Smoking and How You Look

Tobacco smoking seriously affects internal organs, particularly the heart and lungs, but it also affects a person's appearance by altering the skin and body weight and shape. While these changes are generally not as life threatening as heart and lung disease, they can, nevertheless, increase the risk of more serious disorders and have a noticeable aging effect on the body.

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Smoking and the Skin
The skin is affected by tobacco smoke in at least two ways. Firstly, tobacco smoke released into the environment has a drying effect on the skin's surface. Secondly, because smoking restricts blood vessels, it reduces the amount of blood flowing to the skin, thus depleting the skin of oxygen and essential nutrients. Some research suggests that smoking may reduce the body's store of Vitamin A, which provides protection against some skin-damaging agents produced by smoking.[1] Another likely explanation is that squinting in response to the irritating nature of the smoke, and the puckering of the mouth when drawing on a cigarette, cause wrinkling around the eyes and mouth.[2]

Skin damaged by smoke has a greyish, wasted appearance. Recent research has shown that the skin aging effects of smoking may be due to increased production of an enzyme that breaks down collagen in the skin.[3] Collagen is the main structural protein of the skin which maintains skin elasticity. The more a person smokes, the greater the risk of premature wrinkling. Smokers in their 40s often have as many facial wrinkles as non-smokers in their 60s. In addition to facial wrinkling, smokers' may develop hollow cheeks through repeated sucking on cigarettes: this is particularly noticeable in under-weight smokers and can cause smokers to look gaunt.2 Prolonged smoking also causes discoloration of the fingers and fingernails on the hand used to hold cigarettes. Smoking also results in a yellowing of the teeth and is a cause of halitosis (bad breath).

Smoking and Psoriasis
Compared with nonsmokers, smokers have a two to threefold higher risk of developing psoriasis, a chronic skin condition which, while not life-threatening, can be extremely uncomfortable and disfiguring. Some studies have found a dose-response association of smoking and psoriasis, i.e. the risk of the disease increases the longer a person continues to smoke. Smoking also appears to be more strongly associated with psoriasis among women than among men.[4] Smoking may cause as many as one quarter of all psoriasis cases and may also contribute to as many as half of the cases of palmoplantar pustulosis, a skin disease involving the hands and feet, that some experts view as a form of psoriasis.2

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Smoking and Weight
When people stop smoking, they usually put on weight. Although this often a cause for concern, the average weight gain is around 2 to 3 kg although this may be temporary. Although the reasons for weight gain are not fully understood, it may be partly explained by the fact that smoking increases the body's metabolic rate - i.e. the rate at which calories are burned up. In addition, nicotine may act as an appetite suppressant so that when smokers quit an increase in appetite leads to an increase in calorie intake. The effect of nicotine on metabolic rate may also explain why smokers tend to weigh less than nonsmokers Experts believe that one way smoking raises metabolic rate is by stimulating the nervous system to produce catecholamines - hormones which cause the heart to beat faster, thus making the body burn more calories. Nicotine also produces more thermogenesis, the process by which the body produces heat. This too, causes the body to use up more calories.2

However, a smoking-induced increase in metabolic rate only accounts for about half the difference in weight between the average smoker and average non-smoker. Another likely mechanism is that smoking alters the body-weight set point, i.e. the weight towards which a person tends to return despite attempts to gain or lose weight. Smoking appears to lower a person's normal weight and the weight gained on stopping reflects a return to the body's natural weight set point.2

While weight gain is common immediately after stopping smoking, in the longer term, ex-smokers weight may return to the comparative weight of someone who has never smoked. A Japanese study examined the relationship between weight gain and the length of time after stopping smoking. Researchers found that although heavy smokers experienced large weight gain and weighed more than never smokers in the few years after smoking cessation, thereafter they lost weight to the never smoker level. Among former light and moderate smokers, weight was gained up to the never-smoker level but without any further excess gain.[7]

Women and girls tend to be more concerned about their weight and body shape than men, and weight control may be influential in causing the higher incidence of smoking among teenage girls.[5] However, post-cessation weight gain can be modified by eating a low-fat, calorie-reduced diet and by moderately increased exercise. One study found that stopping smoking resulted in a net excess weight gain of about 2.4 kg in middle-aged women but that among those women who increased physical activity after stopping smoking, weight gain was between 1.3 kg and 1.8kg.[6]

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Body shape
Although smokers tend to be thinner than nonsmokers, the effect of smoking on the endocrine system (glands which secrete hormones) causes smokers to store even normal amounts of body fat in an abnormal distribution. Smokers are more likely to store fat around the waist and upper torso, rather than around the hips. This means smokers are more likely to have a higher waist-to-hip ratio (WHR) than nonsmokers A high WHR is associated with a much higher risk of developing diabetes, heart disease, high blood pressure, gallbladder problems and (in women) cancer of the womb and breast. In one study of nearly 12,000 pre- and postmenopausal women aged 40 to 73, the waist to hip ratio increased as the number of cigarettes smoked per day increased.2 A study of American men also found a dose-response relationship between the number of cigarettes smoked and waist-to-hip ratio.[8]

However, changes to WHR induced by smoking need not be permanent. A Swedish study examined the effect of smoking and smoking cessation on the distribution of fat in a representative sample of women. The study found that women who stopped smoking experienced less upper-body fat deposition than would be expected by their accompanying weight gain. This suggests that while some weight gain after stopping smoking can be expected, it is less of a health risk because it is not deposited in the upper torso, where it is associated with increased risk of heart disease.[9]


References

[1] Joffe,I. Cigarette smoking and facial wrinkling. (Letter) Annals of Internal Medicine, 1991; 115: 659.
[2] Cigarettes: What the warning label doesn't tell you. American Council on Smoking and Health. 1996.
[3] Lahmann, C et al. Matrix metalloproteinase-1 and skin aging in smokers. The Lancet 2001; 357: 935-6
[4] Naldi, L et al. Association of early-stage psoriasis with smoking and male alcohol consumption. Archives of Dermatology 1999; 135: 1479-1484 [View abstract]
[5] Charlton, A. Smoking and weight control in teenagers. Public Health, London. 1984; 98: 277-281.
[6] Kawachi, I. Et al. Can physical activity minimize weight gain in women after smoking cessation? Am J Pub Health. 1996; 86: 999-1004.
[7] Mizoue, T et al. Body mass decrease after initial gain following smoking cessation. Int. J Epidemiology. 1998; 27: 984-988. [View abstract]
[8] Shimokata, H et al. Studies in the distribution of body fat. JAMA, 1989; 261: 1169-73.
[9] Lissner, L et al. Smoking initiation and cessation in relation to body fat distribution based on data from a study of Swedish women. Am J Epidemiology, 1992; 82: 272-275.