Exploratory study of the reproducibility of the SCore for INtrinsic and EXtrinsic skin aging (SCINEXA) scale in "Ruta Escondida de la Mitad del Mundo", Ecuador, 2017.

Background: Few studies have been published related to the analysis of different skin aging parameters for whole-body skin using the SCINEXA scale for skin damage. The aim of this study was to evaluate the reproducibility of the SCINEXA scale (SCore for INtrinsic and EXtrinsic skin Aging) in South-Americans non-Caucasian population of a region of Ecuador.

Methods: Exploratory observational study. Thirty subjects of both genders, over 40 years old and living in a rural area with particular characteristics regarding sun exposure were included. The SCINEXA scale was applied at three different time points to assess its reproducibility. Repeated measures analysis of variance was used for comparison of mean SCINEXA scores. Intraclass correlation coefficient, 95% CI and "Cronbach's alpha" coefficient were performed to measure reproducibility.

Results: Among participants, 86.7% were female; mean age was over 67 years old, with mainly low educational level, and almost half had more than six hours of sun exposure per day. Test-retest reproducibility of this scale demonstrated almost perfect agreement. The SCINEXA score was greater than 2 points in half of the subjects, reflecting aging due to sun exposure.

Limitations: Most participants were women from one town in a particular geographical area, and the sample size was small. Genetic determinants of skin phenotypes were not assessed.

Conclusions: The SCINEXA score is reproducible in South American non-Caucasian subjects of a particular region of the country. Damage from sun exposure was evident in participants.