NONINVASIVE MEASUREMENT OF THE EFFECT OF LIFETIME EXPOSURE TO THE SUNON THE AGED SKIN

The cumulative and comparative effects of chronological and actinic ch anges to the skin were studied in an elderly population. Two adjacent sites with different degrees of exposure to the sun were examined to d istinguish the contribution of each factor, by means of noninvasive me asurements. The following parameters were measured on the skin of the low neck (an exposed site), as well as on the adjacent clothes-protect ed skin of 30 elderly women: electrical conductance, color, microrelie f, biomechanical properties and the thickness of both the full skin an d the subepidermal nonechogenic band (SENEB), using ultrasound measure ments. Persistent exposure to the sun accentuated most of the age-indu ced modifications. The following changes were significantly more marke d in exposed skin: SENEB thickening, full-skin thinning, loss of exten sibility and elasticity, and color heterogeneity. The cumulative effec ts of sun exposure and chronological aging lead to atrophy in elderly people. These results suggest that, if there is an autoprotective skin reaction, such as thickening in young adults, it is eliminated in old people.