TABLE 3.
Association of 25-hydroxyvitamin D at 6 weeks and 6 months of age with incidence of diarrhea, upper respiratory tract infection, acute lower respiratory tract infection, and clinical malaria during follow-up
| Vitamin D at 6 weeks of age | <10 ng/mL | P | 10–19.9 ng/mL (Reference) | P | ≥20 ng/mL |
| Diarrhea | |||||
| Mean diagnoses/year | 1.12 | 1.01 | 1.30 | ||
| Crude IRR (95% CI) | 0.85 (0.67–1.08) | 0.18 | 0.78 (0.63–0.97) | 0.02 | Ref. |
| Adjusted* IRR (95% CI) | 0.82 (0.63–1.07) | 0.14 | 0.82 (0.65–1.03) | 0.09 | Ref. |
| URI | |||||
| Mean diagnoses/year | 3.98 | 3.47 | 4.02 | ||
| Crude IRR (95% CI) | 0.97 (0.83–1.13) | 0.68 | 0.86 (0.75–1.00) | 0.05 | Ref. |
| Adjusted* IRR (95% CI) | 0.94 (0.79–1.11) | 0.46 | 0.87 (0.75–1.01) | 0.08 | Ref. |
| ALRI | |||||
| Mean diagnoses/year | 0.74 | 0.73 | 0.85 | ||
| Crude IRR (95% CI) | 0.85 (0.64–1.14) | 0.29 | 0.86 (0.65–1.14) | 0.29 | Ref. |
| Adjusted* IRR (95% CI) | 0.84 (0.61–1.17) | 0.30 | 0.81 (0.60–1.08) | 0.15 | Ref. |
| Clinical malaria | |||||
| Mean diagnoses/year | 0.98 | 0.87 | 0.97 | ||
| Crude IRR (95% CI) | 1.00 (0.76–1.31) | 0.97 | 0.91 (0.70–1.18) | 0.48 | Ref. |
| Adjusted* IRR (95% CI) | 1.09 (0.80–1.49) | 0.58 | 0.96 (0.72–1.26) | 0.75 | Ref. |
| Vitamin D at 6 months of age | <20 ng/mL | P | 20–29.9 ng/mL (Reference) | P | ≥30 ng/mL |
| Diarrhea | |||||
| Mean diagnoses/year | 0.52 | 0.42 | 0.44 | ||
| Crude IRR (95% CI) | 1.21 (0.82–1.80) | 0.34 | 1.01 (0.71–1.44) | 0.96 | Ref. |
| Adjusted* IRR (95% CI) | 1.20 (0.83–1.75) | 0.33 | 1.03 (0.74–1.45) | 0.85 | Ref. |
| URI | |||||
| Mean diagnoses/year | 2.92 | 2.76 | 2.97 | ||
| Crude IRR (95% CI) | 0.99 (0.82–1.19) | 0.91 | 0.97 (0.84–1.12) | 0.70 | Ref. |
| Adjusted* IRR (95% CI) | 0.99 (0.83–1.19) | 0.93 | 0.98 (0.85–1.14) | 0.81 | Ref. |
| ALRI | |||||
| Mean diagnoses/year | 0.56 | 0.47 | 0.69 | ||
| Crude IRR (95% CI) | 0.82 (0.68–1.16) | 0.27 | 0.72 (0.53–0.97) | 0.03 | Ref. |
| Adjusted* IRR (95% CI) | 0.81 (0.57–1.15) | 0.23 | 0.67 (0.50–0.91) | 0.01 | Ref. |
| Clinical malaria | |||||
| Mean diagnoses/year | 0.97 | 0.86 | 0.75 | ||
| Crude IRR (95% CI) | 1.31 (0.96–1.78) | 0.08 | 1.20 (0.92–1.56) | 0.17 | Ref. |
| Adjusted* IRR (95% CI) | 1.33 (0.97–1.82) | 0.08 | 1.22 (0.93–1.59) | 0.15 | Ref. |
ALRI = acute lower respiratory tract infection; IRR = incidence rate ratio; URI = upper respiratory tract infection; 25(OH)D = 25-hydroxyvitamin D.
*Multivariate models adjusted for maternal age, maternal education, parity, wealth tertile, child sex, randomized regimen, breastfeeding method, low birthweight (<2500 g), prematurity (<37 weeks), and season of 25(OH)D assessment.