A twin study of perceived facial aging

bumblebums

I got lost in a Google Scholar warp a few days ago and dug up this interesting study (2nd link takes you to the full pdf, with pictures of some of the twins):

http://journals.lww.com/plasreconsurg/Abstract/2009/04000/Factors_Contributing_to_the_Facial_Aging_of.19.aspx
http://drbahmanguyuron.com/wp-content/uploads/2012/03/Factors-Contributing-to-the-Facial-Aging-of-Identical-Twins.pdf

The key finding from this study that would be of interest to this forum: a higher BMI makes younger people look older, and older people look younger. The effect is more subtle than this, as there is an interaction between the amount of extra weight and where the tipping point is. But the general finding is not that shocking or counterintuitive. This is something to be aware of if you are worried about the appearance of your face as you try to lose fat in middle age. (Yes yes, I am aware that BMI is not the same thing as body fat %, but when you are calculating over 186 pairs of twins, it's a pretty close estimate as I doubt very many bodybuilding twins were at that Twinsburg, OH festival.)

Sarauk2sf

Tagging to have a look at - coz, well, I am getting on a bit

bumblebums

An old Korean lady at a nail salon asked me if I was my friend's mom. My friend and I were both 36 at the time, but she was about 40 lb overweight. It stung (I mentioned the "Korean" part because it is notoriously hard to estimate the age of people of a different race, and the "old lady" bit might have something to do with the utter lack of inhibition about asking bizarre and inappropriate questions of strangers.) Anyway, yeah, this is on my mind, too, because I don't mind looking my age but I don't want to look older than necessary.

The way they handled the BMI/perceived age correlation in the paper is a bit complex, because the interaction is complex. They binned twins by BMI: 0 pt difference, 4 pt difference, vs 8 pt difference. If all the other factors are held constant (smoking, sun exposure, hormone replacement were some of the other factors), then a 0 pt difference meant the twins looked about the same age. If a twin had a 4 pt higher BMI, s/he looked older than the thinner twin up until about the age of 40, but after that point, s/he looked older. If a twin had an 8 pt higher BMI, s/he looked older until about age 55, and then the effect reversed.

paprad

Interesting! I must check whether greying hair is one of the variables

If a twin had a 4 pt higher BMI, s/he looked older than the thinner twin up until about the age of 40, but after that point, s/he looked older. If a twin had an 8 pt higher BMI, s/he looked older until about age 55, and then the effect reversed.

I got a bit lost with 's/he' in the first sentence - I presume that meant the thinner twin (by 4 pts) starts looking older after 40?

This is also vaguely depressing because i was podgy right through my 40s (when I must've looked older than my non-existent twin) - and now that I am determinedly trying to lose weight, I will look older in my 50s. That is, if I read that right.

This study was focussed on just the face - but surely the perception of age must also take into account the rest of the body - being thinner/fitter would lead to better posture, gait. <clutching at straws here, heh>

bumblebums

Interesting! I must check whether greying hair is one of the variables

If a twin had a 4 pt higher BMI, s/he looked older than the thinner twin up until about the age of 40, but after that point, s/he looked older. If a twin had an 8 pt higher BMI, s/he looked older until about age 55, and then the effect reversed.

I got a bit lost with 's/he' in the first sentence - I presume that meant the thinner twin (by 4 pts) starts looking older after 40?

That's right. There are other ways they could have done it, rather than binning by BMI, that would have been less confusing. But this is the simplest stats one can do on this kind of interaction.

This is also vaguely depressing because i was podgy right through my 40s (when I must've looked older than my non-existent twin) - and now that I am determinedly trying to lose weight, I will look older in my 50s. That is, if I read that right.

This study was focussed on just the face - but surely the perception of age must also take into account the rest of the body - being thinner/fitter would lead to better posture, gait. <clutching at straws here, heh>

I agree. Past a certain point, you have to decide, perhaps, whether you would rather look young below the neck or above the neck. Or whether you'd rather look younger or feel younger.

And yeah, you are totally right about hair. Gray hair should be an obvious one, but there are other factors like hair length and hair style. Judging from the pictures in the paper, they did not control hair in any way, although for all but one pair of the twins they pictured, hair texture and style are surprisingly similar. They could have covered it up for the pictures, and probably should have.

Sarauk2sf

Bumping this as I still want to check it out and have not got around to it

wild_wild_life

Very cool. Sun exposure makes a big difference too. So fit people who spend more time outside look older after age 40? I'm willing to live with that.