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BF: Artificial Nipple and Duration of Breastfeeding (2008)

Citation:

Cunha AJ, Leite AM, Machado MM. Breastfeeding and pacifier use in Brazil. Indian J Pediatr. 2005; 72: 209-212.

PubMed ID: 15812114
 
Study Design:
Prospective cohort study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

 

To determine the relationship between pacifier use and the duration of exclusive breastfeeding in the first six months of age, among poor children with unfavorable birth weight, from an underdeveloped region in Brazil.

 

 

Inclusion Criteria:
  • Mothers who had given birth in maternity services selected and whose newborns had birth eight of less than 3,000g (unfavorable birth weight)
  • Newborns in good health and with expected release from the maternity service, as determined by the medical team of the nursery, before the fifth day of life
  • Mothers residing in the city of Fortaleza who had no plans to change residence within the next six months
  • The Ethics Committee of the School of Medicine from Federal University of Ceará approved the study
  • An informed consent was obtained from mothers before their participation.
Exclusion Criteria:
  • Mothers with twin gestations
  • Newborns with health problems that required intermediate or intensive care
  • Mothers that resided in other locations or that had serious health problems requiring some kind of in-patent treatment.
Description of Study Protocol:

Recruitment

Data from this analysis came from a randomized and controlled trial conducted with a group of mothers and their newborns. Data was analyzed from the non-intervention group Infants were followed from birth to six months of age. A sample of mothers and their babies was selected from eight maternity hospitals in the city of Fortaleza, Brazil. In order to select the study population, four interviewers (two nurses and two social workers) visited the maternity services November 1996 to April 1997.

Design

Prospective cohort study with infants followed from birth to six months of age.

Blinding used

Structured questionnaires were used by trained data collectors unaware of the study’s aim.

 

 

Statistical Analysis

  • The hazard ratio was used as the measure of association and a survival analysis was conducted using Kaplan Meier curves and the Cox Proportional Hazard Model
  • For statistical inference Wilcoxon test, Log Rank test, maximum likelihood ratio test and confidence interval were used
  • The level of significance was 0.05.
Data Collection Summary:

Timing of Measurements

  • Data were collected at the maternity hospitals within the first 24 hours of birth and during home interviews conducted at the first and the sixth months after enrollment
  • Mothers fulfilling the inclusion criteria were interviewed during the initial 48 hours after childbirth
  • Home visitation activities included interviews with mother; observation of the home environment; observation of all aspects involved with the breastfeeding including technical ones, as well as those related to the mother-child relationship.

Dependent Variables

The main outcome measure was: Time to stop exclusive breastfeeding at the first and sixth month of children’s age. Exclusive breastfeeding was present if the child only received breast milk from its mother, wet nurse, or collected breast milk and did not receive any other liquid or solid food, with the exception of vitamins, mineral supplements or medication.

Independent variables

  • Pacifier use at the first and sixth month of age (main exposure measures)
  • Information on family income
  • Maternal schooling
  • Demographic conditions
  • Pre-natal care and conditions surrounding the pregnancy
  • Characteristics and health conditions of the newborn.

Control Variables

Hazard ratio for breastfeeding duration and use of pacifiers was adjusted for: Mother’s age, mother’s working outside home, quality of pre-natal care, children’s hospitalization the first six months of life and new pregnancy during the six months.

Description of Actual Data Sample:
  • Initial N: 500 children were enrolled.
  • Attrition (final N): 425 (64 were lost to follow-up by the first month and 11 more by the end of the sixth month).
  • Age: Infants from birth to six months of age. Adolescent mothers(<20 years) =150 of the 500 included in the study.
  • Location: Fortaleza, Brazil.

 

 

Summary of Results:

By the first month only half of the children were still exclusively breast-fed and this rate dropped to 6% by the six month. The use of a pacifier was very common, with more than 50% of the children using it at both intervals.

Table One: Breastfeeding Practice and Use of Pacifiers at First and Sixth Months

 
N
 Percentage
Breastfeeding At First Month
189/436
43.3
Sixth Month
31/388
6.0
Use of Pacifier At First Month
252/429
58.7
Sixth Month
229/376
60.9

Mothers reported that most children had started using pacifiers during the first month of life. The average number of days for exclusive breastfeeding, comparing pacifier usage and non-usage at the first and sixth month of life was statistically and significantly different (P=0.0001).

Table Two: Breastfeeding Rates at First and Sixth Months and Pacifier Use

 

Use of Pacifier At
Breastfeeding Duration
 
 
Average Number of Days
SD1
P-Value
First Month User
90.9
4.0
 
Non-user
123.3
5.0
0.002 
Sixth Month User
87.0 
4.9
 
Non-user
125.3
3.8
0.0001 

 

1SD: Standard Deviation
2 Wilcoxon Test.

The hazard ratio comparing time to stop breastfeeding among pacifier users and non-users was also statistically significant and remained so even after adjusting for potential confounders. Children using pacifiers were one to nine more likely to have stopped exclusive breastfeeding at the sixth month compared to non-users.

Table Three: Hazard Ratios One for Breastfeeding Duration and Use of Pacifiers

Use of Pacifier At
Hazard Ratio (CI)2
Non-adjusted
Adjusted3 
First Month
1.5 (1.2-1.9)
1.61 (1.3-2.0) 
Sixth Month
1.8 (1.4-2.2)
1.9 (1.5-2.4) 

Results from Cox Modeling

  • CI=95% confidence interval
  • Adjusted for: Mother's age, mother's working outside home, quality of pre-natal care, children's hospitalization the first six months of life, new pregnancy during the six months.
Author Conclusion:

Pacifier use was associated with the early termination of breastfeeding in Brazil among poor children with unfavorable birth weight, living in an underdeveloped area. As a possible marker of early weaning, pacifier use can help health workers identify those mothers in need of extended counseling to reinforce breastfeeding practices.

  • By the first month, only half of the children were still exclusively breast-fed and this rate dropped to 6% by the sixth month. The use of a pacifier was very common, with more than 50% of the children using it at both intervals.
  • Mothers reported that most children had started using pacifiers during the first month of life. The average number of days for exclusive breastfeeding, comparing pacifier usage and non-usage at the first and sixth month of life was statistically and significantly different (P=0.0001).
  • The hazard ratio comparing time to stop breastfeeding among pacifier users and non-users was also statistically significant and remained so even after adjusting for potential confounders. Children using pacifiers were one to nine more likely to have stopped exclusive breastfeeding at the sixth month compared to non-users.

Limitations

  • A major discussion is whether pacifier use is only a marker to early weaning and is not casually related to it
  • Even after controlling for potential confounders in the observational study design, evidence was not strong enough to confirm a causal relationship
  • Another potential confounders not measured by this study is the amount of time a pacifier was used by the children. It seems that occasional pacifier use had no effect on breastfeeding duration.

 

 

 

Funding Source:
Government: Community Health Department
University/Hospital: Federal University of Rio de Janeiro,Brazil;eara Federal University
Reviewer Comments:

Analytical longitudinal surveys refer to what epidemiologists term prospective or cohort studies. A Cohort Study is a study in which patients who presently have a certain condition or receive a particular treatment are followed over time and compared with another group who are not affected by the condition under investigation. Studies of this kind provide a better opportunity than one time cross-sectional studies to examine whether certain behaviors do in fact lead to (or cause) the disease.             

The limitations and critique of the study, as stated by the authors appear to be very appropriate.

 

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? N/A
  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? 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? 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? Yes
  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? N/A
  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? 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? 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)? 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? Yes
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