BMI, Biological Aging, and Skin Longevity: Beyond Weight in Dermatology

Dominik Thor discusses how obesity, metabolic health, and biological aging intersect to influence skin health and longevity. Learn why BMI alone may be insufficient, which functional and body composition measures better reflect healthy aging, and how chronic inflammation, cellular senescence, and “biological readiness” may impact dermatologic and aesthetic outcomes.

Transcript

My name is Dominik Thor. I'm the president of the Geneva College of Longevity Science, which is the first educational institute in the world focusing entirely on longevity science. I also happen to be a visiting professor at Mayo Clinic and at Carol Davila University in Bucharest.

How should dermatologists interpret the relationship between BMI, metabolic health, and biological aging when counseling patients about skin and overall longevity?

Dr Thor: I mean, the BMI is a very interesting metric but it's more interesting from a research perspective because there could be, you know, false readings into these numbers. So, if you have somebody that has a ratio, you know, of weight, you don't really know their body composition now. Not every doctor has access to a DEXA scan to really look into that, but there are more simple measures that you can do, like waist circumference, that might actually give you a better understanding. I think the importance that we attribute to BMI comes from the fact that we need more functional testing in general for patients. But very often it's more about, you know, the relation of their tissue, right? So, you need more muscles when you want to look for healthy aging. You have to ensure that you're fighting sarcopenia as you grow older. This waste, or this loss of muscle mass, that you're typically experiencing, and you need these muscles to continue moving around to do your groceries, to enjoy your time. So, this is what we have to look for, and BMI is an interesting tool, but it's definitely not the one that we want to put all our trust in. So, maybe other things like functional testing of grip strength and others might be actually better indicators.

Given the limitations of BMI, what alternative clinical measures—such as body composition or functional assessments—should providers incorporate into practice?

Dr Thor: Well, this, of course, is a question of what is available to the providers. So, it depends on the setting that you are in. There are a lot of, you know, clinicians that work in a smaller setup, so obviously they won't have access to a DEXA scan. Also, that is a question of whether you want to expose yourself to that kind of frequencies and radiation, if you will. And then also of cost and availability. So, I think that the simple things are really what matter. That's the beauty about longevity science or longevity medicine as we now understand it. And even if you look towards the very famous influencers like Brian Johnson, he recently released a list of the things that you should be doing from his own experience. And he tries out a lot of things, which I'm not endorsing. But still, actually the list is very sensible, the one that I saw at the very least. So, these are the basic things. And the same goes for the doctors. You start with the basic things. You have to look at your patient. I think dermatologists are very good in many cases. Getting an idea about the health status of their patients just from the skin as our biggest organ that is outward facing and gives you ideas. Beyond that, you have to go into advanced blood panels and all other kinds of tests that you can do. And then when it comes to functional testing, it is grip strength; it is waist circumference that might give you a better idea, okay, how much lean mass is that which is what you're looking for as you grow older. And then there are other things like maybe gait analysis and so on that could also be interesting.

How does obesity-driven inflammation and cellular aging translate into visible dermatologic changes, and what role can dermatologists play in early intervention?

Dr Thor: Well, that's the interesting thing, right? If you look at obesity on the one hand and aging on the other, we see that both are influencing similar pathways. So, you could say that by being obese, you are rapidly aging, and that is something you want to avoid. From a dermatological perspective, of course, the most interest goes into the skin, right? And the changes there are very often driven by certain hallmarks of aging, like cellular senescence, where you see a buildup of cells that are not properly functioning anymore, not replicating, but instead releasing a mix of signaling molecules that increases local information in the tissue. At some point, that might become systemic. a low-grade chronic inflammation that has no purpose, if you will, because inflammation is part of the healing process, so that is not something you want to avoid. But once it gets chronic, once it gets systemic, then it starts influencing tissues around it. It might lead to fibrosis. It leads to many different things, and it's a self-repeating loop, if you will. Because with that senescence comes inflammation, with that inflammation becomes more senescent cells, that become more predominant. Some of the organs and tissues are a little bit more likely. So, there are tissues that have less turnover or lower turnover rates, so usually this is where you see more of the senescent cells accumulating. But, in general, these are the things that you want to look out for, and you can test for them.

With some of the blood panels, you can actually measure the rate of local inflammation, and that is what is messing up. Maybe sometimes also the results of aesthetic intervention. So, this is this idea of biological readiness, which I mentioned before, where you want to ensure that a patient is ready to be capable of regenerating. Because a lot of the interventions in aesthetics are about the concept of hormesis, where you induce local stress in order to challenge the body and entice some local regenerative effects. But of course, when we want to do that, we need to ensure that the body's answer can be as we would like it to see. If you just create stress that the body can't handle, then it's not going to be positive. In other words, the visual results will not be what you are expecting.