Data support hypothesis that high-calorie intake early in life promotes germ cell tumor pathogenesis

Taller men may be at higher risk for testicular cancer, according to German researchers.

In a matched case-control study, Klaus-Peter Dieckmann, MD, of the Urologische Abteilung, Albertinen-Krankenhaus, Hamburg, and colleagues compared 6,415 men with germ cell tumors (GCTs) and a group of healthy-arm conscripts. Noting that the median height of German men aged 18-40 years ranges from 176 to 179 cm, the researchers established 175-179 cm as the reference group for the study.

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Compared with the reference group, men taller than 195 cm were at three times higher risk of GCT after adjusting for BMI, the researchers reported in the British Journal of Cancer (2008;99:1517-1521). Men 190-194 cm tall were at two times higher risk. Short stature appeared to be protective: Men less than 170 cm tall were at 20% lower risk.

“The association of tallness with testicular cancer risk lends much support to the nutrition hypothesis of GCT pathogenesis,” the authors stated.

According to this theory, high-calorie intake during early childhood promotes GCT precursors, Dr. Dieckmann’s group noted. Height is a biomarker for nutrition early in life because nutrition is the most important environmental factor affecting childhood growth, they said.

The new findings are in line with those of previous studies. For example, a Japanese study found a positive association between dairy products, specifically cheese, and testicular cancer, according to a report in the International Journal of Cancer (2002;98:262-267). Four case-control studies revealed a link between GCT risk and dairy-food consumption, but three others did not, they observed.

“Overall, direct evidence by controlled studies to support the nutrition hypothesis of GCT is scarce; however, the bulk of indirect evidence is clearly in favor of the hypothesis,” they wrote.

Dr. Dieckmann and his colleagues concluded that sufficient evidence now exists to acknowledge tallness as a recognized risk factor for testicular GCT.

Study strengths include the large sample size and a low likelihood of selection bias because patients were accrued nationwide by 228 participating institutions across Germany, the authors said. In addition, cases and controls were exactly matched by date of birth, ruling out confounding by age.

As for study weakness, the researchers noted that they controlled only for age and BMI, and anthropometric measures of case patients were mostly self-reported, whereas controls had precise measurements.