Studies related to Lifestyle Medicine Flashcards
- In relation to Lifestyle heart Trial for CAD by Ornish which of the following options are incorrect:
A. It was a randomised double blind controlled trial
B. A low carbohydrate diet was compared with the American Heart Association Step 2 diet.
C. LDL reduction in experimental group compared to lipid lowering drugs in ambulatory population was 40% at one year.
D. The treatment group had a 7.9% reduction in coronary stenosis at 5 years while the controls had a progression of 27.7% for a net difference of -35.6%
E. The controls who were not taking lipid lowering medication had a progression of 46.7% for a net difference of -54.6%
A and B are incorrect.
A. it was a randomised parallel design.
B. low fat diet (10% fat) was compared with the AHA step 2 diet
- The following are components of multifactorial life style intervention in the Lifestyle Heart trial ( Ornish) except
A. Low fat vegetarian diet ( Fat constituted 10% on total calories)
B. Anaerobic exercise
C. Stress management
D. Smoking cessation
E. Group psychosocial support
B Aerobic exercise was included, not anaerobic
- In relation to Lifestyle Heart Trial (Ornish), which one is incorrect:
A. LDL reduction 40% at 1 year and 20% at 5 years in the experimental group
B. AHA step 2 diet LDL reduction 5% or less
C. Rate of cardiac events almost 2x in control group vs experimental group (45 vs. 25)
D. At 1 year 91% reduction in anginal episodes in experimental group compared to control group where there was165% increase in anginal episodes.
E. 50% lost to follow up.
E: 27% lost to follow up.
No lipid lowering medications were used
5-year RCT
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- Diabetes Prevention program Research Group, all of the following are true except:
A. NNT to prevent 1 case of diabetes for Metformin group was 6.9 and for life style group it was 13.9
B. Life style program goal was 14% weight loss and 300 minutes of physical exercise per week.
C. Placebo vs Metformin group: Metformin reduced diabetes incidence by 31%
D. Placebo vs Lifestyle group: Life style group reduced incident of diabetes by 58%.
A and B
A: 13.9 in metformin group and 6.9 in life style group
B: Goal 7% weight loss and 150 minutes/week of physical exercise.
- DASH diet Dietary approaches to stop HT which one is incorrect
A. previously called combination diet
B. diet low in sodium
C. the greatest reduction in BP with DASH diet which was low in sodium. compared to control diet high in sodium.
D. SBP reduction of 7.1 mmHg in HT patient and SBP 11.5 reduction in non HT patient.
D. SBP reduction of 11.5mmHg in HT patient and SBP 7.1 reduction in non HT patient.
DASH
compared *control diet
*diet rich in fruit and veg
*combination diet rich in fruit, veg, low fat dairy products, reduced in sat fat, total fat and dietary cholesterol
weight and sodium intake were constant between groups.
Fruit and veg diet reduced BP more than control diet.
combination diet had greatest reduction. its was true for both patient with HT or without HT.
Those with HT BP reduction SBP 11.4 mmHg
DBP 5.5mmHg compared with control diet.
- Portfolio diet for treatment of Hypercholesterolemia. which option is incorrect?
A. Diet very low in saturated fat
B Low in plant sterols, soy protein, viscous fiber and almonds.
C 28.6% reduction in LDL-C with portfolio diet.
D. 30.9% reduction in LDL-C with 20mg Lovastatin
B its high not low
- Lyons diet heart Study looked at secondary prevention of CHD mediterrnean diet vs AHA step 1 diet
Mediterranean arm had fewer of the composite CVD outcomes. results maintained at 4 years study follow up after each participant’s first MI.
- Esselstyn plant based diet for CAD.
A very low fat plant based diet was shown to reverse and prevent major cardiac event in 177 adherent patient over 3.7 years, Among 177 adherent patient cardiac event rate was 0.6%. among 21 non adherent patients 13 ( 62%) experienced major cardiac events.
The CHIP complete health improvement program and plant based dietary intervention with cost savings.
The program was found to be effective in treating type 2 DM and to have a positive return on investment with in a few months.
percutaneous angiography compared with exercise training in patient with stable CAD.
- to determine if patients with stable CAD can improve myocardial perfusion and reduce disease progression
- to compare the effects of exercise training to standard PCI with stenting on: clinical symptoms, angina free exercise capacity, myocardial perfusion, cost effectiveness, frequency of combined cardiac events
( death of cardiac cause, CABG, angioplasty, Acute MI, worsening of angina resulting in hospitalisation) - duration 12 months
- 101 male patient <=70 Germany
- Ergo spirometry
- 20 mins of bicycle ergometry
- cost effectiveness was calculated on average expanse US dollars needed to improve the Canadian cardiovascular society class by 1 CCS
*
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Key results: exercise training associated with
- high event free survival 88% vs 70% for PCI resulting in 26% low risk in exercise group than PCI group.
- increased O2 uptake 16%
- increased exercise tolerance to by 20%
- increased ischaemic threshold by 30%
- significantly increased HDL after 12 months HDL decreased in control. LDL remained unchanged during study period.
- in the PCI group only ischaemic threshold showed a significant increase after 12 months.
- clinical symptoms improved in both groups
- to gain 1ccs class $6956 PCI vs $3429 in training group
- in both groups symptoms significantly improved
- physical work capacity increased 133w to 159w in exercise group but no change in PCI group
- resting heart rate was low in exercise group and the maximal heart rate and Vo2 max higher in exercise group at the end of the study.
- exercise training more cost effective due to lower repeat hospitalisations and revascularisation as exercise capacity improved in exercise group.
VO2 max: 22.6 ml/kg to 26.2in exercise group
22.3 to 22.8 in PCI group.
Comparison of Atkins ( low carb), Ornish (Low Fat), Weight Watchers ( calorie restriction) , and Zone’s diet (macronutrient balance) for weight loss and heart disease.
- RCT one year JAMA 2005 Boston MA USA
- Each diet reduced LDL/HDL ratio by 10% and no significant effect on glucose or BP @ one year.
- the amount of weight loss was associated with self reported dietary adherence levels but not with diet type.
- for each diet weight loss was associated with decreased total cholesterol and HDL ratio, CRP and insulin with no significant difference between diets.
- overall adherence rate was low. <25%
- 160 patients 40 each for each diet.
- discontinuation rate 50% for Ornish, 48% for Atkins both extreme diets, 35% for Zone and WW both Moderate diets: reason not yielding enough weight loss and too hard to follow.
- Adherence and intensity of intervention is more important than the specific diet for weight loss. Intensity is directly related to adherence.
The Geminal Study: Gene expression modulation by intervention with nutrition and lifestyle: Ornish Magbanua USA 2008
Pilot study to determine changes in prostate gene expression in a population of men with low risk prostate cancer undergoing intensive nutrition and life style intervention.
* N; 30
* 3 days intensive residential retreat followed by an outpatient phase of weekly tel contact.
* careful surveillance of tumour progression.
* outcomes significant improvement in weight, abdo obesity, BP, lipid profile,
* biopsy taken before and 3 months post intervention
*pairing in RNA samples
* low fat 10% calories from fat, whole food plant based diet, patients were provided with all their food,
diet was supplemented with Soy ( a daily serving of Tofu, 58gm of fortified soy protein, powdered beverage) fish oil 3gm daily, vit E 100 units daily, selenium 200mg daily, vit C 2gm daily
* stress management: 60 mins of daily yoga based stretching, breathing meditation, imagery, or progressive relaxation.
* moderate aerobic exercise 30 mins walking /day 6 days a week.
* a one hour of group support session per week.
* after 3 months they reported: 11.6% of fat cal/day, exercising 3.6 hours/week, and practising stress management 4.5 hours/week.
*limitations: small group, absence of comparison group: this prevents us from definitely saying that gene expression changes are due to the comprehensive lifestyle modification and not due to normal changes in the gene expression.
Large RCT needed.
* Bonferroni correction: to correct large no: of data points.
* only 30% biopsies had tumour tissue. these results are based on normal tissue for male with prostate cancer. This indicate that lifestyle modifications can affect cancer and normal tissue and benefits of lifestyle modifications not only restricted to gene associated with prostate Ca.
although the results are largely based on normal tissue in male with prostate cancer that doesn’t mean that the results indicate that life style modifications doesn’t apply to prostate cancer.
Questions:
1. The following statements related to Geminal Study are true:
A: late stage prostate cancer was studied in 300 men.
B. It was a RCT.
C. Significant improvement in Weight, Abdo obesity, BP, lipid profile
D. diet was 10% cal from carbohydrates.
F. 60mins of Tai Chi based stretching.
G. after 3 months they reported: 11.6% of fat cal/day, exercising 3.6 hours/week, and practising stress management 4.5 hours/week.
H. large study carried out for a year.
Answer: CG
Reversal of Type 2 Diabetes: Normalisation of Beta Cell Function in Association with Decreased Pancreas and Liver Triacylglycerol
Hollingsworth et al, 2011
P347 of manual
Objectives
1) Can both beta cell failure and insulin resistance be reversed by dietary restriction of energy intake?
2) Does acute negative energy balance alone reverse Type 2 Diabetes by normalising both beta cell function and insulin sensitivity?
Study design
Case-control study (intervention study)
Intervention group
N=11
Type 2 Diabetes
Age 35-65 yrs
HBA1c 6.5-9.0% (48-75mmol/L)
Diabetes duration < 4yrs
BMI 25-45kg/m2
Asked to continue their habitual pattern of eating till start of the study.
For the study, restricted 600 calorie/day diet and statin therapy continued
Control group
N=9
Matched for weight, age, sex
Assessments of beta cell function, insulin sensitivity, liver and pancreatic fat content and total body fat at:
Baseline (day -1), after 1, 4 and 8 wks of low-energy diet
Results
After one week of restricted energy intake
- Fasting plasma glucose normalised in diabetic group
- Insulin suppression of hepatic glucose output improved vs control group
- Hepatic triacylgycerol content fell in diabetic group by week 8
- First-phase insulin response increased during study period and approached control values
- Maximal insulin response became supranormal vs controls
- Pancreatic triacylglycerol decreased
Strengths
- Demonstrated for the first time that normal blood glucose levels without medication achievable after 1 week with a very low energy diet and accompanied by reversal of hepatic and pancreatic triacylglycerol in the subsequent 3-4 weeks.
Limitations
- Small sample size (necessary to allow for metabolic investigation and examination by magnetic resonance techniques)
- Pancreatic fat measurements included intraorgan adipocyte fat content because current methodology precludes assessment of the more mechanistically important islet intracellular fatty acid content. Animal data suggests the two variables are linked.
- Participants selected to have a relatively short duration of Type 2 DM (up to 4 years). Further studies must establish the extent of reversibility with longer duration Type 2 DM.
- Observations made after 12 weeks of return to a normal diet limited.
- The G allele of the PNPLA3 gene determines high liver fat levels, but in a form that is not associated with metabolic abnormality. Provides a clear genetic basis for the observed individual variation in susceptibility to insulin resistance despite raised liver fat content, and offers a partial explanation of the overlapping hepatic fat levels in type 2 diabetic and control groups. Likely other genetic factors yet to be defined.
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Conclusions
- Normalisation of both beta cell function and hepatic insulin sensitivity in Type 2 diabetes achieved by dietary energy restriction alone. Associated with decreased pancreatic and liver triacylglycerol stores.
- Abnormalities underlying Type 2 Diabetes reversible by reducing dietary energy intake.
Questions
1) Which of the following statements about this study is false?
a. The study used a case control design.
b. Participants were selected to have a short duration of Type 2 Diabetes- < 2 years.
c. The primary outcomes were beta cell function and insulin sensitivity.
d. Participants were asked to continue their usual pattern of eating until the start of the study.
2) Which of the following statements is true regarding the intervention group?
a. HBA1c 48-75mmol/L
b. Diabetes duration <8yrs
c. Participants asked to continue their habitual pattern of eating until one week before the start of the study.
d. Age 35-70 years
3) Which of the following statements is true regarding the methodology?
a. N=15 in the intervention group.
b. Participants in the intervention group were asked to discontinue their statin medication.
c. Assessments of beta cell function, insulin sensitivity, liver and pancreatic fat content and total body fat were carried out at baseline immediately prior to dietary intervention (day -1) and after 1,4, and 12 weeks of the very low-energy diet.
d. Participants were on a restricted 600 calorie per day diet during the study.
4) Which statement accurately describes the key conclusions of the study?
a. After one week of restricted energy intake, fasting plasma glucose did not normalise in the diabetic group.
b. The first phase insulin response decreased during the study period.
c. Normalisation of both beta cell function and hepatic insulin sensitivity in Type 2 Diabetes was achieved by dietary restriction alone.
d. Pancreatic triacylglycerol increased.
Answers: 1)b 2)a 3)d 4)c
The DIETFITS Randomized Clinical Trial (The Diet Intervention Examining The Factors Interaction with Treatment Success) JAMA 2018
By Gardner, Trepanowski , Del Gobbo
Objective
To determine the effect of a healthy low-fat diet versus a healthy low-carbohydrate diet on weight
change, and to determine whether genotype pattern or insulin secretion are related to the dietary
effects on weight loss.
Study design
12-month randomized clinical trial
Sample population
N = 609 adults (18–50 years old) without diabetes with a body mass index (BMI) of 28–40.
Location/venue
Not specified
Intervention
Health educators delivered the behaviour modification intervention to the healthy low-fat participants, (N = 305) and the healthy low-carbohydrate participants, (N = 304) via 22 diet-specific small group sessions administered over 1 year.
Control group
N/A
Outcome(s) of interest
• Effects of a healthy low-fat diet vs a healthy low-carbohydrate diet on weight change
• Relationship of genotype pattern or insulin secretion to dietary effects on weight loss
Summary of methods and intervention
N = 609 overweight adults. Participants were randomized to the 12-month healthy low-fat (HLF);
(N = 305) or healthy low-carbohydrate (HLC); (N = 304), diet.
Key results
• Among 609 participants, 244 (40%) had a low-fat genotype; 180 (30%) had a low-carbohydrate genotype; mean baseline INS-30, 93 μIU/ml
• For the healthy low-fat versus healthy low-carbohydrate diets, respectively:
•The mean 12-month macronutrient distributions were: 48% vs 30% for carbohydrates; 29% vs 45% for fat; and 21% vs 23% for protein.
•Weight change at 12 months was −5 .3 kg (−11 .7 lbs) for the healthy low-fat diet versus −6 .0 kg (−13 .2 lbs) for the healthy low-carbohydrate diet (mean between-group difference, 0 .7 kg [95% CI, −0 .2 to 1 .6 kg], or 1 .5 lbs [95% CI, −0 .4 to 3 .5 lbs]). This difference in weight loss was not statistically significant.
•No significant diet-genotype pattern interaction (P = 0 .20) or diet-insulin secretion (INS-30) interaction (P = 0 .47) with 12-month weight loss.
•Eighteen adverse or serious adverse events were evenly distributed across the two diet groups
Limitations
• 481 (79%) completed the trial.
• These results are inconsistent with similar analyses of other dietary weight loss intervention cohorts, and it seems implausible there is no interaction between genotype and weight loss with different macronutrient dietary patterns. It is possible there were confounding factors. For instance, it could be that for the range of macronutrients consumed in this study there is no difference in the interaction, or that the study was underpowered and therefore unable to detect a small difference.
• It is impossible to identify the effect of a gene (genotype) without measuring the epigenetic state and knowing if the gene is active or quiescent. The epigenome was not assessed in this study, a major limitation in any genotype association study.
Strengths
Health educators delivered the behaviour modification intervention to both groups via 22 diet-specific small group sessions administered over 1 year. The sessions emphasized diet quality and focused on ways to achieve the lowest fat or carbohydrate intake that could be maintained long-term.
Key conclusions
There is considerable scientific interest in identifying the genetic variants that help explain inter-individual differences in weight loss success in response to diet interventions, particularly diets with varying macronutrient compositions. In this 12-month weight loss diet study, there was no significant difference in weight change between a healthy low-fat diet versus a healthy low-carbohydrate diet. Also, neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss. In the context of these two common weight loss diet approaches, neither of the two hypothesized predisposing factors was helpful in identifying which diet was better for whom. Significance for lifestyle medicine
Dietary modification remains key for successful weight loss, yet no one dietary strategy is consistently superior to another for the general population. Previous research suggests genotype or insulin-glucose dynamics may modify the effects of diets. This study demonstrates that epigenetics must be part of the measures assessed in lifestyle diet intervention studies. Diet determines the expression of many genes.
Questions
1.Which of the following statements about this study are not true?
A. This study was a meta-analysis of 20 RCTs
B. The intervention sought to reduce caloric intake to 500–600 calories per day.
C. The primary outcome was weight loss at 6 months.
D. Weight loss was not statistically different between the two dietary patterns.
E. This study was comparison of healthy low fat diet Vs Plant based diet.
F. Only 50% subjects completed the trial
2.Which of the following statements most accurately describes the findings of this study?
A. Weight loss was about the same for both dietary patterns, and there was no interaction between dietary pattern and genotype.
B. 22 diet-specific small group sessions were administered over 1 year.
C. There was a slight interaction between genotype and insulin level 30 minutes after glucose ingestion, but it was not statistically significant.
D. Subjects with metabolic syndrome were found to lose more weight on the healthy low-carbohydrate diet.
E. Weight loss was greater for the low-carbohydrate dietary pattern.
F. N = 609 overweight adults. Participants were randomized to the 12-month healthy low-fat (HLF); (N = 305) or healthy low-carbohydrate (HLC); (N = 304), diet.
Answers
1.Answer: A, B, C, E, F
2.Answer: A, B, F
DiRECT trial
Population
- adults, NIDDM < 6 yrs w BMI 27-45, not on insulin
- n = 306 from 49 practices.
Design: Open label cluster RCT at 49 1’ care practices in
Scotland & England (statistician blinded)
Intervention
1) Withdraw anti-diabetic and BP drugs
2) Total diet replacement (850 cal/d) with liquid formula x 3-5 months then stepped food reintroduction (2-8 wks) &
structured support for LTM weight loss maintenance
Control: best-practice care by guidelines
Outcome: Wt. loss > 15 kg & Remission of DM (HbA1c <
6.5% after at least 2 months off all diabetic meds
Results: 1) Mean decrease in weight: 10.0 vs 1.0 Kg -
delta 8.8 Kg (P<0.0001)
a) Loss of > 15 kg in 24% v 0%; P<0.0001
2) QOL (EuroQol VAS) improved by 7.2 points vs decrease by 2.9 points. (delta 6.4 points; p=0.0012)
3) DM remission 46% vs 4%, OR 19.7; P<0.0001
4) Primary predictor of remission was weight loss:
- none in those who gained weight.
- 86% in those who lost 15kg or more
Comparison with Lookahead:
Overall Direct had a 46% remission rate for NIDDM vs 11.5% (both at 1 yr) in Lookahead (& 2% on ADA diet)
- due to differences in dosing strength (1,200-1,800 cal/d in Lookahead vs 850 cal/d in Direct).
- used a low energy liquid replacement diet.
