According to a study published in the International Journal of Cancer, boys born to higher-weight mothers may be more likely to develop testicular cancer.
Cancer of the testicles is the most common cancer in men 15-34 years old. The testicles are part of the male reproductive system and are located inside the scrotum (a loose sac of skin that lies directly under the penis). Sperm and male hormones are produced in the testicles. Testicular cancers were among the first types of cancers to be cured by radiation or chemotherapy. Currently, most patients with testicular cancer are cured. In western countries, the incidence of testicular cancer has increased since the 1950s.
Although the causes of testicular cancer are not fully understood, first-trimester exposure of the fetus to high levels of estrogen is thought to play a role. Boys born to higher-weight mothers are more likely to have been exposed to high estrogen levels than boys born to lower-weight mothers. Higher maternal weight results in higher insulin levels and lower levels of the protein that normally binds estrogen, resulting in higher levels of free estrogen that can cross the placenta and reach the fetus.
In order to assess the relationship between maternal weight and risk of testicular cancer in sons, researchers in Norway conducted a study of births between 1931 and 1955. They selected this time period because it spans World War II and represents a time when nutritional conditions in the country changed. The researchers assessed whether there was a relationship between the weight of women who gave birth during these years and the frequency of testicular cancer in men who were born during these years. They found that the frequency of testicular cancer increased as maternal weight increased.
The researchers conclude that increasing maternal weight may partially explain the increasing incidence of testicular cancer observed in several countries over the past few decades.
Reference: Aschim EL, Grotmol T, Tretli S et al. Is there an association between maternal weight and the risk of testicular cancer? An epidemiologic study of Norwegian data with an emphasis on World War II.