Table 2.
Association Between Vitamin D Concentrations and Risk of Incident Tuberculosis Disease
| Median (IQR) | Person-years | Incident Tuberculosis Diseasea | Univariable Model, HR (95% CI) | Multivariable Model,b AHR (95% CI) | |
|---|---|---|---|---|---|
| All follow-upc | |||||
| Vitamin D deficient, <50 nmol/L | 33.9 (22.4, 41.4) | 4146.7 | 51 | 1.1 (.6–2.1) | .8 (.4-1.6) |
| Vitamin D deficient, <30 nmol/L | 17.3 (9.0, 24.3) | 1595.6 | 26 | 1.3 (.8–2.3) | 1.5 (.7-3.1) |
| Vitamin D concentration | |||||
| Tertile 1 (n = 258) | 18.6 (9.8, 25.8) | 1706.8 | 27 | 1 (referent) | 1 (referent) |
| Tertile 2 (n = 258) | 37.4 (34.3, 41.0) | 1698.1 | 19 | .7 (.4–1.3) | .8 (.5–1.5) |
| Tertile 3 (n = 258) | 51.4 (47.3, 58.8) | 1773.3 | 16 | .6 (.3–1.1) | .7 (.4–1.4) |
| Ptrend | .083 | .4229 | |||
| Less than 1 year of age | |||||
| Vitamin D deficient, <50 nmol/L | 33.9 (22.4, 41.5) | 624.0 | 22 | .9 (.4–2.1) | .7 (.3–1.7) |
| Vitamin D deficient, <30 nmol/L | 17.3 (9.0, 24.3) | 242.0 | 13 | 1.3 (.6–2.5) | 1.5 (.7–3.1) |
| Vitamin D concentration | |||||
| Tertile 1 (n = 258) | 18.6 (9.8, 25.8) | 250.4 | 16 | 1 (referent) | 1 (referent) |
| Tertile 2 (n = 258) | 37.4 (34.2, 41.0) | 253.8 | 10 | .6 (.3–1.4) | .8 (.4–1.8) |
| Tertile 3 (n = 258) | 51.4 (47.3, 58.8) | 254.6 | 8 | .5 (.2–1.1) | .8 (.3–1.9) |
| Ptrend | .101 | .5607 |
Abbreviations: AHR, adjusted hazard ratio; CI, confidence interval; HIV, human immunodeficiency virus; HR, hazard ratio; IQR, interquartile range.
aThis is the number of incident tuberculosis cases in the specified row but may not include all cases in the comparison group. For example, in the first row describing the “Vitamin D deficient, <50 nmol/L” group, the number of incident tuberculosis disease cases is 51 but the number of cases in the vitamin D insufficient/sufficient comparator group is not listed.
bAll models were adjusted for sex of the child, study site, season of birth, and maternal HIV using Cox regression models.
cAll follow-up time was restricted to certain ages based on distance from birth. The specified time indicates the starting point time. For example, the primary outcome is follow-up for tuberculosis disease starting at <1 year of age until the end of follow-up.