EFFECT OF CIGARETTE SMOKE ON SKIN 239 2O 18 16 • 14 I-- 12 10 Effect of Cigarette Smoke and age on barrier functions Active Smokers Passive Smokers Effect of Cigarette smoke and sun exposure on barrier functions Active Passive smokers Smokers Non Non Smokers Smokers [] age 35-45 [] age 46-55 • age 56 [] Slight sun I• Moderate [] Severe Figure 4. a: Effect of chronological age and cigarette smoke on barrier functions. b: Effect of sun exposure and smoke skin barrier functions measured via transepidermal water loss. exposure, and skin dryness (Figure 5). The panelists with slight sun exposure did not exhibit as much skin dryness as those having medium or severe UV exposure. Excessively sun-exposed smokers had 76% drier skin as compared to non-smokers with low sun exposure. As observed in Figure 5b, the skin of non-exposed non-smokers who received minimal sun exposure was was not as dry as that of smokers having the same sun exposure (p = 0.078). Passive smokers exhibited a significantly more arid (p = 0.026) skin than non-smokers. Efj•ct of chronological age and sun exposure on skin wrinkling. More wrinkles were observed in non-smokers over 56 years of age, but below 55 years of age there was no significant dose response. Sun exposure appeared to exhibit a good dose response with the intensity of wrinkling. As observed in Figure 6b, non-exposed non-smoking individuals exposed to mild-to-slight sun exhibited a significantly lower (p 0.001) skin wrinkling than active smokers having the same sun exposure. DISCUSSION Stratum corneum, composed of skin surface lipids, is responsible for the epidermal water 7.5 o_ m 6 • 5.5 : 4.5 '• 4 3.5 3 Effect of Cigarette Smoke and age on Skin Dryness I I Active Passive Non Smokers Smokers Smokers Effect of Cigarette Smoke and []age 35-45 sun exposure on skin dryness m•age 46-55 I m age 56 [] Slight sun •a Moderate ml[] SevI , i i Active Passive Non Smokers Smokers Smokers Figure 5. a: Effect of chronological age and cigarette smoke on skin dryness. b: Effect of sun exposure and smoke on drying of skin.

240 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 90 80 =• 7o e- 60 '•_ • 5o -• 40 30 20 Effect of Cigarette Smoke and age on skin wrinkles i Active Smokers Passive Smokers Non Smokers Effect of Cigarette Smoke and Sun exposure on skin wrinkles i Active smokers Passive Smokers [] age 35-45 [] age 46-55 [] age 56 ElSlight [] Moderate [] Severe Non Smokers Figure 6. a: Effect of chronological age and cigarette smoke on skin wrinkling. b: Effect of sun exposure and smoke on skin wrinkling. barrier (14). Measurement of TEWL is used in many laboratories for characterization of the skin barrier function (11). Air temperature and humidity are the main factors that could interfere with the mea- surement of skin barrier functions as measured with TEWL (11). Skin dryness is also directly related to the rate of TEWL. Nevertheless, unless the skin is excessively dam- aged or broken as in a diseased condition, the differences in TEWL can be related to demographic factors like smoke exposure, sun exposure, and age. Observation of non-smokers by age and sun exposure indicated that age, unlike smoke, played no significant role in skin damage. Contrary to expectations, TEWL was lower in non-smokers over 56 years of age, while below 45 years of age the skin barrier appeared to be slightly worse (Figures 4a,4b). These results are consistent with other findings (11) where no correlation between age and TEWL was observed. In some studies a slight decrease in TEWL was observed after 60 years of age (15). Degree of sun exposure appeared to exhibit a good dose response with the increase in TEWL. This could be due to actinic damage and drying of skin overexposed to the sun. Active smokers who received severe sun exposure exhibited a significantly worse skin barrier (p = 0.025) than non-exposed non-smokers who received the same UV exposure. Observation of the individuals who avoided the sun over the years showed that exposure to environmental smoke significantly (p -- 0.02) changed skin barrier functions in terms of transepidermal water loss. From these results it can be inferred that sun exposure and cigarette smoke could play a stronger role in the barrier function of skin than age. A combination of excessive sun exposure and cigarette smoking occurring together exhibited a 62% higher rate of TEWL. According to Elias (7), factors like residual intercellular proteinaceous attachment (des- mosomes), the overlapping geometry of corneocytes, and the generation of excessive numbers of cells may underlie all or part of the observed stratum corneum desquamation. Observation of non-smokers by age and sun exposure showed that age played no sig- nificant role in skin dryness (Figures 5a,5b). Sun exposure appeared to exhibit some correlation with skin dryness. The skin of the