Table 2.
Observational studies correlating vitamin D deficiencies with respiratory tract infection and influenza.
| Study | Length | Study type | Study population | Control population | Average 25(OH)D level associated with increased RTI/influenza ng/ml (nmol/l) | Average 25(OH)D level in controls ng/ml (nmol/l) | P-value | 95% confidence interval |
|---|---|---|---|---|---|---|---|---|
| Laaksi et al.66 | 6 months | Prospective cohort | 24 (100% male, age 18–29) | 628 (100% male, age 18–29) | <16.0 (40.0) | 32.1 (80.2) | 0.004* | 1.15–2.24 |
| Roth et al.67 | 2 months | Case–control (ALRI) | 25 (20% female, median age 4.2 months) | 25 (20% female, median age 4.2 months) | 11.7 (29.1) | 15.7 (39.1) | 0.0146* | 0.30–0.96 |
| Wayse et al.68 | 4 months | Case–control (ALRI) | 80 (36.3% female, median age 23.9 months) | 70 (45.7% female, median age 23.9 months) | 9.12 (22.8) | 15.4 (38.4) | 0.001* | 0.03–0.24 |
| Karatekin et al.69 | 4 months | Case–control (ALRI) | 25 (36% female, 10.9 days) | 15 (60% female, 5.6 days) | <10.0 (25) | 16.3 (40.8) | 0.041* | 1.058–17.070 |
| McNally et al.70 | 7 months | Case–control (ALRI) | 105 (41% female, median age, 13.8 months) | 92 (42% female, median age, 13.4 months) | 32.5 (81) | 33.3 (83.0) | 0.71 | N/A |
| Roth et al.71 | 3 months | Case–control (ALRI) | 64 (36% female, median age 8.4 months) | 65 (25% female, median age 13.3 months) | 30.8 (77) | 30.9 (77.2) | 0.960 | 0.998–1.002 |
| a Ginde et al.72 | 4 years | Retrospective Cohort | 3588 (47.3% female) | 15,295 (52% female, median age 38) | 10 (25.0), 28 (69.9) | 29.0 (72.4) | <.05*<.001* | 1.18–2.05 1.11–1.47 |
ALRI = Acute Lower Respiratory Tract Infection.
Values in nmol/l given in parentheses.
*
P-values of less than 0.05 considered significant.
a
Categories separated by severe (<10 ng/ml) vitamin D deficiency and rest of patient population.