The evidence for smoking and UV exposure on skin quality

Skin, sun and smoking: Smoking truly is bad for your skin. It ages it, gives you wrinkles and the effects are even worse when combined with sun damage. Stopping smoking is not easy, but we can always tell a smoker’s skin by its lack lustre grey thickened appearance.
Many of the patients at Clinica London come to see the Dermatologist, Dr Jennifer Crawley because they feel their skin is ageing due to chronic photo-damage and exposure to smoke, pollution and lack of sleep. She provides them with advice on how to look after their skin, including various vitamin A products such as Tretinoin 0.05%, sun protection with SPF-50, good hydration and sleep.
In this blog, I am going to talk a little bit more about the scientific evidence for extrinsic ageing factors on the skin. In 2001 Yin et al. did a study on 83 patients where they collected data on external ageing factors of smoking and UV exposure by patient questionnaire. They looked at the upbringing, lifestyle, job and hobbies to estimate the degree of sun exposure and they assessed the facial skin through a clinical scale. They then looked at specimens of skin for histological analysis.
The results showed that an average daily skin exposure to two hours was associated with a significant increase in wrinkling with an odds ratio of 2.65, which indicates that even two hours of the sun per day could cause wrinkling as we get older. They found a greater odds ratio between tobacco, smoking and wrinkling showing that, although the sun can be bad for you, smoking is extremely bad for your skin.
The study by Yin is regarded as the first good quality study correlating environmental factors with clinical signs of damage. The Danielli study in 1971 was the first good study where he looked at the severity of wrinkling in 1104 subjects who smoked regularly after he adjusted for their age and outdoor sun exposure. The association between cigarette smoking and wrinkling was striking for both men and woman after the age of 30. They found that patient’s aged 40 to 49 looked as wrinkled as non-smokers aged 60 to 69 if they smoked the equivalent of one pack a day.
By 2017, we have enough studies to show that smoking and sun exposure are both positively correlated with skin ageing, whatever clinical measure of skin ageing is used; whether it be skin wrinkles, elastosis, telangiectasia, smoking was worse than the sun in all of the studies. However sun exposure longer than five hours a day becomes a strong independent factor for wrinkling, as strong as smoking.
Lastly, a study in 2002 in the UK looked at 792 subjects over the age of 60. They took a history for environmental exposure to sun and smoking and assessed the skin clinically on the face, neck and back of her hand. They assessed the cumulative sun exposure by asking the subjects about their estimated time outside, and they concluded that cigarette smoking rather than the sun was a strong predictor of skin ageing. Since this study was done in The UK, you could well argue that we did not have enough sun. Also, the study was done on patients already attending a dermatology clinic who may not have represented the general population and may well have been more aware of their skin health.
Jennifer Crawley is a 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.