The Epidemiological Study of Skin Aging in a High Temperature Environment

Background: Forty percent of solar irradiation arriving on the ground surface is infrared rays (IR). However, these have received little attention. Chronic experimental exposure to IR has been found to cause degenerative changes to dermal connective tissue and an accumulation of ground substances, which is similar to changes which occur by photoaging. Objective: To investigate the effects of persistent heat exposure on the cutaneous aging symptoms such as wrinkles, dyspigmentation and telangiectasia. Methods: A total of 306 male volunteers, aged between 26-68 years, were recruited from steel factories with a torrid working environment. Each volunteer was interviewed for demographic information, cumulative sunlight exposure levels and their smoking history. Skin examination and measurement of erythema/pigmentation levels were also performed on the crow's feet area of the face and/or the upper inner arm. Results:1. The group of males, aged 50years or over, who had been exposed to high temperatures for more than 10years showed a tendency to have severer wrinkles (5.11.5) than an age-matched control group (3.70.1).2. There was no correlation between dyspigmentation and heat exposure.3. Erythema indices decreased and were found to be dependent on the duration of heat exposure to the face in the group of males over 40years of age, and to the upper inner arm in the group of males over 50years of age. Conclusion: Chronic heat exposure might contribute to the development of skin wrinkles and shows the possibility of potentiation of extreme ultraviolet effects.