TABLE 1.

Comparison of age-standardized characteristics between baseline (1996–1999) and follow-up (2010–2011) in the Nurses’ Health Study II¹

	Baseline	Follow-up	P
n	831	831
Age at blood collection,2 y	45 ± 5	58 ± 4	<0.001
BMI, kg/m2	24.6 ± 3.5	26.3 ± 4.7	<0.001
Weight, kg	66.4 ± 10.2	70.7 ± 12.8	<0.001
Total energy intake, kcal/day	1886 ± 364	1756 ± 409	<0.001
Alcohol, g/day	3.9 ± 5.8	6.2 ± 8.2	<0.001
Current smokers, %	4.1	1.5	<0.001
Physical activity, MET-h/wk	17.8 ± 15.2	23.5 ± 22.2	<0.001
Postmenopausal, %	20.6	72.1	<0.001
Current PMH use in postmenopausal, %	85.5	23.9	<0.001
Hypertension, %	10.9	29.4	<0.001
Hypercholesterolemia, %	15.1	35.1	<0.001
PDI	55.9 ± 4.8	57.8 ± 4.7	<0.001
hPDI	55.2 ± 5.7	54.3 ± 6.2	0.60
uPDI	54.0 ± 5.7	48.0 ± 5.8	<0.001
Plasma biomarkers
Total adiponectin, µg/mL	7.0 [1.4]	7.4 [1.5]	<0.001
Leptin, ng/mL	17.0 [1.8]	19.4 [2.0]	<0.001
Soluble leptin receptor, ng/mL	24.8 [1.2]	25.0 [1.3]	<0.001
Free leptin index3	0.7 [2.0]	0.8 [2.3]	0.001
Insulin, µU/mL	5.1 [1.6]	5.5 [1.7]	0.11
RBP-4, µg/mL	32.8 [1.2]	35.7 [1.2]	<0.001
High-sensitivity CRP, mg/L	0.99 [2.55]	1.03 [2.58]	0.10
IL-6, pg/mL	0.87 [1.54]	0.91 [1.57]	0.02

¹Values are means ± SDs for continuous variables except plasma biomarkers, geometric means [geometric SDs] for all plasma biomarkers, and percentages for categorical variables; and are standardized to the age distribution of participants. P value is calculated based on paired t test (for continuous variables) or McNemar's test (for binary variables). CRP, C-reactive protein; hPDI, healthful plant-based diet index; MET-h, metabolic equivalent task hours; PDI, overall plant-based diet index; PMH, postmenopausal hormone; RBP-4, retinol-binding protein-4; uPDI, unhealthful plant-based diet index.

²Value is not age adjusted.

³Free leptin index is defined as the ratio of leptin to soluble leptin receptor.