Stress-related salivary biomarkers - cortisol, dehydroepiandrosterone, alpha amylase, and suicidal ideation among young women living in Kampala's informal settlements.
BACKGROUND Young women living in informal urban settlements experience intersecting structural disadvantages that may contribute to stress-related physiological changes and suicidal ideation. Evidence on salivary stress biomarkers in this population remains limited. OBJECTIVE To examine associations between salivary cortisol, dehydroepiandrosterone (DHEA), α-amylase, the cortisol-to-DHEA ratio, and suicidal ideation among young women in Kampala's informal settlements. METHODS This cross-sectional analysis included 300 women aged 18-24 years recruited from three informal settlements in Kampala, Uganda. Suicidal ideation was assessed using four items from the Columbia-Suicide Severity Rating Scale. Morning and afternoon salivary biomarkers were measured using COBAS E411 and C-111 analyzers. Independent-samples t-tests compared biomarker levels by suicidal ideation status, and modified Poisson regression examined adjusted associations. The final model was used to estimate the prevalence ratio (PR) and its 95% confidence interval (CI). RESULTS Overall, 46.0% reported suicidal ideation and 57.7% met the threshold for probable depression. Approximately 39% had DHEA values below published reference ranges at both collection times. Participants reporting suicidal ideation had lower square root-transformed morning DHEA levels than those without ideation (3.96 vs. 4.65; p = 0.048) and higher square root-transformed morning cortisol-to-DHEA ratios (1.19 vs. 1.00; p = 0.027). In the adjusted model, each one-unit increase in the square root-transformed morning cortisol-to-DHEA ratio was associated with a 12% higher prevalence of suicidal ideation (PR = 1.12; 95% CI: 1.04-1.21). CONCLUSION Suicidal ideation was common, and square root-transformed morning cortisol-to-DHEA ratios were independently associated with suicidal ideation. These findings highlight the importance of understanding suicidality through integrated biological, psychological, and social perspectives and reinforce the need for accessible, gender-responsive suicide prevention and mental health services in low-resource urban settings.