Skin ageing across different ethnicities – is 'skin deep' deeper than we thought?

I am a PhD student here at the University of Bradford, but I am also Bradford born and bred; I have always lived and studied here. When I was a teenager and getting into typical things such as skincare products like moisturisers and sunscreen, I always struggled to find the right products for me. In part, it is because I have a medium skin tone which was historically not well catered for. Beyond the superficial colour, the underpinning science always fascinated me. This has led to my research looking into skin ageing across differing ethnic groups with rich variations in skin colour and biological behaviour.

We all know that as we get older the structure and function of different organs and tissues in our bodies decline over time. Ageing is often visible. In the skin, we classically think of wrinkles developing. But beyond wrinkles, what is ageing?

Ageing is not just these visible changes; they often reflect internal damage within our cells and tissues that cause them to change over time. A good example of this is how within sunlight, ultraviolet radiation (UV) can penetrate our cells and damage our DNA which can speed up ageing over time. Ageing is not just based on how old we are (intrinsic ageing) but is also dependent on damage within our cells and DNA (extrinsic ageing). It is a very complicated process and goes beyond cosmetics, it reflects our health. That is why as a PhD student my role is to better understand how the skin ages and changes over time.

Why is skin so important to ageing?

We all know what skin is, it is the fleshy organ that protects our bodies from infection and physical impact. However, bacteria, brute force and sharp objects are not the only threat to the skin.

Skin is, effectively, our biological barrier made up of layers of different types of cells that provide different types of protection. One of these cell types are called melanocytes, these produce a pigment called melanin which provides our skin with colour. This pigmentation protects our skin from sunlight which can damage our cells and DNA, they are our skins shield from UV. This crucial protection prevents the damage that accelerates ageing.

Is skin colour important?

So if melanin protects the skin from damage and ageing, does that mean darker skin is much more protected from sunlight?

Well, we do not yet fully understand this aspect of ageing, hence this PhD project's existence. What I will say is that some research does find that darker skin tones “age” in different ways than paler skin, though colour does not necessarily seem to have a linear association with ageing and skin damage. Rather than always displaying wrinkles, pigmented skin often shows other types of ageing such as hyperpigmentation (regions of darker skin) and lentinges (age spots).

Within skin science we often refer to the Fitzpatrick scale which determines a skin’s susceptibility to sun damage and burning based on pigmentation. It describes the palest skin type, Type I, being the most susceptible to burns whereas the darkest type it describes, Type VI, is supposedly better defended against UV. Though this is a valuable model, questions exist as to whether it is truly representative of different skin types and ageing as skin colour alone does not determine the skins resilience to UV and these external stressors. Many modern researchers are looking to improve this viewpoint.

When reflecting on how melanin protects from UV and certain types of damage, researchers have started to explore whether these skin types age differently to one another.

Understanding skin of all colours 

As a scientist, I often get caught up in the excitement of the biology and lab work. Even by simply looking down a microscope, you can often see if epidermal melanocytes (pigment generating cells from the skin) are highly pigmented or not as the melanin is very clearly visible as black/brown dots. Though that may seem simple, I think it goes to show just how visible and important our skin and its colour is. To me, even small details like this in a morning are highly rewarding and are a reminder of the project's purpose and value.

Skin colour is more important than just understanding the biology of these skin types, however. Within research, volunteers and therefore our results are often focused on paler skin tones and people from Western/European backgrounds. Largely, wider historical and cultural reasons have encouraged this disparity such as colonialism, institutionalised racism, bias, and a mutual lack of engagement between researchers and participants. This is why ageing across different skin colours and ethnic backgrounds is currently not well understood and needs to be challenged so research can be decolonised and made accessible for all.

Including all skin tones and a range of ethnic backgrounds is a huge leap towards promoting equality, equity, inclusion and diversity in research. That is a very professional way of saying that projects such as mine will improve health outcomes in different skin colours. It also means that future products and interventions may be able to better help people with ageing skin across different populations. Additionally, by better understanding skin ageing across different ethnicities we will be able to improve upon our education, in both research and for the public, so that we better understand how our bodies work. I think research like this could also be impactful to the research community overall, having more diverse research take place challenges the disproportionate norm.

Key takeaways

As a researcher, I'm keen to make my work as useful as possible in the real world, so here are my top-tip takeaways...

• Ageing is not just cosmetic (wrinkles and greying hair) it goes further than skin deep. It reflects damage within our cells. Look after yourself: drink water, eat a balanced diet, get a goods night sleep and be kind to yourself. That will support your skin the best. No miracle cream can make up for having no sleep!
• We need to better understand how different skin types of age both scientifically and to promote equality, equity, diversity and inclusion in research and society
• Wear your sunscreen, your skin will thank you for protecting it against the UV, especially in this weather!

Photos

• Photo 1: Lara-Kay Shafi
• Photo 2: Lara-Kay in the lab
• Photo 3: Cultured human epidermal melanocytes in vitro