The results of this study showed that, generally, HL is low among older adults in southeast of Iran, so that 38.8% of the subjects have inadequate HL level. Previous studies in Iran and around the world have reported broad range of HL among older adults and other groups. A study in Iran showed that 79.6% of older adults had inadequate level of HL that was much more than the present study (
13). Kutner reported that only 3% of the adults in United States have adequate level of HL (
14). Another study conducted by Paasche-Orlow reported that 26% of adults have limited HL in England (
8). Overall, the results from different studies in other countries show a wide range of low health literacy among different groups in societies. Some studies have shown the inadequate HL level of people to be up to 68% (
8). Von Wagner reported that 11.4% of adults have inadequate HL in England (
15).
The previous national study in Iran demonstrated that HL in 56% of the Iranian people is inadequate or at a limited level (
16) that is parallel with the results of the present study in southeast of Iran. Our study showed that only 32.5% of older adults in southeast of Iran have sufficient level of HL that is more than a previous national study in Iran (
16). However, the place of study, age range and sample size could explain this difference.
The level of education was the most important determinant of HL in this study, so that the highest level of HL belonged to people who had academic education. On the other hand, the level of HL in adults was associated with gender and monthly income. However, low level of HL in males and moderately higher level of HL in older age groups in bivariate analysis, excluding the effect of the two mentioned variables in multiple regression model, approved the actual association of educational level and HL. This result is concordant with a previous national study in Iran (
16). National Work Group on Literacy and Health in the United States recommends health content to be written in the level of fifth grade of educational level, but it seems that this level is still difficult for 25% of the population (
17).
The study of Paasche-Orlow showed that there is no association with low levels of HL and gender (
8), but in the present study the level of HL among women was more than men. The gender differences regarding HL level could be due to the fact that the responsibility of Iranian women is low outside their home and they have enough time to attend training sessions related to health issues and classes. On the other hand the importance of health for women is more than men in Iran and thus their health literacy levels is more than men.
Regarding the results of this study in bivariate analysis, the higher monthly income could be another predictor for high level of HL among adults and HL level is high among individuals with higher level of monthly income. It seems that most people with higher monthly income belong to groups with higher level of education and they are more interested to get health information and health errands. Otherwise these individuals participate in health related meetings more than others (
16).
Parker recommended that during clinical meetings, the communication of the physicians with their patients should be according to the patient's actual HL. Some simple techniques for this purpose include the use of simple language, speaking slowly and the participation of family members of the patient in health information exchange (
18). On the other hand, non-print media is one of the effective ways to pass health messages to those who have little practical HL. The media may include video and radio tapes, video tapes or computer programs. Even patients with high level of education prefer non-print materials such as pictorial books, video tapes and audio tapes.
Generally, assessment and determination of the HL level health in order to design effective methods for information transition to people with low reading comprehension and writing skills is very important for the health system. However, it should be made sure that the people can understand and implement the medical prescriptions regarding their health status. Considering high prevalence of chronic diseases including cardiovascular disease and cancer among elderly population (
19), and also due to rising trend of these diseases around the world, the adequate level of HL for participation in different groups in order to participate in the health care system and appropriate health decisions is essential. On the other hand, increasing the HL level of people, could empower them to apply information and instructions about their health (
20) and eventually HL directly influences these factors. Thus, low level HL, especially among older adults is a warning to authorities and policy makers.
There were several limitations in our study. First, in spite of satisfactory methodology and sampling design method, our findings should not be generalized to all cities in Iran because our sample was derived from southeast of Iran that its atmosphere is different from other universities. Low understanding and abilities of the participants in response to questions was another limitation of the present study.
5.1. Conclusions
This study approved that the level of education of a person could be used as an independent predictor for his/her HL level. The results of this study show the necessity for more attention to HL in health promotion programs. To reach the mentioned goal and to enhance the level of HL, authorities are required to collaborate with mass media as the most important source of health information for most people. In general, provision of comprehensive programs, development of simple and understandable educational media for people with inadequate HL, could be an effective step for the development of HL skills in the society, especially in developing countries.