Early life events predict adult testicular function; data derived from the Western Australian (Raine) birth cohort

CONTEXT: The impact of early life events on testicular function in adulthood is not well understood.

OBJECTIVE: To study the early influences of fetal growth, exposures to cigarette smoke in-utero and cord blood estrogens, and the influences of growth and adiposity in childhood through adolescence; on testicular function in adulthood.

DESIGN: Male members of the Western Australian Pregnancy Cohort (Raine) were contacted at 20-22 years of age. Of 913 contacted 423 (56%) agreed to participate; 404 underwent a testicular ultrasound, 365 provided a semen sample and reproductive hormones were measured (384). Fetal growth measurements (n=137), umbilical cord estrogen concentrations (n=128), cord testosterone (n=125), and child-adulthood growth charts (n=395) were available.

RESULTS: Median sperm output for the 18.6% of men exposed in-utero to smoking was lower than non-exposed (82.4x10(6) vs 123.1x10(6), p=0.029). Sperm output in adulthood was inversely correlated with cord serum oestradiol(p=0.019) and estrone (p=0.018). The sperm output of men whose cord blood estradiol and estrone were <50th centile vs >50th centile was 191.1x10(6) vs 100.5x10(6) (p=0.002) and 190.0x10(6) vs 106.0x10(6) (p=0.012) respectively. Men with favorable fetal growth patterns in-utero were less likely to have total motile sperm counts (TMS) within the lowest quartile (p=0.011), and men born prematurely had reduced serum testosterone levels in adulthood, (13.4 vs 16.6nmol/L, p=0.024). Consistent height above the 50th centile for age through childhood was associated with larger adult mean testicular volume (TV) (p<0.001). Optimal BMI trajectory through childhood and adolescence was associated with larger TV (p=0.009), and higher serum inhibin B (p=0.010) and testosterone (p=0.003) in adulthood.

CONCLUSIONS: Exposures to maternal smoking and higher cord blood estrogens at delivery were associated with a reduced sperm output in adulthood. Optimal adult testicular function depends on being born at or above average weight, and maintaining optimal growth and adiposity into adulthood.