Table 3.

Odds ratio (OR) and 95% confidence intervals (CI) for the association between family history (FH) of cancer and bladder cancer risk, stratified by selected characteristics of participants

Family history of cancer, stratified by selected characteristics of participants	Cases		Controls		OR	95% CI	p-interaction, FH of bladder cancer
	n	%	n	%
Age							0.07
< 55 years
No FH of cancer	72	6.0	127	9.0	Ref.	Ref.
FH of bladder cancer	10	0.8	5	0.4	5.2	(1.5, 17.8)
FH of other cancer	108	9.1	123	8.7	1.7	(1.1, 2.6)
≥ 55 years
No FH of cancer	379	31.8	484	34.1	Ref.	Ref.
FH of bladder cancer	46	3.9	36	2.5	1.5	(0.93, 2.5)
FH of other cancer	578	48.4	643	45.3	1.1	(0.90, 1.3)
Gender							0.98
Male
No FH of cancer	357	29.9	465	32.8	Ref.	Ref.
FH of bladder cancer	41	3.4	26	1.8	1.9	(1.1, 3.2)
FH of other cancer	513	43.0	548	38.6	1.2	(0.96, 1.4)
Female
No FH of cancer	94	7.9	146	10.3	Ref.	Ref.
FH of bladder cancer	15	1.3	15	1.1	1.8	(0.7, 4.2)
FH of other cancer	173	14.5	218	15.4	1.2	(0.8, 1.7)
Smoking status							0.33
Smokers
No FH of cancer	385	32.3	397	28.0	Ref.	Ref.
FH of bladder cancer	47	3.9	22	1.6	2.1	(1.2, 3.6)
FH of other cancer	585	49.0	526	37.1	1.1	(0.91, 1.3)
Never smokers
No FH of cancer	65	5.4	213	15.0	Ref.	Ref.
FH of bladder cancer	9	0.8	19	1.3	1.3	(0.5, 3.2)
FH of other cancer	101	8.5	240	16.9	1.5	(1.01, 2.2)
Occupational risk							0.97
High-risk occupation**
No FH of cancer	336	28.2	419	29.5	Ref.	Ref.
FH of bladder cancer	37	3.1	20	1.4	1.8	(0.9, 3.5)
FH of other cancer	524	43.9	497	35.0	1.2	(0.9, 1.5)
No high-risk occupation**
No FH of cancer	111	9.3	187	13.2	Ref.	Ref.
FH of bladder cancer	19	1.6	21	1.5	1.9	(0.99, 3.5)
FH of other cancer	155	13.0	264	18.6	1.2	(0.9, 1.5)

^*Adjusted for state, age group, gender, race/ethnicity, smoking status, high risk occupation, personal history of cancer, except in the case where stratified on that variable

^**High risk occupations are those with an odds ratio of at least 1.5 and at least 10 exposed participants