Table 5.
Concurrent factors associated with citrulline, kynurenine, and tryptophan concentrations and the KT ratio at baseline in young Laotian children
| Variables | Citrulline (µmol/L)§ | Kynurenine (µmol/L) | Tryptophan (µmol/L) | KT ratio (ratio × 1,000) |
|---|---|---|---|---|
| Age (months) | 0.14 (0.03, 025)* | −0.03 (−0.05, −0.01)† | −0.21 (−0.48, 0.07) | −0.30 (−0.55, −0.05)* |
| District | ||||
| Nongbok | Ref | Ref | Ref | Ref |
| Xebangfai | 0.05 (−1.14, 1.23) | −0.16 (−0.35, 0.02) | −1.54 (−4.38, 1.31) | −1.03 (−3.67, 1.61) |
| Gender | ||||
| Male | Ref | Ref | Ref | Ref |
| Female | 0.32 (−0.8, 1.44) | 0.01 (−016, 0.18) | −0.20 (−2.89, 2.50) | 0.44 (−2.05, 2.92) |
| Anthropometry | ||||
| LAZ | 0.02 (−0.51, 0.55) | −0.09 (−0.17, −0.01)* | −0.67 (−1.94, 0.61) | −0.85 (−2.03, 0.33) |
| WAZ | −0.07 (−0.63, 0.48) | −0.7 (−2.03, 0.63) | −0.05 (−0.14, 0.03) | −0.28 (−1.51, 0.95) |
| WLZ | −0.14 (−0.77, 0.49) | 0.0 (−0.1, 0.1) | −0.52 (−2.04, 1.00) | 0.45 (−0.96, 1.85) |
| Stunting (LAZ < −2 SD) | 0.12 (−1.05, 1.28) | 0.17 (−0.01, 0.34) | 0.74 (−2.07, 3.55) | 2.02 (−0.56, 4.61) |
| Underweight (WAZ < −2 SD) | 0.14 (−1.11, 1.39) | 0.13 (−0.06, 0.32) | 2.03 (−0.98, 5.04) | 0.41 (−2.37, 3.19) |
| Wasting (WLZ < −2 SD) | 0.37 (−1.81, 2.55) | −0.08 (−0.41, 0.25) | −0.22 (−5.48, 5.04) | −0.88 (−5.73, 3.97) |
| Biochemical indicators‖ | ||||
| Hemoglobin (Hb) | 0.38 (−0.25, 1.00) | 0.03 (−0.06, 0.13) | 0.57 (−0.94, 2.08) | 0.01 (−1.38, 1.41) |
| Anemia (Hb < 110 g/L) | −0.40 (−1.53, 0.73) | 0.01 (−0.16, 0.18) | −0.70 (−3.43, 2.02) | 0.73 (−1.79, 3.25) |
| CRP (mg/L) | −1.02 (−1.37, −0.67)‡ | 0.0 (−0.05, 0.06) | −1.80 (−2.66, −0.93)‡ | 1.11 (0.3, 1.91)† |
| CRP ≥ 5 mg/L | −3.65 (−5.30, −2.00)‡ | −0.24 (−0.5, 0.01) | −6.41 (−10.44, −2.38)† | 0.13 (3.63, 3.90) |
| AGP (g/L) | −2.80 (−3.78, −1.82)‡ | 0.05 (−0.11, 0.21) | −3.17 (−5.62, −0.72)* | 2.84 (0.58, 5.10)* |
| AGP ≥ 1 g/L | −3.12 (−4.43, −1.81)‡ | −0.01 (−0.22, 0.20) | −3.88 (−7.11, −0.64)* | 2.39 (−0.61, 5.39) |
| PZC (µg/dL) | 3.01 (0.32, 5.69)* | −0.01 (−0.42, 0.4) | 4.72 (−1.79, 11.2) | −3.79 (−9.80, 2.22) |
| PZC ≤ 65 µg/dL | −1.09 (−2.39, 0.22) | 0.13 (−0.07, 0.33) | −0.35 (−3.50, 2.80) | 2.32 (−0.58, 5.22) |
| Retinol-binding protein concentration (µmol/L) | 4.17 (1.52, 6.81)† | 0.14 (−0.27, 0.55) | 7.42 (0.99, 13.85)* | −3.46 (−9.42, 2.51) |
| Ferritin (µg/L) | −0.37 (−1.10, 0.36) | 0.01 (−0.11, 0.12) | −1.25 (−3.02, 0.52) | 0.85 (−0.79, 2.48) |
| Storage iron deficiency (ferritin < 12 µg/L) | 0.82 (−0.45, 2.09) | −0.02 (−0.22, 0.17) | 1.76 (−1.30, 4.82) | −1.24 (−4.07, 1.58) |
| sTfR (mg/L) | −0.56 (−1.85, 0.73) | 0.02 (−0.18, 0.21) | 0.11 (−3.01, 3.22) | 0.28 (−2.59, 3.15) |
| Functional iron deficiency (sTfR > 8.3 mg/L) | −0.50 (−1.68, 0.68) | 0.14 (−0.04, 0.32) | −0.88 (−3.73, 1.97) | 2.75 (0.14, 5.37)* |
| Hair cortisol (pg/mg) | −0.08 (−0.72, 0.56) | −0.04 (−0.14, 0.06) | −1.84 (−3.37, −0.31)* | 0.54 (−0.88, 1.96) |
| Infant and young child feeding practices¶# | ||||
| Breastfed, in the previous month | −0.75 (−2.1, 0.59) | −0.16 (−0.36, 0.04) | −2.67 (−4.91, 1.57) | −1.47 (−4.39, 1.44) |
| Adequate dietary diversity | 0.69 (−0.55, 1.93) | −0.02 (−0.20, 0.17) | 2.68 (−0.31, 5.67) | −2.06 (−4.78, 0.67) |
| Minimum meal frequency | 0.17 (−1.09, 1.43) | −0.05 (−0.23, 0.14) | −0.48 (−3.52, 2.56) | −0.53 (−3.27, 2.20) |
| Maternal characteristics¶ | ||||
| Maternal age (years) | −0.01 (−0.10, 0.08) | 0.0 (−0.01, 0.02) | 0.17 (−0.06, 0.40) | −0.08 (−0.29, 0.13) |
| Maternal BMI (kg/m2) | −0.07 (−0.27, 0.12) | −0.01 (−0.04, 0.02) | −0.08 (−0.54, 0.38) | −0.16 (−0.59, 0.27) |
| Maternal education (years) | −0.08 (−0.28, 0.12) | 0.0 (−0.03, 0.03) | −0.1 (−0.58, 0.39) | −0.02 (−0.47, 0.43) |
| Household characteristics¶# | ||||
| HFIAS | −0.04 (−0.2, 0.12) | 0.0 (−0.02, 0.03) | −0.25 (−0.64, 0.14) | 0.19 (−0.16, 0.55) |
| Socioeconomic status index | 0.38 (0.08, 0.68)* | 0.0 (−0.05, 0.05) | 0.87 (0.15, 1.60)* | −0.50 (−1.16, 0.17) |
| No animals in household | −0.27 (−1.73, 1.20) | −0.29 (−0.51, −0.06)* | −5.45 (−9.04, −1.87)† | −0.65 (−3.98, 2.67) |
| Use of improved drinking water source | 1.75 (0.04, 3.46)* | 0.09 (−0.17, 0.35) | 3.45 (−0.83, 7.72) | −1.36 (−5.18, 2.46) |
| Handwashing | −1.64 (−3.04, −0.25)* | 0.05 (−0.16, 0.26) | −1.03 (−4.43, 2.37) | 1.34 (−1.75, 4.44) |
| Latrine access | 0.31 (−0.95, 1.58) | 0.06 (−0.13, 0.25) | 1.1 (−1.96, 4.16) | 0.45 (−2.34, 3.24) |
AGP = α1-acid glycoprotein; BMI = body mass index; CRP = C-reactive protein; HFIAS = household food insecurity access scale; KT = kynurenine:tryptophan; LAZ = length-for-age Z-score; PZ = preventive zinc; PZC = plasma zinc concentration; sTfR = soluble transferrin receptor; TZ = therapeutic zinc; WAZ = weight-for-age Z-score; WLZ = weight-for-length Z-score. *P < 0.05, †P < 0.01, ‡P < 0.001.
§ Models adjusted for age at enrollment and district. Values represent beta coefficient and 95% CI from linear regression models. For continuous predictors, this represents the change in outcome corresponding to a one unit increase in the predictor. For dichotomous predictors, this corresponds to the change in mean concentration from the reference group.
‖ AGP, CRP, PZC, retinol-binding protein, ferritin, sTfR, and hair cortisol were natural log-transformed; PZC, retinol-binding protein, and ferritin were adjusted for elevated acute-phase proteins28; and estimates of the prevalence of deficiency are based on inflammation-adjusted micronutrient biomarker concentrations.
¶ Breastfeeding, MMF, n = 320; ADD, latrine access, n = 322; maternal BMI, n = 281; improved drinking water source, n = 283; animals in household, n = 302.
# Infant and young child feeding practices defined by the WHO32; HFIAS from the Food and Nutrition Technical Assistance III Project35; socioeconomic status index based on available indicators of household socioeconomic status, education, income, and ownership of assets, land, and animals; handwashing defined as report of consistent handwashing after defecation and/or before meal preparation compared with occasional or no handwashing after defecation and before meal preparation; improved drinking water source defined by the WHO.48