The possible association between the risk of
kidney cancer development and the levels of
calcium and
magnesium in
drinking water from municipal supplies was investigated in a matched
cancer case-control study in Taiwan. All eligible
kidney cancer deaths (1778 cases) of Taiwan residents from 1999 through 2008 were compared with deaths from other causes (1778 controls), and the levels of
calcium and
magnesium in
drinking water of these residents were determined. Data on
calcium and
magnesium levels in
drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation (TWSC). The control group consisted of individuals who died from other causes, and the controls were pair-matched to the
cancer cases by gender, year of birth, and year of death. The adjusted odd ratios for death attributed to
kidney cancer for individuals with higher
calcium levels in their
drinking water, as compared to the lowest tertile, were 0.89 (95% CI = 0.72-1.11) and 0.78 (95% CI = 0.62-0.98), respectively. The adjusted odd ratios were not statistically significant for the relationship between
magnesium levels in
drinking water and
kidney cancer development. The results of the present study demonstrate that there may be a significant protective effect of
calcium intake from
drinking water against the risk of death due to
kidney cancer.