Table 2.

Comparison of metal levels in toenails measured at baseline versus 4–10 years later; Sister Study (2003–2009). All cases were breast cancer free at baseline.

Metal	Overall (n=221)		Controls (n=110)		Cases (n=111)		Mean differencea	95% CI
	Spearman R	95% CI	Spearman R	95% CI	Spearman R	95% CI
Arsenic	0.40	(0.28, 0.50)	0.37	(0.20, 0.52)	0.42	(0.25, 0.56)	−0.04	(−0.10, 0.01)
Cadmium	0.38	(0.26, 0.49)	0.36	(0.19, 0.51)	0.40	(0.23, 0.54)	−0.19	(−0.24, −0.13)
Cobalt	0.34	(0.22, 0.45)	0.46	(0.30, 0.59)	0.24	(0.05, 0.41)	−0.05	(−0.11, 0.01)
Chromium	0.23	(0.10, 0.35)	0.29	(0.11, 0.45)	0.19	(0.01, 0.37)	−0.18	(−0.25, −0.10)
Copper	0.54	(0.44, 0.62)	0.59	(0.45, 0.70)	0.49	(0.34, 0.62)	−0.003	(−0.02, 0.02)
Iron	0.40	(0.28, 0.51)	0.45	(0.29, 0.59)	0.36	(0.18, 0.51)	−0.03	(−0.08, 0.03)
Mercury	0.71	(0.63, 0.77)	0.74	(0.64, 0.82)	0.67	(0.55, 0.76)	−0.07	(−0.12, −0.01)
Manganese	0.41	(0.29, 0.51)	0.46	(0.30, 0.60)	0.37	(0.19, 0.52)	−0.10	(−0.18, −0.01)
Molybdenum	0.35	(0.23, 0.46)	0.25	(0.06, 0.42)	0.45	(0.29, 0.59)	−0.07	(−0.12, −0.01)
Nickel	0.20	(0.07, 0.32)	0.40	(0.23, 0.54)	−0.02	(−0.21, 0.16)	−0.16	(−0.28, −0.03)
Lead	0.47	(0.36, 0.57)	0.42	(0.25, 0.56)	0.52	(0.37, 0.64)	−0.28	(−0.34, −0.22)
Antimony	0.18	(0.05, 0.31)	0.23	(0.04, 0.40)	0.12	(−0.07, 0.30)	−0.01	(−0.08, 0.05)
Selenium	0.58	(0.48, 0.66)	0.65	(0.53, 0.75)	0.51	(0.35, 0.63)	−0.002	(−0.02, 0.01)
Tin	0.26	(0.14, 0.38)	0.21	(0.02, 0.38)	0.24	(0.06, 0.41)	−0.04	(−0.10, 0.02)
Vanadium	0.45	(0.34, 0.55)	0.41	(0.24, 0.56)	0.49	(0.33, 0.62)	−0.05	(−0.12, 0.01)
Zinc	0.64	(0.55, 0.71)	0.66	(0.54, 0.76)	0.62	(0.49, 0.72)	0.01	(−0.00, 0.02)

CI: Confidence Interval

^aComparing log₁₀ metal levels from toenails collected at the first versus second time points

log₁₀ metal level time 2 – log₁₀ metal level time 1