Thyroid Hormone Replacement Therapy Improves Olfaction and Taste Sensitivity in Primary Hypothyroid Patients: A Prospective Randomised Clinical Trial.

Smell and taste are known to be influenced by thyroid function changes. However, many hypothyroid patients and physicians are unaware of their dysosmia and dysgeusia. The present study was performed to shed more light on the relation between hypothyroidism and olfactory loss. 32 primary hypothyroid patients and 31 controls enrolled in the prospective randomized interventional study. Newly diagnosed Primary hypothyroid patients were treated with L-thyroxine for 3-6 months. The control group was selected on the basis of the biochemical evidence of a normal thyroid function. Psychophysiological olfactory testing was performed using odor dispensers similar to felt-tip pens ("Sniffin' Sticks", Burghart, Wedel, Germany). Taste function tests were made using "Taste Strips" (Burghart, Wedel, Germany) which are basically tastant adsorbed filter paper strip. Smell identification, threshold, discrimination, TDI scores, bitter and sweet taste scores were significantly lower in untreated hypothyroid patients compared to controls (12.31±1.09 vs. 14.03±1.05, p<0.001; 7.09±1.15 vs. 8.89±1.12, p<0.001; 11.47±0.95 vs. 13.06±0.85, p<0.001; 30.90±2.70 vs. 35.89±2.07, p<0.001; 4.88±1.6 vs. 6.64±0.96, p<0.001; and 5.5±2.22 vs. 6.58±1.28, p=0.021) respectively. Comparison of scores at the third month of treatment and before treatment of hypothyroid patients revealed significant improvement in smell and taste functions in terms of identification, threshold, discrimination, TDI scores, bitter, sweet and salty tastes (12.31±1.09 vs. 13.84±1.22, p<0.001; 7.09±1.15 vs. 8.02±1.16, p<0.001; 11.47±0.95 vs. 12.41±1.21, p<0.001; 30.90±2.70 vs. 34.27±3.25, p<0.001; 4.88±1.6 vs. 6.06±1.4, p<0.001; 5.5±2.22 vs. 6.38±1.28, p<0.001; and 6.12±2.32 vs. 6.62±1.48, p=0.044) respectively. On correlation analysis, there was a negative correlation between TPO-Ab levels and discrimination, identification and TDI scores (r=-0.409, p=0.02; r=-0.424, p=0.016; r=-0.532, p=0.002), and also between Tg-Ab levels and identification, TDI, and bitter scores (r=-0.423, p=0.016; r=-0.468, p=0.007; r=-0.409, p=0.02) respectively. Primary hypothyroidism was found to have a negative effect on smell and taste. RAI treatment was found to be most destructive on smell and taste compared to surgical and autoimmune hypothyroidism. Treatment of hypothyroidism was positively correlated with an improvement of both senses. Thus, the future workup of patients with smell/taste loss should include investigations for thyroid functions.

Trace Element Levels in Congenital Hypogonadotrophic Hypogonadism.

Cardiometabolic diseases are prevalent in hypogonadism. The pathophysiologic mechanism of increased cardiometabolic risk in hypogonadal patients is not clear. Recently, trace elements have been linked to the development of chronic disease especially cardiovascular disease. We investigated the trace element levels in an unconfounded population of congenital hypogonadotrophic hypogonadism (CHH) and also searched for the relationship with metabolic risk factors. A total of 89 patients with CHH (mean age 21.8 ± 2.0 years) and 80 healthy control subjects (mean age 21.3 ± 1.1 years) were enrolled. The demographic parameters, homeostatic model assessment of insulin resistance (HOMA-IR) levels and plasma zinc, copper, and selenium levels, were measured in patients and healthy controls. The patients had higher waist circumferences (p = 0.014), triglyceride (p = 0.04), insulin (p = 0.004), HOMA-IR levels (p = 0.001), and lower selenium (p = 0.049), zinc (p = 0.004), and copper (p = 0.012) levels when compared to the healthy controls. There was a significant relationship between zinc levels and HOMA-IR levels (p = 0.015). In the regression analysis, zinc levels were independently associated with the calculated HOMA-IR levels (p = 0.015). The results of the present study show that plasma selenium, zinc, and copper levels are decreased in patients with CHH. Also, plasma zinc levels are independently associated with insulin resistance in patients with hypogonadism. Long-term follow-up studies are warranted to investigate the effect of trace elements on the increased cardiometabolic risk in hypogonadism.

Osteoprotegerin, fibroblast growth factor 23, and vitamin D3 levels in male patients with hypogonadism.

Cardiometabolic disorders and osteoporosis are prevalent in patients with hypogonadism. Osteoprotegerin (OPG) and fibroblast growth factor-23 (FGF-23), are co-secreted from bones and vascular endothelium, regulating bone mineral metabolism and vascular functions. Vitamin D is another hormone with dual effects on bone and vascular metabolism. The aim of this study was to search for any difference between the serum levels of OPG, FGF-23, and vitamin D in patients with hypogonadism and the healthy controls. We also aimed to search for any relationship between these parameters and endothelial dysfunction or insulin resistance. Forty-nine male patients with congenital hypogonadotropic hypogonadism (CHH) (mean age 20.71 ± 1.75 years) and 43 BMI matched healthy male subjects (mean age 21.37 ± 1.04 years) were enrolled. OPG, FGF-23, vitamin D, and asymmetric dimethylarginine (ADMA) levels were measured from the fasting serum samples. The insulin sensitivity was estimated by homeostatic model assessment-insulin resistance (HOMA-IR) formula. Triglycerides, insulin, HOMA-IR, and ADMA levels in the patient group were significantly higher than the values of the control group (p = 0.014, p = 0.002, p = 0.003, p < 0.001, respectively). The OPG, FGF-23, and vitamin D levels of the patients were not significantly different from the healthy controls. In addition, these markers were not correlated to ADMA or HOMA-IR levels. The results show that young and treatment naive subjects with CHH have endothelial dysfunction and insulin resistance when compared to their healthy counterparts. However, the OPG, FGF-23, and vitamin D levels were similar in the 2 groups. In addition, these parameters are not significantly related to the endothelial functions or insulin resistance in these subjects.