The age-dependent decrease of skin thickness was studied with a morphometric procedure on upper inner arm skin biopsies. Epidermal thickness decreased somewhat faster in men (7.2 % of the original value/decade) than in women (5.7 %). The total dermal thickness decreased at about the same rate in men and women (6%/decade). The thickness of the superficial layer of the dermis exhibited a biphasic evolution with age and these variations were not significantly different between men and women because of the large individual variations. This may be due partially to the difficulties of delineating with precision the limit between superficial and reticular dermis. These results are somewhat lower than those obtained by physical measurements of skin thickness. This may be due to fixation artifacts and also to the overestimation of skin thickness by physical measurements.

Biopsies were taken from the upper and inner arm of 10 60-year-old male cigarette smokers and compared with 10 age-matched controls who were non-smokers. The mean relative area, number and thickness of the elastic fibres were significantly increased in the cigarette smokers compared to the controls. These results were confirmed using antibodies to elastin or the microfibrillar component of elastic tissue. In the smokers the broader and more fragmented elastic fibres in the skin were not as intensely stained as those of the non-smokers and the ultrastructural alterations of the elastic fibres were similar to those in solar elastosis.

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