THE RELATIONSHIP BETWEEN CHRONOLOGICAL AGE AND THE ERYTHEMAL RESPONSE TO ULTRAVIOLET-B RADIATION

To investigate whether erythemal responses to ultraviolet radiation alter with age, we have reviewed the results of monochromator phototesting in adults and children, and have measured the dose-response curves for UVB erythema in a further 38 subjects. There was no significant difference between adults and children in minimal erythema dose (MED) at 300 nm; the median MED in 254 adults was 34 mJ/cm2 (range 14-80 mJ/cm2) and in 24 children aged less than 15 years was 30 mJ/cm2 (range 10-80 mJ/cm2). Objective measurements of UVB-induced erythema were performed in 15 subjects aged below 25 years and 23 subjects aged above 60 years. A dose response curve for UVB erythema was constructed for each subject and the slope of the steepest part of each curve calculated by logit regression: the values in the young subjects were greater than in the older group (P < 0.02). However, there was no difference between the two groups in either the visually assessed MED or the calculated UVB dose required to produce a constant degree of mild erythema.