Hair dye use, regular exercise, and the risk and prognosis of prostate cancer: multicenter case–control and case-only studies

Table 3 Prostate-cancer-specific death according to hair dye use and regular exercise in a Cox regression model

N	Total 608		Prostate-cancer-specific death 48	HR	(95 % CI)	AHR^a	(95 % CI)
Variables	N (%)		N
Hair dyes
No	443	(72.9)	35	1.00		1.00
Yes	161	(54.4)	13	0.89	(0.45-1.65)	1.14	(0.47-2.59)
Missing	4		0
Years of use
Never	443	(72.9)	35	1.00		1.00
≤10 years	85	(14.0)	9	1.16	(0.52-2.31)	1.46	(0.54-3.56)
>10 years	64	(10.5)	2	0.35	(0.06-1.15)	0.33	(0.02-1.74)
Missing	16		2
Frequency of use (times per year
Never	443	(72.9)	35	1.00		1.00
≤6	83	(13.7)	5	0.75	(0.26-1.74)	0.62	(0.14-1.94)
>6	63	(10.4)	7	1.07	(0.43-2.28)	2.15	(0.70-6.03)
Missing	19		1
Regular exercise
No	252	(41.4)	34	1.00		1.00
Yes	353	(58.1)	14	0.27	(0.14-0.50)*	0.37	(0.16-0.83)*
Missing	3		0
Frequency of exercise (times per week)
Never	252	(41.4)	34	1.00		1.00
1-6	161	(26.5)	7	0.34	(0.14-0.73)*	0.66	(0.22-1.82)
≥7	188	(30.9)	6	0.20	(0.08-0.45)*	0.23	(0.07-0.65)*
Missing	7		1
Clinical stage^b
Localized	290	(47.7)	7	1.00		1.00
Locally advanced	158	(26.0)	7	1.95	(0.67-5.71)	1.56	(0.41-5.69)
Bone metastasis	154	(25.3)	34	12.10	(5.64-29.99)*	10.15	(3.22-35.98*
Missing	6		0

Abbreviation: AHR adjusted HR, HR: hazard ratio
*P-value < 0.05; ^aAdjusting for clinical stage, PSA, age, marital status, blood type, education, family history of PC, cigarette smoking, alcohol drinking, and betel nut chewing
^bTumor, node, metastasis system staging by American Joint Committee on Cancer (1997): Localized, T1/T2 N0 M0; Locally advanced, T3/T4 N1 M0; Bone Metastasis, M1

ISSN: 1471-2407