1. Introduction
mproving health care in recent decades and increasing life expectancy have led to the growing population of the elderly, especially in developing countries [1, 2]. Elderly people need to follow a healthy lifestyle in order to have a good life [5, 8]. Nutritional lifestyle is one of the most important factors affecting the health of the elderly [9]. The poor nutritional status of the elderly paves the way for many chronic diseases such as osteoporosis, type 2 diabetes and cardiovascular disease [10, 11]. Unhealthy eating style is closely linked to low levels of nutrition knowledge and attitude [12, 13, 14]. Appropriate educational interventions need to be designed and implemented to promote nutritional knowledge and practice [15, 16].
One of the important points in designing educational interventions for the elderly target groups is to pay attention to their health literacy. Health literacy is an important mediating factor in the effectiveness of health education interventions [17]. There is a mutual relationship between health education and health literacy. On the one hand, health literacy is one of the key outcomes of health education programs, and on the other hand, implementing health education interventions, regardless of the level of learners’ health literacy, will have a negative impact on the effectiveness and benefits of these interventions [17, 18]. The purpose of this study was to determine the effectiveness of educational intervention based on health literacy level on knowledge, attitude and nutritional behaviors of elderly in Ilam city.
2. Methods & Materials
An experimental study was conducted from May to September 2016. The study sample was selected from individuals aged 60 years and over who referred to Ilam health centers. In order to select the samples, 5 health centers in different areas of Ilam were selected randomly, and then from each center, those with inclusion criteria were included. The subjects were divided into four groups (48 samples in each group), including two intervention groups with adequate health literacy and inadequate health literacy, as well as two control groups with adequate health literacy and inadequate health literacy.
Data Were Collected Using Three Questionnaires
1. Demographic Questionnaire includes 5 items for assessment of age, sex, marital status, educational status and occupational status of the subjects.
2. The Test of Functional Health Literacy in Adults (TOFHLA), which consists of two sections, computational and reading comprehension and each section assessed with 50 items. The health literacy score is divided into three levels of inadequate (0-59), borderline (60-74) and adequate (75- 100). The validity and reliability of this questionnaire has been confirmed in Iranian society in previous studies. Cronbach’s alpha values were 0.79 for the computational comprehension section and 0.88 for the reading comprehension section [28، 29].
3. The researcher-made questionnaire for assessing nutritional knowledge, attitude, and practice in the elderly. This questionnaire consists of 39 items. The knowledge section was assessed with 19 items and the score was between 0 to 38. The attitude section was assessed with 10 items and the score was between 10 to 50. The behavior section was also assessed by 10 items, with scores ranging from 0 to 30. To determine the reliability of the questionnaire, internal consistency of items was calculated by Cronbach’s alpha. Cronbach’s alpha values for knowledge, attitude and behavior were 0.75, 0.79 and 0.72, respectively.
Educational intervention for intervention groups was performed in two groups of elderly with adequate and inadequate health literacy. The subjects were divided into four groups of 24 subjects. For each group, two 60-minute sessions of lecture and question and answer session were conducted. In addition, a training manual with an educational pamphlet on aging nutrition was given to the intervention participants as reminder. The educational content includes the principles of aging nutrition, food groups, methods of preparation and cooking, food hygiene and nutritional observations in the elderly. The control group did not receive any educational intervention. However, all groups received routine interventions by the health centers.  The SPSS V. 21 was used for data analysis. Descriptive statistics and Chi-square, paired t-test and Fisher’s exact test were used for data analysis. Significance level of 0.05 was considered for data analysis.
3. Results
3. Results
 The mean±SD age of the men was 61.24±2.38 years and the mean age of women was 61.35±2.45 years. The majority of men with adequate health literacy were men (84.37%), while the proportion of men and women in those with inadequate health literacy was almost the same. Also, all participants with adequate health literacy and 89.58% of those with inadequate health literacy were married.
After the educational intervention, the mean scores of knowledge, attitude and behavior in the intervention group with adequate health literacy increased significantly (p≤0.013), (p≤0.015) and (p<0.001), respectively. In the intervention group with inadequate health literacy, only knowledge mean score after the intervention showed a significant increase, (p≤0.035). However, there was no significant change in the mean scores of knowledge, attitude and behavior in both control groups (p>0.05). The mean scores and standard deviation of the knowledge, attitude and behavior in study groups at the baseline and two month follow-up are shown in Table 1. 



4. Conclusion
The Results of this study showed the effectiveness of educational intervention in promoting knowledge, attitude and nutritional behaviors of the elderly with adequate health literacy. Also, educational intervention significantly improved nutritional knowledge of the elderly with inadequate health literacy. However, there was no significant change in the attitudes and nutritional behaviors of the elderly with inadequate health literacy. These findings suggest that providing the same nutritional education program for the elderly regardless of their level of health literacy will have a different effect on their nutritional outcomes. In order to increase the effectiveness of educational interventions, it is recommended that educational content, educational methods as well as media and educational aids be selected based on educational needs assessment, audience analysis and proportionate to their level of health literacy [2, 27]. Although the educational intervention presented in the present study significantly increased nutritional knowledge of the elderly with inadequate health literacy, the educational program was more in line with the elderly with adequate health literacy. Accordingly, this study can be used as a suitable framework for promoting nutritional behaviors of elderly with adequate health literacy.
Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Research Ethics Committee of Shahid Beheshti University of medical sciences.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Authors' contributions
All authors equally contributed to preparing this article.
Conflicts of interest
The authors declared no conflict of interest.


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