Title: Effects of health literacy to self-efficacy and preventive care utilization among the older adults
Running title: Healthy literacy, self-efficacy and preventive care
Authors:
Ji-Zhen Chen1,2, M.S., Hui-Chuan Hsu2*, Ph.D., Ho-Jui Tung2, Ph.D., Ling-Yen Pan3 Ph.D.
Affiliations:
1 Clinical Trials Center, China Medical University Hospital 2 Department of Health Care Administration, Asia University 3 Planning Unit, Bureau of Health Promotion, Department of Health
*Corresponding author: Hui-Chuan Hsu
Address: No. 500, Lioufeng Road, Wufeng, Taichung, 41354, Taiwan, R. O. C. TEL: 04-23323456#1827, FAX: 04-23332970,
Effects of health literacy to self-efficacy and preventive care utilization among the older adults
Abstract
Purpose: This study examined the relations between health literacy, self-efficacy, and preventive care utilization among older adults in Taiwan. Methods: The data were from a longitudinal survey, “Taiwan Longitudinal Study in Aging” in 2003 and 2007. A total of 3479 participants who completed both two waves were included for analysis. Health literacy first was constructed through education, cognitive function, and disease
knowledge through structural equation modeling (SEM); then, the associations of health literacy to later self-efficacy and preventive care were examined. Results: The model fit of SEM was good, indicating that the construct of health literacy was appropriate. Healthy literacy showed positive effect on both self-efficacy and preventive care utilization and also had indirect effect on preventive care utilization through self-efficacy. Conclusions: Health literacy increases self-efficacy and utilization of
preventive care. Promoting people’s health knowledge and health literacy is suggested.
Effects of health literacy to self-efficacy and preventive care utilization among the older adults
Introduction
According to World Health Organization, “Health literacy represents the cognitive and social skills which determine the motivation and ability of individuals to gain access to, understand and use information in ways which promote and maintain good health” (Nutbeam, 1998). Health literacy is an individual’s cognition to use preventive care (Lee, Avis, and Arthur, 2007), and it affects individual’s health status. When one’s health literacy is inadequate, his/her has worse self-care ability, higher morbidity of chronic disease, and worse physiological and psychological status (Lee, Arozullah, Cho, 2004; Wolf, Gazmararian, Baker, 2007). Results from National Assessment of Adult Literacy of the United States in 2003 showed that only 3% of the elderly had good health literacy, and 29% of them were inadequate (CDC, USA, 2009). This indicates that the healthy literacy deficiency may be serious among the elderly population. Research has found the relationships among health literacy, self-efficacy, health behavior, and preventive care utilization (Lee et al., 2007; Lee et al., 2004; Wagner et al., 2009; Jayanti and Burns 1998; Evangelos, 2006; Cho et al., 2008). However, the direct and indirect relationships of these components are less explored. The purpose of this study was to explore the effects of health literacy to health self-efficacy and preventive care utilization among the older persons.
Measures of health literacy
Some scales of health literacy are developed: Test of Functional Health Literacy in Adults (Parker, Baker, Williams and Nurss, 1995), Rapid Estimate of Adult Literacy in
Medicine (Davis et al., 1993), and Wide Range Achievement Test (Jastak and Wilkinson, 1984). There also are Mandarin versions scales, such as Taiwan Health Literacy Scale (Su et al., 2008) and Mandarin Health Literacy Scale (Tsai et al., 2010). However, not all of these scales are widely applied in large surveys, and the application is not confirmed. Some other research used proxy measures for health literacy, such as knowledge about disease control and health management, education, cognitive function, and compliance with medication (Baker, 2006; Hernandez, 2009; Weiss et al., 1995; Baker et al., 2008). Health/disease knowledge is the most important component because it is direct and specifically measure “literacy” about health, not just the effect from the educational level (Baker, 2006; Hernandez, 2009). Education is a leading and assessing factor to health literacy, and people having higher education usually have higher health literacy (Pandit et al., 2009). Better cognitive function is related to better health literacy and retention of health information (Wilson et al., 2010).
Decline of cognitive function also increases the barriers in reading and realizing in health-related information (Weiss et al., 1995; Baker et al., 2008), which may be more essential among the older people. Based on the previous findings, we hypothesize that education, health/disease knowledge, and cognitive function are good proxy measures to construct the concept of health literacy (H1).
Relations among health literacy, self-efficacy in health management, and preventive care utilization
Older people having lower health literacy have less disease knowledge, poorer self-care, worse compliance with medication, worse health decision making, and more likely to perform risk behaviors of health, such as smoking, drinking alcohol, and sedentary lifestyle, compared with those who have better health literacy (Lee et al., 2010; Wolf et
al., 2007; Smith et al., 2009); they also have higher morbidity in chronic diseases and worse health status (Wolf et al., 2005). In addition, people with higher health literacy were found to use less emergency room and hospital services because they had greater disease knowledge, healthier behaviors, more preventive care use, and higher degree of compliance with medication (Cho et al., 2008). People having lower health literacy usually use less preventive care (Miller et al., 2007; Garber et al., 2009). Higher health literacy is beneficial to healthy behaviors and health management and, further, to reduce health risks. Thus, we hypothesize that the older persons who have higher health
literacy will use more preventive care (H2).
Health literacy is positively related to self-efficacy to participate in health screening or health examinations (Wagner et al., 2009), and through self-efficacy, the compliance with medication and self-care skills are improved (Wolf et al., 2007; Osborn et al., 2010; Wood et al., 2010;). Jayanti and Burns (1998) found that health knowledge would improve response efficacy (belief in health care reacting to disease threat) and indirectly improve preventive health care behaviors. Thus, we hypothesize that older persons with better health literacy will have higher health self-efficacy (H3).
In addition, people with higher self-efficacy are more aware of their physical or psychological health status and have higher confidence in using preventive care, so they are more likely to use preventive care to avoid threats from diseases (Jayanti and Burns, 1998; Evangelos, 2006) and more willing to perform healthy behaviors, such as regular exercise or preventive health care services (Jayanti and Burns, 1998; Hou and Chen, 2004). Thus, we hypothesize that older persons having higher self-efficacy in health management will use more preventive care (H4).
Health literacy has been noticed to be an important issue in health promotion and prevention. However, the existing scales are not widely empirically verified and proven to be applicable to all populations. Appropriate and available measures of health literacy are necessary at this moment. In addition, most studies about health literacy are cross-sectional, and the causal relationship among health literacy, self-efficacy, and
preventive care utilization are not very clear. The purpose of this study was to construct the measurement of health literacy and to examine the relations among health literacy, self-efficacy, and preventive care utilization by a large nationally representative data among the older people.
Methods
Data and samples
The data used in this study were collected as part of the survey of “Taiwan
Longitudinal Survey on Aging”. Face-to-face interviews were conducted with a random sample of individuals (aged ≥60 years) taken from the entire elderly population of Taiwan. A few of the participants lived in institutions, but most (99.0%) lived in a community. A three-stage proportional-to-size probability sampling technique was used. The interviews were conducted in 1989, 1993, 1996, 1999, 2003, and 2007, and supplement cases aged 50-66 years were added in 1996 and 2003. Participants who completed both in 2003 and 2007 surveys and only those self-reported were included in the analysis reported herein.
Measures
Health literacy was measured by education, cognitive function, and disease
knowledge in 2003. Education was measured by educational years. Cognitive function was measured by Short Portable Mental Status Questionnaire (Pfeiffer, 1975), score
0-10. Disease knowledge was measured by the knowledge about kidney disease, diabetes, and hypertension prevention. The respondents were asked by multiple-choice questions, such as “Do you know how to prevent kidney disease?”, “Do you the initial symptoms of diabetes?”, and “Do you know how to prevent/control diabetes and hyper tension?”, and scored based on their replies. Total score ranged from 0 to 19.
Self-efficacy in health management was measured by asking the respondents how much they were confident in the following items in 2007: Doing exercise to reduce disease risks, controlling diet (such as less salt/sugar/oil diet) to reduce disease risks, managing their daily lives to prevent being affected by health problems, and managing their emotions to prevent being affected by health problems. Scores of each item ranged from 1 to 5, with 1 indicating “not confident” and 5 “very confident” in managing the above-mentioned items.
Preventive care utilization was defined by the total items of preventive care services used in the past year, including blood pressure examination, blood sugar examination, general blood test (including urine acid, cholesterol, and liver and renal function), flu and pneumonia vaccination, and general health checkup. The preventive care utilization was according to the data in 2007. Thus, the time sequence of the model was
reasonable. Analysis
Descriptive statistics and Pearson’s correlation were first conducted. Next, confirmatory factor analysis was used to construct the measure of health literacy. At last, structural equation modeling was analyzed to explore the relationships among health literacy, self-efficacy, and preventive care utilization. Data were analyzed by SPSS/PC 12.0 for windows and LISREL 8.8. The original data were randomly split into
two subsamples: subsample 1 with 1742 persons and subsample 2 with 1737 persons. The subsample 1 was used to test the plausible models, and the subsample 2 was used for confirmation of the best model to examine the cross-validation. These two
subsamples were not significantly different in age and gender distribution examined by goodness of fit test.
Results
The average age of the samples was 64.6 years (standard deviation [SD] = 9.98). There were 48.7% males and 51.3% females. The mean and SD of the main variables are shown in Table 1, including disease knowledge, education years, cognitive function, four items of self-efficacy, and preventive care utilization. The current elderly cohort of the Taiwanese had lower education level, indicating low literacy. Table 1 also shows the correlation among the variables. The older persons who had more disease knowledge, higher education, better cognitive function, and higher self-efficacy used more
preventive care. Those who had higher self-efficacy, more disease knowledge, higher education, and better cognitive function also had higher self-efficacy.
Health literacy measurement: Confirmatory factor analysis
The confirmatory factor analysis of health literacy was first conducted in
subsample 1 and shown in Figure 1. The goodness of fit of the construct was acceptable (root mean square error of approximation [RMSEA] = 0.0583, standardized root mean square residual [SRMR] = 0.0327, normed fit index [NFI] = 0.980, non-normed fit index [NNFI] = 0.964, comparative fix index [CFI] = 0.983, adjusted goodness of fit index [AGFI] = 0.965, critical N [CN] ＝ 568.732, χ2 ＝ 81.91, df = 13, p < 0.001). The factor loading λΧ of education (λ ＝ 3.913), disease knowledge (λ ＝ 1.701), and cognitive function (λ ＝ 0.663) with health literacy were all significant. The results
indicated that the construct fitted well to the data and supported our hypothesis that these three measures could be good proxy measure for health literacy.
Model verification: Structural equation modeling
Next, we examined the hypothetical model using subsample 1. The hypothetical model included our hypotheses H2, H3, and H4 as shown in Figure 2. The assumptions were made and tested using subsample 1, and then, the model was further verified in subsample 2 and the total sample (subsamples 1 and 2). The results are shown in Table 2. The goodness-of-fit index of the model by 3 sets of data (subsamples 1 and 2 and the total samples) is reported as follows: χ2 ranged from 84.91 to 158.34, df = 13, p < 0.001; RMSEA ranged from 0.0583 to 0.0565; SRMR ranged from 0.0297 to 0.0327; NFI ranged 0.980 to 0.982; NNFI ranged from 0.964 to 0.066; CFI ranged from 0.983 to 0.984; AGFI ranged from 0.965 to 0.967; and CN ranged from 568.732 to 609.207. Although χ2 value was not perfect (the p value was small), it is possibly because of large sample size. Other indexes showed a quite good goodness of fit. Thus, the model was acceptable. The λs, βs, and goodness of fit of two subsamples and the total sample are shown in Table 2, which were very close across the subsamples. The results indicated that higher health literacy was significantly related to higher self-efficacy (β ＝ 0.373, p < 0.001) and more preventive care utilization (β ＝ 0.024, p < 0.001). Self-efficacy also was positively related to preventive care use but not significant (β ＝ 0.001, p > 0.05).
Discussion
This study constructed the proxy measure of health literacy and examined the relations among health literacy, self-efficacy, and preventive care utilization of the older persons in Taiwan. We found that education, disease knowledge, and cognitive function
were good proxy measures to health literacy. In addition, health literacy has direct and positive effect on preventive care and also had an indirect effect to preventive care through self-efficacy.
Although the goodness of fit of the model in this study was good, it does not mean that the measures of health literacy are the best; we may only confirm that the model fitted the data very well. However, our findings are consistent with those in Baker (2006), Hernaez (2009), Weiss et al. (1995), and Baker et al. (2008). Thus, we are convinced that the indices used in this study are acceptable proxy measures for the older Taiwanese people before a widely verified and acceptable scale has been developed.
The positive relations among health literacy, self-efficacy, and preventive care utilization are consistent with previous studies (Wagner et al., 2009; Baker et al., 2008; Wolf et al., 2005; Osborn et al., 2010; Wood et al., 2010). Adequate disease knowledge is a performance of good health literacy (Baker, 2006; Hernadexz, 2009), and people having more disease knowledge are more likely to accept preventive care concept, receive preventive care services, and follow the indications of preventive screening.
Previous studies indicate the positive correlations of self-efficacy and preventive care utilization, and people with higher self-efficacy have higher confidence in
completing preventive care services (Wagner et al., 2009; Jayanti and Burns, 1998; Hou and Chen, 2004). However, the relation of self-efficacy and preventive care utilization was not significant in this study. There are two possible explanations. First, the
measures of self-efficacy in health management in this study may not be closely relevant to the preventive care utilization. Second, there may be a gap between the self-efficacy in health management and the ability to perform the activities because of the environment, time, or economic factors.
There were some limitations in this study. First, because of the available variables in the data, the variables in self-efficacy were related to general health but not specific to preventive care. Second, although the time sequence of causal relationships have been considered in the study, health literacy may still change across time, for example, disease knowledge may increase over time. The growth curve was not considered in this study. Third, only the self-reported respondents who usually had better cognitive function were included in the analysis. Thus, the results may be overestimated.
In summary, education, cognitive function, and disease knowledge are components of health literacy, and disease knowledge is changeable. The results suggest that health education and promotion in health management and disease knowledge may improve health literacy and indirectly promote healthy lifestyle. We suggest that our construct of health literacy be verified in the population other than the elderly to examine the
validity. We also suggest conducting a longitudinal study in the future to examine the causal relationships of health literacy, self-efficacy, and preventive care.
Acknowledgments
The data was provided by the Population and Health Research Center, Bureau of Health Promotion, Department of Health, Taiwan, Republic of China. The interpretation and conclusions contained herein do not represent those of Bureau of Health Promotion. This study does not have any potential conflicts of interest.
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Variables (SD) Disease knowledg e Educatio n Cognitiv e function efficacy in doing exercise Self-efficacy in diet control efficacy in not affecting daily lives efficacy in not affecting emotions Preventiv e care use Disease knowledge 3.14 (3.40) ----Education 6.38 (4.53) 0.422** ----Cognitive function 9.32 (1.40) 0.255** 0.391** ----Self-efficacy in doing exercise 3.31 (1.54) 0.207** 0.217** 0.175** ----Self-efficacy in diet control 3.67 (1.34) 0.210** 0.140** 0.111** 0.447** ----Self-efficacy in not affecting daily lives
3.57
(1.32) 0.169** 0.228** 0.212** 0.474** 0.386**
----Self-efficacy in not
affecting emotions 3.57 (1.30) 0.152** 0.224** 0.210** 0.433** 0.368** 0.839** ----Preventive care use 3.29
(1.50) 0.127** 0.038* 0.032 0.131** 0.136** 0.058** 0.053**
Variables
Subsample 1 (n=1742) Subsample 2 (n=1737) Total samples (n=3479)
Health literacy Self-efficacy Preventiv e care use Health literacy Self-efficacy Preventiv e care use Health literacy Self-efficacy Preventive care use λ1 Education 3.327*** ---- ---- 2.857*** ---- ---- 3.070*** ---- ----λ2 Disease knowledge 1.584*** ---- ---- 1.734*** ---- ---- 1.662*** ---- ----λ3 Cognitive function 0.769*** ---- ---- 0.805*** ---- ---- 0.790*** ---- ----λ4 Self-efficacy in doing exercise ---- 1.100*** ---- ---- 1.068*** ---- ---- 1.084*** ----λ5 Self-efficacy in diet control ---- 0.721*** ---- ---- 0.884*** ---- ---- 0.806*** ----λ6 Self-efficacy in not
affecting daily lives ---- 1.150*** ---- ---- 1.100*** ---- ---- 1.123***
----λ7 Self-efficacy in not
affecting emotions ---- 1.081*** ---- ---- 1.089*** ---- ---- 1.087***
----λ8 Preventive care use ---- ---- 5.017*** ---- ---- 4.842*** ---- ---- 5.521***
β1 Health literacy ---- ----
----β2 Self-efficacy 0.349*** ---- 0.395*** ---- 0.373***
----β3 Preventive care
----indexes NFI =0.980, NNFI =0.964, CFI＝0.983, AGFI =0.965, CN =568.732 NFI =0.981, NNFI =0.966, CFI＝0.984, AGFI =0.966, CN =592.505 NFI =0.982, NNFI =0.964, CFI＝0.983, AGFI =0.967, CN =609.207 Note: *p<0.05, **p<0.01, ***p<0.001.
