Demographic factors associated with skin barrier function in a large population-based study.

The skin plays a vital role in homeostasis, but there are conflicting data on skin barrier function-associated factors. We evaluated the relationship between participant characteristics and barrier function measures (baseline transepidermal water loss, barrier integrity [number of tape strips required to increase transepidermal water loss by 4 times baseline], dynamic barrier function [area under the curve of number of tape strips plotted against repeated transepidermal water loss measurements], and barrier recovery [percentage recovery in transepidermal water loss 24 hours after tape stripping]) in 286 participants aged 32-97 years in the Baltimore Longitudinal Study of Aging cohort. Multivariable analysis indicated that older age, female sex, Black race, and higher body mass index were associated with at least 1 measure of better barrier function: older age was associated with better dynamic barrier function (beta = -0.071, P = .035) and baseline barrier permeability (beta = -0.045, P = .018), female participants had better dynamic barrier function (beta = -2.028, P = .010) and barrier recovery (beta = 13.216, P = .001), Black participants also had better dynamic barrier function (beta = -2.956, P = .006) and barrier integrity (beta = 6.794, P < .001), and higher body mass index was associated with better barrier integrity (beta = 0.289, P = .033). Subanalysis of protein expression from tape strips among 20 participants showed that protein families linked to barrier composition and insult response were higher among participants with above-median barrier function and below-median C-reactive protein (P < .01).