Health Disparities

HD: Effectiveness of Nutrition Intervention Methods (2010)


Differential response to an exclusive breastfeeding peer counseling intervention: The role of ethnicity. Anderson AK, Damio G, Chapman DJ, Perez-Escamilla R. J Hum Lact. 2007 Feb; 23 (1): 16-23.

PubMed ID: 17293547
Study Design:
Randomized controlled trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

In a low-income inner city population:

  1. To examine how different ethnic groups respond to an exclusive breastfeeding peer counseling program
  2. To document the determinants of exclusive breastfeeding at three time-points: Hospital discharge, one month postpartum and two months postpartum.
Inclusion Criteria:

Pregnant women:

  • Considering breastfeeding
  • No known health condition precluding successful breastfeeding
  • Carrying a single fetus
  • Planning to deliver at Hartford Hospital
  • No more than 32 weeks gestation at the time of recruitment
  • Income below 185% of the federal poverty level
  • Willing to stay in the study area for at least three months after delivery.
Exclusion Criteria:

None specifically identified

Description of Study Protocol:


Method of recruitment not described


 Randomized controlled trial; method of randomization not described

Blinding used



Intervention group:

  • Three prenatal home visits by a peer counselor (involving exclusive breastfeeding education and counseling)
  • Perinatal in-hospital hands-on support (daily during hospitalization)
  • Nine postpartum home visits and counseling
  • Conventional breastfeeding education provided by the hospital.

Control group

Conventional breastfeeding education provided by the hospital

Statistical Analysis

  • P<0.05 (two-sided)
  • Chi-square analysis to compare the characteristics of women across ethnic groups and between intervention and control groups
  • Bivariate analyses to identify EBF determinants within each of the two study groups at each time-point
  • Backward stepwise multivariate logistics regression to determine the independent influence of each independent variable with EBF at hospital discharge and two months postpartum.


Data Collection Summary:

Timing of Measurements

  • Baseline (enrollment)
  • During postpartum hospitalization
  • Weekly telephone interview post-discharge times four weeks
  • Biweekly telephone interview post-discharge until the infant was three months of age.

Dependent Variables

Exclusive breastfeeding defined as "whether the infant had received anything besides breast milk within the previous 24 hours before the interview (yes/no)." 

Independent Variables

  • Planned vs. unplanned pregnancy
  • WIC participation
  • Infant feeding intentions
  • Infant's maternal grandmother residing in the United States
  • Marital status
  • Previous breastfeeding experience
  • Head of household identity
  • Ethnicity
  • Maternal age
  • Parity
  • Respondents' education*
  • Respondent breastfed as a child*
  • Food stamp recipient*
  • Type of delivery*
  • Infant gender*
  • Smoking status*
  • Use of alcohol*.

The variables with an asterisk (*) were not listed by the authors in the section "Independent Variables" but were reported in results.

Control Variables

  • Age
  • Parity.


Description of Actual Data Sample:
  • Initial N: 182 pregnant females
  • Attrition (final N):
    • 162 mother-infant pairs
    • 133 minority participants
    • 16 Caucasian enrollees were not reported secondary to the low sample size of this ethnic group
  • Age: Mean 24.5±5.4; range 18-39 years
  • Ethnicity: 51.1% Puerto Rican, 30.8% non-Puerto Rican Hispanic, 18.1% Black
  • Other relevant demographics:
    • Anthropometrics: Yes
    • Location: Hartford, Connecticut, USA.


Summary of Results:

Key Findings

Exclusive breast feeding at three time intervals (percentages)
  Treatment Group Control Group
Time of hospital discharge 53.5 41.9
One month postpartum 33.8 6.5
Two months postpartum 28.2 1.6

To examine how different ethnic groups respond to an exclusive breastfeeding peer counseling program:

Variables Treatment Group
Measures and confidence intervals

Control Group
Measures and confidence intervals

    Statistical Significance of Group Difference
  Puerto Rican Other Hispanic Black Puerto Rican Other Hispanic Black  
Exclusive breastfeeding at hospital discharge 15 (42.9%) 9 (64.3%) 5 (55.6%)  11 (33.3%) 18 (66.7%) 6 (40.0%)   
Exclusive breastfeeding at one month postpartum 7 (20.0%)a 14 (51.9%)a 3 (33.3%)  0 (0%) 4 (28.6%) 0 (0%)  aP<0.001 treatment vs. control 
Exclusive breastfeeding at two months postpartum 4 (11.4%)b 12 (44.4%)b 4 (44.4%)  0 (0%) 1 (7.1%) 0 (0%)  bP<0.008 treatment vs. control 



Determinants of exclusive breastfeeding at three time-points
  Treatment     Control     Odds Ratio  
  At hospital discharge One month postpartum Two months postpartum At hospital discharge One month postpartum Two months postpartum At hospital discharge Two months postpartum
Prenatal intention to exclusively breastfeed        P<0.05     2.24, 95% CI 1.07-5.00  
Respondent's mother not in the US P=0.044       P<0.05    OR 0.41, 95% CI 0.17-0.98   
Non-Puerto Rican Hispanic         P<0.05       
Planned pregnancy P=0.017
OR 3.46; 95%CI 
Respondent not head of their household   P<0.05             
Not of Puerto Rican descent    P<0.05  P<0.01
OR 66.22, 95% CI 1.30-614.94
Respondent breastfed as a child     P<0.01
OR 5.98, 95%CI 1.43-25.13
        5.98, 95% CI 1.43-25.13
Puerto Rican descent     OR 10.35, 95% CI 1.03-103.65           

Other Findings



Author Conclusion:

Exclusive breastfeeding peer counseling intervention is successful. Non-Puerto Ricans mothers respond better than Puerto Rican mothers to the intervention.

Funding Source:
Government: Centers for Disease Control and Prevention; Conneticut Latino Health Disparities NIH Export Center
Reviewer Comments:
  • This study may demonstrate mortality or attrition bias:
    • It is unclear whether the enrollees were a representative sample of the relevant population
    • 182 women were recruited: 162 were entered into the study (133 minorities, 16 Caucasians were not reported). Therefore 20 recruits are missing from the initial "N" (182-162=20). Another 13 enrollees are missing from those entered into the study (162-133-16=13). This attrition is not addressed in the study.
    •  The (unidentified) randomization method yielded unequal distributions between the control and intervention groups. Disproportionate randomization may influence the results.
  Control Intervention
Puerto Rican 33 35
Non-Puerto Rican Hispanic 14 27
Black 15 9
Total 62 71


Information about the training for peer counselors and number of sessions completed by each enrollee was not described. It is unknown whether the enrollees received other breastfeeding support measures (i.e., physician, family, LaLeche League). The results may have been confounded by other support measures.


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? ???
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) No
  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? 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? 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? ???
  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? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  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? ???
  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? 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)? 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? No
  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? N/A
  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