Assessing spatio-temporal variability of risk surfaces using residential history data in a case control study of breast cancer

Table 4 Standardized difference of residences for premenopausal and postmenopausal breast cancer cases and controls by decades;

	Decades	Case	Control	Standardized differences	No. of areas^a > 2SD	No. of areas^a > critical values^b
Premenopausal	1940s	36	86	-2.35–2.12	2	0
	1950s	222	461	-2.45–3.15	9	0
	1960s	341	633	-4.02–3.78	21	2
	1970s	514	1025	-3.89–3.96	35	2
	1980s	552	1005	-4.26–4.50	24	3
	1990s	457	723	-4.06–4.14	32	5
Postmenopausal	1930s	389	676	-2.51–2.62	24	0
	1940s	809	1253	-3.01–3.04	23	0
	1950s	1158	1968	-3.66–2.91	22	0
	1960s	1247	2072	-4.18–2.99	18	0
	1970s	1100	1839	-4.98–3.13	21	0
	1980s	960	1651	-3.84–2.85	23	0
	1990s	943	1542	-4.40–3.57	22	0

^a Areas refer to the rectangular grid overlaid on to the study area, ^b Critical values of 3.88 for premenopausal and 3.71 for postmenopausal residences.

ISSN: 1476-072X