Monday, August 31, 2015

Moy et al (Low Fat Diet for CHD Risk Factors)

Hooper et al included this trial by Moy et al as a reduced fat trial in their 2012 meta-analysis and as a reduced SFA trial in their 2015 meta-analysis


Methods

Participants were 235 ‘apparently healthy people’* aged 30-59 years old who were brothers and sisters of people who were diagnosed with CHD before 60 years of age.  The participants were randomised to ‘nurse counselling’ or to ‘usual care by their primary physicians’ for 2 years.  The purpose of this study was to examine whether dietary counselling from specially trained nurses would be more effective than the usual care provided by doctors

The nurse counselling involved individualised instructions to lower total fat intake usually to < 40g of total fat, as well as self-monitoring logs that were used for the first 1–2 months and regular check-ups approximately every 6–8 weeks to reinforce the diet, evaluate dietary compliance, and measure lipids.  For more information see the methods

* Additional eligibility criteria included at least one of the following: LDL-C ≥ 3.4 mmol/l (130 mg/dl), blood pressure ≥ 140/90 or current use of anti-hypertensive medication, or currently smoking

** The groups were similar at baseline except for significantly more smokers in the usual care group (39 vs. 53) and slightly lower LDL-C in the usual care group (4.7 vs. 4.3 mmol/l)

Results

The nurse counselling group slightly reduced their calorie, total fat and saturated fat intake.  Protein and carbohydrate intake were not reported, but probably didn’t change much as the reduction in fat is responsible for almost all (85%) the reduction in calories.



Nurse Counselling
Usual Care
Energy (kcal)
Baseline
1977
1978
Change
-152
114
Total fat
Baseline
85.1 (38.0%)
85.0 (38.3%)
Change
-14.3 (-3.9%)
4.7 (-0.27%)
Saturated fat
Baseline
30.2 (13.5%)
29.7 (13.4%)
Change
-4.9 (-1.4%)
1.9 (0.0%)

After 2 years triglycerides significantly decreased and HDL-C slightly increased in the low fat group perhaps due to some weight loss (which wasn’t significant, P = 0.4398) from the reduction in calories (P = 0.0085).  LDL-C was the only significant difference between the groups regarding BMI and blood lipids



Nurse Counselling
Usual Care
BMI
Baseline
28.5
29.5
Change
-0.10
0.21
LDL-C
Baseline
4.7
4.3
Change
-0.69
-0.4
HDL-C
Baseline
???
???
Change
0.044
0.008
Triglycerides
Baseline
???
???
Change
-0.4
-0.06

CHD/CVD events and mortality was not reported in the study.  Hooper et al reported the following outcomes:


Nurse Counselling
(N = 117)
Usual Care
(N = 118)
Myocardial Infarction
(all were non-fatal)
2
1
CHD Events
3
1
Stroke
1
1
Combined CVD Events
5
3

Hooper et al assessed this trial as having a high risk of bias in ‘systematic difference in care’ and an unclear risk of bias in ‘dietary differences other than fat’

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