Skin Barrier Function And Its Related Influential Factors In 160 Healthy Chinese

【Objective】To greater understand the possible age,gender,regional and seasonal variation of skin barrier function in healthy Chinese.【Methods】The stratum corneum(SC) hydration,sebum content,skin surface pH and transpedermal water loss(TEWL) were measured seasonally for a year on the forehead,left forehead,nose,chin,zygomatic area,cheek,perioral area,dorsal hand(sun-exposed site) and volar forearm(sun-protected site) of the same 160 Chinese subjects with MoistureMeter SC,Skin analyzer SHP88 and VapoMeter.The SC and epidermal thickness were measured seasonally on the forehead,zygomatic area,dorsal hand and volar forearm of 49 Chinese volunteers with confocal microscope,Vivascope 1500.【Results】TEWL were significantly different(P＜0.05) in all age groups in the nose,the zygomatic area,the cheek,the dorsal hand and the volar forearm. Male TEWL was significantly(P＜0.05) higher than female except the volar forearm.TEWL exhibited regional difference(P＜0.05).The nose TEWL values were the highest,followed by the perioral area,chin,left forehead,forehead, zygomatic area,dorsal hand and volar forearm.Seasonal variations in TEWL were found(P＜0.05) and could be generally ranked as follows:winter＞spring＞autumn＞summer.SC hydration were not identical(P＜0.05) among different age groups in all tested regions.SC hydration of the age 50～60 group was significantly lower than other age groups in all studied sites.In the left forehead,and volar forearm,the male SC hydration were higher than the female,while in the chin and zygomatic area,SC hydration was higher in the female(P＜0.05).SC hydration were the highest in the zygomatic area,followed by chin,left forehead,forehead,perioral area,nose,cheek,volar forearm and dorsal hand. SC hydration showed significant(P＜0.05) seasonal variations:Summer＞spring＞autumn＞winter.The sebum content of almost all tested areas(except the cheek) were significantly influenced(P＜0.05) by age.The sebum content decreased with age.The sebum content in all investigated areas was significantly(P＜0.05) higher in the male group than the female group.Anatomical differences of sebum content were found(P＜0.05) and could be ranked as follows:nose,chin,left forehead,forehead,perioral area,zygomatic area,cheek,dorsal hand,and volar forearm.The sebum content differed seasonally(P＜0.05):summer＞spring＞autumn＞winter.The skin surface pH were affected by age(P＜0.05),with pH of the age 50～60 group the most alkaline in comparison to other groups.In the forehead, zygomatic area,cheek,perioral area,dorsal hand,and volar forearm,the female pH were higher than the male(P＜0.05).The skin pH indicated regional variations(P＜0.05) and could be put in the following order:cheek,perioral area,cheek,zygomatic area,dorsal hand,volar forearm,chin,forehead,nose, left forehead.The pH in the winter and autumn were higher than in the spring and summer(P＜0.05).The male forehead and dorsal hand SC thicknesses were higher than the female (P＜0.05).SC thickness differed locationally:dorsal hand＞volar forearm＞forehead= zygoma。The SC thicknesses were not influenced by age and seasons. The forehead epidermal thickness of the age 40～49 and 50～60 group were thicker than that of the age 20～29 group.The volar forearm epidermal thickness of the age 50～60 group were thicker than that of the age 40～49 group.The male dorsal hand epidermal thickness was thicker than the female(P＜0.05).The dorsal hand epidermal thickness was the thickiest,followed by the zygomatic area, forehead,and volar forearm.Seasonal variations were not found in the epidermal thickness.Parameters correlated with each other.TEWL correlated positively with the sebum content in the forehead,chin,left forehead,zygomatic area,cheek, perioral area,and dorsal hand.Negative correlations were detected between the sebum content and skin pH in the zygomatic area,dorsal hand,and volar forearm.TEWL correlated with SC hydration positively in the forehead,nose, left forehead,cheek,and volar forearm,but negatively in the chin and zygomatic area.Negative correlations were found between the SC hydration and skin pH in the forehead,nose,chin,left forehead,zygomatic area,cheek, perioral area and volar forearm.The forehead and dorsal hand SC hydration correlated negatively with the SC thickness.The SC hydration correlated negatively with the epidermal thickness in the dorsal hand and volar forearm. The zygomatic,dorsal hand and volar forearm SC hydration correlated positively with the corresponding epidermal thickness.【Conclusions】The SC hydration,sebum content,skin surface pH and TEWL showed age,gender,regional and seasonal variations in Chinese healthy skin. Parameters correlated with each other to a certain extent.Age,gender, anatomical sites and seasons as well as related biophysical parameters must be considered comprehensively in the selection of more appropriate skin care products and medications.