Background: In many countries, illiteracy rates among aged people are quite high. However, only few studies have specifically investigated the impact of illiteracy on depression.
Methods: Data for 1,890 elderly individuals (aged ≥65 years) were obtained from a nationwide dementia epidemiological study conducted in South Korea. Based on their reading ability, the participants were divided into three groups: totally illiterate, partially illiterate, and literate. The Korean version of the Geriatric Depression Scale - Short Form (SGDS-K) was used to detect depression (cut-off score = 8). Multivariate logistic regression analyses were used to assess the association between illiteracy and depression. To explore clinical features of depression in illiterate people, we performed logistic regression to calculate odds ratios of positive responses (or negative responses to reverse-coded items) for each SGDS-K item using literate individuals as the reference group.
Results: Totally illiterate participants had 2.41 times the odds and partially illiterate individuals had 1.59 times the odds of being depressed compared with literate participants after controlling for other variables. Compared with literate individuals, illiterate elderly persons were at increased odds for responding negatively to the majority of SGDS-K items, including "having memory problems," "others are better off than me," and "feeling worthless" even after controlling for various demographic and clinical factors.
Conclusions: Illiteracy in elderly individuals was associated with a higher rate and increased severity of depression. Illiteracy negatively affected depression symptomatology, especially factors associated with self-esteem. Therefore, clinicians should carefully monitor for the presence of depression in illiterate elderly adults.