P–675 Endocrine disrupting toxic chemical affect the development of the male reproductive system but do not appear to affect the female reproductive system

Study question To assess whether geographical variations in oestrogenic disruptor contamination affect both sexes equally: on spermatogenesis and oogenesis. Summary answer There is a clear relationship between oligozoospermia and genital malformations dependent on the accumulation of endocrine disruptors in the mother, but not on ovarian reserve. What is known already Our Centre has conducted several population-based studies on semen quality, and have analysed the semen assessment and the medical history of 1,239 volunteers aged 18 to 30 years. The results showed a prevalence of oligozoospermia that was highest in Valencia (22.7%), Barcelona (22.7%) and the Basque Country (18.7%). These are the regions of Spain with the highest degree of industrialisation in the last 50 years. It was lowest in Galicia (8.5%) and Andalusia (13.7%), the regions with the least industry. Study design, size, duration This is a cross-sectional study with 10,443 healthy women aged between 20 and 45 years from eleven different communities in Spain. We determined AMH values for each age and in groups of 5 years. Linear regression analyses were used to calculate ovarian age Participants/materials, setting, methods All AMH values were assessed using an ELISA assay (AMH Gen II ELISA assay; Beckman Coulter, Brea, CA, USA). All samples were processed in the same central laboratory. Main results and the role of chance The mean age of the women was 36.6 years ± 4.3 years. Reference values for AMH, expressed as 25th, 50th, and 75th centiles by age and five year groups, were obtained. There were significant differences in AMH values between groups of women aged 30-<35 years, 35-<40 years, and 40–45 years. No significant differences were observed in AMH values in the first two age groups (20-<25 years, and 25-<30 years). The 50th centiles of mean AMH ranged from 3.45 to 0.72 ng/ml. AMH values were found to be significantly, and inversely, correlated to age (r = 0.35; p < 0.001). From the regression equation, the estimated yearly decrease in AMH was 0.2 ng/ml. The range of AMH values in Spanish women were higher than those reported for other European countries and the USA, and lower than those reported for China. Statistically significant differences were found between the results from different geographical areas but no pattern was found to justify them. It was hypothesised that in the more industrialised areas AMH levels should be lower and that this would correspond to the higher prevalence of oligozoospermia in male volunteers, but this was not the case. Limitations, reasons for caution The results for males were assigned to the geographical area where their mother was raised in all cases. For females, it was not possible to do so in all autonomous communities. Wider implications of the findings: These results suggest that oestrogenic disruptors stored in maternal fat interfere with the action of testosterone in the foetal testis inducing testicular dysgenesis syndrome. But it does not affect embryonic/fetal ovarian development, we propose that this is because higher oestrogen levels do not alter the process. Trial registration number Not applicable