A reversed gender pattern? A meta-analysis of gender differences in the prevalence of non-suicidal self-injurious behaviour among Chinese adolescents

Table 1 The gender difference in NSSI prevalence by sample types

	Number of studies	Men		Women		Odds Ratio	95% CI	Test of heterogeneity
	Number of studies	Events	Total	Events	Total	Odds Ratio	95% CI	Test of heterogeneity
College students	10	2425	7892	2304	9846	1.56	1.30,1.87***	Q(9) = 34.33, p < 0.0001
Middle school students^a	19	8404	37,806	10,000	42,642	0.83	0.73,0.94**	Q(18) = 211.71, p < 0.00001
Clinical sample	6	392	392	560	560	0.88	0.41,1.89	Q(5) = 70.48, p < 0.00001
Total	35	11,221	46,090	12,864	53,048	0.96	0.84,1.10	Q(34) = 575.84, p < 0.00001
Heterogeneity: τ ² = 0.14, χ ² = 575.84, df = 34 (p < 0.00001), I² = 94% Test of overall effect: Z = 0.59 (p = 0.56),
Test for subgroup difference: χ ² = 31.05, df = 2 (p < 0.00001), I² = 93.6%

*p < 0.05 for total effect, **p < 0.01 for total effect, ***p < 0.001 for total effect
^a There are 17 studies among middle school students, but one of which provided three groups of data (Yang, Han & Shao, 2013), therefore, there are 19 groups of data were included into the analysis

ISSN: 1471-2458