What's on your skin might offer real clues about what lies beneath: Researchers say women with more wrinkles have less bone.

And that means a few extra laugh lines could point to serious osteoporosis risk.

Researchers from Yale University examined 114 post-menopausal women in their late 40s and early 50s who weren't taking hormone drugs and had not undergone any cosmetic surgery procedures to smooth or remove wrinkles.

Then, they performed an exercise almost guaranteed to lead to self-consciousness: They gave each woman a "wrinkle score" based on the number and depth of their lines and creases.

They also used a device to test skin firmness on the forehead and cheeks and took X-rays to measure bone density in the hip, lumbar spine and heel.

What they found was more than just skin deep: Women with more wrinkles had less bone density -- and women with firm skin had greater bone density -- even after adjusting for risk factors.

The researchers said at a recent Endocrine Society meeting that skin and bones are both made of collagens -- so sagging skin could be an outward sign that your levels of these proteins are waning on the inside.

But whatever you do, don't start taking osteoporosis meds. As I've warned you before, these drugs can actually break the very bones they claim to protect. (Read more here.)

Instead, take the natural steps now that can protect your bones later on no matter how wrinkly -- or how smooth -- your skin is.

You might think the answer here is calcium, but it's not -- not by itself anyway, because calcium needs vitamin D and magnesium to help keep your bones strong.

Many women already get all the calcium they need -- but they're way low and even downright deficient in D and magnesium.

If you can't get these critical nutrients from diet and sun exposure, add some supplements to your regimen.

They may not smooth your wrinkles... but they will keep your bones strong, and that's a heckuva lot more important.