TABLE 1.

The association between selenium status and epithelial cell apoptosis within the prostate.

	Selenium Status1
	Low (<0.67 ppm)	Moderate (0.67–0.92 ppm)	High (>0.92 ppm)
Toenail selenium concentration (ppm)
Range	0.43–0.66	0.67–0.88	0.94–1.22
Mean	0.56	0.76	1.03
Number of dogs2	23	26	12
Mean apoptotic index3	1.0 ± 1.3	2.6 ± 3.1*	2.2 ± 2.1
Likelihood of apoptotic hot spots4
Odds Ratio (95% CI)5	1.0 (reference)	4.1 (1.1–15.3)**	1.6 (0.3–8.6)

¹Selenium concentration in toenails of dogs in low, moderate and high selenium groups are equivalent to plasma concentrations of <100, 100–137, >137 μg/L, respectively, using the equation: plasma selenium (μg/L) = toenail selenium (ppm)/0.0067 (Waters et al. 2005). Rationale for using these cut-points is described in Data Analysis section of Materials and Methods.

²Complete information on explanatory and response variables was available for 61 of 69 dogs.

³Apoptotic index was defined as the median number of cells with positive nuclear staining per 200X microscopic field.

⁴Apoptotic hot spots were defined as regions of prostate acini in which there were >30 apoptotic cells per 200X microscopic field.

⁵Odds ratios are considered significant if 95% confidence interval (CI) does not include 1.0.

^*Different from the low selenium group, P = 0.025

^**Different from the low selenium group, P = 0.04