Table 2.

Tissue levels of zinc, selenium, calcium, and iron in cases and controls

Element[Tissue concentration (ng/cm2) / sulfur content (ng/cm2)] × 100
Median (interquartile range)
P*
Cases (n = 251)Controls (n = 249)
Zinc0.91 (1.04)0.81 (0.83)0.01
Selenium0.031 (0.027)0.027 (0.023)0.94
Calcium8.33 (18)7.48 (12)0.17
Iron2.38 (6.13)2.12 (4.36)0.04
  • * P values were derived from the Wilcoxon rank-sum test with normal approximation.