average scores than males. By race, non-blacks have higher average score than blacks. When stratified by dietary patterns, vegans have the highest average score compared to other dietary patterns. Vegetarians in general, have a higher score than the average composite score among the AHS-2 cohort.
This table shows the average WCRF/AICR score for selected characteristics among the 75,131 participants. The average score is higher with increased age, increased level of education, being married, greater household income, and those who never smoked cigarettes.
This graph here shows the average WCRF/AICR score according to the dietary patterns. There appears to be a step-wise increase in average composite score toward a more plant-based diet. Non-vegetarians have the lowest score, and vegans have the highest score.
The graph here shows the average score according to gender and by race. Females have consistently higher scores than their male counterparts for black and non-blacks. Non-blacks have higher scores than blacks.
Among males, there is a step-wise increase in average WCRF/AICRF score towards a plant-based diet. Vegans tend have better scores than other dietary patterns in blacks and non-blacks. Non-vegetarians consistently have lowest scores. Similar trends are observed in females.
The average composite score is 9.09, ranging from 2 to 16. There is a step-wise increase in the average WCRF/AICR score moving toward a plant-based diet. Overall, non-black female vegans have better dietary and lifestyle quality than their black non-vegetarian male counterparts, with the average score being higher with increased age, increased level of education, being married, high household income, and those who never smoked cigarettes.
The WCRF/AICR scores represent a comprehensive healthy lifestyle index. In the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, the score ranges from 0 to 6 for males, and 0 to 7 for females. This observed difference is due to differences in the operationalization depending on the availability of the collected data, and interpretation for cut-off points specific to the study population. Not all studies have available data to satisfy all 10 recommendations outlined by the WCRF/AICR. There is a need to compare to other studies with similar operationalization criteria using the WCRF/AICR recommendations. This provides opportunities for further improvements to better operationalize the recommended individual components, and make meaningful comparisons between studies cohorts.
Data collected from AHS-2 cohort were applicable to 9 out of 10 recommendations. Thus, applying WCRF/AICR index to this cohort is appropriate in assessing overall dietary and lifestyle behaviors. Our study suggest that vegan dietary pattern may be a good surrogate measure for healthy lifestyle. Future studies could explore WCRF/AICR scoring index as an exposure variable relating to various outcomes including cancers and other chronic diseases of lifestyle.
