Abstract
Introduction/Objectives:
The Centers for Disease Control and Prevention recognizes routine vaccination, sufficient sleep, and adequate physical activity as behavioral approaches to reduce the incidence of influenza. We aimed to determine the joint national prevalence of these health behaviors among U.S. adults, which has not been reported.
Methods:
We used the 2020 National Health Interview Survey to assess prevalence of receiving influenza vaccination in the past 12 months, obtaining sufficient sleep, and achieving adequate physical activity among U.S. adults (n = 30,312). We calculated the joint prevalence overall and by sociodemographic and health-related variables.
Results and Conclusions:
The overall joint prevalence was 8.5% (95% CI, 8.0-9.0). Prevalence was lower among older persons (vs younger); Hispanic and non-Hispanic Black persons (vs non-Hispanic White); current and former smokers (vs never smokers); postpartum women (vs neither pregnant nor postpartum); and those with a history of coronary heart disease, hypertension, stroke, diabetes, and chronic obstructive pulmonary disease (vs not having those respective condition). In addition to recommending annual vaccination, primary care providers might encourage sufficient sleep and adequate physical activity—especially among patients who have increased risk for influenza complications and are less likely to achieve these behaviors.
Introduction
Seasonal influenza virus accounted for about 79 million medical visits, 2 million hospitalizations, and 166 000 deaths in the United States from October 2015 to September 2020. 1 The economic impact is considerable—estimated using 2015 data to total $3.2 billion annually in direct medical costs and $8.0 billion annually in indirect costs, mostly from lost earnings and work absenteeism. 2 Each year, an estimated 20 million productive work days are lost due to influenza, excluding those associated with death. 2 Given these significant health and fiscal consequences, it is important to maximize strategies for primary prevention. The Centers for Disease Control and Prevention (CDC) recognizes annual vaccination and healthy habits to reduce the incidence of influenza. Two components of the 24-h movement cycle are highlighted by CDC as protective against influenza: getting enough sleep and being physically active. 3 Annual vaccination, sufficient sleep, and adequate physical activity are imminently modifiable, but to our knowledge no study has examined the national joint prevalence of these 3 influenza preventive behaviors. We sought to fill this gap using a nationally representative sample of the U.S. adult population in 2020. These results may inform influenza prevention, as well as physical activity and sleep promotion strategies in primary care settings.
Methods
Survey and Population
For this cross-sectional study we obtained data from adult participants of the 2020 National Health Interview Survey (NHIS). The NHIS is an annual household survey conducted by the US Census Bureau for CDC’s National Center for Health Statistics. NHIS provides estimates on health indicators, health care utilization and access, and health-related behaviors among the civilian, noninstitutionalized population of the United States. The survey is approved by the National Center for Health Statistics, and all participants provide consent. 4 Given data collection challenges during the COVID-19 pandemic, the 2020 NHIS sample adult population included both adults interviewed in 2020 (response rate: 48.9%) and those originally interviewed in 2019 and reinterviewed in 2020 with the 2020 questionnaire (response rate: 29.6%). 5
Measures
We defined receipt of seasonal influenza vaccination as answering yes to the question: “During the past 12 months, have you had a flu vaccination?” We determined sleep duration from the question: “On average, how many hours of sleep do you get in a 24-hour period?” We defined adherence to the Physical Activity Guidelines for Americans 6 as “meets both criteria” on the recoded NHIS variable PA18_05R_A, which combines data from aerobic and muscle-strengthening questions. 7 We excluded participants (n = 1256) who were missing information on 1 or more behaviors. Complete behavioral data were available for 30 312 participants.
We used Healthy People 2030 objectives to define achievement of each influenza preventive behavior. Joint prevalence is defined as individuals receiving influenza vaccination in the past year (objective IID-09), obtaining ≥7 h of sleep per 24-h period (SH-03), and achieving the combined guideline of ≥150 min/week of moderate-intensity equivalent aerobic activity and ≥2 episodes/week of muscle-strengthening activity (PA-05). 8 We elected to include aerobic and muscle-strengthening activity because both are associated with lower influenza mortality9,10 and lower incidence of respiratory infections, including COVID-19. 11
Statistical Analysis
We used SAS v9.4 (SAS Institute, Cary, NC) and SAS-callable SUDAAN release 11.0.3 (RTI International, Research Triangle Park, NC) to account for weighting and the complex survey. We calculated the joint prevalence and 95% confidence interval (CI) of all 3 behaviors, overall and by reported participant characteristics: sex; age group; race and ethnicity; education; smoking; body mass index category; pregnancy status (pregnant during the 2019-2020 influenza season, postpartum and not pregnant during the 2019-2020 influenza season, or neither); and history of coronary heart disease (CHD), hypertension, stroke, diabetes, cancer, immunosuppression (due to prescriptions, procedures, or health conditions), asthma, and chronic obstructive pulmonary disease (COPD). 7 We compared joint prevalence using unadjusted and adjusted prevalence ratios (aPR) and 95% CI using predicted marginals under logistic regression models. Adjustments include sex, age group, and race and ethnicity. We also calculated prevalence of individual behaviors and of behavior combinations. Significance within strata was defined by t test of P < .05 for comparison with referent level within each category. No data suppression was required. 12 The Strengthening the Reporting of Observation Studies in Epidemiology (STROBE) statement on cross-sectional studies was used to develop this report. 13
Results
Among 30 312 adults included, 8.5% (95% CI, 8.0-9.0) had received an influenza vaccination, got sufficient sleep, and engaged in adequate physical activity (Table 1). Joint prevalence was low across subgroups, with none exceeding 16%, and it was lower among women versus men, older adults versus those aged 18 to 34 years, non-Hispanic Black and Hispanic versus non-Hispanic White adults, and those without a college degree versus with a college degree. Current smokers had 76% lower adjusted prevalence than never smokers (aPR = 0.24; 95% CI, 0.19-0.32). Postpartum women had 57% lower adjusted prevalence than women of reproductive age who reported no pregnancy or recent live birth (aPR = 0.43; 95% CI, 0.22-0.85). Health conditions associated with a lower joint prevalence included CHD, hypertension, stroke, diabetes, and COPD. Individual behavior prevalence was 48.0% (95% CI, 47.0-48.9) for influenza vaccination, 72.5% (95% CI, 71.8-73.2) for sufficient sleep, and 24.2% (95% CI, 23.5-25.0) for adequate physical activity (Table 2). Approximately 40% of adults were vaccinated but did not achieve 1 or both of the other behaviors (Table 3).
Joint Prevalence a of Influenza Preventive Behaviors Among U.S. Adults—National Health Interview Survey, 2020.
Abbreviations: CHD, coronary heart disease; CI, confidence interval; COPD, chronic obstructive pulmonary disease; PR, prevalence ratio.
Joint prevalence of receiving an influenza vaccination in the previous 12 months, obtaining the recommended amount of sleep (≥7 h/24-h period), and meeting the physical activity guideline (≥150 min/week of moderate-intensity equivalent aerobic activity and ≥2 episodes/week of muscle-strengthening activity). Due to missing data, not all variables have 30 312 respondents.
Adjusted for sex, age group, and race and ethnicity.
Asked of women aged 18 to 49 years (or whose age was unknown or not reported). Pregnant was defined as reporting pregnancy during the 2019 to 2020 influenza season (July 2019 to March 2020). Postpartum was defined as reporting a pregnancy that ended in a live birth during the past year and not pregnant during the 2019 to 2020 influenza season.
Ever told by a doctor or other health professional that they had the condition. Diabetes includes pre-diabetes or borderline diabetes. Immunosuppression was assessed with 2 questions: (1) “In the past 12 months, have you taken prescription medication or had any medical treatments that a doctor or other health professional told you would weaken your immune system?” (2) “Do you currently have a health condition that a doctor or other health professional told you weakens the immune system?” Prevalence ratios reflect comparison to not reporting the condition.
Statistically significant (P < 0.05 by t-test for comparison with referent level within each category).
Individual Prevalence of Influenza Preventive Behaviors Among U.S. Adults—National Health Interview Survey, 2020.
Abbreviations: aPR, adjusted prevalence ratio; BMI, body mass index; CHD, coronary heart disease; CI, confidence interval; COPD, chronic obstructive pulmonary disease; HS, high school; NH, non-Hispanic.
Due to missing data, not all variables have 30 312 respondents.
Received seasonal influenza vaccination in the previous 12 months.
On average, obtained ≥7 h of sleep per 24-h period.
Achieved ≥150 min/week of moderate-intensity equivalent aerobic activity and ≥2 episodes/week of muscle-strengthening activity.
Asked of women aged 18 to 49 years (or whose age was unknown or not reported). Pregnant was defined as reporting pregnancy during the 2019 to 2020 influenza season (July 2019 to March 2020). Postpartum was defined as reporting a pregnancy that ended in a live birth during the past year and not pregnant during the 2019 to 2020 influenza season.
Ever told by a doctor or other health professional that they had the condition. Diabetes includes pre-diabetes or borderline diabetes. Immunosuppression was assessed with 2 questions: (1) “In the past 12 months, have you taken prescription medication or had any medical treatments that a doctor or other health professional told you would weaken your immune system?” (2) “Do you currently have a health condition that a doctor or other health professional told you weakens the immune system?” Prevalence ratios reflect comparison to not reporting the condition.
Statistically significant (P < .05 by t-test for comparison with referent level within each category).
Prevalence of Combinations of Influenza Preventive Behaviors Among U.S. Adults—National Health Interview Survey, 2020 (n = 30 312).
Abbreviation: CI, confidence interval.
Received seasonal influenza vaccination in the previous 12 months.
On average, obtained ≥7 h of sleep per 24-h period.
Achieved ≥150 min/week of moderate-intensity equivalent aerobic activity and ≥2 episodes/week of muscle-strengthening activity.
Discussion
Based on a nationally representative survey conducted in 2020, over 90% of US adults had not received a seasonal influenza vaccination, obtained sufficient sleep, and achieved adequate physical activity. Although prevalence estimates of each behavior have been reported previously,14 -16 to our knowledge this is the first analysis of joint prevalence in the United States. Primary care providers (PCPs) may be instrumental in promoting these behaviors across the population, with an emphasis on patients who are older, Hispanic or non-Hispanic Black, postpartum, or who have a history of CHD, hypertension, stroke, diabetes, or COPD—all factors associated with an increased risk of influenza complications. 17
By individual behavior, we found that prevalence was greatest for sufficient sleep, followed by influenza immunization and adequate physical activity. A wide discrepancy in these behaviors is observed across the globe. Bedford and colleagues reported a 90% prevalence of sufficient sleep among adolescents and adults in Hong Kong, which they note exceeds the 57 to 88% prevalence in population-based surveys conducted in European countries. 18 A recent study indicated that influenza vaccination coverage among the general population in other countries varied greatly (e.g., 10% in Poland, 17% in China, 37% in Canada, and 57% in Brazil). 19 The World Health Organization estimates that 72% of the world’s adult population achieve their recommended amount of physical activity, although prevalence varies greatly across regions. 20 We add to these studies by providing a composite measure of 3 behaviors in a large, nationally-representative sample.
PCPs should follow recommendations from the Advisory Committee on Immunization Practices 21 when offering vaccination during routine health care visits and hospitalizations. Survey data suggest that PCPs routinely recommend seasonal influenza vaccination to all adult patients. 22 Evidence-based strategies associated with higher vaccination coverage among adults in the primary care setting—such as standing orders and patient reminders23,24—could be applied to the other behaviors. For example, sleep and physical activity could be added as “vital signs” to standard clinical intakes, providing opportunities and reminders to counsel patients who are not achieving recommended levels.25,26 Effectiveness may increase if PCPs gain confidence in behavioral change counseling. Whereas over half of family physicians and general internists in 1 survey reported high self-efficacy about counseling adult patients on influenza vaccination, 22 other surveys suggest lower frequency of and confidence in counseling for sleep27,28 and physical activity.29,30
At least 4 limitations apply to these findings. First, all data are self-reported and may be susceptible to recall and social desirability biases. Second, physical activity questions are restricted to leisure-time activities, and therefore may miss physical activity occurring in the transportation, occupational, and household domains. Third, data were missing for some stratification variables. Finally, although survey weights incorporated nonresponse patterns, bias associated with nonresponse may remain. 5
Conclusions
The prevalence of joint influenza preventive behaviors among US adults is low. To reduce the incidence and severity of seasonal influenza, PCPs may wish to combine vaccination campaigns with counseling on sleep and physical activity. An emphasis may be placed on populations most vulnerable to influenza complications and with the lowest joint prevalence of influenza preventive behaviors, including patients who are older, are Hispanic and non-Hispanic Black, are postpartum, or have a history of CHD, hypertension, stroke, diabetes, or COPD.
Footnotes
Acknowledgements
We thank Moira Urich, Centers for Disease Control and Prevention, for copyediting our manuscript.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Disclaimer
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
