Early Puberty, Again.

Plenty of adolescent fare popped up in media this week including perennial favorites early puberty and the perils of screen time (in addition to smoking pot, depression and anorexia). I might have let these media darlings go but they kept re-appearing on my homepage and radio. I have two middle-schoolers, I could not not comment.

I especially couldn’t ignore the early puberty banter considering it came from a name I know well - Laurence Steinberg, a foremost adolescence expert and professor of psychology at Temple University - who just happened to pen an opinion piece published at CNN entitled Obesity,early puberty and why we should be concerned

The high obesity rate among very young children is worrisome for many reasons. One is that obesity causes children to go through puberty earlier. American children have been maturing at an increasingly younger age, and one of the reasons is that more youngsters are overweight.

Oh I'm concerned. Very. His central argument rests on the assumption that girls and boys are entering puberty at increasingly younger ages:

Just how much has the age of puberty fallen? At the beginning of the 20th century, the average American girl got her first period sometime between the ages of 14 and 15. Today, it is closer to 12. The first signs of puberty -- like "breast budding" -- are visible even earlier. In 1960, the average age of breast budding was 13. By the mid-1990s, it had fallen below 10.

It sounds so plausible. Unfortunately, the evidence is limited and far from conclusive, mainly because the baseline data is practically non-existence. Granted, there is better evidence for earlier breast development though this research only started in the past few decades, mostly in the US. It’s anyone’s guess how early colonial girls needed training bras. Cotton Mather didn’t mention it.

As for age at first period, the jury is still out. Those “average American girls” Steinberg refers to? I believe he's referencing a small group of northern European girls living in the rural US circa 1900 who stumbled upon a country doctor who took notes on menstruation. There is some evidence suggesting no historical shifts occurred and yes, even some suggesting increasing age of first menarche. Also note, the Tanner Scales, the current reigning medical benchmark of pubertal development (still in use today!) comes from observations of British youth living in orphanages in the 1950s and 60s, war orphans. Enough said. I’ve written about the evidence related to increasing earlier puberty before and won’t get into it here.

The obesity claim. Yes there is some evidence but it is mixed. Even news-ish sources like WebMD, the fine purveyor of medical knowledge, don't pretend obesity is the single, overwhelmingly most important factor of early puberty. Fortunately someone there decided to list at least a few other potential risk factors like ethnicity and international adoption.

Oh Steinberg does mention a few others:

The high rate of childhood obesity over the past 40 years is not the only reason our children are maturing earlier sexually. Children's exposure to chemicals called "endocrine disruptors" -- substances found in foods and in many consumer products, from plastics to cosmetics that throw off normal hormonal functioning -- is probably playing a role.

There is also speculation that increased exposure to light—including artificial light emitted by computers, tablets, and smartphones—may be a contributor. CNN

So the esteemed psychologist mentions not the familial or socio-cultural factors linked to earlier puberty, the ones studied for decades and decades, but targets plastics and artificial light. Does anyone else find this slightly odd? 

He ignores in this article hereditary factors, family discord, absence of a father and other chronic social stressors linked to earlier puberty. So light from tv might cause girls to sprout breasts but not living with chronic stress. Light bad, elevated cortisol levels, okay? For love of PMS, he edited the first volume of The Handbook of Adolescent Psychology published in 2009. The chapter on puberty addresses the issue of earlier onset of puberty including many risk factors.

To speak of obesity as if it is definitely driving youth into puberty earlier than ever does not fit the facts. To speak of it as a done deal is not accurate. So of course I was curious why Steinberg latched on to obesity and earlier puberty. Frankly I'm still not clear but he took to the media (including NPR) to promote his new book:
In Age of Opportunity, Steinberg leads readers through a host of new findings — including groundbreaking original research — that reveal what the new timetable of adolescence means for parenting 13-year-olds (who may look more mature than they really are) versus 20-somethings (who may not be floundering even when it looks like they are). He also explains how the plasticity of the adolescent brain, rivaling that of years 0 through 3, suggests new strategies for instilling self-control during the teenage years. Packed with useful knowledge, Age of Opportunity is a sweeping book in the tradition of Reviving Ophelia, and an essential guide for parents and educators of teenagers. Amazon.

That small paragraph is remarkable.

New timetable of adolescence

Plasticity of the adolescent brain...

…rivaling that of years 0 to 3

Reviving Ophelia

Translation: Parents, don’t relax now. You have one more chance in adolescence to mess up your child for good. 

The book received rave reviews from big names in and out of academia. Martin Seligman, yes that guy (positive psychology etc. etc.), called it "simply the best book I have ever read on adolescence." Carol Dweck (praise effort not ability or intelligence) and Angela Duckworth (grit) loved it. As did my fave Madeline Levine (Teach Your Children Well). Jennifer Senior too (All Joy and No Fun), now that she's a parenting expert. 

But I still don’t see why all the fuss about obesity and puberty. Maybe nutrition is Steinberg’s side project. Maybe he is fixated on childhood obesity. Maybe he's been invited to Michelle Obama's vegetable garden. Maybe this is an excerpt from the book (I hope not). Does he feel the need to convince parents that kids are developing earlier so they (we) have more time to worry? I haven't read it yet, it will arrive on my doorstep tomorrow.

In any event it doesn’t justify the use of shoddy historical data or misrepresenting the so-called “causes” of early puberty. 

This mess certainly doesn't help this parent of two adolescents who is trying to navigate the complexities of screen time, homework-related screen usage, the screen-related social demands of adolescence or the new school requirement that each middle schooler bring a very expensive, fragile, highly addicting laptop to school every day. 

Oh well, there goes my Visiting Fellowship at Temple University. 

Next up: Save some of your screen time for adolescence and screen time/media use.

Correction: Steinberg edited the first volume of the Handbook of Adolescent Psychology not Social Psychology, the latter hefty tome sits collecting dust in my office. My bad. 

Update: Laurence Steinberg wrote to say that he did cover the many other factors involved in early puberty in the book, in fact, he was the first to publish evidence showing a relationship between adolescent-parent conflict and earlier puberty. He also noted the tight word limit. Indeed, readers here are all too familiar with the constraints of the new media including not enough space for the finer details and nuance. 


Andrea Riley said...

Are they sure it's not due to unsupervised use of artificial sweeteners? Can they study that? Wait, do mice get boobs?

Polly Palumbo, Ph.D. said...

Clearly early puberty and obesity are also likely to be caused by recreational Splenda use and I suspect parents who don't engage in enough meaningful play too.