Association of Endogenous Seminal L-Carnitine Levels with Post-Thaw Semen Parameters in Humans

Table 1

Correlations between levels of endogenous seminal L-carnitine (n = 125; µg/ml) and background characteristic values.

Variable	n	Median (min–max)	Unadjusted		Adjusted for semen volume
			r	p	r	p
Age (years)^a	125	35 (23–57)	0.013	0.895	−0.062	0.531
BMI (kg/m^2)^b	113	24.7 (17.4–40.2)	−0.116	0.221	−0.029	0.761
Sexual abstinence (days)^b	125	3 (1–7)	0.069	0.484	0.139	0.158
Semen volume (ml)^b	125	4 (1–8)	−0.415	<	—
Sperm concentration (10^6/ml)^b	125	38 (5–239)	0.695	<	0.672	<
Total sperm count (10^6)^b	125	126 (14–521)	0.496	<	0.672	<
Rapid progressive sperm motility (a, %)	110	25 (2–55)	0.356	<	0.415	<
Progressive sperm motility (a + b, %)	110	40 (11–63)	0.238		0.295
Total sperm motility (a + b + c, %)	110	51 (18–74)	0.178	0.067	0.246
Immotile sperm (d, %)^b	110	50 (26–82)	−0.178	0.069	−0.246
Sperm vitality (%)^c	125	61 (19–88)	0.194	0.047	0.210	0.032
Normal sperm morphology (%)^b	120	8 (1–32)	0.099	0.311	0.089	0.368
Sperm head defects (%)^d	120	88 (56–99)	−0.076	0.437	−0.083	0.403
Spem neck midpiece defects (%)	120	28 (3–55)	−0.058	0.554	−0.091	0.358
Sperm principal piece defects (%)^b	120	12 (3–31)	−0.160	0.102	−0.145	0.139
Fragmented sperm DNA (%)^a	125	15 (2–88)	−0.150	0.126	−0.189	0.054
Seminal sORP (mV)^b	124	41 (3–172)	0.004	0.965	0.046	0.640

BMI, body mass index; sORP, static oxidation-reduction potential; r, correlation coefficient. p values ≤ 0.01 were considered statistically significant. Pearson’s correlation analysis was used to determine correlation between levels of endogenous L-carnitine in seminal plasma and semen parameters. Pearson’s partial correlation analysis was used for adjusted data. Data are presented as unadjusted and adjusted for semen volume. All variables were continuous. ^aLog-transformed variables. ^bSquare-root transformed variables. ^cPower transformed variables. ^dCubic transformed variables.