Table 4. Hazard ratios of mortality for all causes, except for accidents and cancer of all sites by blood levels of SOD activity and Zn/Cu ratio, and serum levels of SOD activity and TBARS among the follow-up residents.

Components	Quartile	No. of subjects	Person years	No. of death	Mortality rates	Model 1	p	Model 2	p
						H.R.(95%C.I.)		H.R.(95%C.I.)
Blood SOD activity (unit/ml)	Q1 (low)	115	2010.0	15	7.46	1.20 (0.56-2.58)	0.64	1.35 (0.64-2.97)	0.46
	Q2	123	2092.5	20	9.56	1.80 (0.87-3.70)	0.11	1.61 (0.77-3.35)	0.21
	Q3	104	1812.5	11	6.07	1.48 (0.64-3.39)	0.36	1.48 (0.63-3.45)	0.37
	Q4 (high)	117	2052.0	12	5.85	1.00		1.00
						trend p=0.40		trend p=0.63
Blood Zn/Cu ratio	Q1 (low)	108	1874.0	12	6.40	1.99 (0.87-4.56)	0.10	1.95 (0.85-4.48)	0.12
	Q2	120	2056.5	18	8.75	1.98 (0.93-4.26)	0.08	2.23 (1.03-4.79)*	0.04
	Q3	116	1987.0	17	8.56	1.71 (0.80-3.67)	0.17	1.94 (0.90-4.21)	0.09
	Q4 (high)	115	2049.5	11	5.37	1.00		1.00
						trend p=0.28		trend p=0.20
Serum SOD activity (unit/ml)	Q1 (low)	139	2429.5	17	7.00	1.67 (0.80-3.49)	0.14	1.64 (0.76-3.55)	0.21
	Q2	103	1738.0	19	10.93	2.15 (1.04-4.42)*	0.04	2.07 (0.99-4.31)	0.05
	Q3	106	1857.0	9	4.85	1.04 (0.44-2.48)	0.93	0.84 (0.36-2.14)	0.78
	Q4 (high)	111	1942.5	13	6.69	1.00		1.00
						trend p=0.12		trend p=0.09
Serum TBARS level (nmol/ml)	Q1 (low)	130	2274.0	13	5.72	0.88 (0.41-1.92)	0.76	0.74 (0.33-1.67)	0.47
	Q2	106	1854.5	12	6.47	1.19 (0.54-2.64)	0.66	1.03 (0.45-2.34)	0.94
	Q3	123	2086.5	20	9.59	1.11 (0.55-2.25)	0.77	1.18 (0.58-2.42)	0.65
	Q4 (high)	100	1752.0	13	7.42	1.00		1.00
						trend p=0.88		trend p=0.65

Hazard ratios (H.R.) and 95% confidence intervals (95%C.I.) were calculated using Cox proportional hazard model (StatView statistical package, Power Macintosh), after adjusting for sex and age (Model 1), or after adjusting for sex, age, habits of smoking status and alcohol consumption, and BMI (Model 2).

* : p < 0.05.

Mortality rates = [No. of deaths/ person years] × 1000