High or Low Vitamin D Levels Increase Prostate Cancer Risk

The findings were reported in the January 1, 2004, issue of the International Journal of Cancer.

Researchers used data from serum samples of more than 200,000 Nordic subjects, identifying 622 prostate cancer cases and comparing them to 1,451 matched controls. The results showed that both low (< 19 nmol/l) and high (> 80 nmol/l) concentrations of vitamin D were associated with an increased risk of prostate cancer. The lowest risk was found in men with average serum concentrations of 40-60 nmol/l.

The researchers note that no other experimental data support the idea that high concentrations of vitamin D can enhance the development of cancer. Quite the opposite result has been found in many studies, which is that as vitamin D concentrations increase, so do the beneficial effects. Thus, the current results are puzzling. One possible explanation given by the researchers is that both low and high concentrations may cause an imbalance, so that vitamin D is not able to control mitotic activity.

The researchers caution that although synthetic vitamin D derivatives are recommended for cancer prevention because of their low calcemic effects, they are inactivated slowly in the living organism and thus may increase vitamin D exposure. They suggest that other studies are needed. The research was led by Dr. Pentti Tuohimaa, of the University of Tampere Medical School (Tampere, Finland) and colleagues from Finland, Sweden, and Norway.




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