Wednesday, April 08, 2015

Breast Feeding Might Not Reduce Childhood Obesity: Gasp

Breast milk might not be the new Slim Fast for the stroller set. A new paper suggests breastfeeding might not greatly reduce risk of childhood obesity. Yes, a study that questions one of the oft-hyped benefits of breast milk. Note it on your calendar. Note too that the media ignored it.

So let me fill you in...

Researchers from The Cincinnati Children's Medical Center reviewed studies relevant to a link between breastfeeding and childhood obesity. They report some research shows a link but caution the evidence is riddled with some serious limitations (e.g., confounding factors, publication bias, analysis bias). They argue breastfeeding likely impacts obesity in a more indirect and moderate manner than previous research has suggested. This makes a lot of sense. It’s not like breast milk marches into the infant, finds the obesity switch and flips it to slim.

The routes from boob to BMI, they argue, are more circuitous and involve factors like maternal weight, early taste preferences and digestion/gut flora. For instance, breast milk appears to provide more good gut bacteria which might play a role in later obesity. Breastfed babies also tend to have fewer ear infections and respiratory illnesses so this might lead to less exposure to antibiotics that have been linked to obesity. Or take diet preferences. Breastfed babies have been shown to like a wider range of healthy food. Research has not yet provided a link between breastfeeding, food preference and later childhood diet but it's plausible. 

So what do the authors conclude?

The best observational evidence to date, compiled across over 80 separate studies conducted over at least 20 years, suggests that breastfeeding, especially for longer durations or more exclusively, is associated with a 10–20 % reduction in obesity prevalence in childhood. However, the complex nature of the relationships between breastfeeding and obesity, including the fact that human milk is variable between women and breastfeeding may have differing effects in specific population subgroups, suggests that the concept of promotion of breastfeeding as a front-line strategy for the primordial prevention of obesity is not supported by the literature. [my bold]

In other words breastfeeding in and of itself will not greatly prevent childhood obesity. So don’t look for the Skinny Bitch Breast Milk Latte quite yet.

Speaking of products, the lead author receives funding from Mead Johnson, yes Big Formula. Does this instantly discredit this study? No. The authors report they believe a true link exists between breast milk and weight and advocate for more research elucidating the link. To some degree it’s in the formula industry’s best interest to identify (and then replicate) the seemingly magical ingredients in breast milk. The authors have provided a balanced review and addressed the limitations of existing research, a rarity in the breastfeeding literature. 

Some of these flaws include:

Establishing this relationship between breastfeeding and obesity protection has been notably difficult for many reasons, including imprecise recall of breastfeeding timing and intensity, incomplete accounting for covariates that may affect both the decision to breastfeed and obesity propensity, and long intervals between the exposure (human milk or breastfeeding) and outcome (obesity development).

Again, these concerns apply to a large swatch of BF research.

The closing, however is rather curious.

One assumption of this review is that a relationship between breastfeeding and obesity development in the offspring is real, and even plausibly causal. However, what if breastfeeding and human milk are actually not the drivers of differential obesity development in offspring? This is also possible and would shape a different set of questions relating to the relationship between breastfeeding and obesity risk. In this instance, breastfeeding behavior needs to be considered as embedded in a fabric of other positive attributes. For example in the USA, the decision to breastfeed may be a marker for mothers otherwise pursuing a healthy lifestyle, with knowledge about healthy choices, and the time, income and social support to translate that knowledge into the non-trivial choice to initiate and continue breastfeeding, in order to accrue the many known benefits for their infant’s and their own health. Thus, encouraging breastfeeding among those not otherwise inclined, without improvement in maternal diet, physical activity and other healthy lifestyle factors, may have limited impact on childhood obesity, as the often-cited PROBIT study suggests.
So one of the authors is funded through Mead Johnson and might have some motivation to downplay the link between breastfeeding and obesity. But also maybe some motivation to find the link, if it’s really there!

Some will bash this paper based solely on the formula connection. I don’t think it’s fair. It presents research in a balanced light and takes a more skeptical approach to the literature.

And let me pose a question. 

What about the heavily cited study from the Harvard researcher claiming breastfeeding would save 900 babies from dying every year in the U.S., mind you, the same woman who also actively advocates for banning infant formula? 

How is she less biased than the present authors? At least the latter disclosed their conflict on the paper, as per new requirements and practices that explicitly refer to funding. So readers know about the funding when they get to the end of the paper where the disclosure appears. The Harvard suboptimal breastfeeding paper, by the way, has been cited by the Surgeon General, received gobs of media attention and contains no such mention of activism or possible conflict of interest (and is not required to do so). The present authors also don't make any extreme claims - like the outlandish one that more breastfeeding would have saved children in the United States from dying, for instance, from asthma. 

Nor do the present authors hide behind any scientific goodbledygook or mysterious calculations (not fully explained in the paper) that might deter readers from asking too many questions or readily understanding or even identifying their outcome measures and thus ultimately the meaning of their results. Ahem. 


You can read the present study in a PDF for free or find the summary at Science Daily.

Wednesday, April 01, 2015

Parenting Books: Do parents deserve thought-provoking books?

No question, parenting books appear more popular than ever. Amazon lists over 200,000 selections. Someone must be buying parenting books. Do you? I wonder why people seek these books and better yet, what kind they actually read, find useful and enjoy. I ask because, like every other psychologist and mommy blogger, I'm working on one too. When I've shown bits and piece of the manuscript (or even described it), I've found people like the idea but sometimes report the writing is too academic, too detailed, too serious in parts. A kind and generous reader likened it to reading an article in The New Yorker or Atlantic. A great if not particularly accurate compliment but she meant it wasn't the type of parenting book she was expecting or normally read. No surprise, it's a lot like this blog, both in style and content.

Another reason I bring this issue up, there are non-fiction books on the best-seller lists right now that are equally detailed, serious and academic as my manuscript. But they aren't written for parents. Is there a different standard for parenting books? If so, why? I suspect it involves a complicated societal relationship with motherhood. Although the status of women and mothers has come a long way since the 1950s at times parenting, the greater burden still placed on women, garners disrespect. Perhaps this also explains why news about children more often lands in the lifestyle or culture pages and not the more vaunted front page (or homepage). It's women's work and frankly, anyone can do it. In this age of supposed hyper-parenting why the disrespect for parenting literature? Has the vast heap of parenting books turned parents off book? Then why the pile up at Amazon?

The good news, a number of more intellectual books for parents have received a lot of praise and attention, say Eula Biss's On Inoculation. It isn't an easy read. Far From The Tree by Andrew Solomon, by the way, almost 1,000 pages. Yet these remain the exception. Apparently books about children and pregnancy are to be relatively simple informative affairs. Amusing too.

So I must ask, do you seek parenting books out more for entertainment, practical advice or something else, perhaps a greater understanding of the parenting experts or their recommendations or research?

Wednesday, March 25, 2015

Debunking Gets It's Fifteen Minutes in the Media

Debunking got some media attention this past week! Hurray! NPR's Bob Garfield hosted an On The Media chat with Craig Silberman, a fellow at Columbia's Tow Center for Journalism and bestill my heart, founder of Emergent, a rumor tracking/news debunking website. The topic: Uncorrected Rumors. My ears perk up and my spirits rise when I hear talk of "unverified claims" and "misinformation" and on my birthday too, a perfect gift.

Silverman, the debunker-in-chief pins a lot of blame on the media. He told Garfield "when it comes to misinformation, in many ways news organizations are part of the problem rather than the solution." In fact he makes an even stronger case for the media botching it from the get-go in a report he compiled for the Tow Center:
News websites dedicate far more time and resources to propagating questionable and often false claims than they do working to verify and/or debunk viral content and online rumors. Rather than acting as a source of accurate information, online media frequently promote misinformation in an attempt to drive traffic and social engagement. Lies, Damned Lies and Viral Content 

Readers here know the many ways the media perpetuate error and innuendo. One of the most common missteps that fortunately Silverman addresses includes failing to following up on rumors or stories that turn out to be false. In journalistic lingo, the media fails to follow through on verification. After the news media linked a mass grave in Mexico to students that had been killed, only about third of the outlets bothered reporting weeks later there was no correction according to Silverman. I'd argue that there is very little verification when it comes to children's health news. Other than the debunked link between autism and vaccines, when is the last time you recall reading an article correcting any factoids or inaccurate coverage of children's health let alone parenting advice?

Then there are the headlines. Silverman brings up several types that don't need much explanation here. Parents practically get hit over the head with the strong headlines. For example, ones like these:
  • The headline that makes a claim seem truer or stronger than it is. Watching TV Makes Kids Violent. (Notice the casual language.)
  • The headline with the question mark, also making claim appear stronger. TV Encourages Aggressive Behavior? (these are all my examples here, duh!)
Either through casual language or the strategic question mark, the headlines regularly introduce more certainty that than the scientific evidence suggests. I'd also argue headlines also up the ante and drama with absolute ratios. Daily TV Linked to Five-Fold Increase in Violence. Not Breastfeeding Doubles Risk of Obesity. 

Contrast this with the striking scenario I noticed on reporting of the new peanut allergy research, yes that landmark, game-changing study - the media chose that remarkable moment to insert some uncertainty, some hesitation into the headlines. CNN: Early Consumption May Prevent Peanut Allergies, NPR: Feeding Babies With Foods With Peanuts Appears To Prevent Allergies, NY Times: Feeding Infants Peanut Products Could Prevent Allergies. Seriously, I cannot make this stuff up. Who knew the media would chose that moment to hedge their bets? Headlines misinform or distort in some pretty subtle ways. Another tactic, Breastfed Kids Smarter! So here a correlational result (a correlation between breastfeeding and intelligence) gets translated into headline that I'd bet most people interpret as breastfeeding makes kids smarter. The seed is planted, firmly, especially when the nuance gets buried in the final paragraph or by the lead researcher telling us how surprised she was to find such a big difference between breastfed and formula-fed kids.  I designed the study but wow, I was so surprised by the results!

We at Momma Data also know too well that readers tend to believe the claim in the headline as Silver pointed out. People still tend to believe the headlines, even if after reading the article that raises some uncertainty. After a claim gets planted in the head, it's hard to dislodge. Especially with repetition. Social psychologists have worried for decades about how false information sticks like super glue.

As much as it pains me, sigh, even debunking carries risks. As Silverman and Garfield both lamented, reading or hearing false or inaccurate information over and over, even if in a debunking context, lends it some credibility. Debunking doesn't appear to change the minds of people with extreme or strongly held views, in fact it can backfire strengthening opinions and beliefs. The autism-vaccine-measles debacle very well may become the textbook phenomenon for understanding the role of the media in perpetuating and correcting misinformation and also in the realms of public and psychology, how people respond to misinformation and its correction. Researchers already have published studies but the results are not encouraging as I've reported. There have been no singular, clear solutions for how to address or change people's incorrect beliefs, especially about vaccinations, although there are some hints. Silverman in a report for the Tow Center shows some reporting tactics for correcting misinformation and argues, amen, an important step involves journalists using more skeptical thought before reporting questionable information.

Read Silverman's Lies, Damn Lies and Viral Content paper here.
Listen to the On The Media podcast here.