A prospective controlled study of the impact of hyperthyroidism on reproductive function in males.

The aim of this prospective controlled study was to ascertain the effect of hyperthyroidism on sperm quality and composition. We studied 23 thyrotoxic male patients, aged 43.8 +/- 2.4 yr (mean +/- SEM), and 15 healthy male controls of approximately the same age (42.2 +/- 2.2 yr). Two semen analyses at intervals of 2-3 wk were obtained before and about 5 months after euthyroidism was achieved either by methimazole alone (14 patients) or (131)I plus methimazole (9 patients). Total fructose, zinc (Zn), and magnesium (Mg) were also measured in seminal plasma in 16 patients, because 7 had semen volume less than 2 ml. In the control group semen analysis was performed only once. Mean (+/-SEM) semen volume was within normal range both in patients (3.3 +/- 0.2 ml) and controls (3.5 +/- 0.4 ml; P = NS). Mean sperm density was lower in patients, although the difference compared with controls did not reach statistical significance (35.7 +/- 5.3 vs. 51.5 +/- 6.1 x 10(6)/ml; P = 0.062). The same was found with sperm morphology (68 +/- 7% vs. 78 +/- 8%; P = NS). Finally, mean motility was lower in thyrotoxic males than in controls (28 +/- 8% vs. 57 +/- 7%; P < 0.01). After treatment, sperm density and motility improved [35.7 +/- 5.3 vs. 43.3 +/- 6.5 x 10(6)/ml (P = NS) and 28 +/- 8% vs. 45 +/- 7% (P < 0.05), respectively], but sperm morphology did not change (68 +/- 7% vs. 70 +/- 6%; P = NS). Mean values for fructose, Zn, and Mg did not differ between controls and patients either before or after achievement of euthyroidism [9.2 +/- 0.7, 3.0 +/- 0.5, and 4.2 +/- 0.7 nmol/liter vs. 8.6 +/- 0.9, 3.0 +/- 0.5, and 4.7 +/- 0.8 nmol/liter (patients before) and 9.1 +/- 0.7, 3.1 +/- 0.6, and 4.5 +/- 0.9 nmol/liter (patients after treatment) for fructose, Zn, and Mg, respectively]. Moreover, according to the treatment given, no statistically significant differences were found before or after treatment. Finally, seminal plasma fructose, Zn, and Mg levels did not correlate with sperm parameters or with pretreatment thyroid hormone levels. In conclusion, the results of our study indicate that male patients with hyperthyroidism have abnormalities in seminal parameters, mainly sperm motility. These abnormalities improve or normalize when the patients become euthyroid. Restoration of sperm parameters was independent of the treatment provided for the hyperthyroid syndrome. Moreover, seminal plasma elements, such as fructose, Zn, and Mg, did not correlate with sperm density, motility, or morphology.

Seminal volume and total sperm number trends in men attending subfertility clinics in the greater Athens area during the period 1977-1993.

The trends for such important parameters of male fertility as seminal volume and total sperm number were assessed in men living permanently in the Greater Athens area over a prolonged period of time. To this end, the records of three andrological laboratories employing the same method for semen evaluation were analysed retrospectively. Out of 23,850 men examined from 1977 to 1993 (17 years) for couple subfertility, a total of 2385 (10%) were selected for evaluation by a randomization procedure. Analysis of the data included (i) estimation of mean seminal volume and total sperm number per year, (ii) assessment of percentage frequency distribution of each seminal parameter and (iii) evaluation of seminal volume and total sperm number changes in relation to the year of observation and age of the subjects. A significant decrease (P < 0.01) of total sperm number was observed over the years with a mean (+/-SEM) of 154.3 +/- 19.2 x 10(6) at the beginning (1977), dropping to 130.1 +/- 13.3 x 10(6) in the final year (1993). Mean seminal volume was lower in the final year of observation, but its difference from the initial year value was not significant. Frequency distribution analysis showed a marked decline in the 240-400 x 10(6) sub-set of the range of sperm number values from 16.9 +/- 4.5% (1977) to 10.6 +/- 1.6% in the final year (P < 0.01). Multiple regression analysis of seminal volume, total sperm number, age and year of assessment revealed a significant decline of the two seminal parameters along the years of observation (P < 0.05 and P < 0.0001 respectively). Over the same period, a marked deterioration of some air pollution indices was observed in that area. It is concluded that in this racially and ethnically homogeneous sample of men, living under the same environmental conditions, a significant decline in seminal volume and total sperm number occurred over the 17 years of observation.