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Journal of Human Lactation

DOI: 10.1177/0890334409331506 2009; 25; 350 originally published online Apr 15, 2009; J Hum Lact

Julie Smith, Mark Dunstone and Megan Elliott-Rudder Accurately Conveyed by the Titles and Abstracts of Journal Articles?

Health Professional Knowledge of Breastfeeding: Are the Health Risks of Infant Formula Feeding

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350

Assembly endorsed recommendations for 6 months of exclusive breastfeeding and continued breastfeeding to 2 years and beyond, along with appropriate comple­mentary foods.3

A clear majority of public opinion in the United States supports the view that breastfeeding is healthier for babies, yet substantially more than half of the surveyed population disagree that feeding a baby formula instead of breast milk increases the chances the baby will get sick.4 United States breastfeeding rates—although increasing—are low, with only around 74% of mothers initiating breastfeeding in 2004 and around 42% of babies still breastfed at 6 months.5

The accumulating evidence on the importance of breastfeeding is recognized by the American Academy of Pediatrics (AAP), as is the important role of health providers in advising mothers on infant feeding. The AAP policy statement on breastfeeding and human milk6 urges pediatricians and other health care profes­sionals to “promote, support, and protect breastfeeding

Health Professional Knowledge of Breastfeeding: Are the Health Risks of Infant Formula Feeding Accurately Conveyed by the Titles and Abstracts of Journal Articles?

Julie Smith, BEc (Hons), BA, PhD, Mark Dunstone, BSc, Grad Dip Ed, and Megan Elliott-Rudder, MBBS, DRANZCOG, FRACGP

Editor’s Note: The editorial staff is proud to announce the addition of a new recurring col-umn in JHL called “Research Methods” edited by Dr. Genevieve Becker. In this column, readers will gain an understanding of the latest research tools to build the evidence base that we use as we assist the mothers and infants in our care.

Abstract

Effective promotion of breastfeeding is constrained if health professionals’ knowledge on its importance is deficient. This study asks whether formula feeding is named as the risk factor in published research or whether it is considered the unspoken norm. A systematic analysis is conducted of the information content of titles and abstracts of 78 studies that report poorer health among formula­fed infants. This shows a surprising silence in the studies examined; formula is rarely named in publication titles or abstracts as an exposure increasing health risk. In 30% of cases, titles imply misleadingly that breastfeeding raises health risk. Only 11% of abstracts identify formula feeding as a health risk exposure. Initiatives to increase breastfeed­ing have described the importance of accurate language and well­informed health professional support. If widespread, this skew in communication of research findings may reduce health professionals’ knowledge and support for breastfeeding. J Hum Lact. 25(3):350-358.

Keywords: breastfeeding, health education, health knowledge, attitudes, practice, health personnel, health promotion, delivery of health care, health services, clinician support, communication

Received for review March 10, 2008; revised manuscript accepted for December 17, 2008.

Julie Smith, BEc (Hons), BA, PhD, is a health economist and breastfeed­ing counselor with research interests and publications in economic aspects of breastfeeding and the market for mother’s milk. Mark Dunstone, BSc, Grad Dip Ed, is a public policy advisor with a background in biological sciences and interest and publications on legal and public policy aspects of infant feeding and breastfeeding promotion. Megan Elliott-Rudder, MBBS, DRANZCOG, FRACGP, is a physician in general practice and a breastfeeding counselor and is preparing a doctoral dissertation on general practice support for breastfeeding.

This research is supported in part by an Australian Postdoctoral Fellowship and Discovery Project funding from the Australian Research Council held by Julie Smith. Address correspondence to Julie Smith, B Ec (Hons), BA, PhD, Australian Centre for Economic Research on Health, College of Medicine and Health Sciences, College of Medicine, Biology and Environment, Building 62, cnr Mills and Eggleston Roads, The Australian National University ACT 0200, Australia.

J Hum Lact 25(3), 2009DOI: 10.1177/0890334409331506© Copyright 2009 International Lactation Consultant Association

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The important role of early nutrition in later life is increasingly evident in scientific research into human health and development.1,2 In 2001, the World Health

Research Methods

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enthusiastically” and take “a strong position on behalf of breastfeeding” in light of the published evidence. Many studies report that health practitioners accept they have an important responsibility for promoting breast­feeding. Nevertheless, physician apathy and misinfor­mation are leading barriers to breastfeeding. The AAP for example, notes that “lack of guidance and encourage­ment from health professionals” is one of the obstacles to initiation and continuation of breastfeeding.

Health professionals need knowledge about the risks of early weaning from breast milk so as to sincerely and effectively promote breastfeeding. Likewise, skilled and knowledgeable support is crucial to help mothers manage breastfeeding problems. However, for many health professionals, breastfeeding training is inadequate and personal experience or passive learning is the main source of knowledge on breastfeeding.7 If health professionals are to increase their knowledge of breast­feeding within their usual and preferred processes of ongoing learning, the structure of published research is relevant.8,9

In this study we perused the titles and abstracts of a sample of published scientific studies of health impacts of breastfeeding versus formula feeding to assess whether health professionals have access to clear and unbiased information on the health implications of formula feeding. We ask 2 questions: does the information conveyed to the casual reader of relevant scientific journals accurately convey their findings that formula­fed infants have worse health and development outcomes than the norm, that is, breastfed infants? Or, alternatively, is breastfeeding damned with faint praise while formula feeding is presented as the research norm and by association reaffirmed as the cultural norm?

Methods

The 2005 AAP policy statement on breastfeeding and the use of human milk supports breastfeeding over formula feeding. It cites 78 scientific studies as evidence that breastfeeding is protective against a range of infectious and chronic diseases. We systematically analyzed the information content of titles and abstracts for these key studies on the health significance of breastfeeding.

This strategy is chosen because the statement by the AAP can be argued to be authoritative among physicians and policy makers and the 78 articles to be available to medical practitioners as a reasonably unbiased selection of evidence of the importance of breastfeeding. Nor would we expect from pediatricians any bias toward

silence on the relationship between infant formula feeding and elevated child health risks. The research analyzed in this study10­87 is cited by the AAP for the following findings on breastfeeding: strong evidence of decreased incidence and/or severity of a wide range of infectious diseases in both developed and developing countries (including bacterial meningitis, bacteremia, diarrhea, respiratory tract infection, necrotizing entero­colitis, otitis media, urinary tract infection, and late­onset sepsis in preterm infants) and reduced postneonatal infant mortality rates in the United States; suggestion of decreased rates of sudden infant death and reduced incidence of a range of chronic health conditions (type 1 and type 2 diabetes mellitus; lymphoma, leukemia, and Hodgkin’s disease; overweight and obesity, hyper­cholesterolemia; and asthma); and association with slightly enhanced cognitive performance. Maternal benefits include decreased postpartum bleeding and decreased fertility decreased risk of breast or ovarian cancer and possibly decreased risk of osteoporosis.

These articles support the AAP’s conclusion that formula feeding increases the incidence of illness and disease in infants and mothers compared to breastfeeding.

In this study, 3 researchers were involved in cate­gorizing the titles and abstracts of the above articles. Each researcher categorized the articles independently, reducing the potential for bias. One researcher is a health economist with qualifications in breastfeeding education and counseling, one has a background in biological sciences and public policy advice, and one is a physician in private practice and a qualified breastfeeding counselor. All procedures followed were in accord with the Australian National University’s Policies & Procedures for Research (including ethics guidelines).

The researchers classified each of the articles as “misleading,” “neutral or silent,” or “naming,” depending on the information conveyed in the titles. Table 1 sets out the categories and examples of titles in each category.

For abstracts, we used a slightly different categori­zation that reflected how the findings of the article were described in the abstract (Table 2). The abstracts are available through Medline.

A kappa statistic was calculated to evaluate the consistency of the assessments. This statistic is a common measure that determines whether the extent of agreement between investigators is greater than would be expected by chance, for example, in diagno­sing a condition or identifying an adverse event. A

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value of 1 indicates perfect agreement. A value of 0 indicates that agreement is no better than chance. Although there is debate on using the kappa statistic as a measure of the level of agreement, a score of less than 0.40 is generally considered as poor interrater

agreement, 0.40 to 0.60 as fair, 0.61 to 0.80 as good, and 0.81 to 1.0 as excellent.88

A kappa statistic89 was used to evaluate 3 sets of ratings: researcher 1 versus researcher 2, researcher 2 versus researcher 3, and researcher 1 versus researcher

Table 1. Categorization of Titles

Category Description Examples

Misleading Title associates breast milk or breastfeeding with an illness. Breast Feeding and the Sudden Infant Death Syndrome in Scandinavia87

Breastfeeding and Childhood Obesity83

Breastfeeding and the Risk of Postneonatal Death in the United States74

Breastmilk and Neonatal Necrotising Entercolitis43 Risk Factors for Primary Invasive Haemophilus Influenzae Disease51

Neutral or silent Title is neutral or silent on results or includes positive Breastfeeding and Lowering the Risk of Childhood Obesity82

statement about breast milk or breastfeeding but does Brainstem Maturation in Premature Infants86

not mention infant formula. Longer Breast­feeding and Protection Against Childhood Leukaemia and Lymphomas78

Names formula Title includes a reference to artificial infant feeding Differences in Morbidity Between Breastfed and Formula­fed Infants67 or formula. Cow’s Milk Exposure and Type I Diabetes Mellitus61

Table 2. Categorization of Abstracts

Category Description Examples

No mention of No mention of formula or does not compare “Children who were ever breastfed had 0.79 times the risk of never breastfed formula formula feeding to breastfeeding except in children for dying in the post neonatal period. Longer breastfeeding was describing method. associated with lower risk…promoting breastfeeding has the potential to save or delay approximately 720 post­neonatal deaths in the United States each year.”74

“The salutary effect of exclusive breastfeeding on cognitive development was greater for children born small for gestational age (SGA) than those born appropriate for gestational age (AGA). Based on a linear association between duration of exclusive breastfeeding and intelligence quotient (IO), children born SGA and exclusively breastfed for 24 weeks were predicted to have a 11­point IQ advantage over those breastfed for 12 weeks, as opposed to a 3­point advantage for children born AGA with similar durations of breastfeeding.”23

“Exclusive breastfeeding during the first months after birth is associated with lower asthma rates during childhood.”60 “Among children 2 to 71 months of age who had been exposed to environmental tobacco smoke, those who had ever been breast­fed had significantly reduced risks of asthma and wheeze compared with those who had never been breast­fed.”73

Neutral/breastfeeding Breastfeeding better compared with formula “Human milk feeding among very low birth weight infants (VLBW) was better than formula feeding: This category comprises those associated with a lower incidence of retinopathy of pre­maturity compared studies that compared breastfeeding with to exclusively formula­fed VLBW infants after adjusting for confounding formula feeding. Mostly conclusions couched variables.”52 in terms of breastfeeding advantages/or “Infants who were fed breast milk more than infant formula, or who were benefits over formula, not elevated risks breastfed for longer periods, had a lower risk of being overweight during from formula feeding. older childhood and adolescence.”60

Increased risk of ill Formula feeding associated with increased “Exclusive formula feeding could account for an estimated 500 extra cases of health associated risk of ill health: This category comprises necrotising entercolitis each year.”43 with formula those abstracts that conveyed that formula­ “The results of the analysis show that there is an association between feeding—names fed infants had higher risks of ill health, or bottle­feeding and SIDS.”40 formula it was clear that formula feeding was not “We tested the hypothesis that formula feeding in infancy programs greater the norm or control. leptin concentrations relative to fat mass in later life.”16

“The combined analysis indicated that bottle­fed infants were twice as likely to die from SIDS.”40

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3. Then a weighted kappa statistic was calculated for the 3 raters.88,90 Finally, we calculated the average percentage of titles and abstracts judged to be in each category, by reexamining those where the researchers disagreed and reaching a consensus assessment on the rating for the article.

Results

Table 3 shows the distribution of the articles when categorized by their title. There was a good to excellent level of agreement between the 3 pairs of assessments, with the kappa statistic between 0.71 and 0.87. The weighted kappa statistic for the 3 comparisons was 0.87.

The researchers disagreed on categorization for 14% of the titles. When titles were reassessed and a consensus rating determined, only 3 of the 78 articles (4%) were considered to refer to infant formula in the title, for example, “Differences in morbidity between breastfed and formula­fed infants”67 and “Cow’s milk exposure and type I diabetes mellitus.”61 Around two thirds of articles (67%) had only a neutral statement in the title or referred to the protection conferred by breastfeeding, reinforcing the cultural norm of breast­feeding as ideal rather than usual or ordinary. Around one third of the titles (30%) misleadingly associated breastfeeding with illness or disease, through state­ments implying guilt through association, such as “Breast feeding and risk of post neonatal death in the United States,”74 “Breastfeeding and the sudden infant death syndrome,”87 and “Breastfeeding and neonatal necrotizing entercolitis.”43

Table 4 sets out similar data for the information content of the abstracts for these publications. Two

articles were excluded as abstracts were not available. Agreement between assessments was fair, with kappa scores ranging from 0.49 to 0.62. The weighted kappa statistic was 0.68.

Abstracts show a similar skew in communication of findings (Table 4). Only 8 of the 76 abstracts examined (11%) were considered to communicate either explicitly or by implication that artificial infant feeding was associated with elevated risk of illness. These included, for example, statements such as “exclusive formula feeding could account for an estimated 500 extra cases of necrotizing entercolitis each year”41 and “the results of the analysis show that there is an association between bottle­feeding and SIDS.”38 A further 13 of the articles’ abstracts (17%) compare breastfeeding to artificial feeding with conclusions couched in terms of the “advantages” of breastfeeding. The remaining 55 abstracts (72%) make no mention of artificial infant formula but would not challenge a reader’s erroneous belief that artificial feeding does not increase health risks for infants.

Discussion and Conclusion

The AAP policy statement on breastfeeding and human milk91 states that “exclusive breastfeeding is the reference or normative model against which all alternative feeding methods must be measured with regard to growth, health, development and all other short­and long term outcomes.” This has implications for research design that are rarely considered. Breastfeeding is the physio logical norm; however, most studies examined above hypothesized formula feeding as the norm and treating breastfeeding as the exposure or intervention.

Table 3. Categorization of Titles

Frequency Percentage

Researcher 1 Misleading 24 30.8 Neutral 49 62.8 Names formula 5 6.4 Total 78 100.0Researcher 2 Misleading 23 29.5 Neutral 52 66.7 Names formula 3 3.8 Total 78 100.0Researcher 3 Misleading 28 35.9 Neutral 45 57.7 Names formula 5 6.4 Total 78 100.0

Table 4. Categorization of Abstracts

Frequency Percentage

Researcher 1 No mention 57 75.0 Breastfeeding better 12 15.8 Increased risk from artificial feeding 7 9.2 Total 76 100.0Researcher 2 No mention 53 69.7 Breastfeeding better 18 23.7 Increased risk from artificial feeding 5 6.6 Total 76 100.0Researcher 3 No mention 46 60.5 Breastfeeding better 18 23.7 Increased risk from artificial feeding 12 15.8 Total 76 100.0

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This cultural normalizing of formula feeding may bias scientific research in 2 ways: through misinter­preting results that fail to detect a difference in outcomes between breastfed and formula­fed infants and through misspecifying the exposure variable. That is, studies with large sample sizes are costly and less common, so research studies finding different health outcomes for breastfed and formula­fed infants may nevertheless be too small to achieve statistical significance. Where formula feeding is the norm and the onus is on showing that the practice is harmful, the scientific literature will not challenge the incorrect view that formula feeding does not increase health risks. (Elevated risks attribu­table to formula feeding may be present but simply not detected by that study to a statistically significant level—a false negative or Type II error.) Also, norma­lizing formula feeding by defining breastfeeding as the “exposure” results in wrongly classifying as “breastfed” those many infants exposed to formula feeding within months, weeks, or even days of birth. This results in downward bias in effect sizes attributable to breast­feeding if exposure to any formula feeding increases health risks.

Hence, the cultural context that frames breastfeeding research may result in a systemic bias toward a finding of no increased risk from formula feeding and toward an underestimation of the effect size of this exposure. There thus remains a need to scrutinize whether a predominant practice of treating formula feeding as the cultural and biological norm rather than as the feeding intervention affects research design, findings, and interpretation and whether this in turn influences the policy positions of health professional bodies or governments and the practices of health professionals.

However, this study has focused on the distinct and separate issue of how the language of abstracts and titles downplays the risks of formula feeding evident in study data or the researchers’ interpretation of it. In recent years commentators have highlighted the negative effects on breastfeeding practices of language that normalizes artificial feeding by referring to “the benefits of breastfeeding” rather than “the risks of formula feeding.” 92 The significance of language use in reporting scientific research is highlighted by the finding that such framing of health choices affects decisions—“loss framing” affects health behavior more than “gain framing” of health choices.93

Current health policy initiatives including social marketing campaigns aim to promote breastfeeding through more informed choice about infant feeding.

Research has shown the important role of health professionals in mothers’ breastfeeding decisions. However, significant breastfeeding knowledge deficits have been found among health professionals working with mothers and babies, including regarding known health disadvantages faced by formula­fed infants.6,94­96 For example, research has shown health professionals are not well informed about the nutritional differences between breast milk and formula,96­101 the increased incidence of gastroenteritis in formula­fed infants,97,102,103 and the higher rates of breast cancer among women who have not breastfed.97,102

Our analysis of the AAP­cited articles’ titles shows a surprising prevalence of silence and misleading association among titles and abstracts of articles likely to be used by physicians to access information on health effects of breastfeeding versus formula feeding. Titles and abstracts did not fit the data and researchers’ findings and/or interpretation of their data. Even articles one would anticipate to clearly communicate the health significance of breastfeeding were found to be silent, ambivalent, or contradictory because of language use. Such muted or misleading communi­cation of research findings, if widespread, could help explain why numerous surveys have shown that health professionals feel poorly equipped for the role they are expected to play in promoting breastfeeding.

Furthermore, in clinical practice, the communication of risk has been shown to require different strategies depending on whether the risk/benefit ratio is clear­cut or whether it is a preference­sensitive choice. A preference­sensitive choice is where uncertainty or lack of information on the risk/benefit ratio means there is no right or wrong decision. Where a health choice (such as breastfeeding) or an intervention (such as formula feeding) is known to be effective (or risky) for health, a different, more directive strategy for communicating risk is considered appropriate.104 Where practitioners themselves are poorly informed of the relative health risk of not breastfeeding, including by receiving unclear information from research, we surmise that the practitioner may inappropriately adopt the ambivalent, nondirective strategy to risk communication and facilitation of decision making on infant feeding.

Health professionals access a range of information, and the articles analyzed here are only a small proportion of the information available as the basis for advice to clients on infant feeding. It is of concern that many health professionals working in contact with mothers and babies appeared unaware of AAP and

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WHO infant feeding recommendations.105­107 The articles we analyzed were selected because they were judged to constitute evidence of higher health risk from formula feeding. As such, their titles and abstracts could be expected to be unambiguous in the message conveyed about the investigated risk factor and study findings. The AAP statement has considerable authority and influence as a statement by the professional body of pediatricians and could be expected to be a widely accessed gateway to information in this area.

A weakness of this study is that its generalizability depends on classifications by the researchers, which are to a degree subjective. We tried to minimize this by setting out clear criteria for categorizing the title and abstract of each study. We also tried to minimize subjectivity by the using a well­accepted statistical method of comparing the extent of consensus of health professional opinions and by using processes by which researchers made independent judgments on classification.

Titles and abstracts may not accurately reflect the whole of text of a published article, where findings are fully laid out. A full content analysis of the articles would be preferable but is beyond the scope of this study. Furthermore, the abstract of an article in a medical journal may be all that is read of the article,108 emphasizing the importance of its accurately summarizing the study and research findings.

Further research could survey a wider range of health professionals or researchers in this field as well as examine a wider range of information sources that are used by health professionals for their ongoing learning. Comparison of research summaries in the scientific literature with those in the popular media would also be useful to assess the extent of any mismatch between research findings and infant feeding messages in the wider public domain.

Our findings of unclear or misleading representations of infant­feeding research findings may be a sign of deeper cultural controversies.109 Van Esterik110 observed that contradictory scientific messages enable powerful interests to simplistically promote one message over another,110(p19) so that for example the literature on contaminants in breast milk scares mothers about breastfeeding but fails to discuss the risks of alternative feeding methods.110(p13) Industry heavily lobbied the Bush Administration to radically alter a US breastfeeding promotion campaign highlighting the risks of not breast­feeding rather than the usual benefits of breastfeeding, because saying that not breastfeeding is risky means that using commercial infant formula is risky.111(p413)

The cultural ambivalence about breastfeeding in the United States is further exacerbated by a feminist “silence on suckling” that arises from unresolved tensions in feminist agendas.112 The diffidence of feminist engagement in debates about breastfeeding is said to contribute to a dominance of medical and scientific discourse, which disempowers and blames women and ignores the social and structural context of infant­feeding decisions. As Hausman comments, “With regard to the choice of breast­ or bottle feeding, serious contradictions arise in the context of writers’ attempts to present both options fairly, with the consequence that the biomedical support for breastfeeding, touted as a significant advantage of this practice, is basically wiped out in the consideration of infant formula.”109(p30) She asks how, in these circumstances, “are mothers to make informed choices about breast­ or bottle feeding when the risks of both practices are so difficult to identify or assess? How do laypeople interpret medical information, especially since so much of it is conveyed though media sources or advice literature? What are the cultural meanings attached to both breast­ and bottle feeding that affect mothers’ choices?”109(px)

It is important that health and medical journals and other sources of information for health professionals accurately and efficiently communicate information on the latest research findings on the health implications of premature weaning, not least to challenge the erroneous beliefs of many that formula feeding is little different from breastfeeding in its effect on health. Health professionals who have easy access to clear and accurate information and are more knowledgeable about the health contributions of breastfeeding are more likely to be motivated and able to convincingly promote it in keeping with their professional responsibilities.

Our analysis of the titles and abstracts of a small but structured sample of scientific research on the health importance of breastfeeding has shown that journals may not currently provide health professionals with quick and ready access to the information they need to guide their practice and give advice to new mothers. We found that even where a study shows that artificial feeding increases health risks, journal article titles and abstracts systematically fail to state findings in language that clearly and directly links artificial infant feeding to increased morbidity. Indeed, in many cases, the research title or abstracts mislead readers by implicitly associating breastfeeding with the illness or disease. Formula is rarely named as a risk factor for morbidity. Furthermore, most of the cited articles do not take breastfeeding as the

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norm, either in the design of research or in the evaluation and presentation of results. If exclusive breastfeeding was the norm against which other methods are measured, breastfeeding would not be “protective” and breastfed infants would not enjoy “lower risks of ill health”; they would instead be referred to as “normal,” whereas formula­fed infants would be considered “exposed” to increased risk of poor health and development. Research is needed on a wider sample to establish whether this pattern is generalized.

If the literature available to health professionals is ambiguous about whether breastfeeding is protective or an exposure variable for health risk, they and the public may even wrongly believe that breastfeeding increases rather than decreases risk of certain illness or disease.

Neither mothers nor their health professional advisors can exercise informed choice on infant feeding in such circumstances. Vigilance and diligence are needed to ensure that researchers accurately commu­nicate their research findings about the health risks of artificial infant feeding and consider implications for research design of treating breastfeeding as the inter­vention rather than the norm. Health practitioners seeking information on infant feeding choices need to be aware of potentially misleading titles and abstracts in journals.

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