Association between total serum cholesterol and suicide attempts in subjects with major depressive disorder: Exploring the role of clinical and biochemical confounding factors

Objectives We tested whether serum total cholesterol levels might be associated with recent suicide attempts in subjects with major depressive disorder, after controlling for relevant individual characteristics. Design and methods We conducted a comparative cross-sectional study including consecutive inpatients with major depressive disorder. We differentiated subjects admitted for a recent serious (violent or non-violent) suicide attempt and those without such recent history. Total cholesterol was measured from fasting blood tests. Results At univariate analyses, suicide attempters had levels of total cholesterol (174.0 ± 45.7 mg/dL) lower than non-attempters (193.9 ± 42.6 mg/dL) (p = 0.004). This was confirmed among both violent (174.1 ± 46.2 mg/dL) and non-violent (173.8 ± 46.1 mg/dL) suicide attempters (p = 0.035 and 0.016, respectively). However, logistic regression analyses, sequentially including demographic, clinical (comorbid alcohol and personality disorders), and biochemical factors, did not show any association between serum cholesterol and recent suicide attempts (p = 0.172). Similar findings were observed in multinomial logistic regression analyses, for both violent (p = 0.512) and non-violent (p = 0.157) suicide attempts. Conclusions Our findings do not support the hypothesis that serum cholesterol and suicide attempts are associated among subjects with major depressive disorder. The identification of valid and accessible biological markers of suicidal behaviors still represents a challenge for future research.