Age at diagnosis in relation to survival following breast cancer: a cohort study

Table 4 Age at diagnosis in relation to breast cancer-specific mortality with stratification for diagnostic period; five-year follow-up period

Diagnostic period	Age at diagnosis (years)	Subjects	Person-years	Breast cancer deaths (all deaths)	Breast cancer mortality/10,000 ^a	Relative risk (95% CI)	Relative risk ^b (95% CI)	Relative risk ^c (95% CI)
1961-1970	<40	51	214	16 (18)	747	1.39 (0.79-2.45)	1.69 (0.96-2.98)	1.23 (0.69-2.20)
	40-49	214	940	50 (56)	532	1.00	1.00	1.00
	50-59	256	1,008	82 (88)	813	1.53 (1.07-2.17)	1.51 (1.06-2.16)	1.46 (1.00-2.11)
	60-69	274	1,107	65 (93)	587	1.10 (0.76-1.59)	1.15 (0.79-1.67)	1.12 0-75-1.66)
	70-79	189	673	45 (92)	669	1.25 (0.83-1.86)	1.33 (0.88-2.02)	1.35 (0.87-2.09)
	≥80	108	252	29 (82)	1,151	2.10 (1.33-3.32)	1.39 (0.86-2.27)	1.21 (0.72-2.03)
	All	1,092	4,193	287 (429)	684
1971-1980	<40	44	201	8 (10)	399	1.16 (0.54-2.51)	1.17 (0.54-2.55)	1.09 (0.50-2.39)
	40-49	211	960	33 (39)	344	1.00	1.00	1.00
	50-59	343	1,535	65 (76)	423	1.23 (0.81-1.87)	1.15 (0.75-1.77)	1.18 (0.76-1.82)
	60-69	386	1,633	84 (116)	514	1.49 (1.00-2.23)	1.65 (1.09-2.48)	1.69 (1.11-2.57)
	70-79	287	1,084	72 (122)	664	1.92 (1.27-2.90)	1.78 (1.16-2.72)	1.81 (1.17-2.81)
	≥80	181	518	44 (119)	849	2.43 (1.55-3.82)	2.27 (1.38-2.73)	2.41 (1.44-4.02)
	All	1,452	5,931	306 (482)	516
1981-1991	<40	69	307	16 (17)	521	1.45 (0.80-2.62)	1.49 (0.82-2.70)	1.15 (0.62-2.13)
	40-49	205	946	34 (38)	359	1.00	1.00	1.00
	50-59	287	1,258	48 (62)	382	1.06 (0.68-1.65)	1.30 (0.84-2.03)	1.33 (0.85-2.09)
	60-69	402	1,819	55 (74)	302	0.84 (0.55-1.29)	0.85 (0.55-1.31)	0.90 (0.58-1.41)
	70-79	342	1,389	60 (116)	432	1.20 (0.79-1.82)	0.67 (0.43-1.04)	0.82 (0.52-1.30)
	≥80	270	837	57 (177)	681	1.88 (1.23-2.87)	0.79 (0.50-1.24)	1.06 (0.65-1.72)
	All	1,575	6,557	270 (484)	412

CI = Confidence Intervals.
^aBreast cancer-specific mortality per 10,000 person-years.
^bAdjusted for tumor size, axillary lymph node status and distant metastasis.
^cAdjusted for BMI, parity, tumor size, axillary lymph node status, histological type, tumor location, and distant metastasis.

ISSN: 1477-7819