EAL

DLM and Physical Activity

Citation:

Stefanick ML, Mackey S, Sheehan MS, Ellsworth N, Haskell W, Wood PD. Diet and Exercise for elevated risk trial. N Engl J Med. 1998;339:12-20.

Worksheet created prior to Spring 2004 using earlier ADA research analysis template.

Study Design:

Randomized Controlled Trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

POSITIVE: See Quality Criteria Checklist below.

Research Purpose:

Inclusion Criteria:

1. TG <500 mg/dl 2. Resting BP <160/94 mm Hg 3. Fasting BG: <140 mg/dl 4. 2 hour GTT: BG <200 mg/dl 5. BMI <32 for women and <34 for men

Exclusion Criteria:

1. History of heart disease, stroke, diabetes, recent cancer, other life-threatening illness, condition limiting ability to engage in moderate-intensity exercise 2. On insulin or meds for heart disease, blood pressure, or lowering lipids 3. Smoked >9 cigarettes/d 4. Drank >4 alcoholic drinks/d

Description of Study Protocol:

Diet and Exercise for Elevated Risk Trial Dietary Intervention by RD: 12 week intensive program 1. individualized counseling 2. Eight 1 hour group classes 3. 6 to 8 month maintenance program: monthly contacts (phone or mail, individual or group) with RD Exercise Intervention: 1. Individual session with staff 2. 6 week adoption phase: 1 hour exercise sessions, 3 times/week 3. 6 to 8 month maintenance program: attend group sessions or home activities equivalent to 10 miles of brisk walking/wk Dietary assessment: Baseline and 1 year: 24-hour dietary recall questionnaires (computer assisted telephone interviews)

Data Collection Summary:

Random assignment to 1 of 4 groups: 1. NCEP Step 2 diet (n=46 women, 49 men) 2. Aerobic xercise (n=43 women, n=47 men) 3. NCEP Step 2 diet + aerobic exercise (n=43 women, 48 men) 4. Control group (n=45 women, 46 men) Outcome measures: Plasma lipoproteins

Description of Actual Data Sample:

Postmenopausal women: 45-64 years of age HDL chol - 60 mg/dl LDL chol >125 mg/dl to <190 mg/dl Men: 30-64 years of age HDL chol ¯ 45 mg/dl LDL chol >125 mg/dl to <210 mg/dl

Summary of Results:

180 postmenopausal women and 197 men Mean age of women: 56.9+5.1 yr Mean age of men: 47.8+.9 yr Dietary intake of fat and cholesterol and body weight ¯ during the 1 year study period. In the diet group or the diet + exercise group compared with controls (P<0.001) and the exercise group (P<0.05). LDL chol was significantly ¯ among women (¯ 14.5 +22.2 mg/dl)(P<0.05) and men (¯ 20.0+17.3 mg/dl)(P<0.001) in the diet + exercise group compared with the control group. LDL chol was significantly ¯ in men in the diet + exercise group compared with men in the exercise group (P<0.001) LDL chol was not significantly decrease in the diet group in the women or men. The NCEP Step 2 diet failed to lower LDL cholesterol levels in men or women with high-risk lipoprotein levels who did not engage in aerobic exercise. These data strongly support recommendations to add exercise to diet for the management of lipoprotein levels associated with a increased risk for CHD. Weight loss should be further emphasized particularly in counseling men and women who have decreased HDL chol and increased LDL chol.

Author Conclusion:

The amount of exercise in this study did not significantly ú HDL chol, however diet alone decrease HDL chol. Well controlled study. Since the subjects were following the Step I diet at baseline, it is possible that following the Step II diet had no additional benefit for these subjects.

Funding Source:

Government:

NHLBI

Reviewer Comments:

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	No
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		No
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	No
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	No
	4.4.	Were reasons for withdrawals similar across groups?	???
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	No
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		No
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	???
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	No
	6.6.	Were extra or unplanned treatments described?	No
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	???
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	No
	7.7.	Were the measurements conducted consistently across groups?	???
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	No
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	No
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes