The "working mom = fat children" study: How the news media say it

A new study is out linking longer working hours for mothers with a one- to two-pound increase in weight for their children, especially in the 11 to 12 age range (or a gain of 1 lb every 5 months beyond the typical expectations for age for every 5.3 months mom is employed). The PDF for the full paper is available here. Note that there a few points to embed in your brain before we move to what the news media have done with this one.

1. The role of fathers' employment was not investigated here.

2. There already have been studies linking weight and maternal employment. Can we get some studies that look at the role of fathers in mediating these factors, say, fathers who do more of the domestic work? Or even better as a sex-control, mom-mom households? At any rate, this study isn't exactly "news."

3. One fifth of the sample of 990 children was overweight. Note that this does not say "obese." In fact, nowhere in the paper does it say "obese" in reference to the findings. The authors note the "increasing rate of obesity" in general, but nowhere do they describe the children in this cohort as being obese. Remember that as you read what the news reports say.

4. They did not find evidence that "nonstandard" work--nights, evenings, weekends--was associated with greater weight gain in children, and they seem to be rather bothered by this finding. I can see why...and I refer you to (5) below.

5. The authors of the study speculate that the peak weight-gain risk they identified in children of working mothers might be explained as follows:

It is possible that because fifth and sixth graders generally have more independence and less adult supervision over their time use and food choices than third graders, maternal employment precipitates poorer food choices and more sedentary activity. Children’s lesser supervision at older ages may be related to the diminished likelihood of being in an after-school program and a greater likelihood of being in self-care (Johnson, 2005). The ways in which the link between maternal employment and child health may be moderated by child age warrants more research attention.

This speculation is less likely to make sense if you don't find greater evidence of weight gain among children whose mothers work "non-standard" hours--when children are even more likely to be left unsupervised, especially in single-parent homes.

6. Finally, I refer you to these findings from the paper:

Results from the RE models, which compare outcomes across different children, did not reveal any significant associations between mothers’ employment, or nonstandard employment, and their children’s BMI. Looking at the within-child FE regression models (our preferred models), which related within-child changes in mothers’ employment experiences to changes in that child’s BMI over time, we see in Model 1 that an additional period of maternal employment over the child’s lifetime was associated with a 10% of a standard deviation increase in children’s BMI (d = 0.10; 0.02/0.204). The fact that such an association was found in the FE models, but not the RE models, may be due to the different nature of such models; specifically, RE models compared across different children whose mothers had different employment experiences, while the FE models related an individual child’s accumulation of maternal employment to changes in that same child’s BMI. There were no significant associations between maternal employment status at a given time point (Model 2) and BMI, and also no associations (at conventional levels of significance) between maternal nonstandard work and child BMI (Models 3 and 4).

That strikes me as equivocal, but dammit, Jim, I'm a biologist, not a statistician.

The news reports make many references to "latchkey" kids gorging themselves on after-school garbage while Mom is not around. Not one single writeup I've read so far mentions that the children in this study, in large part, each had another parent. Rarely does a report include discussion of the possibility that two parents might be involved in the health of their child, might have a role in a child's weight gain.

Many, many of these reports bring up, yet again, the "childhood obesity epidemic" and either directly or obliquely blame working mothers for having a role in it. Some even mention how working moms don't "cook from scratch." (For the record, this working mom does that all the time). This, my friends, is 1950s interpretation of 21st-century findings, and it irritates the hell out of me.

Let's let the ledes and other content speak for themselves, shall we?

From the Telegraph, which had among the more sensible of writeups:

Researchers said that for every 10 hours a week a mother works, the weight of their children increases by on average one and a half per cent.

From the Daily Mail Online (you should check out the story just for the overwrought and truly awful art they included):

Children whose mothers work are six times more likely to be overweight, research shows.

They believe that a diet of fatty ready meals and snacks eaten unsupervised after school is causing them to pile on the pounds.

They are often left to prepare their own dinners which may consist of a high-calorie ready-meal left out in the fridge, as opposed to a family dinner cooked from scratch.

Note here the introduction of the June Cleaver-evoking "cooked from scratch" phrasing. It was not, for the record, a phrase the authors used in the paper. Ah, for the good old days. What did I do with those pearls?

From HealthDay:

As if working mothers don't have enough to feel guilty about, a new study suggests that the more time they spend working, the heavier their children become.

My favorite over-interpretation from MSNBC:

Children whose mothers work continuously over their lifetime are more likely to have a higher body mass index (BMI) than those whose moms work less, according to a new study, but they're not necessarily worse off in terms of their overall health.

From Fox...in desperate need of a copy editor:

Childhood obesity has been steadily rising in the U.S. in the past 30 years, and a new study from American University in Washington, D.C. has found that a child’s weight may depend on how much their mothers were away at work growing up.

NPR pours salve into the wound, bless 'em:

So does that mean Mom should stay at home and not work? Not at all, says Taryn Morrissey, a developmental psychologist at American University and lead author of the study appearing in the journal Child Development.

For one thing, the difference was small, Morrissey says. For every five months or so a mother was employed while her child was growing up, a kid of average height would gain about a pound more than otherwise expected.

There you have it, straight from a study author's mouth. It's a good study. It's findings are worth discussing, in context. But that context needs to be the 21st century, not some ideal of a time long since passed.

Headline roundup

• The more mom works, the heavier her kids get (HealthDay)
• How long moms work linked to slight increase in kids' weight (NPR blogs, nice nuanced headline)
• Working moms to blame for kids' obesity problems? (The Boston Globe Website--this headline sucks)
• Kids put on pounds when moms work (MSBNC, blunt and needs nuance)
• Children's body mass index rises the longer mom works (The Baltimore Sun)
• Latchkey kids more likely to be obese, report finds (The Telegraph: completely misleading, canceling out their triumph of a calm-toned lede)

Today's BIG BAD HEADLINES (and more!) WINNERS

• Study: Moms' work schedule is making kids fat (Fox: WINNER for most egregiously misleading garbage of a headline)
• Children with working mothers are six times more likely to be fat (The Daily Mail: WINNER (tie) for the headline; WINNER (also) for most idiotic images and cutlines)
• Had to come back to add this whopper for WINNER, worst headline and opening grafs: Study links working moms to fat kids (Parentdish.com):

All you working mothers can quit feeling guilty about leaving your children as you head to the office.

The kids fat and happy. Well, fat anyway.

Researchers say the more years you work outside the home, the more likely your children will sit in front of the TV and say, "Gosh, I miss Mommy. Pass the Cheetos."