Table 2.

Average vitamin D serum levels and deficiency/insufficiency in the Qatari population at different age groups.

Age group		Study	Study	Average serum vitamin D levels	Prevalence of vitamin D <75nmol/L
Years*	n		n	(nmol/L)	(%)
<16	698	Bener et al.42,43#	170	46.2±23.0	85
		Bener et al.37	464	66.9±24.7	83
		Racinais et al.39	64	NS	100
		Weighted average§		(60.6-62.2)	(85.9-86.4)
				61.4±10.0	86.2±2.4
16-30	163	Hamilton et al.40	92	NS	100
		Shrief and Rizk38	71	NS	97
		Weighted average		^	93.9±5.3
					(93.5-94.3)
>30	838	Mahdy et al.41	340	29.2	97
		El-Menyar et al.44	498	35.9±27.5	91
		Weighted average		33.2±3.4	93.4±3.1
				(31.9-32.5)	(93.1-93.6)
O verall°	1699	Weighted overall average		45.3±14.3$	90.4±7.2**
				(44.6-46.0)	(90.1-90.8)

*Stratifying vitamin D level by age was carried out from the average age of the study population (Table 1). Stratifying vitamin D level by gender from the selected reports was not possible given the way in which the data were in the original studies.

°Overall represents the entire age range from <16 to >30 years.

#The same study reported in two publications, with additional information in the more recent report.

§Data represent weighted average±standard deviation (SD). Numbers in parentheses are 95% confidence intervals (CI) for weighted average.

^Data in three of the selected studies (ref. ns. 38-40) did not allow this value to be generated.

$Calculated from 1472 subjects extracted from 4 of the selected studies in which the relevant information was available (ref. ns. 37, 41-44).

**Calculated from the 7 selected studies (n=1699). NS, values not stated in the original report.