1.Introduction

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According to Healthy People 2020, limitation of activity refers to the reduction ina person’s ability to perform his or her usual activities over a period of time. The ability to participate in daily activities is an important measure of the overall health and well-being of the population[1]. Studies have shown a positive association between self-reported physical activity and health-related quality of life (HRQOL)[2]. In fact, a sedentary lifestyle is known to increase the risk of developing chronic health conditions such as cardiovascular diseases, hypertension, type 2 diabetes mellitus, colon and breast cancers, osteoporosis, depression, and backaches [2-4]. As such, the Centers for Disease Control and Prevention (CDC) monitors surveillance of health-related quality of life (HRQOL), defined as “perceived physical and mental health over time”[5] . In a previous study, 5.5 percent of adults ages 18 to 44 and 7.3 percent of children under age 18 experience limitation in their daily activities[1]. As the population ages, activity limitation becomes greater. The epidemic of chronic diseases is linked to population aging[6] and physical inactivity is a primary cause of many chronic diseases[7]. It has been noted that roughly 32.6 percent of non-institutionalized adults age 65 and older in the US experience limitations of activities of daily living such as self-care, work, or recreation [8].For example, arthritis and activity limitation due to joint symptoms contributes to limitations which leads to dependency and subsequently decreases QOL [9]. It is also estimated that 41 million American adults 18 and older experience poor physical or mental health that limit their daily activity [10]. Since psychological distress may contribute to further impairment, screening and treatment are recommended for mental conditions that occur in persons with chronic diseases who report activity limitation days (ALD)[11]. This study assesses the prevalence of and factors associated with self-reported ≥ 14ALD due to poor physical or mental health among persons aged 18 years and over in the United States.

2. Materials and Methods

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Data Source

We analyzed data from the 2012 Behavioral Risk Factor Surveillance System (BRFSS)[12, 13].The BRFSS is a collaborative project between all of the 50 states in the U.S., the District of Columbia, three U.S. territories (Puerto Rico, Guam, and the US Virgin Islands) and the Centers for Disease Control and Prevention (CDC). It is designed to measure behavioral risk factors for non-institutionalized adults who reside in the U.S. and its territories.

Sampling and Setting

The BRFSS is nationally coordinated by the CDC and conducted by state health departments in all 50 states and the District of Columbia. BRFSS is used to collect prevalence data among adult U.S. residents regarding their risk behaviors and preventive health practices that can affect their health status. Respondent data are forwarded to CDC to be aggregated for each state.

The BRFSS questionnaire is administered on a continuous basis by telephone using random-digit dial sampling methods. The design consists of a probability sample of all households with telephones in the state. A clustering sample design was used to account for differences in the probability of selection and non-response in order to accurately derive US and state-based population estimates. In 2012, more than 450,000 interviews were conducted through the BRFSS. Annual surveys consist of a core set of questions about various health topics; such health-related risk behaviors, chronic health conditions, and use of preventive services. Sociodemographic data collected include age, sex, race/ethnicity, marital status, education, employment, and household income. The BRFSS data are publicly available and used for health policy development and advocacy at both the national and state levels.

Measures

All measures in this study were based on self-reported data obtained from the 2012 BRFSS.

Independent Variables or Demographic Characteristics

Participants responded to questions about their gender, race or ethnicity, age, education, income, marital status, and region of residence. The term “Southern Black Belt States” and “South remainder” were used to describe sub-regions of the Southern region of the U.S.

Dependent Variable

The ALD question is one of four core health-related QOL measures that have been monitored by states using the BRFSS. Response to the following question was used to determine the prevalence of ALD among persons with poor physical or mental health: “During the past 30 days, for about how many days did poor physical or mental health keep you from doing your usual activities, such as self-care, work or recreation?” The response options were ‘‘_ _number of days,’’ “none,” “don’t know/not sure,” or “refused.” Only those records with “the number of days” were included in the analysis. The items measured in days were dichotomized at a cut-off value of ≥ 14 days of poor health in the past month versus ≤13 [14].

Statistical Analysis

We used univariate analysis to calculate relative frequencies for gender, race or ethnicity, age, education, income, marital status, and region of residence. A bivariate analysis was utilized to conduct an initial assessment of the factors independently associated with ≥ 14ALD due to poor physical or mental health. All of the variables that had achieved p ≤ 0.05 in the bivariate analysis were included in the multivariable logistic regression model. Adjusted odds ratios (AORs) and 95% confidence intervals (95% CIs) were obtained. Bivariate and multivariable analyses excluded persons with responses that were missing or recorded as “don’t know/not sure” or “refused.” A 2 sided p value of ≤ 0.05 was considered to indicate statistically significant. All statistical analyses were performed using SAS version 9.2 [15].

3. Results

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Table 1 displays the socio-demographic characteristics and region of residence identified in the study population. Of the 104,257 individuals who responded to the survey question: “During the past 30 days, for about how many days did poor physical or mental health keep you from doing your usual activities, such as self-care, work or recreation?”, 62, 512 (60%) reported ≤13 days of activity limitation due to poor physical or mental health in the past 30 days, while 41, 745 (40%) reported ≥ 14 days of activity limitation. The majority of the respondents who reported ≥ 14 days of activity limitation were females (63%), non-Hispanic Whites (72%), between the ages of 45-64 (49%). Included in this group of respondents were those who had a high school education or less (53%), had annual household incomes less than $25,000 (60%), were married (41%), and were from the Southern region of the U.S. (35%).

Table 1

Table 2 presents the results of multivariable logistic regression analysis for socio-demographic (gender, race or ethnicity, age, education, income, marital status, and region of residence) variables regressed on self-reported days of activity limitation due to poor physical or mental health in the past 30 days. After adjusting for the aforementioned socio-demographic and region of residence variables and comparing to those who reported ≤13 days of activity limitation due to poor physical or mental health, male (AOR1.17, 95% CI: 1.14-1.21), respondents who were 45-64 years of age (AOR: 2.13, 95% CI: 2.06-2.23), those who were 65-74 years of age (AOR: 2.10, 95% CI: 2.00-2.21), respondents aged ≥ 75 years(AOR: 2.31, 95% CI: 2.20-2.24), being American Indian or Alaska Native (AOR=1.15;95% CI=1.01, 1.30), those with some college education (AOR: 1.42, 95% CI: 1.37,1.48), those with high school or less education (AOR: 1.42, 95% CI: 1.37-1.21), those with a < $75,000 annual household income, those who were separated (AOR: 1.23; 95% CI=1.14-1.32), divorced (AOR: 1.10; 95% CI=1.06-1.15), and those from the Southern region of the U.S. (Southern Black Belt States and the Southern Remainder) were more likely to report ≥ 14 days of activity limitations due to poor physical or mental health in the last 30 days. As compared to non-Hispanic Whites, non-Hispanic Blacks or African Americans were less likely to report ≥ 14 days of activity limitations (AOR=0.87; 95% CI=0.82, 0.93), as were Hispanic or Latino (AOR=0.84; 95% CI=0.79, 0.89), and Asian (AOR=0.56; 95% CI=0.43, 0.72).

Table 2

4.Discussion

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Persons 60 years and older are increasing worldwide; aging is likely to be the next global public health challenge [16, 17]. In the U.S., poor physical or mental health and their related ALD will require public health attention and health systems strategies to address the needs of older adults [17], especially given the epidemiologic transition from acute illness to chronic disease [2]. As the population ages and chronic disease ensues, disabling conditions such as arthritis, chronic joint symptoms, and other causes for ALD become more likely [18]. Thus, continuous monitoring of the HRQOL, developed by the CDC, complements clinical research and practice and helps public health agencies to assess, protect and promote public health [2].

Our findings show that forty percent of the 2012 BRFSS survey participants reported ≥ 14 days of ALD due to poor physical or mental health. Of particular importance is how self-reported ALD varied within this study population. Consistent with previous studies, advancing age and marital status were associated with an increased likelihood of ≥14ALD, regardless of demographic and geographic factors [2, 19-22]Specifically, one study shows that older adults and those who were separated, widowed, or divorced were considerably more likely to experience limitations in their activities [21]. Another study found, however, when controlling for age and education, gender and race were most predictive of ALD although marital status was also important[23]. Differences in the prevalence of chronic disease in African American women were believed to account for this finding [23, 24]. With respect to level of income and educational attainment, previous studies have also shown that those with a lower level of income and educational attainment are more likely to report ≥14ALD as compared to those of higher socioeconomic status [19,25, 26]. Our study used a national representative sample to confirm these significant findings.

Our findings also reveal that respondents from the Southern region of the U.S. were more likely to report ≥14ALD as compared respondents from Northeast. Other studies have also shown regional variations in HRQOL of older adults, particularly in the southern U.S.[25, 27].This is not surprising, especially when considering the regional differences in the distribution of high blood pressure, stroke, diabetes, and other chronic diseases in the southeastern U.S.[25]. In other words, longer days of activity limitation cannot only be seen in isolation from the individual’s demographic and socio economic status, but place of residence also interacts and influences self-reported ≥14ALD. This finding suggests an avenue for further investigation and suggests resources for physical and mental health interventions for ALD should be allocated for specific regions and populations. Such targeted approaches are critical, as the number of people with chronic conditions is projected to increase over the next several decades[28] and the healthcare system will need to accommodate this increase. ALD is a primary contributor to most chronic diseases [7].

This study has at least two limitations to consider, regarding the data source. First, the BRFSS is a telephone-based survey and is administered to civilian, non-institutionalized adults. Therefore, the BRFSS excludes individuals without telephone service, those on military bases, and individuals in institutions. For this reason, generalizability to the entire US population is limited. Second, this study relied on self-reported information which may have introduced recall or reporting bias.

We conclude that socio-demographic factors and region of residence are associated with ≥14 ALD among individuals aged ≥ 18 years in the US as these were significant predictors of longer days of activity limitation. Longitudinal studies that incorporate quantitative and qualitative measures are essential to identify other factors associated with self-reported ≥14 ALD and to identify the best targets for public health interventions and in reducing or eliminating the ALD Americans experience due to physical or mental health issues. This is especially important as we focus on ensuring the best QOL for the aging population.

5. Acknowledgments

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We would like to acknowledge the Morehouse School of Medicine Master of Public Health Program. The authors have no financial conflicts of interest to report.