Manganese superoxide dismutase Ala-9Val polymorphism and risk of breast cancer in a population-based case–control study of African Americans and whites

Table 1 Manganese superoxide dismutase (MnSOD) genotype and allele frequencies and odds ratios for breast cancer in African Americans and whites

MnSOD genotype and allele	Cases	Controls	Odds ratio (95% confidence interval)^a
African Americans	n = 760	n = 677
Genotype frequencies^b
Val/Val	259 (34%)	196 (29%)	Reference
Val/Ala	372 (49%)	357 (53%)	0.8 (0.6–1.0)
Ala/Ala	129 (17%)	124 (18%)	0.8 (0.6–1.1)
Cochran–Armitage trend test, P = 0.08
Val/Val or Val/Ala	631 (83%)	553 (82%)	Reference
Ala/Ala	129 (17%)	124 (18%)	0.9 (0.7–1.2)
Allele frequencies^c
Val	0.59 (0.56–0.61)	0.55 (0.53–0.58)
Ala	0.41 (0.39–0.44)	0.45 (0.42–0.47)
Chi-square test, P = 0.08
Whites	n = 1265	n = 1135
Genotype frequencies^b
Val/Val	273 (21%)	266 (23%)	Reference
Val/Ala	681 (54%)	586 (52%)	1.2 (0.9–1.4)
Ala/Ala	311 (25%)	283 (25%)	1.1 (0.8–1.4)
Val/Val or Val/Ala	954 (75%)	852 (75%)	Reference
Ala/Ala	311 (25%)	283 (25%)	1.0 (0.8–1.2)
Cochran–Armitage trend test, P = 0.59
Allele frequencies^c
Val	0.49 (0.47–0.51)	0.49 (0.47–0.51)
Ala	0.51 (0.50–0.55)	0.51 (0.49–0.53)
Chi-square test, P = 0.60

^a Adjusted for offsets and age. ^b Data presented as n (%). ^c Data presented as frequency (95% confidence interval).

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