Health Disparities

HD: Effectiveness of Nutrition Intervention Methods (2010)


Elder JP, Ayala GX, Campbell NR, Arredondo EM, Slymen DJ, Baquero B, Zive M, Ganiats TG, Engelberg M. Long-term effects of a communication intervention for Spanish-dominant Latinas. Am J Prev Med. 2006 Aug; 31(2): 159-166. Epub, 2006 Jun 15. PMID: 16829333



PubMed ID: 16829333
Study Design:
Randomized control trial.
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To examine the one-year impact of behavior change approaches to reduce dietary fat and increase fiber. 

Inclusion Criteria:
  • Spanish-dominant Latinas from two San Diego County areas 
  • Females between the ages of 18 and 65 living in the home.
Exclusion Criteria:
  • No adult females between 18 and 65 living in the home
  • If the target adult female was pregnant or on a special diet for medical reasons
  • If the target female was planning to leave the San Diego area during the study period.
Description of Study Protocol:


Participants were obtained by random-digit dialing using a telephone list of Hispanic surname households from the central and southern regions of San Diego County; they were then asked to participate in a 14-week, tailored nutrition communication intervention.


  • Women were asked to participate in a 14-week, tailored nutrition communication intervention
  • They were assessed for eligibility via random-digit dialing using a telephone list of Hispanic surname households from the central and southern regions of San Diego County
  • Women were randomly assigned to one of three groups:
    • Promontoras: Weekly dietary counseling via lay health advisors (promontoras) at home or by telephone calls over a 14-week period, plus 12 tailored newsletters with homework assignments delivered via the mail to participants homes
    • Tailored: 12 tailored print newsletters and homework assignments delivered via the mail
    • Control: A control condition consisting of 12 off-the-shelf materials targeted at Spanish-speaking Latinos delivered via mail 
  • Assessments were completed at participants' homes at baseline (M1), at 12 weeks (M2), at six months post-intervention (M3) and at 12 months post-intervention (M4)
  • The National Data System (NDS version 4.04) 24-hour dietary recall (developed by the Nutrition Coordinating Center of the University of Minnesota) was used at each of the four time points to assess dietary intake:
    • 120 Latino foods were added from Latino and international cookbook recipes
    • Participants reported on three consecutive 24-hour dietary recalls 
  • Data collection began in spring 2001 and ended in spring 2003
  • Data analyses were completed in summer 2004
  • Acculturation was measured using the Acculturation Rating Scale for Mexican-Americans, consisting of 30 items. A higher score reflects greater assimilation to the Anglo culture.


  • Promontoras: Weekly dietary counseling via lay health advisors (promontoras) at home or by telephone calls over a 14-week period, plus 12 tailored newsletters with homework assignments delivered via the mail to participants' homes
  • Tailored: 12 tailored print newsletters and homework assignments delivered via the mail
  • Control: A control condition consisting of 12 off-the-shelf materials targeted at Spanish-speaking Latinos delivered via mail. 

Statistical Analysis

  • Descriptive statistics
  • Analyses of covariance (ANCOVA)
  • Mixed-effects regression models
  • Chi-square tests
  • P of 0.05 was used to determine significance.


Data Collection Summary:

Timing of Measurements

  • 14 weeks of tailored nutrition communication intervention
  • One-year follow-up
  • Assessments were completed at baseline, at 12 weeks, six months post-intervention and at 12 months post-intervention
  • Data collection began in the spring of 2001 and ended in the spring of 2003
  • Data analyses were completed in the summer of 2004.

Dependent Variables

  • Total grams of fat
  • Percent calories from dietary fat
  • Total grams of dietary fiber. 

Independent Variables

  • Promotora condition
  • Tailored condition
  • Control condition.


Description of Actual Data Sample:

Initial N

1,545 Latinas.

Attrition (final N)

There were 357 women in the study:

  • 1,035 households were ineligible (no adult females between the ages of 18 and 65 years living in the home)
  • 40 were hard to reach
  • 113 refused.
  • Data was not imputed for participants lost to follow-up; however, all available follow-up information was utilized:
    • 17 refused participation after M2
    • 12 were lost to follow-up (moved or phone disconnected)
    • Four were dropped from study due to health reasons or insufficient literacy in Spanish
    • Six refused participation at M3
    • 17 were lost to follow-up 
    • Two were dropped from study due to illness
    • 18 were lost to follow-up at M4.


18 to 65 years of age, with mean age of 39.71 (SD=9.93).


Spanish-dominant Latinas.

Other Relevant Demographics

  • There were no demographic differences among conditions
  • 79% of participants were married.


Two San Diego County areas. 

Summary of Results:

Baseline Dietary Intake

  • There were no significant baseline group differences on the primary outcome variables (total fat, percent calories from fat, total dietary fiber)
  • There were no significant baseline group differences on the secondary outcome variables (energy, total saturated fat, soluble dietary fiber, insoluble dietary fiber, total carbohydrates, glucose, fructose and sucrose).

Retention Rates

  • At M2, 17 participants refused further participation, 12 were lost to follow-up (moved or phone disconnected), four were dropped from the study due to health reasons or insufficient literacy in Spanish
  • More refusals were observed but fewer were lost to follow-up in the promotora condition compared with the tailored condition at M2
  • At M3, six refused participation, 17 were lost to follow-up, two were dropped from the study due to illness
  • At M4, 18 were lost to follow-up 
  • Total attrition rate was 21%, including 23% of the promotora group, 24% of the tailored print group and 18% of the control group.

Intervention Effects on Dietary Outcomes

  • Immediate post-intervention differences:
    • The Promotora group achieved significantly better levels of nutritional outcomes than either tailored or control groups 
    • The promotora group was significantly (P<0.05) different from the tailored group on total fat, glucose and fructose, or marginally (P<0.10) different from the tailored on energy and total carbohydrates
    • The promotora group was significantly different from the control group on energy and total carbohydrates and marginally different on total fat and saturated fat  
  • Long-term differences:
    • For energy (P<0.03), total fat (P<0.03) and fructose (P<0.02), the group-by-time interaction was significantly different and for total saturated fat it was marginally significant (P<0.07)
    • Group differences seen at M2 were no longer significantly different at M3 and M4
    • For fat, energy and saturated fat, the promotora mean levels increased over time
    • Tukey's test indicated that the promotora condition had an overall significantly lower mean level (Mgm=16.8) than the tailored group (Mgm=19.3). The control group (Mgm=18.1) was not significantly different from either promotora or tailored conditions.

The effects achieved by the promotoras dissipated over the 12-month follow-up period while the effects of the tailored group concurrently improved.

Author Conclusion:

The high interactivity (i.e., calls visits) of promotora conditions may have been the most salient reinforcer and may have led to further tailoring, making this type of intervention more effective than the comparison groups in the short term.  

Funding Source:
Government: National Cancer Institute
Reviewer Comments:

The paper did not specify how many promotora visits were in person vs by phone. 

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? Yes
  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) N/A
  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.) N/A
  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.) Yes
  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? Yes
  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%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? Yes
5. Was blinding used to prevent introduction of bias? No
  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.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  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? Yes
  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? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  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? Yes
  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? 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? N/A
  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