TABLE 3.

Biomarker concentrations before and after 6 wk of intervention, stratified by baseline concentration of biomarker in overweight/obese participants enrolled in a grapefruit feeding trial¹

	Grapefruit (n = 37)			Control (n = 32)
Stratification cutoff	Pre	Post	P value2	Pre	Post	P value2
Plasma sVCAM-1, μg/L			0.70			0.72
Low: <611 μg/L	628 ± 117	614 ± 123		623 ± 125	611 ± 111
High: ≥611 μg/L	712 ± 107	704 ± 109		715 ± 118	697 ± 87
Plasma hsCRP, mg/L			0.10			0.97
Low: <2.18 mg/L	1.0 ± 0.7	1.3 ± 1.3		0.6 ± 0.8	1.0 ± 0.9
High: ≥2.18 mg/L	3.5 ± 1.0	3.0 ± 1.1		4.0 ± 1.1	4.3 ± 1.2
Urinary F2-isoprostanes, ng/mg creatinine			0.004			0.55
Low: <12.7 ng/mg	9.5 ± 3.5	10.2 ± 4.6		9.7 ± 1.7	11.9 ± 5.0
High: ≥12.7 ng/mg	19.3 ± 7.9	15.0 ± 7.4*		19.7 ± 5.7	19.8 ± 10.3

¹Values are means ± SDs. Stratification resulted in the following: n = 34 in the “low“ and n = 32 in the “high” groups for sVCAM-1 and F2-isoprostanes; and n = 33 in “low“ and n = 33 in “high” groups for hsCRP. Baseline median values of each biomarker were determined in the whole sample (control and grapefruit participants combined), and stratification cutoffs were determined on the basis of this median value. *Different from Pre, P < 0.05 (paired t test). hsCRP, high-sensitivity C-reactive protein; sVCAM-1, soluble vascular cellular adhesion molecule 1.

²P values were derived from linear regression models comparing differences between stratification groups (low vs. high), post-intervention, after adjusting for baseline value of biomarker and harvest year (2009–2010 or 2010–2011).