Table 5.
Predictors of vitamin A, B12 and folate status in pregnant women, controlling for trimester: linear regression analyses (dichotomous and ordinal independent variables) and ANCOVA analyses (non-ordinal, multi-categorical independent variables) 1.
| Variable | RBP, Adjusted for APP (µmol/L) 2 | Vitamin B12 (pmol/L) 3 | Folate (nmol/L) 3 | |||
|---|---|---|---|---|---|---|
| Mean (95% CI) | p | Geometric Mean (95% CI) | p | Geometric Mean (95% CI) | p | |
| Current pregnancy, trimester 4 | 0.23 | 0.01 | 0.01 | |||
| First | NA | NA | NA | |||
| Second | 1.10 (1.05, 1.14) | 183.7 (175.4, 192.3) | 11.4 (10.8, 12.0) | |||
| Third | 1.07 (1.04, 1.10) | 163.6 (158.5, 168.9) | 10.1 (9.7, 10.6) | |||
| Season | 0.81 | 0.66 | 0.07 | |||
| June–September (Lean, rainy season) | 1.09 (1.01, 1.18) | 0.53 | 170.2 (155.3, 186.5) | 0.63 | 11.3 (10.2, 12.6) | 0.89 |
| October–February (Post-harvest, cool season) | 1.09 (0.99, 1.19) | 0.60 | 162.1 (145.8, 180.3) | 0.37 | 9.2 (8.2, 10.4) | 0.09 |
| March– May (Hot season) | 1.04 (0.92, 1.16) | REF | 177.9 (156.8, 201.8) | REF | 11.2 (9.7, 12.8) | REF |
| Demographic and socio-economic characteristics | ||||||
| Adolescent | 0.08 | 0.20 | 0.89 | |||
| Yes | 1.13 (1.07, 1.19) | 163.1 (152.5, 174.4) | 10.6 (9.8, 11.3) | |||
| No | 1.07 (1.04, 1.10) | 170.7 (165.6, 175.9) | 10.5 (10.1, 10.9) | |||
| Marital status | 0.02 | 0.09 | 0.48 | |||
| Monogamous | 1.09 (1.06, 1.12) | REF | 170.8 (165.5, 176.3) | REF | 10.6 (10.1, 11.0) | REF |
| Polygamous, first wife | 1.00 (0.93, 1.06) | 0.01 | 158.1 (147.5, 169.4) | 0.04 | 10.1 (9.4, 10.9) | 0.26 |
| Polygamous, ≥2nd wife | 1.08 (1.03, 1.13) | 0.61 | 172.8 (163.4, 182.8) | 0.71 | 10.4 (9.7, 11.0) | 0.51 |
| Ethnicity, maternal | 0.83 | 0.89 | 0.59 | |||
| Hausa | 1.08 (1.05, 1.11) | REF | 169.3 (164.4, 174.3) | REF | 10.5 (10.1, 11.0) | REF |
| Taureg | 1.06 (0.98, 1.13) | 0.56 | 169.3 (156.0, 183.6) | 0.99 | 10.1 (9.3, 11.1) | 0.40 |
| Other (minority) | 1.07 (0.96, 1.18) | 0.83 | 174.3 (154.8, 196.3) | 0.63 | 10.8 (9.6, 12.2) | 0.62 |
| Education, maternal | 0.08 | 0.41 | 0.27 | |||
| None | 1.08 (1.05, 1.12) | REF | 166.5 (160.9, 172.3) | REF | 10.5 (10.1, 11.0) | REF |
| Koranic schooling | 1.11 (1.06, 1.16) | 0.29 | 173.1 (164.1, 182.6) | 0.21 | 10.8 (10.2, 11.4) | 0.46 |
| Primary (1–6 years) | 1.02 (0.96, 1.08) | 0.07 | 173.3 (162.4, 184.9) | 0.27 | 10.0 (9.3, 10.7) | 0.13 |
| Secondary (7–14 years) | 1.03 (0.94, 1.12) | 0.25 | 176.8 (160.3, 195.0) | 0.25 | 10.2 (9.2, 11.2) | 0.48 |
| Obstetric history | ||||||
| Primigravida | 0.74 | 0.34 | 0.52 | |||
| Yes | 1.07 (1.00, 1.13) | 164.0 (152.3, 176.5) | 10.3 (9.5, 11.1) | |||
| No | 1.08 (1.05, 1.11) | 170.2 (165.3, 175.1) | 10.5 (10.1, 10.9) | |||
| Attended ANC in last pregnancy | 0.32 | 0.25 | 0.82 | |||
| Yes | 1.07 (1.05, 1.10) | 169.0 (164.0, 174.2) | 10.5 (10.1, 11.0) | |||
| No | 1.12 (1.03, 1.20) | 178.8 (163.2, 195.9) | 10.4 (9.5, 11.4) | |||
| Result of last pregnancy, n (%) | 0.31 | 0.28 | 0.17 | |||
| Miscarriage, stillbirth | 1.14 (1.02, 1.26) | 0.26 | 189.3 (165.2,217.1) | 0.11 | 11.2 (9.9, 12.8) | 0.35 |
| Live birth, child deceased | 1.11 (1.04, 1.19) | 0.26 | 169.7 (156.4, 184.3) | 0.94 | 9.9 (9.1, 10.8) | 0.12 |
| Live birth, child living | 1.07 (1.04, 1.10) | REF | 169.2 (164.1, 174.4) | REF | 10.6 (10.2, 11.0) | REF |
| Knowledge, attitudes and practices | ||||||
| Attended ANC in current pregnancy | 0.96 | 0.57 | 0.37 | |||
| Yes | 1.08 (1.05, 1.11) | 168.6 (163.3, 174.2) | 10.4 (10.0, 10.9) | |||
| No | 1.08 (1.03, 1.12) | 171.5 (163.1, 180.4) | 10.7 (10.1, 11.3) | |||
| IFA coverage | 0.76 | 0.05 | 0.98 | |||
| Yes | 1.08 (1.05, 1.11) | 165.9 (160.2, 171.8) | 10.5 (10.0, 11.0) | |||
| No | 1.07 (1.03, 1.11) | 175.7 (167.8, 183.9) | 10.5 (10.0, 11.1) | |||
| IFA adherence | 0.54 | 0.17 | 0.97 | |||
| Yes | 1.07 (1.03, 1.11) | 165.8 (159.2, 172.8) | 10.5 (10.0, 11.0) | |||
| No | 1.08 (1.05, 1.12) | 172.2 (166.1, 178.5) | 10.5 (10.0, 11.0) | |||
| Utilization of mosquito net | 0.59 | 0.26 | 0.76 | |||
| Yes | 1.08 (1.05, 1.11) | 170.8 (165.6, 176.1) | 10.5 (10.1, 11.0) | |||
| No | 1.06 (1.01, 1.12) | 164.7 (155.6, 174.4) | 10.4 (9.8, 11.1) | |||
| Quantity of food consumed during pregnancy | 0.89 | 0.20 | 0.18 | |||
| Increased | 1.09 (1.04, 1.14) | 0.73 | 163.5 (154.6, 173.0) | 0.07 | 11.0 (10.3, 11.7) | 0.19 |
| Decreased | 1.07 (1.04, 1.11) | 0.91 | 168.9 (162.9, 175.2) | 0.27 | 10.3 (9.9, 10.8) | 0.73 |
| No change | 1.08 (1.03, 1.12) | REF | 174.7 (166.3, 183.5) | REF | 10.5 (9.9, 11.0) | REF |
| Number of meals consumed during pregnancy | 0.05 | 0.20 | 0.59 | |||
| Increased | 1.11 (1.06, 1.17) | 0.03 | 164.3 (154.7, 174.4) | 0.11 | 10.7 (10.1, 11.4) | 0.63 |
| Decreased | 1.09 (1.06, 1.13) | 0.04 | 167.2 (160.8, 173.8) | 0.15 | 10.4 (9.9, 10.9) | 0.56 |
| No change | 1.04 (1.00, 1.08) | REF | 174.1 (166.7, 181.8) | REF | 10.5 (10.0, 11.1) | REF |
| Adequate minimum dietary diversity—women (MDD-W) | 0.27 | 0.38 | 0.62 | |||
| Yes | 1.05 (1.00, 1.11) | 173.5 (163.7, 183.9) | 10.4 (9.7, 11.0) | |||
| No | 1.08 (1.05, 1.11) | 168.6 (163.6, 173.6) | 10.5 (10.1, 11.0) | |||
| Consumed vitamin A rich foods in past 24 h | 0.52 | 0.19 | 0.54 | |||
| Yes | 1.08 (1.05, 1.11) | 168.4 (163.5, 173.3) | 10.5 (10.1, 11.0) | |||
| No | 1.06 (1.00, 1.12) | 176.7 (165.1, 189.1) | 10.3 (9.6, 11.1) | |||
| Consumed animal source foods in past 24 h | 0.91 | 0.01 | 0.32 | |||
| Yes | 1.08 (1.04, 1.12) | 177.1 (169.7, 184.8) | 10.3 (9.8, 10.9) | |||
| No | 1.08 (1.04, 1.11) | 165.4 (160.0, 170.9) | 10.6 (10.1, 11.1) | |||
| Consumed clay | 0.10 | 0.01 | 0.64 | |||
| Yes | 1.02 (0.94, 1.09) | 153.1 (140.7, 166.6) | 10.3 (9.5, 11.2) | |||
| No | 1.08 (1.05, 1.11) | 171.2 (166.3, 176.1) | 10.5 (10.1, 10.9) | |||
| Nutritional and health status | ||||||
| Malaria antigenemia (elevated HRP2) | 0.01 | 0.77 | 0.64 | |||
| Yes | 1.00 (0.93, 1.06) | 167.9 (156.4, 180.2) | 10.3 (9.6, 11.1) | |||
| No | 1.09 (1.06, 1.12) | 169.7 (164.9, 174.7) | 10.5 (10.1, 10.9) | |||
1 RBP, retinol binding protein; APP, acute phase proteins; ANC, antenatal care; IFA, iron and folic acid; HRP2, histidine rich protein 2; REF = reference; 2 RBP: continuous adjustment to the 10th percentile of study specific C-reactive protein and α-1-acid glycoprotein concentrations.; 3 Vitamin B12 and folate: logarithmically transformed; 4 Data exclude participants in first trimester, n = 1.