Smoking cigarettes can increase a person's risk of developing psoriasis, research shows.
A 14-year study of 116,608 women aged between 25 and 42 years has demonstrated that those who smoked had a 78% higher risk of developing psoriasis than those who didn't smoke.
Women who did not currently smoke but had smoked in the past also had a 37% higher risk of psoriasis than those who had never smoked.
Heavier smokers had a higher risk of psoriasis than those who smoked less cigarettes and their risk of psoriasis decreased at a slower rate after quitting.
Children exposed to passive smoke had an increased risk of developing psoriasis in later life.
Lead author Hyon Choi said: "These findings, along with well-established hazardous health effects of smoking, provide clear incentives for smoking cessation in those at risk of and suffering from psoriasis.
"Beyond the potential effect on psoriasis, smoking cessation would lead to a better overall clinical outcome in psoriasis patients, who often suffer comorbidities related to smoking."