Pollution and lack of sleep on skin ageing
Traffic pollution seems to be getting worse, not better. Diesel cars, in particular, produce particulate matters, PMs.
PMs are currently actively researched in many areas of medicine as they are a recognised harmful precipitant of disease, mainly respiratory and cardiac diseases. PMs exert their effect through oxidative stress, which is a contributor to extrinsic skin ageing. The particles are nano sized, ranging from traffic sources particularly diesel, which is considered to be amongst the most harmful of ambient PMs because they can carry other chemicals such as organic chemicals and metals which may be absorbed into the skin and localised in mitochondria and generate reactive oxygen changes. It has been postulated that long-term exposure to pollution may lead to extrinsic skin ageing through oxidative stress.
A study in Germany looked at 400 women aged 70 to 80 years and used a validated Skinexa Score, which is a score of intrinsic and extrinsic skin ageing, and they found a significant association between traffic related airborne particles and signs of extrinsic skin ageing. Their study provided convincing epidemiological evidence that traffic related particulate matter is an important environmental factor contributing to extrinsic skin ageing.
Sleep deficit also affects skin ageing. In a study by Oyetakin et al. found that in 60 healthy Caucasian women when he graded their sleep quality using the Pittsburgh Sleep Quality Index PSQI, that the good sleepers had significantly lower intrinsic ageing score than poor sleepers, but it did not quite reach statistical significance. Their study suggested that sleep deprivation affected physiological or natural skin ageing rather than external and more work was done in this area. Everybody, however, agrees universally that poor sleep quality caused by sleep apnoea or enforced deprivation of sleep can lead to poorer outcomes on the health and likely on the skin as well.
Still, despite the deleterious effect of pollution on skin health, smoking and sun exposure remain the worse culprits for skin ageing. Going back to the study by Yin et al., he found that when there was excessive skin sun exposure of more than 2 hours a day, together with heavy smoking more than 35 pack years occurring together, the risk of developing wrinkles was 11.4 times higher than on separate exposure.
In conclusion, the literature suggests that there is a healthy relationship between sunlight exposure and smoking with the clinical and histological findings of extrinsic skin ageing. However, sun exposure, cigarette smoking, exposure to pollution and sleep deprivation all play a factor and can be controlled by the patient possibly often with the aid of dermatologists.
These factors have to be addressed by the patient and by the medical practitioner when trying to advise on cutaneous ageing and provide long lasting rejuvenation results. We can choose to modulate exogenous influences on our skin.
Jennifer Crawley is the Consultant Dermatologist at Clinica London with a special interest in dermatology. She is an expert in both adult and paediatric dermatology and has particular interests in research, teaching and leading audit projects.