Genetic polymorphism in the manganese superoxide dismutase gene, antioxidant intake, and breast cancer risk: results from the Shanghai Breast Cancer Study

Table 3 Associations of breast cancer with the manganese superoxide dismutase polymorphism, stratified by lifestyle factors, in the Shanghai Breast Cancer Study

Stratified variable (by median)	MnSOD genotypes
	Val/Val		Val/Ala		Ala/Ala
	n ^a	OR^b (95% CI)	n ^a	OR^b (95% CI)	n ^a	OR^b (95% CI)
Premenopausal women
BMI
≤ Median	250/275	1.0 (ref.)	73/99	0.9 (0.6–1.2)	8/7	1.3 (0.5–3.7)
> Median	300/288	1.0 (ref.)	106/89	1.1 (0.8–1.6)	13/5	2.5 (0.9–7.0)
Years of menstruation^c
≤ Median	203/286	1.0 (ref.)	77/91	1.2 (0.8–1.7)	8/8	1.4 (0.5–3.7)
> Median	347/277	1.0 (ref.)	102/97	0.8 (0.6–1.2)	13/4	2.6 (0.8–8.0)
Postmenopausal women
BMI
≤ Median	126/156	1.0 (ref.)	39/52	1.0 (0.6–1.6)	4/7	0.7 (0.2–2.5)
> Median	152/161	1.0 (ref.)	46/50	1.0 (0.6–1.6)	3/4	0.8 (0.2–3.7)
Years of menstruation^c
≤ Median	128/172	1.0 (ref.)	44/54	1.1 (0.7–1.8)	2/6	0.4 (0.1–2.2)
> Median	150/145	1.0 (ref.)	41/48	0.8 (0.5–1.3)	5/5	1.0 (0.3–3.5)

^aNumber of cases/controls. ^bAdjusted for age. ^cYears of menstruation = menopausal age or age at interview for premenopausal women – menarche age. CI, confidence interval; MnSOD, manganese superoxide dismutase; OR, odds ratio; ref., reference.

ISSN: 1465-542X