People with deep forehead wrinkles may be at a higher risk of dying from cardiovascular disease, new research suggests.
Furrows in the brow could raise a red flag for potential problems such as heart conditions or strokes, according to the 20-year French study.
Those with "numerous deep wrinkles" may be 10 times more likely to be killed by a cardiovascular condition, writes lead author Yolande Esquirol, an associate professor at the Centre Hospitalier Universitaire de Toulouse.
No definite reason for the link is offered but one theory is that it could have to do with the hardening of the body's arteries due to plaque build-up. Because blood vessels in the forehead are so small, they may be more sensitive to such build-up – meaning wrinkles there could be an early sign of their premature ageing.
The study makes clear that wrinkles are still not a better method of evaluating cardiovascular conditions – the biggest killing disease in Europe – than existing methods such as testing blood pressure and lipid profiles.
It analysed a group of 3,200 adults over two decades who were all healthy and were aged 32, 42, 52 and 62 at the start. They were each assigned scores depending on the number and depth of wrinkles on their foreheads.
A mark of zero meant skin was completely smooth while a score of three meant "numerous deep wrinkles".
The authors found that people with a score of one had a "slightly higher" risk of dying of cardiovascular disease than people with a zero rating, while those who had a score of two and three had almost 10 times the risk.
Ms Esquirol said: "The higher your wrinkle score, the more your cardiovascular mortality risk increases.
"You can't see or feel risk factors like high cholesterol or hypertension [so] we explored forehead wrinkles as a marker because it's so simple and visual. Just looking at a person's face could sound an alarm, then we could give advice to lower risk."
She added that such advice could include straightforward lifestyle changes such as taking more exercise or eating healthier food.
Risk of heart disease increases as people age, but lifestyle and medical interventions can mitigate the danger. The challenge has long been in identifying high-risk patients early enough to make a difference.
Dr Esquirol, who will present her study at the European Society of Cardiology's congress in Munich this week, said: "Of course, if you have a person with a potential cardiovascular risk, you have to check classical risk factors like blood pressure as well as lipid and blood glucose levels, but you could already share some recommendations on lifestyle factors.
"This is the first time a link has been established between cardiovascular risk and forehead wrinkles so the findings do need to be confirmed in future studies, but the practice could be used now in physicians' offices and clinics. It doesn't cost anything and there is no risk."