Table 1.

ICCs over 2 to 3 y for dietary biomarkers, among postmenopausal women in the NHS

AnalyteNo. of participants/number of time pointsCV* (%)Median (5th-95th percentile)Within-person CV (%)Between-person CV (%)ICC (95% CI)
Carotenoids, retinol, tocopherols, plasma (μg/L)
 Lutein/zeaxanthin40/24.8228 (102–428)19.438.90.80 (0.66–0.89)
 β-Cryptptoxanthin40/24.293.3 (42.4–231.5)17.948.50.88 (0.79–0.93)
 Total lycopene40/24.7414 (195–691)21.737.30.74 (0.58–0.86)
 α-Carotene40/28.269.6 (28.5–233)34.958.70.73 (0.57–0.85)
 Total β-carotene40/24.7288 (86.9–711)32.954.70.73 (0.56–0.85)
 Total carotenoids40/24.41,098 (511–2,077)18.538.60.81 (0.68–0.89)
 Retinol40/24.9571 (402–798)9.618.90.79 (0.65–0.88)
 γ-Tocopherol40/26.42,295 (398–4,328)24.666.00.88 (0.78–0.93)
 α-Tocopherol40/25.911,535 (7,336–22,844)13.229.80.83 (0.72–0.91)
Fatty acids, red blood cell (% of total fatty acids)
 Saturated40/24.235.6 (30.5–38.3)5.34.20.38 (0.17–0.65)
 Monounsaturated40/25.815.4 (13.2–16.6)5.05.30.52 (0.30–0.73)
 Polyunsaturated-Ω-340/25.14.9 (3.7–6.6)10.515.30.68 (0.49–0.82)
 Polyunsaturated-Ω-640/23.228.1 (24.9–30.0)5.04.10.39 (0.17–0.66)
 Trans40/210.40.99 (0.76–1.64)12.119.70.72 (0.55–0.84)
Vitamin D, plasma
 25-Hydroxyvitamin D (ng/mL)71/310.333.3 (16.6–51.8)18.429.60.72 (0.62–0.80)
 1,25-Dihydroxyvitamin D (pg/mL)71/318.335.7 (21.0–61.0)20.723.50.56 (0.43–0.68)
Phytoestrogens, plasma (nmol/L)
 Daidzein40/23.64.05 (0.25–76.2)123.80.00.00
 Genistein40/25.72.70 (0.40–50.5)143.431.10.03 (0.00–1.00)
 Equol40/237.70.60 (0.00–1.40)53.50.00.00
 Enterolactone40/24.112.3 (3.10–47.0)61.254.90.44 (0.22–0.68)
Phytoestrogens, urine (nmol/mg creatinine)
 Daidzein45/212.30.23 (0.04–2.43)128.10.00.00
 Genistein45/210.60.11 (0.01–1.12)131.024.50.02 (0.00–1.00)
 Equol45/25.40.04 (0.01–0.29)8.93.00.09 (0.00–0.77)
 Enterolactone45/25.21.44 (0.06–7.07)95.3100.00.52 (0.31–0.72)
Isothiocyanates, urine (jm/mg creatinine)45/29.80.02 (0.00–0.12)6.73.20.18 (0.03–0.60)
  • *CV, CV from blinded quality control replicates.

  • Total carotenoids, α-carotene + total β-carotene + total lycopene + lutein/zeaxanthin + β-cryptptoxanthin.

  • CVs for the individual factors were <20% except for decanoic acid, dodecanoic acid, 9c-tetradecenoic acid, 10c-heptadecenoic acid, 8c-eicosenoic acid, 9t-tetadecenoic acid, 9t,12t-octadecadienoic acid, and 9t,12c-octadecadienoic acid, which had CVs of ≥20.