Cigarette Smoking Among Adults --- United States, 2006

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One of the national health objectives for 2010 is to reduce the prevalence of cigarette smoking among adults to <12% (objective 7-1a) (1). To assess progress toward achieving this objective, CDC analyzed data from the 2006 National Health Interview Survey (NHIS). This report summarizes the results of that analysis, which indicated that in 2006, approximately 20.8% of U.S. adults were current cigarette smokers. This prevalence had not changed significantly since 2004 (2), suggesting a stall in the previous 7-year (1997--2004) decline in cigarette smoking among adults in the United States. In addition, the findings indicated that persons with a diagnosis of a smoking-related chronic disease have a significantly higher prevalence of being a current smoker than persons with other chronic diseases or persons with no chronic disease. To reduce smoking prevalence further in the United States, comprehensive, evidence-based approaches for preventing smoking initiation and increasing cessation, including clinical interventions for populations at high risk, need to be fully implemented (3).

The 2006 NHIS adult core questionnaire, containing questions on cigarette smoking and cessation attempts, was administered by in-person interview to a nationally representative sample of 24,275 persons in the noninstitutionalized U.S. civilian population aged >18 years; the overall response rate was 70.8%. To classify smoking status, respondents were asked, "Have you smoked at least 100 cigarettes in your entire life?"; Those who answered "yes" were asked, "Do you now smoke cigarettes every day, some days, or not at all?" Ever smokers were defined as those who reported having smoked at least 100 cigarettes during their lifetimes. Current smokers were those who had smoked at least 100 cigarettes during their lifetimes and, at the time of the interview, reported smoking every day or some days. Former smokers were those who reported smoking at least 100 cigarettes during their lifetimes but currently did not smoke. Never smokers were those who reported never having smoked 100 cigarettes during their lifetimes. Among current cigarette smokers, making at least one cessation attempt during the preceding year was defined as a "yes" response to the question, "During the past 12 months, have you stopped smoking for more than one day because you were trying to quit smoking?" Respondents were categorized as having a chronic disease if they answered "yes" to any one of a series of questions about 42 chronic diseases (i.e., "Have you ever been told by a doctor or other health professional that you had...?"); of these chronic diseases, 16 were considered to be smoking related* (4). Data were adjusted for nonresponse and weighted to provide national estimates of cigarette smoking prevalence. Because the distribution of smoking-related morbidity varies by age, estimates of current, former, and never smokers by chronic disease status were age adjusted to the 2000 U.S. adult population; 95% confidence intervals were calculated using statistical analysis software to account for the survey's multistage probability sample design. Statistical significance was determined by non-overlapping confidence intervals.

In 2006, an estimated 20.8% (45.3 million) of U.S. adults were current cigarette smokers; of these, 80.1% (36.3 million) smoked every day, and 19.9% (9.0 million) smoked some days. Among current cigarette smokers, an estimated 44.2% (19.9 million) had stopped smoking for more than 1 day during the preceding 12 months because they were trying to quit. Of the estimated 91 million persons who had smoked at least 100 cigarettes during their lifetimes (i.e., ever smokers), 50.2% (45.7 million) had quit smoking at the time of the interview.

The prevalence of current cigarette smoking varied substantially among population subgroups. By sex, prevalence was higher among men (23.9%) than women (18.0%) (Table 1). Among racial/ethnic groups, Asians had the lowest prevalence (10.4%). Hispanics had a significantly lower prevalence of smoking (15.2%) than American Indians/Alaska Natives (32.4%), non-Hispanic blacks (23.0%), and non-Hispanic whites (21.9%).

Prevalence also varied by level of education. Smoking prevalence was highest among adults who had earned a General Educational Development (GED) diploma (46.0%) and those with 9--11 years of education (35.4%); overall, smoking prevalence decreased as education level increased. By age group, adults aged 18--24 years and 25--44 years had the highest prevalence of smoking (23.9% and 23.5%, respectively). The prevalence of current smoking was higher among adults living below the federal poverty level (30.6%) than among those at or above this level (20.4%).

Before 2006, certain population subgroups already had achieved smoking prevalences that were lower than the national health objective of 12%, and the prevalences remained low in 2006. These included Hispanic (10.1%) and Asian (4.6%) women, women with undergraduate (8.4%) or graduate (5.8%) degrees, men with undergraduate (10.8%) or graduate (7.3%) degrees, and women aged >65 years (8.3%).

In 2006, the age-adjusted prevalence of current smoking was 36.9% among persons with a smoking-related chronic disease and 19.3% among those without a chronic disease (Table 2). Current smoking prevalence was higher among persons with smoking-related cancers (other than lung cancer) (38.8%), coronary heart disease (CHD) (29.3%), and stroke (30.1%) than among persons without chronic diseases, and nearly half (49.1%) of U.S. adults with emphysema and 41.1% of those with chronic bronchitis were current smokers. With the exception of persons who had a stroke, persons with any smoking-related chronic disease were significantly less likely to have never smoked than those with other chronic diseases (53.5%) or no chronic disease (64.3%). Persons with lung cancer (17.9%) and emphysema (22.3%) were least likely to be never smokers.

Reported by: VJ Rock, MPH, A Malarcher, PhD, JW Kahende, PhD, K Asman, MSPH, C Husten, MD, R Caraballo, PhD, Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.

Editorial Note:

Cigarette smoking remains the leading preventable cause of disease and death in the United States, resulting in approximately 438,000 deaths annually (5). The prevalence of cigarette smoking remained relatively unchanged during the early 1990s but gradually decreased from 1997 (24.7%) to 2004 (20.9%) (Figure). This report indicates that the prevalence of current smoking among U.S. adults in 2006 (20.8%) was not significantly different from the prevalence in 2004 (20.9%), suggesting a stall in previous declines. This lack of a decrease in cigarette use during 2 years might be a result of several factors. Most notably, funding for comprehensive state programs for tobacco control and prevention decreased by 20.3% from 2002 to 2006 (6), and tobacco-industry marketing expenditures nearly doubled from 1998 ($6.7 billion) to 2005 ($13.1 billion) (7). In 2005, approximately 81% ($10.6 billion) of tobacco-industry marketing expenditures were related to discounting strategies (e.g., coupons, two-for-one offers, or promotional discounts for retailers or wholesalers) (7) that reduce the impact of increases in the unit price of tobacco, which are effective in preventing initiation of smoking and increasing cessation.

Among smokers who already have a smoking-related chronic disease, those who quit have a lower risk for death from the disease than those who continue smoking (8). Smokers who quit have a slower rate of decline in lung function and a lower incidence of bronchitis, emphysema, and other respiratory conditions than persons who continue to smoke (8). Among smokers with CHD, those who quit have a lower risk for further CHD-related morbidity and mortality than those who continue to smoke (8). In addition, smokers who have cancer and who continue smoking during treatment decrease treatment effectiveness, overall survival prognosis, and quality of life and increase the risk for having another malignancy or comorbid condition (9). The continuation of smoking among those who have smoking-related chronic diseases described in this report highlights the need for health-care providers to emphasize the importance of quitting. Health-care providers should repeatedly offer intensive smoking-cessation interventions to all of their patients, especially those with smoking-related chronic diseases who continue to smoke.

The findings in this report are subject to at least three limitations. First, estimates of cigarette smoking are based on self-report and are not validated by biochemical tests. However, self-reported population-based data on current smoking status have high validity when compared with measured serum cotinine levels (10). Second, the NHIS questionnaire is administered in English and Spanish only, which might have resulted in imprecise estimates for certain racial/ethnic subgroups because of language barriers. Third, the small NHIS samples for certain population groups (e.g., American Indians/Alaska Natives) resulted in unstable single-year estimates with large confidence intervals.

Since the 1960s, smoking prevalence in the United States has decreased substantially (Figure); however, recent data suggest that declines in both adolescent and adult smoking prevalence might be stalling. Cigarette smoking continues to result in substantial costs. The economic costs of smoking in the United States are estimated at $167 billion annually ($92 billion in productivity losses from premature death and $75.5 billion in health-care expenditures) (5). In 2007, the Institute of Medicine concluded that funding comprehensive tobacco-control programs at levels recommended by CDC and regulations designed to foster policy innovations are essential strategies that should be implemented to reduce tobacco use (3).

References

* Cigarette smoking has been identified by the Surgeon General as a cause of selected malignant neoplasms, cardiovascular diseases, and respiratory diseases (4). Smoking-related chronic diseases include 1) cancers: lung; bladder; cervix; esophagus; kidney; larynx-windpipe; mouth, tongue, or lip; pancreas; stomach; and throat-pharynx; 2) cardiovascular diseases: coronary heart disease, angina pectoris, heart attack, and stroke; and 3) respiratory diseases: emphysema and chronic bronchitis.

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