@article {168148,
	title = {Serum L-carnitine and vitamin D levels may be low among oral sildenafil citrate non-responders.},
	journal = {International journal of impotence research},
	volume = {31},
	year = {2019},
	month = {2019 Mar},
	pages = {85-91},
	abstract = {<p>This cross-sectional comparative study aimed to compare serum L-carnitine and 25(OH)D levels between men with ED non-responding for oral sildenafil citrate and healthy volunteers. Overall, 192 men, recruited from two University Hospitals, were allocated into two equal groups of matched age; healthy potent men and men with ED non-responders for oral sildenafil citrate. Oral sildenafil citrate non-responders self-reported inadequate erectile responses after four attempts using 100 mg with the manufacturer{\textquoteright}s guidelines relative to meals, associated medications, and sexual stimulation/arousal. Exclusion criteria were: diabetes, cardiovascular disorders, beta blockers treatment, morbid obesity, thyroid disorders, post-radical prostatectomy, and hepatic/renal failure. All participants were subjected to; history taking, clinical examination, validated IIEF-5 questionnaire, estimation of serum L-carnitine by calorimetric method and serum 25(OH)D by ELISA method. Compared with potent controls, ED men non-responders for oral sildenafil citrate showed significant decreases in the mean serum L-carnitine level (16.8 {\textpm} 3.6 uM/L versus 66.3 {\textpm} 11.9 uM/L, P = 0.001), the mean serum 25(OH)D level (21.2 {\textpm} 7.1 ng/ml versus 54.6 {\textpm} 7.9 ng/mL, P = 0.001) and IIEF-5 score (7.8 {\textpm} 2.6 versus 23.9 {\textpm} 1.3). Serum L-carnitine showed significant positive correlation with IIEF-5 scores (r = 0.873, P = 001), serum 25(OH)D (r = 0.796, P = 0.001) and significant negative correlation with the age (r = -0.515, P = 0.001). Serum 25(OH)D showed significant positive correlation with IIEF-5 scores (r = 0.855, P = 0.001) and significant negative correlation with the age (r = -0.223, P = 0.005). It is concluded that normal homeostasis of serum L-carnitine and 25(OH)D play a role in male sexual health being significantly decreased in ED non-responding for oral sildenafil citrate.</p>
},
	issn = {1476-5489},
	doi = {10.1038/s41443-018-0036-4},
	author = {Taymour Mostafa and Laila A. Rashed and Sabry, Dina A and Osman, Ihab and Nabil, Nashaat and Kareem, Firas and Mostafa, Ingi A}
}
