EAL

H/A: Dietary Intake (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess the association between dietary patterns identified by cluster analysis and change in body mass index (BMI), CD4 count and viral load.

Inclusion Criteria:

Documented HIV infection and age older than 18 years in the cohort
Only HIV-positive adult males with a BMI more than 20.5 were included in this analysis.

Exclusion Criteria:

Pregnancy
Thyroid disease
Diabetes
Malignancies other than Kaposi sarcoma
Inadequate fluency in English
Wasting.

Description of Study Protocol:

Recruitment

Participants of Nutrition for Healthy Living, a longitudinal cohort study examining the nutritional and metabolic consequences of HIV infection, conducted from February 1995 to June 2005.

Design: Longitudinal cohort study

Statistical Analysis

Analyses were conducted with data from a single visit and change across the study interval
Cluster analysis was performed with SAS statistical software
Multivariate linear regression assessed associations between dietary clusters and change in BMI, CD4 count and viral load
Potential confounders were selected based on their individual relations with clusters and change in BMI, CD4 count and viral load.

Data Collection Summary:

Timing of Measurements

Change in BMI, CD4 count and viral load were examined over a period of eight months.

Dependent Variables

Weight, height, BMI
Body composition assessed by anthropometry and bioelectrical impedance analysis
Skinfold thickness and waist and hip circumferences
Resting energy expenditure (REE) measured through indirect calorimetry
CD4 count
Viral load.

Independent Variables

Dietary patterns evaluated through cluster analysis, which was done on 41 designated food groups derived from three-day food records.

Control Variables

Age
Race
Highly active antiretroviral therapy (HAART) use
BMI
Energy intake per kilogram
REE per kilogram.

Description of Actual Data Sample:

Initial N

348 adult male subjects met inclusion criteria.

Attrition (final N)

348 adult male subjects.

Age

Mean age, 45 years.

Ethnicity

34% were non-white.

Other relevant demographics

77% were on HAART regimens.
Mean viral load=3.2 log₁₀ copies per mL
Mean CD4 count=444 cells per mcL.

Location

United States.

Summary of Results:

Key Findings

Three dietary patterns were observed: juice and soda; fast food and fruit drinks; and fruit, vegetable and low-fat dairy
Subjects in the fast food and fruit drinks pattern had the lowest fiber intake, highest viral load and lowest CD4 count and had a lower income that did subjects in the other two clusters
Subjects in the fruit, vegetable and low-fat dairy diet pattern had higher intakes of protein, fiber and micronutrients and the highest BMI and CD4 count
Subjects in the juice and soda pattern had higher energy intakes and lowest BMI
On average, the fast food and fruit drinks cluster and fruit, vegetable, and low-fat dairy cluster gained 0.33 (P=0.06) and 0.42 (P=0.02), respectively, more in BMI than the juice and soda cluster across the study interval in a multivariate model
Interactions between dietary patterns and HAART use were not significant
The association between dietary patterns and change in viral load and CD4 count across the study interval was not significant.

Author Conclusion:

In a cohort of HIV-positive men, three distinct dietary patterns were identified. Each pattern was associated with specific nutrition, demographic and HIV-related variables.

Funding Source:

Government:	NIDDK of NIH, NHLBI of NIH
University/Hospital:	GCRC of Tufts-New England Medical Center

Reviewer Comments:

Only men studied; analysis of eight-month study interval despite 10 years of follow-up. Authors note the following limitations:

Food group intake was analyzed in grams per day, and clusters may have been different when compared as a percentage of energy contribution
Exclusion of women.

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)	N/A
	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)	N/A

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?		???
	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?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
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?	Yes
	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?		???
	4.1.	Were follow-up methods described and the same for all groups?	???
	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%.)	???
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	???
	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?	N/A
	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?	Yes
	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?		???
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	???
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	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?		???
	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?	???
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	???
	7.5.	Was the measurement of effect at an appropriate level of precision?	???
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
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)?	N/A
	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?	N/A
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