Table 2.

Relative risk of Incident Composite CVD by Baseline and 1-Year Changes in Urea Cycle Metabolites: HRs (95% CI) for Traits as Continuous Variables and by Quartile Levels

	Baseline (n = 984, cases = 231)			1-Year Changes (n = 926, cases = 177) a
	Arginine	Ornithine	Citrulline	Arginine	Ornithine	Citrulline
Model 1
Trait as continuous variable, per SD
HR (95% CI)	0.84 (0.71–0.99)	1.07 (0.91–1.26)	1.00 (0.83–1.20)	0.85 (0.72–1.01)	0.92 (0.77–1.10)	0.85 (0.72–1.02)
P	0.04	0.42	1.00	0.07	0.37	0.08
Trait in quartile categories, as compared with Q1 (reference)
Q2	0.58 (0.37–0.89)	1.06 (0.66–1.71)	0.55 (0.34–0.89)	1.09 (0.68–1.73)	1.04 (0.64–1.69)	0.93 (0.58–1.48)
Q3	0.58 (0.37–0.91)	1.10 (0.69–1.77)	0.91 (0.58–1.40)	0.68 (0.41–1.13)	0.93 (0.55–1.57)	0.68 (0.41–1.13)
Q4	0.68 (0.45–1.04)	1.22 (0.79–1.90)	0.90 (0.59–1.39)	0.69 (0.41–1.16)	0.85 (0.51–1.42)	0.60 (0.36–0.99)
P trend	0.10	0.37	0.78	0.06	0.46	0.02
Model 2
Trait as continuous variable, per SD
HR (95% CI)	0.86 (0.72–1.02)	1.06 (0.89–1.25)	1.04 (0.86–1.25)	0.87 (0.73–1.04)	0.93 (0.77–1.11)	0.87 (0.73–1.04)
P	0.09	0.53	0.71	0.12	0.40	0.12
Trait in quartile categories, as compared with Q1 (reference)
Q2	0.59 (0.38–0.92)	1.16 (0.72–1.89)	0.64 (0.39–1.03)	1.20 (0.74–1.95)	1.19 (0.72–1.98)	0.99 (0.61–1.61)
Q3	0.63 (0.39–0.99)	1.15 (0.71–1.86)	0.98 (0.63–1.53)	0.70 (0.42–1.18)	0.92 (0.54–1.57)	0.75 (0.44–1.26)
Q4	0.70 (0.45–1.09)	1.20 (0.76–1.90)	1.01 (0.64–1.58)	0.73 (0.42–1.25)	0.88 (0.52–1.48)	0.60 (0.35–1.01)
P trend	0.17	0.48	0.54	0.09	0.44	0.03

Model 1 was adjusted for age, sex, family history of CHD, smoking status, and body mass index and was stratified by intervention group. Model 2 was adjusted as for model 1, plus baseline hypertension, dyslipidemia, and diabetes.

Abbreviation: Q, quartile.

^aFifty-eight individuals who provided blood samples at baseline but not at 1 year were not included.