Seasonal variations of epidermal biophysical properties in Kunming, China: A self-controlled cohort study.

BACKGROUND

Epidermal biophysical properties can be affected by many factors, including body site, age, gender, ethnicity, disease, temperature, humidity, and ultraviolet (UV) radiation. Information about variation of epidermal biophysical properties with seasons is still limited. In the present study, we determined seasonal variation of epidermal biophysical properties of women in Kunming, China.

MATERIALS AND METHODS

A total of 72 women, aged 22.96 ± 2.11 years, were enrolled in this study. Transepidermal water loss rates (TEWL), stratum corneum (SC) hydration, sebum content, melanin index (MI), erythema index (EI), and La values were measured on the right cheek and the right forearm, using a non-invasive skin physiological instrument in the spring, summer, autumn, and winter in Kunming, China.

RESULTS

On the cheek, TEWL, SC hydration, sebum, MI, and La values varied greatly with seasons (P < .05). SC hydration, sebum, MI, and avalue peaked in the summer, but went lowest in winter. In contrast, TEWL and Lvalue went lowest in summer but peaked in winter. Similarly, SC hydration, MI, and Lvalue also varied with seasons on the forearm (P < .05). In addition, SC hydration, sebum, MI, EI, and avalue of the cheek were higher than that of the forearm (P < .001), but L*values of the cheek were lower than that of the forearm (P < .001). There were no correlations among TEWL and MI, EI, and L*a*values in any season (P > .05).

CONCLUSIONS

Both epidermal permeability barrier function, sebum, and skin pigment in healthy women vary seasons in Kunming, China.