Table 2

Multivariable poisson regression models of incidence of vitamin D supplementation prescribing in children stratified by sex.

	Male	Female
	IRR* (95% CI)	IRR* (95% CI)
Age group
Up to 6 months	1.00 (Reference)	1.00 (Reference)
6 months–4 years	1.93 (1.21 to 3.07)	1.28 (0.84 to 1.96)
5–11 years	2.47 (1.55 to 3.92)	2.25 (1.48 to 3.42)
12–17 years	4.15 (2.61 to 6.60)	7.41 (4.87 to 11.27)
Ethnicity
White	1.00 (Reference)	1.00 (Reference)
Asian	5.05 (4.60 to 5.54)	4.46 (4.12 to 4.81)
Black	2.83 (2.53 to 3.18)	2.83 (2.58 to 3.10)
Others	2.68 (2.20 to 3.26)	2.72 (2.33 to 3.19)
Mixed	1.93 (1.59 to 2.33)	1.84 (1.57 to 2.16)
Missing	1.48 (1.37 to 1.61)	1.42 (1.33 to 1.52)
Townsend index
1 (least deprived)	1.00 (Reference)	1.00 (Reference)
2	1.03 (0.92 to 1.17)	1.03 (0.94 to 1.14)
3	1.18 (1.06 to 1.33)	1.20 (1.09 to 1.32)
4	1.37 (1.22 to 1.53)	1.37 (1.25 to 1.51)
5 (most deprived)	1.41 (1.25 to 1.59)	1.44 (1.31 to 1.59)
Missing	1.38 (1.19 to 1.60)	1.43 (1.26 to 1.62)
Country
England	1.00 (Reference)	1.00 (Reference)
Wales	0.34 (0.25 to 0.46)	0.33 (0.25 to 0.46)
Scotland	0.24 (0.19 to 0.32)	0.18 (0.14 to 0.23)
Northern Ireland	0.24 (0.16 to 0.37)	0.17 (0.11 to 0.27)
Year
2008	1.00 (Reference)	1.00 (Reference)
2009	2.47 (1.73 to 3.51)	2.61 (1.93 to 3.52)
2010	3.68 (2.63 to 5.15)	4.97 (3.75 to 6.58)
2011	6.72 (4.88 to 9.25)	8.04 (6.12 to 10.56)
2012	14.60 (10.72 to 19.90)	16.16 (12.39 to 2.08)
2013	21.10 (15.52 to 28.67)	22.82 (17.53 to 29.72)
2014	25.81 (18.99 to 35.09)	28.14 (21.60 to 36.65)
2015	29.19 (21.44 to 39.76)	33.53 (25.70 to 43.74)
2016	32.27 (23.64 to 44.05)	38.87 (29.75 to 50.80)

*Adjusted for all variables listed in the table. The multilevel models included the general practice as a random effect.
CI, confidence interval; IRR, incidence rate ratio.