The Association Among Serum Growth Differentiation Factor 15 Level and Suicidal Ideation is Dependent on Testosterone Deficiency in Depressive Patients

Figures & data

Table 1 Patient Characteristics

Characteristic	Testosterone <314 ng/dL		Testosterone ≥314 ng/dL
	With Suicidal Ideation (n=67)	Without Suicidal Ideation (n=84)	With Suicidal Ideation (n=53)	Without Suicidal Ideation (n=97)
Age (years)	47 (25–65)	43 (28–63)	39 (22–59)	46 (28–62)
BMI (kg/m^2)	21.76 (18.92–23.76)	20.47 (17.45–22.94)	18.93 (16.96–24.52)	20.68 (17.84–23.79)
TC (mmol/L)	4.13 (2.67–7.56)	4.02 (2.45–6.87)	3.97 (2.78–7.01)	4.21 (2.55–6.84)
TG (mmol/L)	1.58 (0.84–2.27)**	1.05 (0.76–1.95)	1.44 (0.79–2.19)*	1.16 (0.94–2.23)
HDL-c (mmol/L)	1.09 (0.93–1.38)**	1.42 (0.89–1.85)	1.13 (0.89–1.41)*	1.37 (1.01–1.75)
LDL-c (mmol/L)	2.36 (1.45–3.17)	2.29 (1.62–2.86)	2.31 (1.62–3.01)	2.23 (1.46–2.82)
Lp(a) (mg/L)	201.36 (128.02–295.42)	189.33 (104.37–304.28)	218.53 (112.93–316.39)	204.12 (95.47–295.43)
hsCRP (mg/L)	2.58 (1.08–5.04)**	1.79 (1.18–3.72)	2.25 (0.99–4.72)*	1.75 (1.06–4.28)
FT3 (pg/mL)	3.08 (1.47–5.93)	3.14 (1.52–5.45)	3.19 (1.48–4.92)	3.11 (1.08–4.78)
FT4 (ng/dL)	1.32 (0.79–1.63)**	1.17 (0.82–1.85)	1.28 (0.84–1.79)*	1.09 (0.79–1.88)
TSH (uIU/mL)	1.43 (0.79–2.13)*	1.97 (0.97–2.87)	1.52 (0.82–2.28)*	1.87 (0.96–2.21)
Glucose (mmol/L)	5.02 (4.03–6.16)	5.09 (4.15–5.89)	5.11 (4.11–6.02)	5.07 (4.47–5.84)
Duration of depression (year)	2.13 (0.56–5.03)*	1.24 (0.36–4.27)	1.97 (0.44–4.48)*	1.32 (0.41–4.03)
Current smoking	35 (52.23)	41 (48.81)	35 (66.04)	56 (57.73)
Current alcohol consumption	21 (31.34)	33 (39.29)	21 (39.62)	37 (38.14)
Anti-depressant therapy	39 (58.21)*	22 (26.19)	33 (62.26)*	31 (31.94)

Notes: Values are n (%) or median (interquartile range). Compared with patients without suicidal ideation, *P<0.05, **P<0.01.

Abbreviations: BMI, body mass index; TC, total cholesterol; TG, triglyceride; HDL-c, high-density lipoprotein cholesterol; LDL-c, low-density lipoprotein cholesterol; Lp(a), Lipoprotein(a); hs-CRP, high-sensitivity C-reactive protein; FT3, free triiodothyronine; FT4, free thyroxine; TSH, thyroid-stimulating hormone.

Figure 1 Tukey plot comparing serum GDF-15 levels between patients with or without suicidal ideation.

Abbreviations: GDF-15, growth differentiation factor (GDF)-15; T, testosterone.

Table 2 Univariate and Multivariate Logistic Regression to Identify Factors Associated with Low Testosterone

Variable	Univariate			Multivariate
	OR	95% CI	P	OR	95% CI	P
Age	1.062	0.953–1.103	0.129
BMI	1.183	0.916–1.394	0.285
TC	1.051	0.887–1.396	0.317
TG	1.692	1.205–2.671	0.000	1.542	0.933–2.051	0.215
HDL-c	0.447	0.102–0.875	0.004	0.572	0.117–0.932	0.009
LDL-c	1.562	0.992–2.183	0.572
Lp(a)	0.932	0.827–1.436	0.361
hsCRP	1.105	1.024–1.562	0.014	1.057	0.873–1.657	0.226
FT3	0.673	0.219–0.965	0.006	0.772	0.336–1.014	0.451
FT4	0.329	0.184–1.163	0.417
TSH	0.782	0.418–0.972	0.000	0.673	0.375–0.991	0.014
Glucose	1.426	0.893–2.107	0.219
Duration of depression	0.762	0.395–1.301	0.527
Current smoking	1.306	0.707–1.946	0.225
Current alcohol consumption	0.956	0.672–1.548	0.362
Anti-depressant therapy	1.062	0.783–1.422	0.421
GDF-15	1.217	1.007–1.753	0.000	1.107	1.002–1.683	0.001

Abbreviations: BMI, body mass index; TC, total cholesterol; TG, triglyceride; HDL-c, high-density lipoprotein cholesterol; LDL-c, low-density lipoprotein cholesterol; Lp(a), Lipoprotein(a); hs-CRP, high-sensitivity C-reactive protein; FT3, free triiodothyronine; FT4, free thyroxine; TSH, thyroid-stimulating hormone; OR, odds ratio; CI, confidence interval.

Table 3 Multivariate Regression to Identify Factors Associated with Serum GDF-15 Levels in Patients with Depression

Variable	Standardized β	t	P
HDL-c	−0.318	5.273	0.005
TSH	−0.267	4.093	0.013
Testosterone	−0.484	7.892	0.000

Abbreviations: HDL-c, high-density lipoprotein cholesterol; TSH, thyroid-stimulating hormone.

Table 4 Associations Between Serum GDF-15 and Suicidal Ideation in Patients with Depression

Groups	OR	95% CI	P
All patients
Unadjusted	0.782	0.492–1.105	0.372
Adjusted	0.815	0.439–1.152	0.417
Patients with testosterone ≥314 ng/dL
Unadjusted	1.106	0.874–1.782	0.218
Adjusted	1.206	0.905–1.864	0.269
Patients with testosterone <314 ng/dL
Unadjusted	1.452	1.078–2.062	0.003
Adjusted	1.338	1.062–1.995	0.007

Abbreviations: CI, confidence interval; OR, odds ratio.