Health Literacy Helps to Explain Heterogeneous Treatment Effect in Depression Treatment for Older Adults

Abstract

This study aimed to identify factors related to mental health improvement as a function of health literacy. More specifically, it examined whether older adults with higher levels of health literacy exhibited greater reduction in depression symptoms after participating in the Positive Minds-Strong Bodies Program (PMSB). Presently, there is limited clinical data on how low health literacy contributes to health disparities in older adults’ mental health. This study hypothesized that the health literacy level of older adults would moderate the benefits obtained from participating in the PMSB program. It was expected that participants with higher health literacy levels at baseline would exhibit greater depression reduction after PMSB program completion than those with lower health literacy scores at baseline. Finally, this study also explored trends regarding what specific health literacy scores were associated with the greatest depression changes. Participants’ data were obtained from a larger multi-center randomized trial that demonstrated PMSB effectiveness across participants who spoke English, Spanish, or Chinese languages. The intervention group (n = 153) and the control group (n = 154) were recruited from community clinics and health centers serving predominantly under-served communities in Boston, New York City, Miami, and Puerto Rico. The sample population was ages 60+ years. Data regarding self-report measures of health literacy, education level, and depression symptoms were obtained through clinical interviews by trained interviewers. Analyses focused on additional understanding of the PMSB program effectiveness at the six-month follow-up, as a function of health literacy. Chi-square tests and t-tests were conducted among all study variables comparing differences between the intervention and control group. In contrast to our hypothesis, there was no significant statistical relationship between health literacy level and depression change, after participating in the PMSB program. Exploratory analyses, however, found a linear trend relationship which neared significance (t[269.388] = -1.539, P =.125). Although on average health literacy did not influence the effect of the PMSB program on depression, the intervention appeared more effective in reducing depression symptoms for participants with health literacy scores of 12 and above. These findings suggest that high health literacy may be a potential factor in psychosocial distress and mood symptoms reduction of those participating in the Positive Minds-Strong Bodies intervention.