Background:Research on suicide rarely focuses on protective factors. The goal of this systematic review was to assess the evidence of the associations between protective factors and reduced suicidality among older adults.Method:First, a scoping review was conducted to identify pertinent terms that refer to various protective factors against suicidality. A systematic review, following the PRISMA guidelines, was then conducted on a selection of 15 protective factors (e.g., perceived control, well-being and quality of life, life satisfaction, purpose-in-life, resilience, coping, religiosity, hope, self-regulation, sense of belonging, mattering, positive relationship, social support, social connectedness, and social participation), with separate searches performed on each factor in five databases. Empirical studies were eligible if participants were adults aged 60 years and over, and if the studies reported predictive statistical analysis.Results:A total of 70 studies were retained for the review. Suicidal ideation was the main outcome measure (91%). Significant associations were consistently observed between all protective factors and reduced suicidal ideations or behaviors, particularly for purpose-in-life, resilience, and positive relationships, indicating that these are solid components for suicide prevention. Using scales, instead of a single item, to measure protective factors (e.g. life satisfaction) was more efficient to capture the associations. On the other hand, results were similar whether studies used subjective (e.g., sense of belonging) or objective (e.g., social connectedness) measures.Conclusion:Protective factors were inversely associated with suicidal ideation. Improving protective factors is essential for the development of late-life suicide prevention and interventions, instead of merely focusing on risk factors.

Research has shown the effects of climatic factors on shigellosis; however, no previous study has evaluated climatic effects in regions with a winter seasonality of shigellosis incidence. We examined the effects of temperature and precipitation on shigellosis incidence in Korea from 2002–2010. The incidence of shigellosis was calculated based on data from the Korean Center for Disease Control and Prevention (KCDC, Cheongju, Korea), and a generalized additive model (GAM) was used to analyze the associations between the incidence and climatic factors. The annual incidence rate of shigellosis was 7.9 cases/million persons from 2002–2010. During 2007–2010, high incidence rates and winter seasonality were observed among those aged ≥65 years, but not among lower age groups. Based on the GAM model, the incidence of shigellosis is expected to increase by 13.6% and 2.9% with a temperature increase of 1 °C and a lag of two weeks and with a mean precipitation increase of 1 mm and a lag of five weeks after adjustment for seasonality, respectively. This study suggests that the incidence of shigellosis will increase with global climate change despite the winter seasonality of shigellosis in Korea. Public health action is needed to prevent the increase of shigellosis incidence associated with climate variations.

Precarious employment and unemployment are important factors that impact suicidal behavior. This study investigated (1) how employment transitions among permanent employment, precarious employment, and unemployment are associated with suicidal ideation in working employees and compared (2) whether individuals transitioning among these three states were more vulnerable than those remaining. Using nationally representative longitudinal data between 2012–2017, a total of 25,862 adults aged 25 to 59 years old without a record of suicidal ideation were included at baseline. Transitions in employment status (permanent work, precarious work, or unemployment) and suicidal ideation were analyzed using hierarchical logistic regression models. Compared to the “permanent to permanent” group, individuals in the “permanent to precarious” (odds ratio (OR) 1.74, 95% confidence interval (95% CI) 1.29–2.35], “permanent to unemployment” (OR 1.97, 95% CI 1.32–2.96), “precarious to precarious” (OR 1.86, 95% CI 1.21–2.85), and the “precarious to unemployment” (OR 1.43, 95% CI 1.05–1.95) groups had higher odds of suicidal ideation. The magnitude of such odds was generally higher than that of individuals at annual unemployment or precarious states. The results show that adults moving in and out of different employment states have higher odds of suicidal ideation than individuals at annually static precarious or unemployment status.

Although the effects of age, period, and cohort (APC) on suicide are important, previous work in this area may have been invalid because of an identification problem. We analyzed these effects under three different scenarios to identify vulnerable groups and thus overcame the identification problem. We extracted the annual numbers of suicides from the National Death Register of Korea (1992–2015) and estimated the APC effects. The annual average suicide rates in 1992–2015 were 31.5 and 14.7 per 100,000 males and females, respectively. The APC effects on suicide were similar in both sexes. The age effect was clearly higher in older subjects, in contrast to the minimal changes apparent during earlier adulthood. The birth cohort effect showed an inverted U shape; a higher cohort effect was evident in females born in the early 1980s when period drift was larger than 3.7%/year. Period effect increased sharply during the early 1990s and 2000s. We found that elderly and young females may be at a particularly high risk of suicide in Korea.