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Health Disparities

HD: Effectiveness of Nutrition Intervention Methods (2010)

Citation:

Gill SL, Reifsnider E, Lucke JF. Effects of support on the initiation and duration of breastfeeding. West J Nurs Res. 2007 Oct; 29 (6): 708-723. Epub 2007 Jun 8.

PubMed ID: 17557933
 
Study Design:
Non-Randomized Controlled Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To increase the initiation of breastfeeding and its duration to six months among a group of low-income, Hispanic women through an intervention program which included prenatal education and home-based postpartum support. 

Inclusion Criteria:
  • Women in their second trimester of pregnancy 
  • Women in the waiting rooms at two public health department maternity clinics in a large city in the southwestern United States.
Exclusion Criteria:
  • Women who delivered:
    • Premature infants at less than 37 weeks
    • Low birth weight infants less than 2,500 grams
    • Infants with major congenital anomalies
    • Infants requiring intensive care after birth. 
Description of Study Protocol:

Recruitment

  • Participants were recruited from the waiting rooms at two public health department maternity clinics in a large city in the southwestern United States
  • 100 mothers were recruited for each group
    • Recruitment ceased when 100 mothers meeting the study criteria were enrolled in each group
  • One researcher approached the pregnant woman in the waiting room, explained the study and obtained consent.

Design

  • Study was comprised of two pre-existing groups who received prenatal care at health department-based maternity clinics at the same site as a WIC clinic
  • Participants were not randomized to the intervention
  • The research team consisted of two bilingual International Board Certified Lactation Consultants (IBCLC) and three certified lactation educators, two of whom were bilingual and bicultural
  • Participants were enrolled in study during their second trimester of the pregnancy
  • Prior to delivery, women in the intervention group had individual prenatal education with an IBCLC
  • Between 36 weeks and delivery, women in the intervention group had the opportunity to meet again with the IBCLC to discuss breastfeeding in the hospital and to ask questions
  • At four days, two weeks, three weeks, four weeks and six weeks postpartum, women in the intervention group received telephone calls from a member of the research team to ascertain how the mother and infant were managing breastfeeding
  • At the mother's request and if deemed necessary by the research team, the IBLCL and/or lactation educator made a home visit
  • At three, four, five and six months postpartum, mother again received phone calls from a member of the research team and a home visit if requested
    • Information provided at each telephone contact was based on the participants response to breastfeeding problem assessment tool designed by researchers
  • Follow-up telephone calls by the lactation consultant followed the home visit
  • Investigators weighed infants at each home visit (used Medela Baby Weigh Scale)
  • Every mother in the intervention group had at least one home visit
  • Depending on the mother's situation (in the intervention group) she was given: Bra pads, nipple cream or battery-operated breast pump
  • Participants in the comparison group received an incentive, a cash card for a local grocery store
  • Mothers in the comparison group received standard breastfeeding education
    • Breastfeeding classes were available through the WIC clinic if the mothers chose to attend.

Blinding used 

To prevent information sharing participants, investigators maintained intact groups. 

Intervention 

  • Prenatal education and postpartum telephone calls and home visits
  •  Topics of education and demonstration included
    • Embarrassment
    • Discrete methods of breast feeding
    • Pumping and feeding expressed milk in public
    • If requested mother were given battery operated breast pumps
    • Sore nipples, correct latch on and positioning
    • Feeding frequency and duration
    • Breast care.

 Statistical Analysis

  • The Bayesian approach 
  • Log odds ratio was determined by logistic regression
  • Exploratory analyses log-logistic model.

 

Data Collection Summary:

Timing of Measurements

  • Initiation of breastfeeding 
    • All women in the study were given the cell phone numbers of the research team and advised to call when they had delivered
    • All women in the study were contacted by the research team when they were discharged from the hospital after delivery to determine method of infant feeding that the mother had selected
    • Each participant told researcher when she put baby to breast and how many times a day she was feeding baby at the breast.

 

  • Duration of breastfeeding
    • Intervention participants who were breastfeeding received phone calls as noted above
    • The comparison group participants who were breastfeeding were called weekly to determine if they were still breastfeeding or had weaned
    • If women in either group reported discontinuation of breastfeeding she was asked for the date that she last put her infant to breast and that day counted as the last day of lactation
      • Days of breastfeeding were then counted from delivery to that day.

Dependent Variables

  • Initiation of breastfeeding 
  • Duration of breastfeeding.

Independent Variables

Intensive education and support

Control Variables

 

Description of Actual Data Sample:
  • Initial N: 200 mothers
  • Attrition (final N): 158 women completed study
    • 79 women in the intervention group
    • 79 women in the comparison group
  • Age: Not given
  • Ethnicity: Hispanic (Mexican decent)
  • Other relevant demographics: No significant differences were among study groups
  • Location: A large city in the southwestern United States. 
Summary of Results:

No significant differences were found among study groups in demographic characteristics comparable in terms of age, education level, number of participants that were married, number of previous children who were breastfed, number of women who worked outside the home and number of women who were born in Mexico

Initiating Breast Feeding

  • 65 women initiated breastfeeding (82.3%) in the intervention group 
  • 53 women initiated (67.1%) in the control group
  • The posterior mean odds ratio was ω=2.31 with a 95% credible interval of 1.10:4.96
  • The posterior probability of H1 was 0.98. 

Duration of Breast Feeding

  • The posterior means for the parameters of the log-logistic model were μ=3.89, δ=0.93, α=1.04, and N=0.72
  • There was a lower duration rate for control group than that of the intervention.

The proportion of mothers who breastfed was greater in the intervention than in the control group throughout the 178 days of observation.

  • During the first 30 days, relative probability of those breastfeeding in the intervention group was 1.19 times that of the control
  • The odds of breastfeeding in the intervention group were 1.84 times those in the control
  • By the end of the study the intervention groups' probability rose to 2.08 times that of the control and the odds to 3.15 times that of the control.

 

Author Conclusion:

The intervention group had twice the odds of starting breastfeeding, twice the odds of continuing to breastfeed for six months and only half the tendency to quit at any one time than did the control group. 

Funding Source:
University/Hospital: University of Texas, South Texas Health Research Center
Reviewer Comments:
  • No lactation consultants or lactation educators were employed at either the maternity or WIC clinic where mothers were recruited
  • Focus groups were used to assess barriers to breastfeeding.
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) 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? 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? ???
3. Were study groups comparable? No
  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? ???
  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? 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? 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? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? Yes
  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? Yes
  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? 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? 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? 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? N/A
  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)? Yes
  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