Washington, Dec 22 (Inditop.com) Long-term exposure to sun causes physical and structural changes to the skin and photodamage, says a new report.

Unlike typical skin ageing, characterised by fine wrinkles and skin growths, photodamage includes characteristics like coarsely wrinkled skin, spots of extra pigment or lost pigment and dilated blood vessels on the face.

Sun damage also has been associated with the development of cancerous growths. Up to 40 percent of ageing-related changes are due to non-genetic factors.

Kathryn J. Martires, Case Western Reserve School of Medicine, Cleveland (CWRSM-C) and colleagues studied 65 pairs of twins attending the 2002 annual Twin Days Festival in Ohio.

A total of 130 individuals completed surveys collecting information about skin type, history of skin cancer, smoking and drinking habits and weight.

Clinicians assigned each participant a photodamage score, graded by such characteristics as wrinkling and change in pigmentation. Photodamage scores were highly correlated among both monozygotic (identical) and dizygotic (fraternal) twins.

Other factors associated with higher levels of photodamage included a history of skin cancer, heavier weight and smoking, whereas alcohol consumption was associated with lower photodamage scores, said a CWRSM-C release.

These finding were published in the December issue of Archives of Dermatology, a JAMA/Archives journals.