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An estimated 50-70 million adults in the United States have chronic sleep and wakefulness disorders.1 Sleep difficulties, some of which are preventable, are associated with chronic diseases, mental disorders, health-risk behaviors, limitations of daily functioning, injury, and mortality.1,2 The National Sleep Foundation suggests that most adults need 7-9 hours of sleep per night, although individual variations exist. To assess the prevalence and distribution of selected sleep difficulties and behaviors, CDC analyzed data from a new sleep module added to the Behavioral Risk Factor Surveillance System (BRFSS) in 2009. This report summarizes the results of that analysis, which determined that, among 74,571 adult respondents in 12 states, 35.3% reported having <7 hours of sleep on average during a 24-hour period, 48.0% reported snoring, 37.9% reported unintentionally falling asleep during the day at least 1 day in the preceding 30 days, and 4.7% reported nodding off or falling asleep while driving in the preceding 30 days. Continued public health surveillance of sleep quality, duration, behaviors, and disorders is needed to understand and address sleep difficulties and their impact on health. As a first step, a multifaceted approach that includes increased public awareness and education and training in sleep medicine for appropriate health-care professionals is needed; however, broad societal factors, including technology use and work policies, also must be considered.
BRFSS is a state-based, random-digit—dialed telephone survey of the noninstitutionalized U.S. civilian population aged ≥18 years, conducted by state health departments in collaboration with CDC.3 Based on Council of American Survey and Research Organizations (CASRO) guidelines, response rates* for 12 states† that used the optional sleep module in 2009‡ ranged from 40.0% (Maryland) to 66.9% (Nebraska). Cooperation rates§ ranged from 55.5% (California) to 83.9% (Georgia).
The following questions from the sleep module were asked: “On average, how many hours of sleep do you get in a 24-hour period? Think about the time you actually spend sleeping or napping, not just the amount of sleep you think you should get (categorized as <7 hours and ≥7 hours∥).” “Do you snore? (can have been told by spouse or someone else; categorized as yes or no)?” “During the past 30 days, for about how many days did you find yourself unintentionally falling asleep during the day (categorized as none or at least 1 day reported)?” and “During the past 30 days, have you ever nodded off or fallen asleep, even just for a brief moment, while driving (categorized as yes or no)?” Age-standardized (to the projected U.S. 2000 population) prevalence estimates were calculated by state and by selected characteristics; 95% confidence intervals were calculated, and statistical significance (at p<0.05) was determined by t-test.
Among respondents, 35.3% reported sleeping <7 hours on average during a 24-hour period. Adults aged ≥65 years were significantly less likely to report sleeping <7 hours (24.5%) than persons in all other age categories. Non-Hispanic blacks (48.3%) and non-Hispanic persons of other races (38.7%) were more likely to report sleeping <7 hours than non-Hispanic whites (34.9%). No significant differences were observed by sex. Compared with employed adults (37.4%), those unable to work (46.4%) were significantly more likely to report <7 hours of sleep, but retired adults (25.0%) and homemakers and students (30.8%) were less likely. Adults with at least some college education (35.8%) were significantly more likely to report <7 hours of sleep than those with less than a high school diploma (32.0%) as were divorced, widowed, or separated (39.1%) and never married adults (37.9%), compared with married adults (35.1%).
Snoring was reported by 48.0% of respondents. Persons aged 18-24 years were least likely (25.6%) to report snoring. Hispanics (50.6%) were more likely to report snoring than non-Hispanic whites (46.8%), as were men (56.5%) compared with women (39.6%). Compared with employed persons (50.5%), retired adults (37.9%) and homemakers/students (37.0%) were significantly less likely to report snoring. Persons with less than a high school diploma (51.2%) and with a high school diploma or General Educational Development certificate (GED) (49.9%) were significantly more likely to report snoring than those with at least some college or a college degree (47.0%), as were married persons (49.5%) compared with never married (43.5%) persons.
An estimated 37.9% of adults reported unintentionally falling asleep during the day at least 1 day in the preceding 30 days. Adults aged 18-24 years (43.7%) and ≥65 years (44.6%) were significantly more likely to report this behavior than all other age groups, as were persons from all other racial/ethnic categories compared with non-Hispanic whites (33.4%). No significant difference was observed by sex. Compared with employed persons (33.5%), those who were unemployed (44.0%), unable to work (57.3%), and homemakers/students (39.3%) were significantly more likely to report unintentionally falling asleep during the day. Persons with at least some college education (35.9%) were significantly less likely to report unintentionally falling asleep than those with a high school diploma or GED (39.6%) or less education (43.4%). Never married adults (42.9%) were significantly more likely to report unintentionally falling asleep during the day than married adults (35.9%).
Nodding off or falling asleep while driving in the preceding 30 days was reported by 4.7% of adults. Persons aged ≥65 years (2.0%) were significantly less likely to report this behavior than persons aged 25-34 years (7.2%), 35-44 years (5.7%), 18-24 years (4.5%), 45-54 years (3.9%), and 55-64 years (3.1%). Hispanics (6.3%), non-Hispanic blacks (6.5%), and non-Hispanics of other races (7.2%) all were significantly more likely to report this behavior than non-Hispanic whites (3.2%). Men were more likely (5.8%) to report this behavior, compared with women (3.5%), and employed persons were more likely (5.4%), compared with homemakers and students (2.2%). No significant differences were observed by educational level or marital status.
Persons who reported sleeping <7 hours on average during a 24-hour period were more likely to report unintentionally falling asleep during the day at least 1 day in the preceding 30 days (46.2% versus 33.2%) and nodding off or falling asleep while driving in the preceding 30 days (7.3% versus 3.0%). They also were more likely to report snoring (51.4% versus 46.0%).
Among adults in the 12 states surveyed, reports of <7 hours of sleep ranged from 27.6% in Minnesota to 44.6% in Hawaii. Snoring estimates ranged from 44.8% in California to 54.0% in Hawaii. Estimates of unintentionally falling asleep during the day in the preceding 30 days ranged from 33.0% in Wyoming to 42.8% in Hawaii. Finally, estimates of nodding off or falling asleep while driving in the preceding 30 days ranged from 3.0% in Illinois to 6.4% in Hawaii and Texas.
LR McKnight-Eily, PhD, Y Liu, MS, MPH, AG Wheaton, PhD, JB Croft, PhD, GS Perry, DrPH, Div of Adult and Community Health, National Center for Chronic Disease Prevention and Heath Promotion; CA Okoro, MS, T Strine, PhD, Public Health Surveillance Program Office, Office of Surveillance, Epidemiology, and Laboratory Science, CDC.
This report is the first to present estimates of the prevalence of unhealthy sleep-related behaviors based on responses to questions added to BRFSS in 2009. The results highlight two prevalences of self-reported sleep-related behaviors with potentially dangerous consequences: 37.9% of adults in 12 states reported unintentionally falling asleep during the day at least 1 day in the preceding 30 days, and 4.7% reported nodding off or falling asleep while driving during the same period. The sleep module, consisting of questions derived from surveillance-system and clinically validated sleep surveys, was developed by CDC and the National Sleep Awareness Roundtable¶ in response to an Institute of Medicine recommendation to expand surveillance and monitoring of sleep loss and sleep disorders and to increase public awareness of unhealthy sleep behaviors.1
Nationwide surveillance has not previously assessed the prevalence of either unintentionally falling asleep during the day or nodding off or falling asleep while driving. Drowsy driving, one of the most lethal consequences of inadequate sleep, has been responsible for an estimated 1,550 fatalities and 40,000 nonfatal injuries annually in the United States.4 In the analysis summarized in this report, the prevalence of falling asleep while driving ranged from 2.0% among persons aged ≥65 years to 7.2% among persons aged 25-34 years. Populations previously found at greatest risk included persons aged 16-29 years (particularly males), those with untreated sleep apnea syndrome or narcolepsy, and those who work shifts, particularly night shifts or extended shifts.4 Sleepiness reduces vigilance while driving, slowing reaction time, and leading to deficits in information processing, which can result in crashes.4 Differences among adults in the 12 states in the prevalence of nodding off or falling asleep while driving were substantial (range: 3.0% in Illinois to 6.4% in Hawaii and Texas) and might result from differences in the prevalence of populations at greater risk or differences in the use of safety measures, such as road rumble strips, an evidenced-based intervention that alerts inattentive drivers through vibration and sound.#
Unintentionally falling asleep during the day can be indicative of narcolepsy or hypersomnia and has been associated with obstructive sleep apnea, which, in turn, has been associated with hypertension, cardiovascular disease, stroke, diabetes, and obesity.1 Falling asleep on the job can result in productivity losses for employers and dismissal for workers. In addition, depending on circumstances and level of responsibility, unintentionally falling asleep during the day can have dangerous consequences (e.g., while child caretaking, lifeguarding, or operating heavy equipment). To assess the potential impact of unintentionally falling asleep during the day, additional inquiry regarding the circumstances of this behavior is required.
Snoring, reported by 48.0% of participating adults, is a symptom of increased upper airway resistance during sleep and generally considereda marker for obstructive sleep apnea1,5; pregnant women who snore can be at risk for preeclampsia.5 The finding in this report regarding average hours slept per 24-hour period is similar to findings in other reports. In this analysis, 35.3% of U.S. adults in 12 states reported having <7 hours of sleep on average during a 24-hour period, compared with approximately 29% in the 2004-2006 National Health Interview Survey,6 and compared with 37.1% in the 2005-2008 National Health and Nutrition Examination Survey who said they had <7 hours of sleep on workday and weekday nights.7
Differences in prevalence by sociodemographic characteristics and state were observed for all four sleep-related behaviors. Adults in Hawaii had the highest prevalences for all four behaviors. The reasons for higher prevalences in Hawaii and other variations are unclear and might be subjects for further examination.
The findings in this report are subject to at least three limitations. First, the increase in the number of households with cellular telephones only and the increase in telephone number portability continue to decrease BRFSS response rates, reducing the precision of state estimates and potentially introducing bias. Although in 2009 all states conducted BRFSS surveys for cellular-only households in addition to households with landline telephones, cellular telephone data were not included for the sleep module and other optional modules. Second, institutionalized persons and persons residing in households without landline telephones are not included in the survey, nor are adults from all 50 states and U.S. territories, thereby limiting the generalizability of these findings. Finally, all estimates were based on self-report rather than physiologic measures of sleep behaviors with actigraphy (use of a movement-detection device with software that uses movement patterns to diagnose sleep disorders)1 or polysomnography.
Substantial increases in the percentage of U.S. adults reporting an average of <7 hours of sleep per 24-hour period were observed from 1985 to 2004** and can be attributed in part to broad societal changes, including increases in technology use and shift work.1 Sleep disorders are common health concerns that can be evaluated and treated. However, many health-care professionals might have only limited training in somnology and sleep medicine, impeding their ability to recognize, diagnose, and treat sleep disorders or promote sleep health to their patients.1 The results described in this report indicate that a large percentage of adults in 12 states reported unhealthy sleep behaviors that can be related to disease comorbidity (e.g., obstructive sleep apnea and obesity), including nearly one in 20 persons who reported nodding off or falling asleep while driving in the preceding 30 days. Expanded surveillance is needed to understand and address the public health burden of sleep loss and disorders1 and their associations with health problems and chronic diseases among adults in all 50 states and U.S. territories, which will enable further assessment of state and nationwide trends.
Healthy People 2020 includes a sleep health section, with four objectives: increase the proportion of persons with symptoms of obstructive sleep apnea who seek medical evaluation, reduce the rate of vehicular crashes per 100 million miles traveled that are caused by drowsy driving, increase the proportion of students in grades 9-12 who get sufficient sleep, and increase the proportion of adults who get sufficient sleep.†† Promoting sleep health, including optimal sleep durations, and reducing the prevalence and impact of sleep disorders will require a multifaceted approach. This approach should consider (1) sleep environments (i.e., living conditions and proximity to noise); (2) type, scheduling, and duration of work8; (3) associated health-risk behaviors such as smoking, physical inactivity, and heavy drinking1,9; (4) chronic conditions such as obesity and depression and other comorbid mental disorders1,5; (5) stress and socioeconomic status8; and (6) validation of new and existing therapeutic technologies.1 Drowsy driving also should be addressed, and additional effective interventions developed and implemented. As a first step, greater public awareness of sleep health and sleeping disorders is needed.
The findings in this report are based, in part, on contributions by BRFSS state coordinators in California, Georgia, Hawaii, Illinois, Kansas, Louisiana, Maryland, Minnesota, Nebraska, New York, Texas, and Wyoming; and DP Chapman, PhD, and LR Presley-Cantrell, PhD, Div of Adult and Community Health, National Center for Chronic Disease Prevention and Heath Promotion, CDC.
An estimated 50-70 million U.S. adults have chronic sleep and wakefulness disorders, and the percentage who report <7 hours of sleep on average has increased since the 1980s to approximately one third of all U.S. adults.
What is added by this report?
This report provides the first prevalence estimates from nationwide (12 states) surveillance of unintentionally falling asleep during the day (37.9%) at least 1 day in the preceding 30 days, and nodding off or falling asleep while driving (4.7%) during the same period; in addition, 35.3% reported <7 hours of sleep in a typical 24-hour period.
What are the implications for public health?
Increased public awareness, expanded surveillance and research, training of health-care professionals, and a multifaceted approach that considers related health, employment, lifestyle, and environmental factors will be needed to improve sleep health among U.S. adults and reduce the prevalence of unhealthy sleep-related behaviors and sleep disorders.
*The percentage of persons who completed interviews among all eligible persons, including those who were not successfully contacted.
†California, Georgia, Hawaii, Illinois, Kansas, Louisiana, Maryland, Minnesota, Nebraska, New York, Texas, and Wyoming. (Split sampling was conducted in California, Hawaii, Kansas, Maryland, Nebraska, New York, and Texas.)
‡Additional information available at http://www.cdc.gov/brfss/technical_infodata/surveydata/2009.htm.
§The percentage of persons who completed interviews among all eligible persons who were contacted.
∥The National Sleep Foundation suggests that adults need 7-9 hours of sleep per night. Additional information available at http://www.sleepfoundation.org/article/how-sleep-works/how-much-sleep-do-we-really-need.
¶Additional information available at http://www.nsart.org.
#Additional information available at http://drowsydriving.org/2009/07/countermeasures-rumble-strips.
**Available at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5437a7.htm.
††Available at http://www.healthypeople.gov/2020/topicsobjectives2020/objectiveslist.aspx?topicid=38.
Unhealthy Sleep-Related Behaviors—12 States, 2009. JAMA. 2011;305(15):1528-1530. doi: