Smoking and Skin

Numerous adverse effects and health problems are associated with smoking, but the mechanisms of the adverse effects of smoking on skin are not well documented. The aim of the present study was to elucidate the effects of smoking on the structure, metabolism and appearance of skin. The study population consisted of 98 Finnish males, of whom 47 were current smokers and 51 non-smokers. The main parameters under evaluation were the appearance and physical qualities of skin, including skin wrinkling, thickness and elasticity. Biochemical analyses were performed to assess the rate of type I and III collagen biosynthesis as well as the degradation of the extracellular matrix (ECM) of skin in terms of matrix metalloproteinase levels (MMPs). To compare the morphology of skin between the groups, histological and immunohistological studies were performed, including assessments of the proportional area and width of dermal elastic fibres. The results revealed decreased synthesis of type I and III collagens in smokers as well as changes in the regulatory mechanisms which control the turnover of these and other extracellular matrix proteins. The level of matrix metalloproteinase -8 (collagenase-2), a protease degrading both type I and type III collagen, in suction blister fluid was significantly higher in smokers, indicating enhanced degradation of these collagens. In skin tissue samples, the levels of the active forms of MMP-8 and MMP-9 were significantly lower in smokers compared to non-smokers. Serum levels of MMP-8 were slightly but not significantly higher in smokers, whereas the levels of the matrix metalloproteinases MMP-2 and MMP-9 (72-kDa and 92-kDa gelatinase, respectively) were significantly higher in smokers compared to non-smokers. Salivary MMP-8 and MMP-9 were lower in smokers compared to non-smokers, but only the latter showed a statistically significant difference. The levels of the tissue inhibitor of matrix metalloproteinases (TIMP-1) were significantly lower in the suction blister fluid of smokers compared to non-smokers. In general, there were no significant differences in skin thickness and elasticity or regeneration of barrier function, nor in the amount or width of elastic fibres between the groups. We did not observe significant differences in skin wrinkling between smokers and non-smokers, but smokers looked older than their age compared to non-smokers. It can be concluded that the rate of type I and III collagen synthesis in skin is decreased and the regulation of ECM turnover is altered in smokers, which may lead to deterioration of the tensile strength and resiliency of skin in the long term, even though no morphological changes were detected in the present study.