Relationship Between Health Literacy and Social Support and the Quality of Life in Patients With Cancer: Questionnaire Study

BACKGROUND: Low health literacy is associated with factors such as not taking medication as prescribed as well as poor health status and increased hospitalization and mortality risk, and has been identified as a risk factor for decreased physical function in older individuals. Health literacy is becoming an increasingly important issue because of the increased number of people affected by cancer who must make complicated treatment decisions. Health literacy has been shown to be positively associated with quality of life (QOL), and social support has been identified as important for addressing health-related problems and reducing the relative risk of mortality in patients with cancer. However, few studies have examined the relationship between health literacy, social support, age, and QOL. OBJECTIVE: The aim of this study is to examine the effects of health literacy, social support, and age on the QOL of patients with cancer. METHODS: An anonymous, self-administered online questionnaire was conducted from March 28 to 30, 2017, in Japan on patients with lung, stomach, or colon cancer that were voluntarily registered with an internet survey company. The survey covered basic attributes, health literacy, social support, and QOL. The European Health Literacy Survey Questionnaire, a comprehensive measure of health literacy instrument, was used to measure health literacy; the Japanese version of the Social Support Scale was used to measure social support; and the Japanese version of the Functional Assessment of Cancer Therapy-General (7-item version) assessment tool was used to measure QOL. RESULTS: A total of 735 survey invitations were randomly sent to patients with lung, stomach, or colorectal cancer, and responses were obtained from 619 (82.2% response rate). Significant effects on the QOL in patients with lung, stomach, or colon cancer were observed for health literacy, social support, and age, and for the interactions of health literacy and social support and of social support and age. Health literacy, social support, and the interaction between these variables also showed a significant effect on the QOL in patients 50 years or older, but not on those younger than 50 years. CONCLUSIONS: The results of this study revealed that higher health literacy, social support, and age were associated with the QOL in patients with cancer. In addition, the relationship with QOL was stronger for social support than for health literacy. These findings suggest the importance of health literacy and social support and indicate that social support has a greater effect on QOL than does health literacy, while the QOL in patients with cancer aged younger than 50 years was lower than that of those 50 years or older. Therefore, elucidating the needs of these patients and strengthening social support based on those needs may improve their QOL.