Wrinkles and sag, those two warrior enemies of youth, are not just caused by aging skin, but are also the result of aging facial bones, according to a new study.

A research team led by Dr. Robert Shaw Jr. at the University of Rochester Medical Center analyzed scans of facial bones in young (20 to 40 years), middle-age (41 to 64 years) and older (65 and up) patients to see if facial bone structure changed as people got older.

Researchers saw prominent change in several areas of the facial bone structure over time, reports the study, featured in the January issue of Plastic and Reconstructive Surgery, the official medical journal of the American Society of Plastic Surgeons.

Most significantly, eye sockets became wider and longer with age, while the length of the eyebrow, nose and upper jawbones all reduced. The length and height of the lower jaw became smaller as well.

While the change in eye socket size was observed at the same rate in both sexes, the other changes tended to be experienced first by women between young and middle age, and then later in men -- usually between middle and older age.

"The facial skeleton experiences morphologic change and an overall decrease in volume with increasing age. The bony components of the face are important for overall facial three-dimensional contour, as they provide the framework on which the soft-tissue envelope drapes," writes Shaw and his study co-authors.

More plainly put, that means that enlarging eye sockets coupled with a decrease in eyebrow angle could be a foundational cause of aging symptoms like forehead lines, outer eye corner crow's feet and lower eyelid drooping.

Some plastic surgeons address skeletal aging with "skeletal augmentation," or the use of implants to areas that hollow out because of bone aging, like the cheek, chin and jaw.

"These implants are often made of silicone. However, silicone implants are prone to shifting and even coming out through the skin over time. As such, I prefer to use implants made of porous polyethylene, where the tissue of the face can actually grow into the implant and hold it in place long term," says Wayne, N.J., plastic surgeon Dr. Parham Ganchi.

However, facial implants carry risks. Not only do they require an invasive setting that involves opening the skin down to the bone -- which may even include screws to keep the implant in place -- there is still the risk of the implant shifting and looking more obvious over time as the skin ages and thins.

For these reasons, Ganchi prefers to treat skeletal aging with fat injections instead.

"Fat can be injected with a small needle with no surgical dissection and relatively short downtime. Implants, while available in many shapes and sizes, are still limited. The difference with fat is that we have to go through a small process to harvest the fat before injecting it. This can be done with local anesthesia most of the time," says Ganchi.

Similar to fat transfer breast augmentation, excess fat can be taken from an area like the waist, and injected into the face. In addition to lasting for years and arguably feeling more natural than other filler options on the market, fat injections may also result in the rosier glow of youth.

"Because fat is natural living tissue -- unlike an implant or filler -- it also brings blood supply to the area and seems to enhance the tissues around it. I routinely see that the skin over the injected fat looks healthier and rosier after the injection. Some believe this is due to stem cells that are in the fat. This is a fashionable concept right now, but remains to be proven," says Ganchi.

In cases of extreme facial bone loss, like what one may encounter with a trauma victim, the most common way to augment the face is to transfer the outer part of the skull bone, which has the ability to regenerate itself, says Seattle, Wash., plastic surgeon Dr. Phil Haeck, who is president of the American Society of Plastic Surgeons.

"The skull is a ready source of bone material," says Haeck. "But to do that for cosmetic reasons when given the risks really isn't justifiable. For example, it's a procedure used for people who have been in car accidents," adds Haeck.

While genetics play the major role in the speed and way in which facial bones age, tooth loss will significantly speed up the process because the roots of the upper and lower teeth support the height of your mid-face. In addition to volume loss once you lose teeth, the skin around the mouth will more quickly become lax and flabby, losing its youthful firmness.

"When your teeth come out, you lose bone at a much faster rate -- which is further pushed by the pressure of gums. These people look prematurely old and come in for facelifts at a younger age. I actually just saw a 30-year-old patient who had already lost all her teeth," says Haeck.

Aside from keeping consistent teeth cleaning and healthy hygiene practices to prevent premature tooth decay and loss, experts point to nicotine as another potential factor in advanced bone aging. Nicotine is a very potent vessel constrictor that reduces blood supply to your body, and it has been shown to significantly impact the healing of bone fractures.

"I imagine that nicotine probably also reduces blood supply to your bones, and probably impacts the thickness of your bones after many years of smoking," says Haeck.

But don't throw in the towel on aging just yet. Yes, genetics may be the biggest factor behind how fast our facial bones age -- but there are possibilities lurking in the medical world that could still be studied for a potential solution.

"I think a wonderful adjunct to this study would be to see if calcium and bone-retaining medications used to fight osteoporosis could also prevent facial bone aging. You could study women who have taken osteoporosis drugs for years, versus women who have never taken any. Is there any difference in how fast their facial bones age?" ponders Haeck.

Now that's an answer for which we'd wait on the edge of our seats.

Interested in natural-looking cosmetic surgery? Check out our story and photos about the composite facelift technique.

Also find out 10 signs plastic surgery is not for you.