Table 2.

Sample characteristics of the Otago School Students Lifestyle Survey Two (OSSLS2)^*

	Total (n 681)		Female (n 297)		Male (n 384)
	Median or n	IQR or %	Median or n	IQR or %	Median or n	IQR or %	P value†
Age (years)‡	16·1	15·5–17·0	15·9	15·5–16·9	16·3	15·6–17·2	<0·001
NZDQI-A score‡	52·3	41·4–62·6	52·6	41·9–62·4	51·3	40·8–63·4	0·931
Ethnicity
NZEO	612	90	258	87	354	92	0·067
Māori	59	9	34	11	25	7
Pacific	10	1	5	2	5	1
NZDep2006
1 (least deprived)	278	42	128	44	150	40	0·846
2	130	20	54	18	76	20
3	114	17	48	16	66	18
4	99	15	45	15	54	15
5 (most deprived)	43	6	17	6	26	7
School year
11	300	44	158	53	142	37	<0·001
12	206	30	78	26	128	33
13	175	26	61	21	114	30
School Decile Rating
Middle	268	39	124	42	144	38	0·260
High	413	61	173	58	240	62
Obesity status§
Overweight or obese	181	27	80	27	101	26	0·853
Obese	42	6	14	5	28	7	0·166
Central obesity||
Waist-to-height ratio ≥0·5	87	13	37	12	50	13	0·827

IQR, interquartile range; NZDQI-A, New Zealand Diet Quality Index for Adolescents; NZEO, New Zealand European or Others; NZDep2006, New Zealand Deprivation Index 2006.

^*Continuous variables are presented as median and interquartile range; categorical variables are presented as frequency and percentage.

^† P value of a Mann–Whitney U test for age and NZDQI-A, or of a χ ² test for other variables.

^‡Values represented as median and IQR.

^§Defined using the age- and sex-specific BMI cut-offs by Cole et al. ^{( 50 , 51 )}.

^||Defined as waist-to-height ratio greater than or equal to 0·5.