Health Effects of Smoking that Don’t Make the News

  • Published
  • By Guy Leahy

Cigarette smoking is responsible for over 480,000 deaths per year in the United States. Most of us are familiar with the major negative health effects of smoking; cancer, heart disease, stroke, lung diseases, diabetes and chronic obstructive pulmonary disease. Smoking causes damage to our health in other ways, however, which are not as well known.

One of these is the effect of smoking on telomeres. Telomeres are protective caps at the end of chromosomes. Telomeres shield DNA from shortening during replication. At birth, human telomeres are approximately 10,000 nucleotides in length. Telomeres shorten at the end of each DNA replication cycle. Telomere length is an indicator of biological aging, and therefore, how rapidly we age.

A review of smoking and telomere length found current smokers had shorter telomeres than never smokers. In addition, former smokers exhibited longer telomeres than current smokers, though shorter than those of never smokers (telomeres can be rebuilt by a ribonucleoprotein called telomerase.) The researchers concluded biological aging, as indicated by telomere length, was accelerated in current smokers. Additional evidence that smoking speeds up aging come from a 2013 study of identical twins, where only one twin smoked, or one twin smoked at least five years longer than the other twin. The researchers discovered that twins who smoked, or smoked longer than their twin, displayed multiple examples of facial skin aging relative to the never smoking twins, or twins who had smoked less. Other studies have found smoking results in earlier onset of male pattern baldness, and premature development of grey hair.

Another little known effect of smoking is on injuries in military populations. To date, 18 studies examining military subjects have found smoking is associated with a 20% -70% increased risk of injury, with a dose-response effect; heavy smokers have a higher risk of injury than medium use smokers, and medium use smokers have a higher risk of injury than low level smokers. Not only are smokers at a significantly higher risk of injuries; the injuries they sustain will take longer to heal, as smoking slows down tissue repair processes. This means active duty personnel who smoke will stay in duty/mobility restricted status for longer periods of time than nonsmokers, with a corresponding decline in readiness. One recent military study examined the effect of cigarette smoking and fitness on injury risk. The study found smokers exhibited a 20% - 30% higher injury risk than nonsmokers. Though fitness was protective of injury in nonsmokers, fitness was not protective of injury in smokers; the least fit and most fit smokers had the same injury risk.

Smoking is also a well-documented risk factor for erectile dysfunction. Multiple studies indicate smokers are 1.5-2 times as likely to experience ED as nonsmokers. The risk of ED is dose and duration dependent; the higher number of cigarettes smoked, and the greater number of years spent smoking, is associated with a greater risk of ED. Interestingly, smoking has a stronger association with ED in younger (under 40 years of age) than older smokers.

Most studies on smoking and ED have used combustible cigarettes, which contain numerous ED-causing toxins. Recent studies have investigated the effect of nicotine alone, and have found nicotine also results in an increased risk of ED. This is important, as electronic cigarettes contain no tobacco. The evidence, though preliminary, suggests vaping may not be an effective way to use nicotine and avoid ED risk.

Will smoking cessation reverse ED? In heavy smokers, smokers with severe ED, and smokers over 50 years of age, it appears some of the damage is permanent, and not reversible. Younger smokers, smokers with mild ED, and light smokers (over 10 cigarettes a day) have greater odds of reversing ED. One study found smokers who successfully completed an 8-week smoking cessation program had multiple indices of improved penile function at a 4-week post-cessation follow-up, compared to those subjects who were not successful.

Recent studies have shown smoking causes sexual dysfunction in women as well. As with men, the severity of dysfunction is dose and duration dependent; women who are heavy smokers, and who have smoked for many years, are at greater risk. There are no studies at present which have examined the effect of smoking cessation on reversing sexual dysfunction in women.

If you would like more information, and would like to quit tobacco, contact the Health Promotion Flight at 846-1186. You can also reach us on Facebook (“KAFB Health Promotion”) or on Twitter (@KirtlandHP.)