Can low brain-derived neurotrophic factor levels be a marker of the presence of depression in obese women?

Figures & data

Table 1 Clinical assessments and laboratory findings in obese, preobese, and control groups

Parameters	Control group (n=40)	Preobese group (n=40)	Obese group (n=40)
Age (years)	34.79±11.18	31.65±11.54	36.26±9.68
BMI (kg/m^2)	23.35±1.04	27.86±1.28a,***	34.47±3.27b,***,c,***
WHR (Gw/Gh)	0.81±0.04	0.86±0.07a,**	0.86±0.07b,**
BDI	8.34±2.00	10.62±5.02	15.05±7.75b,***,c,**
BAI	5.00 (3.00–10.00)	7 (1.00–20.00)	8 (0–39)
MMSE	27 (22.00–30.00)	26.00 (24–30)	26.50 (20–30)
BDNF (pg/mL)	119.75 (85.00–188.58)	115.64 (55.68–165.00)	95.75 (42.84–158.06)b,**
Glucose (mg/dL)	93 (68.00–124.00)	91 (82.00–166.00)	99.00 (83.00–132.00)c,**
Trig (mg/dL)	108 (35.00–339.00)	95 (40–292)	122.00 (45.00–295.00)
T chol (mg/dL)	195 (145.00–265.00)	187 (134–306)	192.00 (149.00–265.00)
HDL (mg/dL)	45 (26.00–79.00)	53 (25–95)	50 (34–78)
LDL (mg/dL)	114 (70.00–199.00)	102 (65–192)	114.5 (62–191)
TSH (mIU/mL)	1.87 (0.94–4.28)	2.39 (0.03–5.18)	2.34 (0.71–6.56)
FT3 (pg/mL)	3.44 (2.14–4.29)	3.22 (2.82–4.19)	3.19 (2.64–4.04)b,*
FT4 (ng/dL)	1.25 (0.85–1.48)	1.18 (1.00–1.42)	1.17 (0.88–1.39)
Vit B12 (pg/mL)	336.10 (154.9–740.50)	306 (174.8–759.60)	309.7 (133.7–465.2)
Folic acid (ng/mL)	7.63 (4.60–15.45)	7.79 (5.14–17.17)	8.94 (5–17.01)
Insulin (μlU/mL)	7.75 (3.47–13.48)	11 (5.98–23.19)a,***	12.19 (6.5–29.77)b,***
CRP (mg/L)	2.20 (0.20–8.00)	3 (0.6–12.6)	3.75 (1–14.5)b,**
HbA1c (%)	5.20 (4.10–6.30)	5.3 (3.0–7.30)	5.5 (5–6)b,*
HOMA	1.24 (0.62–2.49)	2.32 (1.21–5.98)a,***	3 (1.48–7.06)b,***

Notes:

* P<00.05

** P<0.01

*** P<0.001

a preobese vs control

b obese vs control

c obese vs preobese. Normally distributed data are presented as mean ± SD, non-normally distributed data are presented as median (minimum-maximum).

Abbreviations: BAI, Beck Anxiety Inventory; BDI, Beck Depression Inventory; BDNF, brain-derived neurotrophic factor; BMI, body mass index; CRP, C-reactive protein; Gw/Gh, waist girth/hip girth; FT3, free triiodothyronine; FT4, free thyroxine; HbA1c, glycated hemoglobin; HDL, high-density lipoprotein; HOMA, homeostatic model assessment; LDL, low-density lipoprotein; MMSE, mini-mental state examination; SD, standard deviation; T chol, total cholesterol; Trig, triglycerides; TSH, thyroid-stimulating hormone; Vit, vitamin; WHR, waist-to-hip ratio.

Table 2 Laboratory findings of obese patients with and without depression

Parameters	Obese nondepression (n=24)	Obese depression (n=16)	P-value
Age (years)	30.9±7.48	38.82±9.6	0.023*
BMI (kg/m^2)	33.68±2.88	34.84±3.44	0.312
MMSE	27.9±3.39	25.7±2.7	0.095
BDNF (pg/mL)	114.27±37.5	85.62±27.34	0.047*
Vitamin B12 (pg/mL)	359.22±97.32	287.83±79.26	0.026*
Folic acid (ng/mL)	9.77±4.17	9.08±3.06	0.365

Note:

* P<0.05.

Abbreviations: BDNF, brain-derived neurotrophic factor; BMI, body mass index; MMSE, mini-mental state examination.

Table 3 Correlation of the Beck Depression Inventory in the obese group with six factors by linear regression analysis

	Regression coefficient	Standard error	P-value
Constant	19.447	8.644	0.033
Beck Anxiety Inventory	0.643	0.054	0.000
BDNF	−0.044	0.016	0.009
FT4	12.873	3.697	0.002
Vitamin B12	0.023	0.006	0.000
Insulin	0.257	0.100	0.016
MMSE	−1.219	0.171	0.000

Notes: A linear regression analysis was used to examine correlation of the Beck Depression Inventory in the obese group with six factors that had a significant correlation by a simple regression analysis. P<0.05 is considered to be statistically significant.

Abbreviations: BDNF, brain-derived neurotrophic factor; MMSE, mini-mental state examination; FT4, free thyroxine.

Table 4 Correlation of the Beck Depression Inventory in the preobese group with seven factors by linear regression analysis

	Regression coefficient	Standard error	P-value
Constant	−1.328	3.292	0.019
Beck Anxiety Inventory	0.760	0.092	0.000
BDNF	−0.056	0.011	0.000
Total cholesterol	−0.027	0.010	0.014
TSH	−1.372	0.350	0.001
Vitamin B12	0.018	0.003	0.000
Folic acid	1.072	0.162	0.000
Insulin	0.470	0.113	0.000

Notes: A linear regression analysis was used to examine correlation of the Beck Depression Inventory in the preobese group with seven factors that had a significant correlation by a simple regression analysis. P<0.05 is considered to be statistically significant.

Abbreviations: BDNF, brain-derived neurotrophic factor; TSH, thyroid-stimulating hormone.

Table 5 Distribution of four parameters from the ROC analysis in obese patients with depression

Variables	AUC	Std error	P-value	95% CI for AUC
				LB	UB
BDNF	0.756	0.103	0.025	0.553	0.958
Vitamin B12	0.547	0.117	0.682	0.318	0.775
BMI	0.602	0.111	0.369	0.384	0.820
Age	0.678	0.106	0.118	0.470	0.886

Note: P<0.05 is considered to be statistically significant.

Abbreviations: AUC, area under the curve; BDNF, brain-derived neurotrophic factor; BMI, body mass index; CI, confidence interval; LB, lower bound; ROC, receiver operating characteristics; Std, standard; UB, upper bound.