In this study, more than 50% of the participants exhibited inadequate health behavior knowledge, including all elderly persons. These finding was consistent with those of other studies [30–33] but higher than the findings in the study by Tian et al. [13, 34] regarding the health knowledge of rural elderly people about chronic diseases.
In general, more than 60% of the elderly showed adequate knowledge of the factors that induce falls, as well as the importance of daily health habits, regular diet, and exercise. In addition, the respondents understood the danger of smoking, importance of social interaction, and effects of living alone. Knowledge of the proper/maximum intake of oil, salt, fruits, vegetables, and liquids, as well as information on elderly depression, need to be strengthened (with less than 60%). Since 1953, the government of the People's Republic of China has implemented disease prevention programs as the focus of health knowledge promotion. In the past 20 years, the government and the Department of Health Education have provided sufficient attention to health education as well as healthy behavior and lifestyle. Thus, most people have acquired adequate knowledge of the components that complete a healthy lifestyle . Inadequate orientation to healthy habits and lifestyle lead to poor understanding of the importance of using appropriate amounts of cooking oil and salt in preparing food, realizing the benefits of appropriate intakes of vegetable, fruits, and liquids, as well as recognizing symptoms of common mental disorders. Thus, these aspects of health knowledge should be the focus of future efforts in health education.
Studies worldwide found that people aged 65 years or older with lower educational level had less health behavior knowledge [35, 36]. A close relationship was found between the elderly health knowledge and their educational level; the higher the educational level, the better their health knowledge [37, 38]. The present study confirmed that the participants who attained high school level or above had 6, 4, and 3 times greater odds of possessing adequate health knowledge than those who attained below primary, primary, and junior high school education, respectively. High reading comprehension level, broad knowledge, analytical ability, and screening information ability were better in people who obtained higher education compared with lower education, which may explain more accurately the similar results .
The current study also revealed that the elderly without previous employment exhibited significantly lower health knowledge than those who were previously employed (participants who used to work as administrative and technical personnel, workers, migrant workers, and farmers had 2.5, 2.3, 3.9, and 2.1 times greater odds of possessing adequate health knowledge than those who were unemployed, respectively). This finding was consistent with the results of other previous studies . People with different occupations had various social interaction as well as access to and distribution of information. Among the Chinese elderly, those who worked as administrative and technical workers obtained a higher level of health behavior knowledge because they had more access to information and knowledge was more easily disseminated in their profession . Those elderly who did not previously hold permanent occupations showed a low educational level, and primarily did the household chores; these people had limited access to information and had fewer ways of acquiring knowledge. In China, more than 40% of the elderly received no basic education, particularly females . The present study confirmed this percentage. Because most respondents were born before 1950, and poor standard of living rendered them incapable of pursuing formal education.
A significant difference in health literacy has been indicated between the Chinese elderly living in urban areas and those living in rural areas : the elderly living in urban areas showed significantly higher health behavior knowledge than did the rural elderly; the number of elderly persons living in cities and exhibiting good health behavior knowledge was 3.5 times greater than those living in rural areas. This result may be attributed to differences in economic conditions, educational attainment, and health resources between those living in urban and rural areas. According to the Rural Health Resource Allocation Report in 2010 , the current health resources of China are mainly allocated to hospitals at or above the county level. Township institutes are generally less prestigious and less sophisticated in terms of technological facility. In addition, their technical personnel generally obtained relatively low educational degrees. Excellent community medical care, health care services, and health education are difficult to provide because of shortage in technical health personnel in town hospitals. Therefore, prompted community health departments should increase the number of skilled personnel in towns and restructure the health department to strengthen health education among rural people, particularly the elderly.
In previous studies, gender and marital status were factors that affecting health knowledge of the elderly. Male, married people have better health knowledge than the one who was female, divorced or widowed [13, 15, 16], but this study do not show this difference, which must be confirmed in future research.
A study showed  that the level of health knowledge among the elderly who were chronically ill was higher than those without chronic diseases. However, these results were contrary to the findings in the present study, which reveals no difference in health behavior knowledge between the elderly who were chronically ill and those who were not. We found that this variation could be attributed to the content of the survey items. The previous study investigated the general health and chronic disease-related knowledge among the elderly, whereas the present study focused on general health knowledge (daily health behaviors). This study also found that those elderly with chronic diseases were more likely to acquire knowledge related to chronic diseases.
With the rapid urbanization in China and the migration of the rural population to the city in recent years, the number of the elderly who left the rural areas increased , and the number of rural stem families declined. This study indicated that the number of old people living with their children was less than one-fourth of the investigated number.
In the present study, the comparison of the health behavior knowledge between the elderly and their children indicated that both groups exhibited a tendency to improve their health behavior knowledge. For example, the elderly possessed adequate health knowledge of the factors that induce falls, as well as the importance of daily health habits, regular diet, and daily exercise. The elderly were also aware of the dangers of smoking, importance of social interaction, and effects of living alone (with an accuracy rate above 80%). However, their knowledge regarding the following must also be strengthened: appropriate amounts of oil and salt used in food preparation; intake of fruits, vegetables, and liquids; and symptoms of early depression (with an accuracy rate below 40%). Family interaction regarding their collective health knowledge also contributed to the improvement of health behavior knowledge. Living in the same environment over a long period of time allowed the members to subtly influence one another.
In addition, the health behavior knowledge of the elderly was significantly lower than that of their children (χ
2 = 141.82, P < 0.001). Knowledge of mental health prominently showed that family members influence one another in terms of health knowledge. Despite the seemingly dominant roles of the elderly in the family, they may not be sufficiently strong to promote solid health knowledge in the family. Logistic regression analysis of the influencing factors of health knowledge among the elderly also confirmed this view. (The item stating “with whom to live together” Was removed from the questionnaire). We interviewed some of the elderly and their children, and the general view of the elderly was that the health behavior knowledge was similar to knowledge of daily life such that they perceived information coming from medical staff to be more credible than information coming from their children. The reason for this observation may be that the elderly had more trust in the medical staff’s experience. The children’s common view was that they had significant health behavior knowledge but that they did not pay sufficient attention to them because the habits formed by long-term living with their parents would weaken their trust in this knowledge.
Accordingly, community health workers should emphasize the importance of education and health awareness and make the children become actively involved and responsible in the implementation of overall family education.