Møller, H. 1998. Trends in sex-ratio, testicular cancer and male reproductive hazards: Are they connected? APMIS 106:232-239.

Møller analyzes recent trends in sex ratio in several Nordic countries documenting a significant decline in sex ratio from 1950 onward.

He then presents data from a Danish case-control study showing a strong association between testicular cancer, low fertility and an excess of females compared to males among offspring.

Observing the link between these syndromes and previously documented links between testicular cancer, low sperm counts and testicular abnormalities (Berthelsen and Skakkebæk 1983, Petersen et al. 1998), Møller concludes by suggesting that "decreasing sex-ratios in populations may be part of a scenario of increasing male reproductive hazards, possibly also comprising testicular cancer, male genital malformations and declining sperm quality. The specific agents that may have caused the observed trends remain to be identified, but agents that act prenatally to disrupt normal development and differentiation of the male reproductive organs may be particularly relevant."

Sex ratio decline: Møller shows that the sex ratio among live born infants in Denmark, Finland, Norway and Sweden has declined significantly since 1945. The change is very small in absolute terms, and according to Møller lacks any practical significance. It is, however, quite significant statistically and the fact that the trend is quite similar among these four countries, which maintain indepedent data sets, adds additional strength to the observation.

Møller's analysis of testicular cancer reveals large and significant increases in the rate since the establishment of cancer registers in 1960. All countries increased. The rate in Denmark is four times that in Finland.

There is strong evidence showing that this change through time is related to birth cohort, implicating an event in the womb as the causal agent (Møller 1993, Møller et al. 1996, Ekbom and Akre 1998 ). According to Møller, "current hypotheses link testicular cancer risk to exposure of the male embryo to maternal or environmental estrogens."

see a 2000 study linking testicular cancer to fetal and perinatal exposure to exogenous hormones

Møller links testicular cancer, male infertility and altered sex ratio through a case-control study in which men diagnosed previously with testicular cancer are interviewed and compared with randomly selected controls. The study examined a large number of risk factors.

This graph illustrates the number of children born to men diagnosed with testicular cancer up to two years prior to the TC diagnoses. Møller took this approach to avoid having fertility influenced directly by symptomatic disease or by treatment. As shown in the graph, "the age-specific cumulative fertilities of men who later developed testicular cancer were lower than in the controls, and the difference became progressively larger with increasing age."

Talk to us: email