Table 2.
Associations Between Socio-Demographic Factors and Diagnosis of Vitamin D Deficiency (n=414 182)a
| Single-level Model |
Multilevel Model |
|||||
|---|---|---|---|---|---|---|
| Characteristic | Adjusted IRRb (95% CI) | P valuec | Adjusted IRRb (95% CI) | P valuec | ||
| Sex, stratified by age group | <0.001 | <0.001 | ||||
| 0-4 years: | Male | 1 | 1 | |||
| Female | 0.73 (0.57-0.93) | 0.72 (0.57-0.92) | ||||
| 5-9 years: | Male | 1 | 1 | |||
| Female | 1.06 (0.87-1.29) | 1.04 (0.86-1.27) | ||||
| 10-14 years: | Male | 1 | 1 | |||
| Female | 1.97 (1.71- 2.27) | 1.97 (1.71-2.27) | ||||
| 15-17 years: | Male | 1 | 1 | |||
| Female | 2.60 (2.18-3.11) | 2.65 (2.21-3.16) | ||||
| Age group, stratified by sex | <0.001 | <0.001 | ||||
| Males | 0-4 years | 1 | 1 | |||
| 5-9 years | 1.22 (0.99-1.50) | 1.20 (0.98-1.48) | ||||
| 10-14 years | 2.22 (1.83-2.70) | 2.19 (1.80-2.65) | ||||
| 15-17 years | 2.39 (1.93-2.96) | 2.36 (1.90-2.93) | ||||
| Females: | 0-4 years | 1 | 1 | |||
| 5-9 years | 1.77 (1.41-2.23) | 1.73 (1.37-2.18) | ||||
| 10-14 years | 6.00 (4.91-7.34) | 5.95 (4.86-7.27) | ||||
| 15-17 years | 8.52 (6.93-10.5) | 8.61 (7.00-10.6) | ||||
| Ethnicityd | <0.001 | <0.001 | ||||
| White | 1 | 1 | ||||
| Asian or Asian British | 22.4 (20.1-24.9) | 7.98 (6.98-9.13) | ||||
| Black or black British | 14.2 (12.5-16.2) | 5.47 (4.70-6.37) | ||||
| Mixed | 5.64 (4.52-7.03) | 2.99 (2.38-3.76) | ||||
| Chinese or other ethnic group | 8.91 (7.38-10.8) | 3.63 (2.96-4.45) | ||||
| IMD quintile | <0.001 | <0.001 | ||||
| 1 (least deprived) | 1 | 1 | ||||
| 2 | 1.98 (1.63-2.41) | 1.34 (1.07-1.67) | ||||
| 3 | 2.40 (2.00-2.88) | 1.41 (1.12-1.77) | ||||
| 4 | 2.67 (2.23-3.20) | 1.63 (1.29-2.05) | ||||
| 5 (most deprived) | 3.54 (2.96-4.24) | 1.96 (1.52-2.53) | ||||
| Calendar year | <0.001 | <0.001 | ||||
| 2008 | 1 | 1 | ||||
| 2009 | 2.20 (1.45-3.35) | 2.19 (1.44-3.34) | ||||
| 2010 | 3.87 (2.62-5.71) | 3.66 (2.48-5.40) | ||||
| 2011 | 6.61 (4.55-9.60) | 6.28 (4.32-9.12) | ||||
| 2012 | 12.7 (8.83-18.2) | 12.1 (8.43-17.4) | ||||
| 2013 | 14.7 (10.2-21.1) | 14.1 (9.85-20.3) | ||||
| 2014 | 14.7 (10.2-21.2) | 15.7 (10.9-22.6) | ||||
CI, confidence interval; IMD, Index of Multiple Deprivation; IRR, incidence rate ratio.
Results of multivariable Poisson regression models of rates of incident diagnosis of vitamin D deficiency. Missing data is handled using complete cases analysis.
Adjusted for all variables listed in the table, including an interaction term between age and sex (likelihood ratio test for interaction p value<0.001). The multilevel model additionally included the general practice as a random effect.
P values from likelihood ratio tests comparing nested models.
Ethnicity data was taken from the child’s THIN or HES record for 84.6% of children. Maternal ethnicity was used as a proxy measure for the remaining 15.4%.