1989 年 23 巻 1 号 p. 22-30
Physiological and morphological changes in the facial skin were investigated in relation to aging in British, French, American (caucasian), and Japanese women to clarify racial differences.
The following parameters were measured; sebum secretion rate, transepidermal water loss, skin surface conductance, skin surface microtopography, corneocyte surface area, and skin color. In any ethnic group it was shown that sebum secretion rate was highest in the 20's to 30's, after which it declined with aging. However, Japanese women showed most remarkable age-associated change.
Transepidermal water loss was inclined to decrease with increasing age and no racial difference was recognized. Skin conductance was low in young age group, and then it increased with aging until 30's or 40's. Caucasian people had higher conductance in every age group examined than Japanese. Skin surface microstructure was considerably changed during the aging process, showing that pore size and irregularity of furrows incresed with aging. From the change in these parameters it was appeared that the skin texture of Japanese women is finer than that of caucasian. British and Japanese women showed almost the same change in corneocyte surface area with aging and so, it was considered that there is little racial difference in the age-related change of turnover time of stratum corneum. It was also found that skin color changes from reddish to yellow and value decreases.