You need sunscreen 13 months a year!

No, it’s not a typo!!

You need to put on your sunscreen all 13 months of the year.

No I am not on anything either__although this 2020 has pushed us all beyond our limits.

So, yes I know by the time I post this video, I have only the people I know watching, thank you so much!! For those who don’t know me, I come from a country where we have 13 months in a year.

Instead of confusing people with 28, 29, 30 or 31 days, our ancestors decided to have 12 months, each 30 days--even and a 13th month that’s 5 days. And 6 days every leap year. We call that… efficiency!

Today we will see why you need sunscreen year around, What UV radiation is, its benefits & risks. In an effort to make videos short, I will have a part two video where you will get every information to help you pick the right sunscreen to protect you from UV effectively.

When the sun “rises” in the morning (The sun stays in its position at the center of our solar system. It doesn't rise and set. But it appears to rise and set because of the Earth's rotation on its axis) to illuminate the day, it doesn’t just send us the visible light. It also sends us heat and ultraviolet (UV) radiation. Fun fact: did you know the sun by the time it hits your face, it’d have traveled 8 minutes and 20 seconds to get to you?

Ultraviolet (UV) light constitutes about 5% of terrestrial sunlight. It is composed of electromagnetic energy with wavelengths from 400 nm to 100 nm. To put things into perspective, visible light extends from about 400nm-the deepest violet we can see, to about 700nm, the deepest red. Just as visible light consists of different colors that become apparent in a rainbow, Photobiologists divide ultraviolet radiation into 3 wavelength bands.

  • UVA (315-400 nm) sometimes called “tanning rays”
  • UVB (290-315 nm) sometimes called “burning rays”
  • UVC (100-280 nm)

They differ in their biological activity and the extent to which they can penetrate our skin. The shorter the wavelength, the more harmful the UV radiation. UVC is highly carcinogenic, for example. Fortunately, as sunlight passes through the atmosphere, all UVC and about 90% of UVB lights are absorbed by ozone, water vapor, oxygen and carbon dioxide. UVA, however, is not filtered as significantly by the atmosphere and accounts for approximately 95 per cent of the UV radiation that reaches the Earth's surface.

Let's see if UV is any good before I take you down this slippery fear-mongering road today.

Beneficial effects of UV radiation include the production of vitamin D, which is a vitamin essential to our health. It helps our body to absorb calcium and phosphorus from food which in turn assists with bone health. The World Health Organization recommends 5 to 15 minutes of sun exposure 2 to 3 times per week.

UV radiation greatly affects the skin, causing aging, sunburns, precancerous and cancerous lesions. UV radiation has an immunosuppressive effect on the antigen-presenting cells within the epidermis and contributes to the likelihood of skin cancer.

UVA radiation penetrates deeper into the skin and is produces free radical oxygen species, indirectly damaging DNA. UVA increases the number of inflammatory cells in the dermis and decreases the number of antigen-presenting cells. UVA exposure suppresses the immune system, causes harmful free radicals to form in skin, and is associated with higher risk of developing melanoma.

more constant throughout the year. It can penetrate into the deeper layers of the skin and is responsible for the immediate tanning effect. Furthermore, it is UVA that contributes to premature skin pigmentation, aging and wrinkling, can act as a co-carcinogen with UVB radiation.

UVB is very biologically active but cannot penetrate beyond the superficial skin layers. It is responsible for delayed tanning and burning; in addition to these short-term effects it enhances skin aging and significantly promotes the development of skin cancer. UVB causes sunburn and DNA strand breaks. It causes pyrimidine dimer mutations, which are associated with non-melanoma skin cancers.

UVB radiation is responsible for sunburn and can induce skin cancer. The oncogenic effect occurs as a result of photochemical damage to epidermal cell DNA, damage to DNA repair mechanisms and suppression of cell-mediated immunity. The tumor suppressor gene p53 has been found to be mutated in over 90% of squamous cell carcinomas of the skin.

Numerous in vitro and in vivo studies have identified ultraviolet B and ultraviolet A as the prime wavelength ranges responsible for photocarcinogenesis and photoaging. skin cancer are basal cell cancer and squamous cell cancer. Typically, they form on the head, face, neck, hands, and arms because these body parts are the most exposed to UV radiation. Most cases of melanoma, the deadliest kind of skin cancer, are caused by exposure to UV radiation.

It is estimated that approximately 9,500 people in the U.S. are diagnosed with skin cancer every day. The International Agency for Research on Cancer (IARC) of the World Health Organization classifies sunlight as a Group I carcinogen. Sun exposure is also strongly associated with photoaging. It is estimated that 80% or more of the changes in the skin that occur over time are due to the extrinsic effects of sunlight

Although the sun is by far the strongest source of UV in our environment, an increasing number of people are exposed to artificial sources such as tanning beds, some lasers and some fluorescent lights.

Let’s discern some facts from myth 

Myth #1: Darker people don’t need to use sunscreen

Fact: Everyone needs sunscreen! Even us-people of color. Yes, we are rich in melanin and melanin absorbs and scatters UV energy in a similar fashion to sunscreen providing Fitzpatrick V and Fitzpatrick VI individuals with a baseline estimated SPF of 7-10. This natural SPF allows darker skin tones to better tolerate UV exposure and typically results in tanning with minimal burning. This means we tan than burn but nonetheless, we want to apply broad-spectrum sunscreen for protection. There is evidence that darker skins can develop squamous cell carcinoma. The natural sunscreen is just not enough.

Sun exposure increases the activity of melanocytes, the number of melanosomes produced and the rate of transfer of melanin to the epidermal keratinocytes. This helps to decrease absorption of UV radiation by DNA and cellular constituents. But also, your dark spots, melasma any form of hyperpigmentation won’t go anywhere unless you avoid this process.

Myth #2: Get the sunscreens out for summer vacay.

In fact, my toddler needs to start going to preschool soon and I have been looking at some schools lately. In their website, most of the schools I was looking at mentioned their policy is to apply sunscreen following the memorial day through labor day mark. For those of you outside of the US, Memorial Day is considered the unofficial start of summer in the United States and Labor Day, which is the first Monday of September, marks the unofficial start of fall. So that means the kids are supposed to be exposed to sunlight the rest of the year.

Fact: we need sunscreen all year around, 13 months a year, throughout the day! Not just during summer, irrespective of where you live.

Yes, UV levels are the highest closer to the equator. Closer to the equator the sun's rays have a shorter distance to travel through the atmosphere and therefore less of the harmful UV radiation can be absorbed.

During early morning or late afternoon hours the sun's rays pass at a greater angle through the atmosphere. Much more UV radiation is absorbed and less reaches the Earth

Also, With increasing altitude less atmosphere is available to absorb UV radiation. With every 1000 m in altitude, UV levels increase by approximately 10 per cent. So my lovely friends in Addis at an altitude of over 2,000 meters, your exposure is ~25% higher.

That means Your UV exposure is 25% higher than dubai (which is just 16meters above) if that helps to simplify. I know people use sunscreen in dubai more because it’s hot but don’t let the modest temperatures of addis fool you.

Myth #3: You need sunscreen only in sunny days

Fact, you need sunscreen irrespective of Clouds and haze

Be careful not to underestimate the amount of UV radiation passing through clouds.

Yes, UV levels are highest under cloudless skies, and cloud cover generally reduces a person's exposure. However, light or thin clouds have little effect and may even enhance UV levels because of scattering. Don't be fooled by an overcast day or a cool breeze!

Many surfaces reflect UV radiation and add to the overall UV levels you experience. While grass, soil or water reflect less than 10 per cent of incident UV radiation, sand reflects about 15 per cent, and sea foam about 25 per cent. Fresh snow is a particularly good reflector and almost doubles a person's UV exposure. Make sure you apply your sunscreen even when its snowing and gloomy.

Now that we have established UV is bad, let’s talk about what we have control over: Shade, hats, sunglasses, and clothing should be part of your sun protection. 

Sunscreen is still a primary prevention method against skin cancer though. Studies have proved that the regular use of sunscreen reduced the incidence of melanoma.

On my next video, I will talk about Sunscreen! When choosing for a good sunscreen, what should you be looking for? What is SPF anyway? Is higher better?

 REFERENCES

Agin, Patricia Poh. "Measuring ultraviolet A protection in sunscreen products." Journal of the American Academy of Dermatology 77.3 (2017): e81.

Brenner, Michaela, and Vincent J. Hearing. "The protective role of melanin against UV damage in human skin." Photochemistry and photobiology 84.3 (2008): 539-549.

Cole, Curtis, Thomas Shyr, and Hao Ou‐Yang. "Metal oxide sunscreens protect skin by absorption, not by reflection or scattering." Photodermatology, photoimmunology & photomedicine 32.1 (2016): 5-10.

Crowther, J. M. "Understanding sunscreen SPF performance using cross‐polarized UVA reflectance photography." International journal of cosmetic science 40.2 (2018): 127-133.

Diffey, Brian L. "Sources and measurement of ultraviolet radiation." Methods 28.1 (2002): 4-13.

Gabros, Sarah, Trevor A. Nessel, and Patrick M. Zito. "Sunscreens and photoprotection." StatPearls [Internet] (2020).

Latha, M. S., et al. "Sunscreening agents: a review." The Journal of clinical and aesthetic dermatology 6.1 (2013): 16.

Linden, Kenneth G. "Commentary: Sunscreen sun protection factor (SPF): Is higher better?." Journal of the American Academy of Dermatology 78.5 (2018): 911-912.

Silva, Elizabet Saes da, and Samuel Carvalho Dumith. "Non-use of sunscreen among adults and the elderly in southern Brazil." Anais brasileiros de dermatologia 94.5 (2019): 567-573.

Trivedi, Megha, and Jenny Murase. "Titanium dioxide in sunscreen." Application of Titanium Dioxide. IntechOpen, 2017.

https://www.aad.org/media/stats-skin-cancer

https://www.who.int/news-room/q-a-detail/radiation-ultraviolet-(uv)#:~:text=Altitude%E2%80%94at%20higher%20altitudes%2C%20a,otherwise%20reach%20the%20Earth's%20surface.

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