Live Long and Well with Dr. Bobby

Episode 10: Does sun protection work?

• Dr. Bobby Dubois • Season 1 • Episode 10

Share episode

Send us a text

Introduction

  • Health Tips: Check out my Instagram for daily health tips (@DrBobbyLiveLongAndWell).
  • If you can message me through my website, it allows me to respond to you.  The podcast comment function gets to me but I cannot respond to you.

Take-home Messages

  • Enjoy the sun but protect your skin and eyes.
  • The evidence on sun exposure's health effects is moderately clear, but leaves some questions unanswered.

Impact of Sun Exposure on Health

  • Skin Aging:  Studies show that UV exposure accelerates skin aging, causing wrinkles and pigmentation changes.
  • Skin Cancer: Types include basal cell carcinoma, squamous cell carcinoma, and melanoma (most severe).

Who's at Risk for Skin Cancer?

  • Skin cancer is quite common 
  • Fair-skinned individuals are most susceptible, as are Australians likely due to fair complexion and high UV exposure.

Evidence on Sun Exposure and Skin Cancer

  • Studies show that childhood sunburns correlate with increased skin cancer risk later in life.
  • The evidence is somewhat less clear about the risk of sun exposure later in life for the development of skin cancer.
  • UV exposure from tanning beds also increases skin cancer risk significantly.

Challenges in Sun Protection

  • Effectiveness of Sunscreens: Sunscreens reduce aging effects and reduce sun burns.  The evidence is not clearcut, but it appears that sun protection reduces the risk of melanoma, and likely other skin cancers as well.   
  • The American Academy of Dermatology recommends the use of spf 30 or higher skin protection when outdoors.
  • Behavioral Factors: People using sunscreen might stay longer in the sun, offsetting protective benefits and making the evidence less striking on reduction in skin cancer.  Men are less likely to use sunscreens.

Practical Sun Protection Tips

  • Types of Sunscreen: SPF 30 or higher recommended; mineral and chemical options available. The best sunscreen is the one that you will use regularly.
  • Application: Apply generously and reapply every couple of hours, especially in sunny and sweaty conditions.
  • Clothing and Accessories: Long sleeves, hats, and UV-protective sunglasses are effective approaches.

Protecting Your Eyes

Conclusion
I protect myself with sun screen, clothing, and sun glasses.  I also see the dermatologist yearly

Dr Bobby Dubois:

Hi, I'm Dr Bobby Dubois and welcome to Live Long and Well, a podcast where we will talk about what you can do to live as long as possible and with as much energy and vigor that you wish. Together, we will explore what practical and evidence-supported steps you can take. Come join me on this very important journey and I hope that you feel empowered along the way. I'm a physician, ironman, triathlete and have published several hundred scientific studies. I'm honored to be your guide. Hundred scientific studies I'm honored to be your guide. Welcome back everyone.

Dr Bobby Dubois:

Summer has officially arrived, although in Texas, where I live, it's felt like summer for quite a while. During the summer, we spend more time outdoors, exposed to the sun, and it's natural at least natural for me to think about what the sun exposure does to us. So today I'd like to explore sun exposure and what the evidence tells us about its impact on our health, and what the evidence tells us about what might protect us from that potential damage. As always, the show notes will have links to some of the studies I'll talk about. If you're interested, I've started regular health tips of the day about 30-second video reels on sleep or exercise or nutrition or any other topic. Just follow me on Instagram DrBobbyLiveLongAndWell. So, as always, I want to begin with the take-home messages on sun exposure. First, have fun in the sun. It's great to be outdoors, but protect your skin and protect your eyes. But protect your skin and protect your eyes. Second, as we will see, the evidence in this area is a bit cloudier than we might want, but I'll hopefully help you find a path through it. The plan for today is to first provide some background on how sun exposure can affect our health, both how long we live and how well we lived. Next, I will walk through the evidence on what causes skin cancer and skin aging and, most importantly, how strong is the evidence on ways to prevent these problems? We will also briefly talk about your eyes and how UV exposure can damage them.

Dr Bobby Dubois:

Now, I haven't shared this before, but I did want to today that I have no financial motivation for anything I say. You may not agree with what I say and by all means, let me know, but no one is providing money for me to say it. The podcast is free. I don't have and will not have sponsors and will not have paid subscriptions. Hopefully this will reassure you that what I say is what I truly believe whether I'm right or whether I'm wrong.

Dr Bobby Dubois:

Many years ago, a colleague shared some advice with me which I've been reflecting on as I've been thinking about how to prepare my podcast moving forward. She said when you're talking with audiences, data or presenting evidence makes it believable, but stories, anecdotes, make it memorable. Today, I hope that I can do both and, depending upon your thoughts and feedback, it may become a standard approach. So if you can, let me know through my website, that would be great. Do you like this approach? So let's start with the story.

Dr Bobby Dubois:

Gail and I live on a ranch in Central Texas, in a town called Dripping Springs, and we spend a lot of time outdoors taking care of the land and the exotic animals and our bed-and-breakfast guests. A few months ago, I had a sore on the top of my scalp. Now I couldn't see it, but I could feel it, and it seemed to be there for quite a while. For quite a while, I assumed I bumped my head, which happens a whole lot around here, whether it's on branches or any number of hard objects I seem to run into. Well, it didn't seem to go away and I asked Gail what she saw. She told me about it, took a picture of it and we looked at it together. It didn't look like much, but since it hadn't healed, I decided to get it checked out. Turned out to be a basal cell carcinoma. I'll explain later what this is. But it's a type of skin cancer. So off to the dermatologist I went, got it biopsied and the skin cancer diagnosis was made. Then to the specialist dermatologist who does the removal. I'm numbed up and don't feel much as he takes it out. Since it was in my scalp he had to pull the edges back together with a bunch of stitches. Now it wasn't particularly painful, but over the next couple weeks it was pretty uncomfortable and the whole thing turned out to be a somewhat bigger deal than I expected. During that time I wondered about how I got the skin cancer and whether the evidence to avoid it was very strong, and with that motivation, I dug into the data, the studies and people, and now, of course, I want to share with you what I found, as summer is taking full force. All right, next section.

Dr Bobby Dubois:

Let's begin with the damage that sun can cause. So the damage from the sun comes from UV ultraviolet exposure and UVA is the wavelength of greatest problem because it's absorbed deeply in the skin. Now UV exposure is worse near the water because of the reflections from snow, from sand, and the sun is strongest between the hours of typically 10 am and 2 pm, and even though it's cloudy, 80% of the ultraviolet penetrates clouds. So when we get to sun protection, even if it's cloudy, you'll want to consider doing it Now. There's no doubt, and we don't need major, major, major studies to know that being in the sun can cause sunburn. It's happened to all of us and everyone we know and we'll see that sunburns can lead to bigger problems later on. Over the long term.

Dr Bobby Dubois:

Sun exposure ages our skin and what does that mean? Well, it makes it thinner, it can make it saggier, we can get brown spots and wrinkles. So there's an interesting study and you know I love my studies. There were 300 women. Now, one group was told to avoid the sun and the other enjoyed being in the sun, and they examined a whole series of signs of skin aging, like wrinkles, the texture of the skin, pigment changes, and what they found was 80% of the skin damage was directly related or correlated with UV exposure. Now, note it wasn't 100%. So there is more to aging than just sun. Part of it's genetics, part of it's just getting older, but obviously the lion's share of it related to ultraviolet. Now, okay, so skin appearance doesn't affect how long we live, but it affects our quality of life and how we feel about ourselves. I mean, as we age, we don't necessarily want to look like we're getting older, and later I'll talk a bit about how we can protect our skin from this photo aging or the sun-related aging.

Dr Bobby Dubois:

Now here's the bigger issue Sun exposure can increase our risk of skin cancer, and that's, of course, what sent me down the rabbit hole of trying to understand the issues and then share them with you. A very, very, very brief pathology lesson. So the skin is composed of a variety of cells and many of these cells can become cancerous like cells elsewhere in our bodies, and the name of the cancer is based on the type of cell it came from. So two of the skin cancers basal cell carcinoma that's the one I had and squamous cell carcinoma these are ones that can bleed and they grow locally, so they'll grow bigger and bigger and into the areas next to it. Now they do grow pretty slowly. Now they can go into lymph nodes, and very rarely they cause serious harm, and if they're found earlier. They should be readily removable and curable, and that's what happened with me.

Dr Bobby Dubois:

Now the third type of cancer, which is again a different cell in your skin, is melanoma. It can metastasize and if it's not caught early, treatment can be really involved and it can even be fatal. And historically, before some of the better medicines came along, it not infrequently was fatal. So melanoma, which is the dangerous skin cancer even melanoma, if it's caught earlier, can be cured by removing it. But if we catch it late and it's spread, it can be problematic. Now we want to avoid any skin cancer, clearly, because it's no fun to have to go through the removal, but melanoma is the most important one. Fortunately that was not the skin cancer I had, but you know we're always at risk and so I'll keep getting things checked out. Now, of all cancers, skin cancer is the most common. There's about almost 5 million skin cancers a year in the US and it outweighs really all other cancers combined. And there are several hundred thousand of those which are melanoma cases, and there's probably over all of people in the United States, over a million people, who have some stage of melanoma. And again, that's the one we really, really want to avoid. Now. Most skin cancers happen in our middle and later ages, in your 50s and 60s and beyond. Now melanoma can show up in people under 30. So we all need to be mindful of it, keep an eye on our skin and try to do what we can to really avoid any problems. All right, so this is sort of the background on skin and skin aging and skin cancer.

Dr Bobby Dubois:

In the next section I'd like to explore with you, well, who's at risk for skin cancer. Basically, it's people with light skin, and there's a whole grading scheme of light skin to very, very dark skin. But the people with the fairest skin seem to have the greatest problems. On the other end of the spectrum, folks that are black. They have far less likelihood of a skin cancer developing.

Dr Bobby Dubois:

Now, one group which you might not necessarily have thought of, who are at risk for skin cancer are Australians. Now, I love Australians, I love the way they talk, and many of them obviously have moved here and it turns out a lot of the research on skin cancer comes from Australia. Now, when we talked about saunas, we talked a lot about Finland, but here skin cancer research and skin cancer risk seems to be higher in Australia. Now why might that be. Now there's lots of theories and nobody knows the full answer. It might be that they're closer to the equator than we are. It may be that the people who historically not the indigenous folks, but the folks who moved there had fair skin. They typically came from Britain and elsewhere, and some blame the hole in the ozone level as the causative factor, and I think that one's been debunked a little bit, but suffice it to say people in Australia are at higher risk and therefore the scientific community has been really focused on that.

Dr Bobby Dubois:

So I want to begin to explore the evidence on sun exposure and its relationship to skin cancer. So the risk of getting melanoma and again, that's the bad skin cancer or the really bad skin cancer it correlates with the number of sunburns you experienced during childhood. Now keep that in mind that there may be a relationship to sun exposure when you're young, to problems when you're old, which is different than the risk goes up as you get older with any time you're in the sun. So what? This study of studies, a meta-analysis? There were 51 studies Now. These were observational studies and, as we've talked about and we'll continue to talk about in future, episodes are not as good as a randomized trial and they basically said did you ever get a major sunburn? Obviously, we all get sunburn, but some people got ones that really blistered. Those are what we're talking about as the bad ones and the ones that got sunburn as a child had a 60% increase over those that did not in having a melanoma and they found what we call our dose response. So the more sunburns you got and six seems to be kind of a magic number more than six of these bad ones was problematic. So again, the more sunburns you had, the greater the risk. Now here's the wrinkle.

Dr Bobby Dubois:

As I alluded to a few moments ago, I mentioned that the number of sunburns seems to relate to the likelihood of getting melanoma. But that's the number of sunburns when you were young. Now, if we start to protect ourselves as we get older, will that stop the problem or reduce the problem? And that's where, as I said, the evidence is a little more cloudy. Now I was talking about melanoma. There's also a correlation between sun exposure and sun burns and the other two non-typically non-fatal ones basal cell carcinoma and squamous cell ones. Basal cell carcinoma and squamous cell.

Dr Bobby Dubois:

It's inevitable whenever I talk to folks about UV exposure, they'll ask me about indoor tanning salons it's like, okay, well, they use more protective rays, and is that okay? Well, interestingly, there's been a lot of studies on this. In one article it was analyzing 36 studies and they found that there was a 25% to 50% increase in melanoma and the other non-melanoma squamous cell carcinoma in people who were regular suntan booth users. And once again there was a dose response. So more than 10 a year was a lot worse than five a year or once a year. So if you go once a year before you're going to a big party, is that going to cause skin cancer? Not likely, but if you're a regular user it can be a problem. And then they also found that suntan booth users, when they did develop skin cancer, it tended to come on earlier than you would otherwise expect. As I said earlier, it's typically in the 50s, 60s and 70s.

Dr Bobby Dubois:

So up until this point in the podcast, the data is pretty strong that ultraviolet exposure can cause troubles. But, as I said, this area is a little bit cloudy and so now I want to talk about where the evidence isn't as straightforward as we'd like. Part of this is that the data is based on observational studies. So in an observational study you look at people who did something and you compare them to people who didn't do something, and then you follow them forward and you try to adjust for the fact that the two groups may not be identical. It's really hard to think about doing a randomized trial of being in the sun or not being in the sun and asking people to follow those rules for 30 years. So you're not likely to get great randomized trials on some of the aspects of this.

Dr Bobby Dubois:

So I like to think about the development of a problem as a series of kind of conceptual links. Now the first three links the evidence is pretty clear. Link number one sun exposure leads to sunburn. Doesn't take a randomized trial for all of us probably to believe that's true. The second link also pretty good data Sunburns are associated with skin cancer. And then the third link is also pretty good Studies show that sun protection reduces your exposure to ultraviolet light and the risk of sunburn.

Dr Bobby Dubois:

So it seems like, oh, we've solved everything, except where the data gets a little cloudy is does reducing that ultraviolet exposure and sunburns lead to fewer cancers? Here's the problem. So we know that sun exposure leads to sunburns which can lead to cancer, and now we want to find out. Can we protect ourself against the sunburns which can lead to cancer, and now we want to find out can we protect ourselves against the sunburns and therefore protect ourselves against the bad things we're trying to avoid? Well, before we get into the data on whether sun protection works as well as we'd like, let's take a slight detour, which is how do you protect yourself against the sun?

Dr Bobby Dubois:

So most people think in terms of sunscreens, and there are different types. There's the mineral and the chemical, or instead of sunscreens, you can wear clothes or you can just avoid being in the sun. Now there's really good evidence that sunscreens reduce skin aging, like the wrinkles and thinning of the skin. So there was a randomized control trial of over 900 people and one group had daily sunscreen use and the other group they didn't really require skin protection at all, and they followed them for four years, which is a really good time to see changes. And they looked at the skin, the fine lines, wrinkles, and they were focused on the left hand, just to keep it very precise, and what they found is the people who were using the sunscreens had 24% less evidence of aging. So the good news is sun seemed to help if your goal is to reduce your skin looking older and older. Now the data is pretty good that it reduces.

Dr Bobby Dubois:

Sunscreens reduce the risk of a melanoma. In a randomized trial of 1,600 people in Australia I mentioned before about Australia they showed that sunscreen use did reduce melanoma by 50% not by 100%, but by 50%. Where it's a little less clear is whether the sunscreen improves other cancers like squamous cell or basal cell. And again, here's another study, randomized trial. There'll be links to these in the show notes, so you're more than welcome to take a look and see what you think. That showed that SPF 15 reduced squamous cell carcinoma, but not the kind I had, the basal cell carcinoma. And in a more recent study this was part of the NHANES survey that's done here in the US on a very regular basis they showed that sunscreen use helped people, but long-sleeved shirts or staying in the shade didn't really change the risk of squamous cell or basal cell carcinoma.

Dr Bobby Dubois:

Now that seems a little odd because you would think that, yes, the sunscreens might help, but shouldn't also staying away from the sun or wearing clothes? You would think that would provide equal benefit. But again, the evidence link isn't as powerful as we would like. Suggestive, but not as powerful Now. This may seem counterintuitive. We made the strong argument that UV exposure is bad and therefore blocking that UV exposure ought to be good. But let me give you a kind of a tasty tidbit for why the protection doesn't look as wonderful as you might think.

Dr Bobby Dubois:

People who put on sun protection may inevitably stay in the sun longer. Oh, I don't have to get out of the sun, I don't need to protect my skin because I put on suntan lotion. So these individuals might be out in the sun not just an hour, but maybe two, three or four hours. So then when you look at, do people with sun protection have reductions in cancer? It can get murky because maybe those people are actually out in the sun longer. And there's an interesting discussion of this, and again I'll link this for you. The other problem is that, although we may say we put on sunscreen, we may not have done it right. We may not have put on enough, and we may not and this is often the case reapplied it multiple times a day. So this is why the data aren't as pure or as perfect as we would like them to be.

Dr Bobby Dubois:

Okay, so let's now kind of take the evidence and shift to so what do we do with all this? How does this all net out? Well, if you think guidelines from national clinical societies are a good thing, then the American Academy of Dermatology. They recommend everybody out in the sun should have SPF 30 or greater sun protection. So that's what they say.

Dr Bobby Dubois:

Well then, of course, is which type of sunscreen do you want? You know, there's the kind of the standard stuff which I mentioned before. There's the chemical and there's the mineral ones, and those can be $8 a bottle, and there's now these fancy ones that are maybe 10 times the price, with titanium and other fancy things, and they often come in very small bottles. So the physical ones do create a barrier and they reflect some of the sunlight, and that's the zinc oxide, like we know from the past. But there's now the newer ones with titanium and the chemical ones. They don't so much block the sun, but they convert the rays into heat. The physical ones also do that as well. Probably there is no difference between the two in effectiveness. There's probably no difference between the zinc oxide and the titanium ones in terms of benefits. Now, it's true that the titanium has these nanoparticles and maybe they absorb a little easier and maybe they don't look quite as awful on your skin, but it's not clear that they're any more powerful.

Dr Bobby Dubois:

For me, the best sunscreen is one you're willing to use, because often we walk outdoors and we're like I don't want that greasy look on my skin. So, whatever you find that works for you, that's what is the right type and ideally you want to apply it multiple times a day and if you're really in the sun and like me in Texas, I sweat like there's no tomorrow, I need to apply it ideally every couple of hours. Now people say, well, I've got this suntan lotion lying around. Is it still good? Well, most of it should last three years or so, so I wouldn't worry if it was, you know, last seasons or even the seasons before. I don't think you need to throw them out and start all over.

Dr Bobby Dubois:

Well, spf, which is sun protection factor, you see all sorts of numbers 15, 30, 50, 100. Most of the studies look at SPF 30. So you don't have to do SPF 50 or 100. The SPF 30 blocks 97% of the UVB rays. Now the real problem is most of us don't apply enough. You know, if you want to do pretty much your whole body, you need to do an ounce, and most of these bottles maybe have eight ounces, so you're using a lot of the bottle. So that's actually one of the bigger problems You're not putting it on enough and you're very often not reapplying it when you could or when you should.

Dr Bobby Dubois:

Now, personally, I like wearing long-sleeve shirts, and I buy the ones that have some SPF protection. I wear ones that are SPF 50. And I like those because then I don't have to worry about putting the greasy stuff all over my arms, and then I typically wear something around my neck to protect my neck as well, so I don't have to put quite as much sun protection creams and things on me. Here's another problem. I'm a man and we men have all sorts of problems in life, but one is that we're not good at sun protection in life. But one is that we're not good at sun protection. Men are, in studies, half as likely to use sun protection as women. Now why might that be? Well, I think it's sort of our masculine culture. We think our skin is stronger and we don't need to worry about it. Women, on the other hand? Many women wear cosmetics, and those cosmetics may have SPF in them, but they're used to putting creams on their skin. Men typically don't. So if people don't tend to put sun protection on, we men are probably worse at it than others, so we need to think really carefully about this.

Dr Bobby Dubois:

All right, so I haven't said anything yet about your eyes, and eyes are really, really, really important. So UV exposure causes eye damage. They can cause cataracts, which are sort of the cloudiness of the lens, and you might then need to get your lens replaced. Now, uv exposure isn't the only risk factor for getting a cataract, but it is an important one, and the other, probably even more worrisome, is macular degeneration, and that's the most common cause of blindness in people who are 65 and older. Now, genetics play a role, smoking plays a role, but also UV exposure is a risk factor, and again, I'll have show notes that will have a link to something that supports that. So we need to protect our eyes as well, and wearing sunglasses with UV protection is really the way to go, and pretty much anytime I'm outdoors I'm wearing that.

Dr Bobby Dubois:

Now I've spent the last 28 minutes talking about the harms of the sun, but obviously there's some good things about the sun, as we've talked about in our sleep pillar, exposure to sun early in the morning helps our circadian rhythm and may well help your sleep. It also helps to produce vitamin D, and there's some question like whether sunscreens might worsen your body's ability to make vitamin D. The evidence that sunscreens are going to cause you to be deficient in vitamin D is not very convincing, but if you have any concerns about that, you can get your vitamin D tested in your blood. It's not routinely recommended, but if you have a concern, by all means talk to your doctor. Well, how about annual skin exams, either with your dermatologist or your primary care doctor? Well, the question seems pretty obvious. If skin cancer is bad, then seeing your doctor should be good, so you can catch it early. Well, it's true, the evidence shows that if you undergo screening regularly, you'll find more skin cancers and including more melanomas. In a large observational study of sort of 600,000 individuals, they showed that if you get screened regularly, you will find more cancers in earlier forms of melanoma, and the likelihood of finding a melanoma will increase almost twice. Well, that seems like a good thing. However, what happens is you may be finding cancers that won't ever cause you harm.

Dr Bobby Dubois:

In a future episode, we're going to talk about to test or not to test, and we'll explore this issue further, but there aren't any randomized controlled trials on. Should you get an annual exam? And yes, you may find things, but that doesn't necessarily mean it's going to change your long-term survival or your long-term well-being. And the US Preventive Services Task Force, which advises groups on screening, has found really no conclusive evidence that one should have annual screening. So where do we go from here?

Dr Bobby Dubois:

As everyone knows, I love end-of-one trials in ourselves to see what works. We take a baseline assessment of an issue like sleep, we try something new and then we see what happens. Unfortunately, since the risk of skin cancer is a lifetime problem, we can't do an end-of-one study. We can't try something in the sun protection realm for a month and say, okay, now I know what works for me. So, even though some of the evidence in the logic chain is cloudier than I prefer, you know, the Dermatology Association recommends sun protection.

Dr Bobby Dubois:

Skin cancer is common. Protecting against the aging process is desirable for many. Will we, with our sun protection, prevent skin cancer? Again, the data is suggestive, but not as strong as I would like. Well, this is where I net out for whatever it's worth. I am careful. I do wear clothing and I wear sunglasses with UV protection all the time when I'm outdoors. I do see a dermatologist yearly and that's definitely going to happen, since I had the basal cell carcinoma. So that's where I net out, so you can look at the evidence and you can decide for yourself what you think.

Dr Bobby Dubois:

Before we close, I want to say that we're going to have a new segment in some of the podcasts on fan mail. Thank you for those who've sent comments and suggestions and topics. Now the fan mail option within the most podcast apps allows you to send me a note, but I can't respond to you. If you want me to respond, and I'm happy to do so, please try to send me a note through my website or on Instagram and then I can respond directly to you. And both of those are Dr Bobby Live Long and Well, and Dr is D-R, not the full spelling. But I have received a few and since there's no way for me to respond directly to you, I want to at least let folks know for some of these that I received your comments. So one person said that I mentioned a table of exercise program and it wasn't available on my website or the show notes. Well, that's been corrected, so you can go to the show notes episode on exercise and you can find a handy dandy summary that might be useful to program your week of activities.

Dr Bobby Dubois:

Somebody asked should we change our activities, our training, the sports we do as we age to spare our bones, joints and ligaments? That's a good question. Somebody asked about additives like calcium that's included in milks and things, and whether that's important. Somebody asked what type of multivitamins should they take and what do I take and what dose or how many per day. Somebody asked about the use of psyllium, or how many per day. Somebody asked about the use of psyllium, which is metamucil, to lower their cholesterol, their LDL cholesterol.

Dr Bobby Dubois:

So I'm going to reflect on how best to answer these questions. If you send it to me directly, I can certainly answer directly and I may. I haven't decided and I need your input whether I have special episodes where I just focus on questions or whether I answer one or two at the end of each episode. So I welcome your thoughts about this. Do send me a note, do send me questions through my website or your podcast app, and I'm particularly interested, if you liked, having a personal anecdote or a story as a way to lead into the podcast. So until next time, may you live long and well, and I am, as always, honored to be your guide on this journey. Thanks so much for listening to Live Long and Well with Dr Bobby. If you want to continue this journey or want to receive my newsletter on practical and scientific ways to improve your health and longevity, please visit me at drbobbylivelongandwellcom. That's drbobbylivelongandwellcom.