Getting risk savvy: presenting evidence to empower infant feeding decisions

Original image by Jack Zalium, flickr. CC BY-NC 2.0

Ever since I started thinking about how research evidence in infant feeding is communicated to the public, something has been irking me, and I never quite realized what it was until recently. The aha! moment? I was excited to land, quite serendipitously, on a book, “Risk Savvy”, by a German psychologist named Gerd Gigerenzer (I’ve shamelessly stolen his title for my blog; watch his TedX talk for more info). Gigerenzer puts forward the premise that essentially, people are way more clever than we give them credit for, and that we owe it to them to communicate clearly on health. It gets a bit more complicated than that when you consider the nitty gritty of statistical presentation (which I’ll go into briefly a bit later), but essentially, that’s it. His ideas have taken on a new lease of life with a recent study that garnered plenty of press coverage, from the Lancet this year.

In the study (a randomized trial), 10-12 year old Ugandan school children either received training about treatment effects and making informed health choices, or no specific intervention other than their standard school education. The children were then assessed on their ability to detect non evidence-based health claims (alternative facts, misinformation). In this pioneering study (summarised in this news article), more than twice as many children who got the training passed the assessment, compared to “control” children. As one of the researchers says, children were enabled to “detect bullshit when bullshit is being presented to them.” (More about the project at the Informed Health Choices website).

Although people can, with training, work their way through garbage if we give it to them, if we want to empower individuals to make the right health decisions for themselves, it’s also important to give people accurate, balanced information about the implications of those decisions. Trisha Greenhalgh explains what that means in her indispensable book, How to Read a Paper:

 “Evidence-based medicine is the use of mathematical estimates of the risk of benefit and harm, derived from high-quality research on population samples, to inform clinical decision making in the diagnosis, investigation or management of individual patients”

This is just as relevant for infant feeding (or indeed any aspect of health where people “do stuff for themselves”, rather than having medications prescribed by eg, doctors) – just replace  “healthcare” for “medicine” and “individuals’” for “clinical” decision making.

Mathematical? Estimates? That’s all a bit hifalutin’, I hear you say…! Well, there are some basic accepted standards for how we ought to be communicating information about risks for decision making in healthcare. Here, “risk” just means “the likelihood something might happen”, not necessarily something bad. (There is a “risk” you might win the lottery; or have a heart attack).

  1. Say what is the reference group
  2. Give absolute risk increases, preferably expressed as natural frequencies
  3. Use “matched framing” (same metric for benefits and harms)

(More information on these principles is available here and here).

Essentially, rather than saying: “smokers are X% more likely to get lung cancer than non-smokers”, we should say “smokers are Y% likely to get cancer whilst non-smokers are Z% likely to get lung cancer”. David Spiegelhalter explains this neatly with a “bacon sandwich” example.

These simple ideas are now being put to great effect by the Harding Center for Risk Literacy, who have developed straight forward “fact boxes” to show the outcomes associated with particular drugs (eg here) and to counter misinformation about vaccines (here). It’s also clear, from a systematic review of 105 studies, that providing accurate statistics about benefits and harms helps people to be more knowledgeable and better informed about health, and to make decisions more congruent with their values – with no observed adverse outcomes (eg anxiety).

I wanted to see if organisations currently do a good job of using these principles in relation to infant feeding. Here’s a collection of examples of the benefits of breastfeeding versus formula feeding, from some major organisations working in this area in the UK:

What do I think is a major problem with each of these communications? Each one provides a long list of possible health “benefits” (of breastfeeding) or “risks” (of not breastfeeding) – eg, otitis media, diarrhoea, obesity, etc. None of them present a single statistic for the “benefit” or “risk” of a particular outcome. Not just that, but we certainly don’t see any absolute statistics, either. We have no idea of the magnitude of that outcome – ie, the degree of benefit which is conferred to the baby (or mother) through breastfeeding. That benefit could be substantial, or, against the background of all the other influences on health, it could be tiny; we have no way of knowing from this information. (As a separate issue, many of the outcomes in the list are not proven, or are only inconsistently linked to breastfeeding – for example, a recent Lancet systematic review found the effects on obesity and diabetes potentially affected by residual confounding, and with restricted evidence).

Therefore, if mothers ask:

“how much more likely is it my baby might get diarrhoea, otitis media, obesity, etc etc, if they are formula-fed, than if breastfed”?

we have no way to answer.

This is the million dollar question. It was one of the most frequent questions I was asked by mothers struggling with feeding when I volunteered as a breastfeeding peer supporter at drop-in clinics and on the phoneline. How much better is a baby’s health likely to be if they are breastfed? How much is it worth my working through all this struggle? Alongside that, was the perennial fear, that if a mother “gave up”, she would be a “bad mother”, because her baby would then be subject to that long, long list – obesity, diabetes, leukaemia, SIDS (let’s not go into the suggestions from some breastfeeding advocates that formula feeding might be linked with autism, multiple sclerosis, or differences in gender orientation!)

Now at this point I hear you say “But breastfeeding is the best! We don’t need to quantify it! We just want as many babies breastfed as possible! We don’t need to give people numbers – I mean, mothers can’t understand statistics anyway it might just make them anxious….” (voice trails off as we remember our bright schoolkids in Uganda, and the systematic review which showed quantifying health outcomes does not lead to anxiety). Or indeed, even worse – “but if we give mothers the numbers, they might decide it’s not worth it and switch to formula (ahem)….”

So, here’s the rub. People will always make decisions. We won’t always like the decisions that they make. Maybe parents will look at the Harding Center vaccine fact boxes and say: “you know what, I’ve decided not to vaccinate with the MMR. I don’t like the fact that 1 in 10,000 vaccinated children might get thrombocytopenia as an adverse event. This is a bigger factor in my decision, than the fact that over 9000 unvaccinated children in 10,000 exposed would get measles”. OK, fair enough; that doesn’t mean we shouldn’t have given them the information. The objective in providing information is to provide unbiased information – not to make individuals’ decisions for them. (I’m a huge vaccine advocate, by the way).

I’d love to see the approaches of major evidence-based healthcare and risk literacy advocates (such as Gerd Gigerenzer, Trisha Greenhalgh, Lisa Schwartz and Steve Woloshin), applied to the issue of infant feeding. This would mean providing infographics, covering absolute risk statistics for the major, causally proven, health outcomes with different feeding modes, expressed in a fact box and embedded in the resources available to prospective and new parents. And you know what? People might trust health professionals (and feeding support services) more if we did that. We already know from research studies that mothers value a realistic approach that recognises their current situation and the decisions and difficulties they are faced with, over and above an “idealised” scenario reiterating the benefits of six months’ exclusivity and two years or more of breastfeeding. Mothers already say that they currently perceive the information they are being given as “rules based”, rather than something which empowers them to make their own decisions. Paradoxically, maybe more mothers would end up breastfeeding if we gave more neutral information: specialised support helps mothers continue feeding for longer, but mothers need to be motivated and willing to access that support. A move away from a style of communication that emphasises what “we” want you to do, and towards a neutral expression of the results of research on maternal and infant health outcomes, would benefit everybody. I can’t express this any more clearly than Professor Sir David Spiegelhalter, who recently said:

 “We reject claims that we live in a ‘post-truth’ society, and that people are fed up with experts. We do acknowledge, however, that the public, professionals and policy-makers are often ill-served by the way in which evidence is communicated.  We hope to work with others to improve how this is done, and empower people to make informed decisions that reflect both existing scientific evidence and their personal values.”

 Amen to that.