Differential association of socio-economic status with gender- and age-defined suicidal ideation among adult and elderly individuals in South Korea

South Korea has the highest suicide rate among countries in the Organisation for Economic Co-operation and Development (OECD), with a rising trend that contrasts with the trend in most other OECD countries. This study assessed differential associations of socio-demographic factors with suicidal ideation in South Korea. We used five waves of data from the 2010 Korea National Health and Nutrition Examination Survey. Study subjects included 5803 men and women aged >25 years. We analysed weighted percentages with consideration of the complex survey sample design and unequal weights. Surveylogistic regressions were applied. Protective effects against suicidal ideation were found for higher household income, higher educational attainment, and being married. Functional limitations and depressive symptoms were risk factors for suicidal ideation. However, these significant factors may exert different effects on vulnerability for suicidal ideation among different genders and age groups. Thus, household income was mainly protective for women and subjects aged 25–44 years, and educational attainment was protective for individuals aged >65 years. Our findings suggest the need for extended social protection policies for the less privileged population and special strategies for different groups.