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Early life events may affect testicular function in adulthood
Maternal smoking status, serum cord blood estrogen concentrations, and fetal and childhood growth patterns are likely associated with testicular function in adulthood, according to recent study findings.
“This study shows that optimal adult testicular function is associated with good intrauterine growth, without exposure to maternal smoking or higher concentrations of endogenous cord serum estrogens, and being delivered at term,” Roger J. Hart, MD, MRCOG, FRANZCOG, CREI, professor of reproductive medicine at the School of Women’s and Infants’ Health at the University of Western Australia, and colleagues wrote. “Optimal testicular function is also associated with good growth through childhood, with a normal BMI trajectory and a lean tissue mass, to become a tall adult.”
Hart and colleagues analyzed data from 423 men aged 20 to 22 years from the Western Australian Pregnancy Cohort (Raine), a pregnancy cohort study that began in 1989. Within the cohort, 404 men underwent testicular ultrasound imaging; 365 provided a semen sample; 384 underwent reproductive hormone measurements. Researchers analyzed available fetal growth measurements (n = 137), umbilical cord estrogen concentrations (n = 128), cord testosterone (n = 125) and child-adulthood growth charts (n = 395). Primary endpoints were sperm output and testicular volume at age 20 years.
Researchers found that men born to mothers who smoked during pregnancy (18.6%) had a lower mean sperm output vs. men born to nonsmoking mothers (82.4 x 10 sperm vs. 123.1 x 10 sperm; P = .029); total motile sperm count also was reduced in men born to smoking mothers vs. nonsmoking mothers (43.4 x 10 sperm vs. 67.3 x 10 sperm; P = .046).
Both sperm output and total motile sperm were associated with lower cord blood serum estradiol (P = .019; P = .035, respectively) and estrone (P = .018; P = .03, respectively) levels. Cord blood estradiol and estrone concentrations greater than the 50th percentile were associated with reduced sperm output (191.1 x 10 vs. 100.5 x 10; 190 x 10 vs. 106 x 10, respectively).
Researchers observed a positive association between favorable childhood growth pattern and testicular volume (P = .001) and a linear association between poor growth and increased odds of mean testicular volume less than 25th percentile (12.6 mL; P = .006). Men in the lowest tertile for height also had lower testicular volume vs. men in the middle and upper height tertiles, with median testicular volumes of 13.8 mL, 15.1 mL and 15.9 mL, respectively (P < .001).
BMI trajectories through childhood and adolescence were associated with larger testicular volume (P = .009), higher serum inhibin B (P = .01) and total testosterone (P = .003) in adulthood.
“A positive association with adult testicular function was determined for a child that is born at appropriate weight for gestational age and maintains a good growth during childhood and adolescence, without being under- or overweight,” the researchers wrote. – by Regina Schaffer
Disclosure: Hart is medical director of Fertility Specialists of Western Australia, reports having equity interests in IVF and also reports receiving grant support from Merck Sharp and Dohme, Merck-Serono and Ferring Pharmaceuticals. Please see the full study for the other authors’ relevant financial disclosures.