Dietary patterns Flashcards
1
Q
What are four CVD facts?
A
- Affects about 7 million in the UK
- More than 1/4 deaths in England
- > 15% total disability adjusted life years in England
- More vulnerable for higher deprived using index of multiple deprivation
2
Q
What are general CVD risk factors?
A
Age, gender, obesity, diet, smoking, inactive excessive alcohol, hypertension, high cholesterol levels, diabetes, dyslipidaemia, insulin
3
Q
What are specific diet risk factors?
A
- Higher dietary fat, especially trans and sat fat (increases atherosclerosis risk)
- Increased sodium (increases hypertension risk)
- Low WG, F&V, nuts and seeds, omega 3, polyunsaturated FA, fibre
4
Q
What effect does fruit and vegetables and dietary fibre have against CVD?
A
A protective effect
5
Q
What happens when you increase saturated fat intake from meat?
A
increased LDL (bad) cholesterol
6
Q
What does research between red meat and CVD show?
A
Contrasting results, difference between processed meat and read meat due to saturated fat and cholesterol amounts
7
Q
What was the largest contribution to the population level CVD mortality burden (both sexes - European CVD stats 2017)
A
Dietary risk factors
8
Q
What does dietary patterns look at?
A
Specific nutrients/foods and their related disease outcomes
9
Q
What is the dietary patterns approach definition?
A
Qualities, quantities, proportions, variety or combinations of different foods and beverages in diets, and the timing, location, frequency with which they are habitually consumed
10
Q
What are the advantages of dietary patterns?
A
- More comprehensive representation of dietary intake (foods, not isolated nutrients)
- Incorporates some of the complexity of food intake
- Captures aspects of dietary behaviour and food choice
11
Q
What is the public health perspective of dietary patterns?
A
It is advantages to be able to identify subpopulations with particular dietary patterns to provide informed dietary recommendations, tailored interventions and monitor changes in patterns
12
Q
How are dietary patterns measured?
A
Not directly
13
Q
What are three methods of assessing dietary patterns?
A
- Index/score
- Data-driven methods
- Specified dietary patterns
14
Q
What is the index/score method?
A
- Uses priori (before data collection) index/score selected at the start
- Scoring system is based on dietary recommendations
- Selected individuals are scored by comparing diet to index/score system
- Externally imposed structure, i.e. index based
15
Q
What are examples of index/scoring methods?
A
- Mediterranean diet score
- Healthy eating index
- DASH score
16
Q
What are the two types of data driven methods?
A
- Cluster analysis
- Factor analysis
17
Q
What is cluster analysis?
A
- Consider dietary intakes then determine groups of people with district patterns e.g. food diary
- Groups are mutually exclusive and relatively homogenous
- Groups are described/defined in terms of the dietary pattern they hold e.g. western diet
18
Q
What is factor analysis?
A
- Consider dietary intakes and then determine foods that are correlated and track together to explain differences in intake across patterns
- Based on dietary intake, elements of diet are identified
- Relationships between dietary patterns and health outcomes examined
19
Q
What are specified diets?
A
- Categorise individuals based on having specified diets or not
- Consider intakes and preferences of individuals
- Typically based on self-reported patterns, not dietary assessment and on what foods are excluded e.g. vegan, pescatarian
20
Q
Summarise the dietary patterns methods?
A
- Selective diets is people who meet/don’t meet criteria
- Index/scores is individual scores on quality and its components
- Cluster analysis: groups of individuals and diet patterns
- Factor analysis: factors explaining variation in individual scores
21
Q
Define the Mediterranean diet?
A
- High intake of fruit and vegetables, nuts, legumes, wholegrain, olive oil, fish, cheese/yogurt, monounsaturated and saturated FA
- Reduced intake of meat, meat products, dairy
22
Q
Define the Western diet?
A
- Increased fat, protein, salt, processed food, fast food, red meat, butter, high fat dairy products, eggs, added sugar, refined grains
- Low intake of fruit & vegetables, wholegrain, fibre
23
Q
Define prudent diet?
A
- Higher fruit and vegetables, legumes, wholegrain, fish, other seafood
24
Q
What are the disadvantages of dietary patterns?
A
- Methods e.g. food diary, introduce bias and error
- Dietary patterns not universally or specifically defined by researchers, no specific number or specification
25
What to be aware of when considering evidence between studies?
- Studies may have the same dietary pattern but different definitions
- Participant treatments may differ e.g. support or not, food provided by researcher or not
- Different scoring methods and versions of scores, dietary patterns may be population specific
26
What was the New American Plague?
CHD
27
When was the Seven Countries Study carried out and by who?
1950s/60s
| Pett et al
28
How many participants in the SCS?
1200 healthy middle aged men in many countries (7)
29
What was the objective of the SCS?
Explore association of diet and lifestyle and disease rates between populations and among individuals, particularly looking at CHD
30
What risk factors were identified as affecting heart attack rates/longevity of participants?
Smoking, blood pressure and high cholesterol
31
How were meats, fish and dairy products used?
As condiments rather than focus of the meal
32
What did the SCS find?
about 10 fold difference in incidence heart disease and mortality between Mediterranean diet and north Europe diet
33
What else did the study find?
Documented a correlation between saturated fat intake and CVD
34
Why is defining MeDiet problematic?
- Broad geographical area
| - Variations in relevant aspects e.g. cultural, religions, agriculture
35
What was different about the initial studies?
The population had increased olive oil, fish, meat, wile greens and physical activity, but decreased energy intake. Also partly Greek Orthodox Christians e.g. fasting/not eating meat, dairy etc
36
How is MeDiet characterised? (Ros et al)
- High olive oil
- High plant foods
- Frequent but moderate wine (esp. red) with meal
- Moderate consumption of fish, seafood, yogurt, cheese, poultry and eggs
- Low red, processed meat and sweets
37
What are suggestions to upgrade MeDiet?
- Change from common olive oil to extra virgin
- More nuts, fatty fish and wholegrain cereal
- Less sodium intake
38
What is the main study for CVD and Mediterranean?
PREDIMED
39
What is PREDIMED?
Landmark study (gold standard with nutrition and health outcomes) assessed long term effects of MeDiet on CVD in men and women at high risk
40
What kind of trial is PREDIMED?
Randomised control trial
41
When did PREDIMED occur and how many?
- 2003 - 2011
- 7447 participants
- Spain
42
Where were the participants recruited from in PREDIMED?
Primary care facilities (high risk of CVD but no clinical disease)
43
What was the recruitment criteria in PREDIMED?
- 55-80 years
- Presence of diabetes or >/= 3 risk factors (smoking, overweight or obese, hypertension, dyslipidemia, family history of early onset CVD)
44
What were the groups in PREDIMED?
- MeDiet + EVOO (2543)
- MeDiet + Nuts (2454)
- Control (2450)
45
Who was the support from? PREDIMED
- Dieticians and participants were coached to follow dietary pattern
46
What was used to assess accuracy? PREDIMED
MeDiet score, FFQ, biomarkers for EVOO (urinary hydroxytirosol) and nuts (plasma alpha-linolenic acid) in subsamples to check they were eating
47
What diet changes came about from this? PREDIMED
- Intervention groups had significant increase in fish and legume consumption and olive oil / nuts for groups as provided
- Non significant reduction in refined grains, red meat
48
What was the primary end point? PREDIMED
Incident of CVD (aggregate of non-fatal myocardial infarction, non-fatal stroke and CVD death)
49
What happened after 4.8 years? PREDIMED
288 major CV events occurred
- 96 from MeDiet + EVOO (3.8%)
- 83 from MeDiet + nuts (3.4%)
- 109 control (4.5%)
50
What are the hazard ratios? PREDIMED
- MeDiet + EVOO: 0.70 (95% cl: 0.53-0.91, p=0.009)
| - MeDiet + nuts: 0.70 (95% cl: 0.53-0.94, p=0.02)
51
What are the rates of the primary end point? PREDIMED
- 8.1 MeDiet + EVOO
- 8.0 MeDiet + nuts
- 11.2 control
* per 1000 person / year
52
What is the effect on all cause mortality? PREDIMED
None
53
Why did the trial end after 4.8 years? PREDIMED
- Early evidence of benefit
| - Under ethical reasons
54
PREDIMED summary?
- MeDiet groups about 30% reduction in risk of major CVD events
- favourable changes in treatment groups: HDL-c, total-c : HDL-c ratio and TG when compared to control diet group
55
What happened with PREDIMED retraction?
- June 2018
- New England Journal of Medicine retracted 2013 paper as error in randomisation procedures affecting a portion of participants
56
What was the error in PREDIMED?
- 21% of participants (1588 of 7447) incorrectly randomised
57
What happened after the error? PREDIMED
- Journal published corrected version with newly analysed data: authors present similar results, toned down conclusion so weaker overall evidence
58
What was the Lyon diet heart study?
RCT to test whether MeDiet reduces recurrence after first myocardial infarction compared with a prudent western-type diet
59
What were the two randomised groups the patients surviving a first MI were separated into? Lyon diet heart
- Experimental group: asked to comply with a MeDiet
| - Control group: advised to follow a prudent diet
60
What are the 3 composite outcomes? Lyon diet heart
combinations of cardiac death, myocardial infarction and some outcomes secondary end points (unstable angina, stroke, heart failure, pulmonary or peripheral embolism)
61
What is composite outcome 1? Lyon diet heart
Cardiac death and MI
62
What were the findings of Lyon diet heart study?
- MeDiet gp (14 events vs. 44 in prudent Western-type diet gp, p=0.0001)
- Adjusted risk ratios for MeDiet ranged from 0.28 to 0.53
63
What is the conclusion of Lyon diet heart study?
The protective effect of the Mediterranean dietary pattern was maintained up to 4 years after the first infarction, confirming previous intermediate analyses
64
Who and when was a MeDiet and cardiovascular risk factor systematic review carried?
Grosso et al, 2014
65
What did the systematic review do?
Systematically review & analyze epidemiological evidence on the role of MeDiet in the prevention of cardiovascular diseases (CVD)
66
How many studies were involved in the systematic review?
58 (33 cross-sectional, 9 cohort, 16 intervention studies)
67
What were the outcomes in the systematic review?
Lipoprotein concentration, antioxidative capacity, inflammatory markers, hypertension, obesity, diabetes, metabolic syndrome
68
What were the findings of the systematic review?
Most showed favourable effects of MeDiet on CVD
69
What were the limitations of the systematic review?
Key differences between studies in terms of methodology & limitations restricted comparisons
70
What did authors of the systematic review recommend?
Further research, especially RCTs to substantiate benefits of MeDiet and shed new light on mechanisms
71
What did the Cochrane review look at?
RCT studies and another requirement was Mediterranean dietary pattern was defined as comprising at least two of the following components:
(1) high monounsaturated/saturated fat ratio,
(2) low to moderate red wine consumption,
(3) high consumption of legumes,
(4) high consumption of grains and cereals,
(5) high consumption of fruits and vegetables,
(6) low consumption of meat & meat products and increased consumption of fish, and
(7) moderate consumption of milk and dairy products.
72
Why were those components chosen?
- They were relevant to MeDiet as defined by reviewers and ranged from 2 to 5
- Only 7 trials specified the intervention as a MeDiet
- PREDIMED not included as they were coached
73
What did the comparison groups receive in the Cochrane review?
No intervention / minimal
74
What did outcomes include in the Cochrane review?
Clinical events and CVD risk factors
75
Describe the variation between trials in participants? Cochrane review
- 4 trials women only; 2 trials men only; 5 both men and women
- 5 trials healthy individuals; 6 trials those at increased risk of CVD/cancer
76
What was the largest trial in the Cochrane review?
Postmenopausal women, (not described as already following MeDiet, meeting only 2 of criteria) reported no difference in CVD between intervention and control groups
77
What were the main results of the Cochrane review?
- Small decrease in total cholesterol ((-0.16 mmol/L, 95% confidence interval (CI) -0.26 to -0.06) and LDL cholesterol (-0.07 mmol/L, 95% CI -0.13 to -0.01) with the intervention)
- Reduction in total cholesterol greater in studies specifying intervention as MeDiet
- Reductions in blood pressure were seen in 3 of 5 trials reporting this outcome
78
What were the authors conclusions of the Cochrane review?
Limited evidence suggests some favourable effects on CV risk factors. More comprehensive interventions describing themselves as the Mediterranean diet may produce more beneficial effects. Further trials required to examine effect of the different participants and dietary interventions to inform appropriate interventions
79
Summarise the MeDiet effects on CVD?
- Evidence supports benefits of MeDiet and CV health, further evidence is recommended
- MeDiet associated with beneficial effects on CVD risk factors e.g. hypertension, diabetes
80
What are the suggested mechanisms of MeDiet against CVD?
- ↓ low-grade inflammation, ↓oxidative stress, ↓blood coagulation, enhanced endothelial function
- Many aspects unknown and research is ongoing to fully describe the metabolic pathways through which MeDiet might confer CV benefit
81
How might vegetarian diet reduce CVD risk?
- ↓ risk metabolic syndrome, diabetes, CHD: data unclear for stroke
- benefits for blood pressure (limited, moderately consistent trends)
- ↓ prevalence of overweight and obesity
82
How does mortality compare between vegetarians and non-vegetarians?
Mortality similar for vegetarians and comparable non-vegetarians, but vegetarian groups compare favourably with the general population
83
What did Huang et al (2012) find?
Meta analysis of 7 studies of vegetarian diet and CVD mortality reported IHD mortality significantly lower in vegetarians than in non-vegetarians [RR=0.71]; 16% lower mortality from circulatory diseases in vegetarians compared to non-vegetarians
84
What is the Adventist Healthy Study-2 (AHS-2)?
A long term cohort study involving 96,000 participants U.S and Canada recruited 2002-2007
85
Describe the participants of the AHS-2?
- Aged 30 to 112 (mean enrolment age 60.2)
- From all 50 US states (inc Canada)
- 64% members of the Adventist church by 15 years old
- 65.1% female
86
What was the dietary status of study members?
- 8% vegan
- 28% lacto-ovo vegetarian (consume milk and/or eggs, no red meat, fish, poultry)
- 10% pesto-vegetarian (eat red meat, poultry, fish less than once per week)
- 6% semi-vegetarian (eat red meat, poultry, fish less than once per week)
- 48% non vegetarian (eat red meat, poultry, fish, milk and eggs more than once a week)
87
What was the aim of the AHS-2 study?
To examine relationship between vegetarian dietary patterns and all-cause and cause-specific mortality
88
How was diet assessed in AHS-2 study?
Diet assessed at baseline FFQ; participants categorised into 5 dietary patterns: nonvegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo–vegetarian, vegan
89
What were the results of AHS-2 study?
- all-cause mortality in all vegetarians combined vs nonvegetarians HR 0.88 (95% CI, 0.80-0.97)
- HR for all-cause mortality in vegans was 0.85 (95% CI, 0.73-1.01);
- lacto-ovo–vegetarians, 0.91 (95% CI, 0.82-1.00);
- pesco-vegetarians, 0.81 (95% CI, 0.69-0.94);
- semi-vegetarians, 0.92 (95% CI, 0.75-1.13) compared with nonvegetarians
- Some associations of vegetarian diets with lower CV mortality for men, CVD mortality (0.71; 0.57-0.90); IHD mortality (0.71; 0.51-1.00)
90
What conclusions did the AHS-2 study make?
Vegetarian diets are associated with lower all-cause mortality and with some reductions in cause-specific mortality. Results appeared to be more robust in males.
91
What does DASH stand for?
Dietary Approaches to Stop Hypertension
92
What is the DASH dietary pattern?
- rich in F&V, low-fat dairy, WG, poultry, fish, and nuts;
- limited saturated fat, SSB (sugar sweetened beverages), sweets and red and processed meats
93
What does the DASH diet lead to compared to usual diets?
- ↑in fiber, potassium, magnesium and calcium and protein
| - ↓in sodium, sat fat, total fat, and dietary cholesterol
94
What was DASH designed to do?
Normalise blood pressure in individuals with hypertension, evidence confirms its benefits
95
How might the DASH positive effects work?
reducing insulin resistance, controlling fasting blood sugar and lipid profiles
96
Which recent systematic review and meta-analysis supported a DASH dietary pattern as beneficial for CV health?
Salehi-Abargouei et al, 2013
| - 6 studies meta analysis
97
Describe Salehi-Abargouei et al (2013) findings?
```
DASH-like diet can significantly reduce: CVD (RR = 0.80; 95% confidence interval [CI], 0.74-0.86; P < 0.001),
CHD (RR = 0.79; 95% CI, 0.71-0.88; P < 0.001),
stroke (RR = 0.81, 95% CI, 0.72-0.92; P < 0.001),
heart failure (RR= 0.71, 95% CI, 0.58-0.88; P < 0.001)
```
98
What is the conclusion of Salehi-Abargouei et al (2013)?
DASH-like diet can significantly protect against CVD, CHD, stroke, and HF risk by 20%, 21%, 19% and 29%, respectively. Furthermore, there is a significant reverse linear association between DASH diet consumption and CVDs, CHD, stroke, and HF risk
99
Which Japanese population is of interest due to its CV benefits?
Okinawa, low CHD rates
100
What is a traditional Japanese diet?
Higher amounts of soybean products, fish, seaweeds, F&V, green tea and lower amounts ofmeats
101
What is the down side of Japanese diets?
High sodium [soy sauce, added salt] probably contributing to relatively high incidence of stroke & some cancers
102
Summary of Japanese diets?
Japanese dietary patterns are promising – however further research is called for re. high rates of stroke and some cancers and epidemiological & trial evidence is limited compared to e.g. DASH and MeDiets
