Determination of minimal erythema dose of normal skin to ultraviolet rays / 中华医学美学美容杂志

ABSTRACT

Objective To investigate the minimal erythema does (MED) of normal skin to UV in Guangzhou city,and to observe its relationship to sex,age,skin type,seasons and the years lived in Guangzhou.Methods 621 healthy subjects were exposed to Solar Simulator (GS2004) and the MED was measured and observed by two professional technicians after (24±2) hours.Results The average MED value of all subjects was (1170.2±333.2) mJ/cm2.In male and female group,the average MED values were (1132.8-339.4) mJ/cm2 and (1182.1 ± 330.7) mJ/cm2,respectively,and there was no significant difference between male and female (P=0.20).The MED value in subjects aged from 30 to 50 (1014.7 ± 359.7) mJ/cm2 was significantly lower than those aged from 20 to 29 (1222.9±304.3) mJ/cm2 and over 50 years (1179.0±374.3) mJ/cm2 (P＜0.01).The MED value in skin type Ⅱ (673.53±228.3) mJ/cm2 was significantly lower than those in type Ⅲ (1224.3±254.2) mJ/cm2 and Ⅳ(1363.1±278.5) mJ/cm2(P＜0.01).There was significant difference of the MED value between different seasons (P＜0.01).The MED value in spring (969.2±355.8) mJ/cm2 was lowest,and followed by summer (969.2± 355.8) mJ/cm2.However,there was no significant difference between autumn and winter (P＞0.05).The MED value in subjects lived in Guangzhou from 5 to 10 years was significantly lower than those whose residence time was from 1 to 4 years and over 10 years,respectively.Conclusions The MED value of the subjects in Guangzhou is quite different from other cities of China,and related to age,skin types,seasons and the years lived in Guangzhou city,while there is no correlation between MED value and gender difference.