TABLE 2.

Association of income quintile areas with breast cancer 5-year survival in Winnipeg, Manitoba and Des Moines, Iowa: Women were diagnosed from 1984 to 1992 and followed-up to December 31, 1997

Income group	Winnipeg, Manitoba				Des Moines, Iowa				Winnipeg/Des Moines Cases
Income group	n	SR	SRR^a	(95%CI)^b	n	SR	SRR^a	(95% CI)^b	SRR^a	(95% CI)^b
All Women Aged 25 and Over
Highest	351	0.748	1.00		313	0.786	1.00		0.95	(0.87, 1.04)
	491	0.733	0.98	(0.89, 1.07)	363	0.739	0.94	(0.86, 1.03)	0.99	(0.88, 1.11)
Middle	622	0.755	1.01	(0.95, 1.07)	325	0.707	0.90	(0.82, 0.99)	1.07	(0.98, 1.16)
	536	0.726	0.97	(0.89, 1.06)	332	0.739	0.94	(0.86, 1.03)	0.98	(0.89, 1.08)
Lowest	383	0.710	0.95	(0.87, 1.04)	212	0.621	0.79	(0.71, 0.88)	1.14	(1.01, 1.28)
Women Aged 25 to 64
Highest	266	0.794	1.00		191	0.854	1.00		0.93	(0.85, 1.01)
	321	0.786	0.99	(0.91, 1.07)	233	0.820	0.96	(0.88, 1.05)	0.96	(0.88, 1.04)
Middle	370	0.778	0.98	(0.90, 1.07)	196	0.700	0.82	(0.74, 0.91)	1.11	(1.01, 1.22)
	263	0.799	1.01	(0.89, 1.15)	135	0.811	0.95	(0.87, 1.04)	0.99	(0.90, 1.09)
Lowest	201	0.754	0.95	(0.85, 1.06)	113	0.615	0.72	(0.63, 0.82)	1.23	(1.06, 1.43)

Notes. n = number of incident cancer cases; SR = survival rate; SRR = survival rate ratio; CI = confidence interval. Data for women aged 65 and over are not shown separately because none of their within- or between-country comparisons were minimally statistically significant. Only the survival trends across income quintiles in the Des Moines samples were significant (all cases [p = .039] and those less than 65 years of age [p = .018]).

A survival rate ratio of 1.00 is the baseline.

Confidence intervals are based on the Mantel-Haenszel chi-squared test.