Table 1. Standardised incidence ratio (SIR)a and 95% confidence intervals (CIs) for bladder cancer among patients diagnosed with benign prostatic hyperplasia in Sweden, 1964–1983.

	All BPH patients			No surgery			TURP			TA
Follow-up years	Obs	Exp	SIR (95% CI)	Obs	Exp	SIR (95% CI)	Obs	Exp	SIR (95% CI)	Obs	Exp	SIR (95% CI)
	(n=79 280)			(n=21 995)			(n=37 410)			(n=19 035)
1	215	70.7	3.04 (2.65–3.47)	84	19.0	4.42 (3.53–5.47)	94	34.2	2.75 (2.22––3.37)	33	16.8	1.96 (1.35–2.75)
2	105	71.0	1.48 (1.21–1.79)	26	16.9	1.54 (1.01–2.26)	49	35.6	1.38 (1.02–1.82)	26	17.8	1.46 (0.95–2.14)
3	84	69.0	1.22 (0.97–1.51)	15	14.9	1.01 (0.56–1.66)	49	35.5	1.38 (1.02–1.83)	20	17.9	1.12 (0.68–1.73)
4	70	66.8	1.05 (0.82–1.32)	14	13.2	1.06 (0.58–1.78)	38	35.0	1.09 (0.77–1.49)	17	17.8	0.95 (0.56–1.53)
5–6	130	125.9	1.03 (0.86–1.23)	11	22.5	0.49 (0.24–0.87)	87	67.1	1.30 (1.04–1.60)	25	34.8	0.72 (0.47–1.06)
7–8	120	101.3	1.18 (0.98–1.42)	14	17.0	0.83 (0.45–1.39)	72	51.7	1.39 (1.09–1.75)	30	31.2	0.96 (0.65–1.37)
9–10	70	68.6	1.02 (0.80–1.29)	16	12.1	1.33 (0.76–2.16)	37	30.2	1.22 (0.86–1.69)	16	25.1	0.64 (0.36–1.04)
11–15	95	81.5	1.17 (0.94–1.42)	19	15.9	1.20 (0.72–1.87)	42	27.3	1.54 (1.11–2.08)	27	36.4	0.74 (0.49–1.08)
16–26	21	21.8	0.96 (0.60–1.47)	3	5.3	0.56 (0.11–1.64)	6	4.7	1.29 (0.47–2.80)	12	11.0	1.09 (0.56–1.90)
	(n=61 312)			(n=12 502)			(n=31 478)			(n=16,565)
4–6	200	192.7	1.04 (0.90–1.19)	25	35.7	0.70 (0.45–1.03)	125	102.1	1.22 (1.02–1.46)	42	52.6	0.80 (0.58–1.08)
7–9	155	139.1	1.11 (0.95–1.30)	24	23.5	1.02 (0.65–1.52)	91	69.0	1.32 (1.06–1.62)	35	44.6	0.79 (0.55–1.09)
10–26	151	134.1	1.13 (0.95–1.32)	28	26.7	1.05 (0.70–1.52)	66	44.9	1.47 (1.14–1.87)	50	59.2	0.85 (0.63–1.11)

Abbreviations: BPH=benign prostatic hyperplasia; TURP=transurethral resection of the prostate; TA=transvesicular adenomectomy.

^aAdjusted for age (in 5-year intervals) and calendar time period (in 5-year intervals).