About a fifth of adult Americans smoke, although their habit is the main reason people die prematurely in the United States. Smoking is slightly more common among men than women, according to the Centers for Disease Control and Prevention, or CDC, and it is least common in people age 65 and older. Regardless of individual traits, if you become a regular smoker, you have about a 50 percent chance of eventually dying because of the habit, according to the American Cancer Society.
Age
The majority of smokers begin smoking tobacco products when they are teenagers, according to the American Cancer Society. About 21 percent of adults in the United States smoked in 2008, reports the CDC, and the percentages of smokers aged 18 to 24, 25 to 44 and 45 to 64 were roughly the same--about 22 percent for each group. However, the American Cancer Society states that approximately 90 percent of all adult smokers were 19 years old or younger when they smoked the first time. In fact, the younger a smoker is when he first starts, the higher his risk of becoming addicted to the nicotine, which increases his likelihood of smoking regularly.
Education and Income
Although smoking used to be an activity associated with financially and professionally successful people, the exact opposite is true as of 2010. The CDC states the majority of smokers in 2008 had no high school diploma or only a general equivalency diploma, or GED. In contrast, just 16.3 percent of smokers were college graduates with an undergraduate or graduate degree. Smokers are also more likely to be poor, with 31.5 percent living in poverty in 2007, according to the CDC.
Ethnicity and Race
Individuals in the United States are most likely to smoke if they are American Indian or Alaskan native. The CDC states both groups comprised 32.4 percent of all adult smokers in 2008. The second largest percentage of smokers was non-Hispanic white people at 22 percent, followed by non-Hispanic black people at 21.3 percent. Americans least likely to smoke are either Asian--with the exception of Pacific Islanders, such as native Hawaiians--or Hispanic. Such smokers constituted just 9.9 percent and 15.8 percent of adult smokers, respectively.
Family and Friends
Young people begin smoking for various reasons, including misleading advertisements that make them believe smoking is attractive and safe, and their desire to behave independently or rebelliously, according to the American Lung Association. Young people also pick up the habit because they witness their parents or friends smoking, or because their peers pressure them to smoke. In addition to environmental and social factors, family genes may impact a person's risk of smoking, according to MayoClinic.com. Heredity helps explain why some people react differently to nicotine, contributing to different rates and degrees of smoking dependence.
Stress and Mental Illness
People who experience stress or have a substance abuse problem or mental illness, such as depression or schizophrenia, are more likely to smoke, according to MayoClinic.com and Smokefree.gov. Smoking cigarettes often helps smokers feel more calm and relaxed, and smoking may serve as self-medication in the case of mental illness. Nicotine is responsible for producing pleasing effects, although the effects last mere minutes, which motivates smokers to light up repeatedly.
