TABLE 1.
Characteristics of the study population (n = 977)1.
| Variables | n | Geometric Mean (95% Confidence Interval) or n (%) |
|---|---|---|
| Sociodemographic | ||
| Age, y | 977 | 28.8 (28.4, 29.3) |
| 15 to <18 | 49 (5.0) | |
| 18 to <26 | 228 (23.3) | |
| 26 to <36 | 452 (46.3) | |
| 36 to 40 | 248 (25.4) | |
| Biochemical | ||
| RBC folate2, nmol/L | 977 | 540.5 (526.2, 555.1) |
| <305 | 74 (7.6) | |
| <748 | 775 (79.3) | |
| Serum folate2, nmol/L | 977 | 16.5 (16.0, 17.0) |
| <7.0 | 34 (3.5) | |
| Hemoglobin3, g/dL | 977 | 11.9 (11.7, 12.0) |
| <12.0 | 405 (41.5) | |
| <8.0 | 29 (3.0) | |
| Serum ferritin4, μg/L | 975 | 10.6 (9.9, 11.2) |
| <15.0 | 599 (61.4) | |
| <20.0 | 709 (72.7) | |
| <25.0 | 790 (81.0) | |
| Body iron index5, mg/kg | 975 | -0.7 (-1.0, -0.4) |
| <0.0 | 506 (51.9) | |
| Serum CRP6, mg/L | 977 | 1.2 (1.1,1.4) |
| ≤1.0 | 425 (43.5) | |
| >1.0 to ≤3.0 | 261 (26.7) | |
| >3.0 to ≤5.0 | 123 (12.6) | |
| >5.0 | 168 (17.2) | |
| Serum α-1 acid glycoprotein7, g/L | 975 | 0.8 (0.8,0.8) |
| >1.0 | 216 (22.2) | |
| Serum vitamin B128, pmol/L | 977 | 155.9 (150.1, 161.8) |
| <148 | 472 (48.3) | |
| 148–221 | 255 (26.1) | |
| ≥221 | 250 (25.6) | |
| Plasma MMA8, μmol/L | 977 | 0.3 (0.3, 0.3) |
| >0.26 | 592 (60.6) | |
| >0.37 | 432 (44.2) | |
| Impaired vitamin B12status8 | 977 | |
| Vitamin B12 <148 pmol/L and MMA >0.26 μmol/L | 370 (37.9) | |
| Plasma homocysteine9, μmol/L | 977 | 6.6 (6.4, 6.8) |
| >10.0 | 157 (16.1) | |
| >15.0 | 65 (6.7) | |
| cB128 | 977 | -0.35 (-0.41, -0.30) |
| ≥1.5 | 20 (2.1) | |
| -0.5 to <1.5 | 517 (52.9) | |
| -1.5 to <-0.5 | 333 (34.1) | |
| -2.5 to <-1.5 | 100 (10.2) | |
| <-2.5 | 7 (0.7) | |
| ≥-0.5 | 537 (55.0) | |
| <-0.5 | 440 (45.0) | |
| Anthropometric | ||
| BMI, kg/m2 | 966 | 22.6 (22.2, 22.9) |
| BMI10,11 | 917 | |
| <18.5 | 176 (19.2) | |
| 18.5 to <25.0 | 440 (48.0) | |
| 25.0 to <30.0 | 213 (23.2) | |
| ≥30.0 | 88 (9.6) | |
| Waist circumference10,12, cm | 966 | 74.6 (73.9, 75.4) |
| >88.9 | 917 | 123 (13.4) |
| Waist-hip ratio10,12 | 917 | 0.8 (0.8, 0.8) |
| ≥0.85 | 191 (20.8) | |
| Metabolic characteristics | ||
| Whole body fat10,12, % | 919 | 30.6 (30.0, 31.2) |
| >35 | 360 (39.2) | |
| Trunk fat mass10,12, % | 919 | 27.8 (27.0, 28.7) |
| >35 | 332 (36.1) | |
| HbA1c13, % | 977 | 5.4 (5.4, 5.5) |
| <5.7 | 732 (74.9) | |
| ≥5.7 to <6.5 | 196 (20.1) | |
| ≥6.5 | 49 (5.0) | |
Geometric means and 95% Confidence Intervals were generated using Proc Genmod among all participants with RBC folate (n = 977). BRINDA, Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia; cB12, combined B12.
Cutoffs for RBC folate deficiency (RBC folate: <305 nmol/L) and RBC folate insufficiency (RBC folate: <748 nmol/L)
Hemoglobin values from complete blood count; adjusted for smoking status [29]
Serum ferritin concentrations were adjusted for inflammation via BRINDA methods [41]; cutoffs for iron deficiency (serum ferritin <15.0 μg/L) and iron insufficiency (serum ferritin <20.0 and <25.0 μg/L) from [33,34]
Values are arithmetic mean (95% CI); body iron index (mg/kg) was estimated using Cook’s equation after adjusting serum ferritin for inflammation via BRINDA methods [41] and converting sTfR to Flowers Ramco equivalents (Ramco = 1.5 × Roche + 0.35) [35]
α-1 acid glycoprotein cutoff (>1.0 g/L) based on WHO criteria [33]
Cutoffs for vitamin B12 deficiency (<148 pmol/L) and vitamin B12 insufficiency (<221 pmol/L) from (30); cB12 was calculated using vitamin B12, MMA, and homocysteine, and categorized (i.e., ≥1.5, -0.5 to <1.5, -1.5 to <-0.5, -2.5 to <-1.5, <-2.5) using methods developed by Fedosov et al. [32]
Elevated vitamin B12 (≥1.5), Adequate vitamin B12 (-0.5 to <1.5), Decreased vitamin B12 (-1.5 to <-0.5) , Possibly deficient (-2.5 to <-1.5) , Probably deficient (<-2.5) Sufficient vitamin B12 (-0.5 to >1.5), Deficient vitamin B12 (<-0.5).
Homocysteine cutoffs (>15.0 and >10.0 μmol/L) from [6]
Among adult participants (>18 y; n = 928)
BMI categories (BMI <18.5, 18.5 to <25.0, 25.0 to <30.0, and ≥30.0 kg/m2) as defined by the WHO [37]
Anthropometric cutoffs (waist circumference >88.9 cm and waist-hip ratio ≥0.85) were defined based on WHO criteria [38]; elevated whole body (>35%) and trunk fat (>35%) were defined based on criteria suggested by the American Association of Clinical Endocrinology [39]
HbA1c cutoffs (<5.7%, ≥5.7% to <6.5%, and ≥6.5%) were defined using the American Diabetes Association criteria [40]