Cigarette Smoking Among Adults, United States

One of the national health objectives for 2010 is to reduce the prevalence of cigarette smoking among adults to less than 12% (Objective no. 27—1a).1 To assess progress toward this objective, the Centers for Disease Control and Prevention analyzed self—reported data from the 2004 National Health Interview Survey (NHIS) sample adult core questionnaire. This report describes the results of that analysis, which indicated that, in 2004, approximately 20.9% of U.S. adults were current smokers. This prevalence is lower than the 21.6% prevalence among US adults in 2003 and is significantly lower than the 22.5% prevalence among adults in 2002.2 The prevalence of heavy smoking (more than 25 cigarettes a day) has also declined during the past 11 years, from 19.1% of smokers in 1993 to 12.1% of smokers in 2004. Tobacco—use prevention and control measures appear to be decreasing both the prevalence of cigarette smoking and the proportion of heavy smokers, who are at high risk for tobacco—related morbidity and mortality. However, to further decrease smoking prevalence among adults and to meet the national health objective, effective comprehensive tobacco—control programs that address both initiation and cessation of smoking should be fully implemented in every state and territory. Study Methods The 2004 NHIS adult core questionnaire was administered by personal interview to a nationally representative sample of 31,326 people in the non—institutionalized US civilian population over age 18; the overall survey response rate for the sample was 72.5%. Respondents were asked, “Have you smoked at least 100 cigarettes in your entire life?” and “Do you now smoke cigarettes every day, some days, or not at all?” “Ever smokers” were defined as those who reported having smoked more than 100 cigarettes during their lifetime. Current smokers were defined as those reporting having smoked more than 100 cigarettes during their lifetime and currently smoking every day or some days. Current smokers who reported that they smoked every day also reported the average number of cigarettes smoked per day. Former smokers were defined as those who reported smoking more than 100 cigarettes during their lifetime but who currently did not smoke. The data were adjusted for nonresponse and weighted to provide national estimates of cigarette smoking prevalence and the number of cigarettes smoked per day. Confidence intervals were calculated using statistical analysis software to account for the survey's multistage probability sample design. In 2004, an estimated 20.9% (44.5 million) of US adults were current smokers; of these, 81.3% (36.1 million) smoked every day, and 18.7% (8.3 million) smoked some days. Among those who currently smoked every day, 40.5% (14.6 million) reported that they had stopped smoking for at least one day during the preceding 12 months because they were trying to quit. Among the estimated 42.4% (90.2 million) of persons who had ever smoked, 50.6% (45.6 million) were former smokers. Varied Substantially Across Population Subgroups The prevalence of current cigarette smoking varied substantially across population subgroups. Current smoking was higher among men (23.4%) than women (18.5%). Among racial/ethnic populations, Asians (11.3%) and Hispanics (15.0%) had the lowest prevalence of current smoking; American Indians/Alaska Natives had the highest prevalence (33.4%), followed by non—Hispanic whites (22.2%) and non—Hispanic blacks (20.2%). By education level, current smoking prevalence was highest among adults who had earned a General Educational Development (GED) diploma (39.6%) and among those with a 9th—11th grade education (34.0%) and generally decreased with increasing years of education. Persons older than 65 had the lowest prevalence of current cigarette smoking (8.8%) among all adults. Current smoking prevalence was higher among adults living below the poverty level (29.1%) than among those at or above the poverty level (20.6%). Hispanic (10.9%) and Asian (4.8%) women, women with less than an 8th—grade education (10.5%), women with undergraduate (10.1%) or graduate (8.1%) degrees, men with graduate degrees (7.9%), men younger than 65 (9.8%), and women over age 65 (8.1%) all had smoking prevalence rates below the national health objective of less than 12%. From 1993 through 2004, the percentage of daily smokers who smoked more than 25 cigarettes a day—i.e., heavy smokers—decreased steadily, from 19.1% to 12.1%. During the same period, the percentage of daily smokers who smoked one to four cigarettes a day and five to 14 cigarettes a day increased, from 2.9% to 4.8% and from 20.6% to 28.4%, respectively. The mean number of cigarettes smoked per day among daily smokers in 1993 was 19.6 (21.3 for men and 17.8 for women), and in 2004 was 16.8 (18.1 for men and 15.3 for women). Among current smokers, the overall percentage of some—day smokers remained stable at approximately 18% to 19% during the same period. The findings in this report indicate that cigarette smoking continues to decrease among US adults overall. Nationally and in 34 states, Puerto Rico, and the US Virgin Islands,3 the majority of adults who ever smoked have now quit smoking. However, the rate of decrease in cigarette smoking among adults is not sufficient to meet the national health objective for 2010, which is to reduce the prevalence of cigarette smoking to less than 12%. Furthermore, although the decline in smoking has been observed nationally, smoking prevalence remains high among certain segments of the population. For example, in 2004, the smoking prevalence among persons with a GED diploma was approximately 40%, and approximately one in three persons with a 9th to 11th grade education smoked. Limitations The findings in this report are subject to at least three limitations. First, estimates for cigarette smoking are based on self—reports and are not validated by biochemical tests. However, self—reported data on current smoking status have high validity.4 Second, the questionnaire is administered only in English and Spanish, which might result in imprecise estimates of smoking prevalence for racial/ethnic populations unable to respond to the survey because of language barriers. Finally, the small sample sizes for certain population subgroups (e.g., Asians and American Indians/Alaska Natives) result in unstable single—year estimates for those groups. In addition to the reduction in smoking prevalence in the adult US population, the number of cigarettes smoked by daily smokers and the proportion of adults who were heavy smokers have also declined during the past 11 years. This study did not assess what proportion of the decline in the prevalence of heavy smokers was attributable to (1) smokers reducing their number of cigarettes per day; (2) smokers quitting; of (3) changes in cohorts of smokers over time in terms of their cigarette consumption. A recent longitudinal study in Denmark reported that smokers who reduced their smoking from an average of 20 to 10 cigarettes per day during an interval of five to 10 years reduced their lung cancer risk by 25%.5 The risk for lung cancer declines steadily in persons who quit smoking. After 10 years of abstinence, the risk for lung cancer is approximately 30% to 50% of the risk for continuing smokers.6 After 15 years of abstinence, the risk for coronary heart disease is similar to that of persons who have never smoked.7 Reduced consumption has not, however, reduced the risk for other diseases with substantial public health burdens, such as chronic obstructive pulmonary disease and coronary heart disease.6 In addition, some long—term studies have failed to show a decrease in overall mortality after cigarette reduction.8 No level of tobacco use is safe; the best option for any smoker is to quit completely.6 Effective smoking—cessation interventions are available, including brief clinical counseling, pharmacotherapy, and state quitlines (available by telephone, 800—QUIT NOW). Comprehensive tobacco—control programs must be fully implemented in every state and territory to accelerate the reduction in smoking prevalence among US adults and decrease the public health burden of smoking—related disease.7,9