Table 2.

Prevalence of anaemia, iron deficiency (ID) and iron-deficiency anaemia (IDA) among schoolchildren aged 7–11 years from Guangzhou, China, 2014–2015

Age (years)	n	Overall (n 5295)	Boys (n 2866)	Girls (n 2429)	P value
		Anaemia (%)
7	1273	7·1	5·8	8·7	0·048*
8	1099	6·7	7·2	6·3	0·549
9	1005	6·7	6·5	6·9	0·800
10	1027	5·4	5·2	5·6	0·783
11	891	7·1	6·8	7·4	0·707
7–8	2372	6·9	6·4	7·5	0·296
9–11†	2923	6·3	6·1	6·6	0·600
Total	5295	6·6	6·2	7·0	0·271
		ID (%)
7	1273	8·0	9·5	6·2	0·032*
8	1099	6·4	7·9	4·7	0·034*
9	1005	5·2	6·7	3·4	0·021*
10	1027	4·8	5·4	4·1	0·335
11	891	6·3	5·1	7·7	0·120
7–8	2372	7·3	8·8	5·5	0·002*
9–11†	2923	5·4†	5·7†	4·9	0·343
Total	5295	6·2	7·1	5·2	0·004*
		IDA (%)
7	1273	0·9	1·0	0·7	0·587
8	1099	0·9	1·0	0·8	0·613
9	1005	0·3	0·4	0·2	0·653
10	1027	0·2	0·2	0·2	0·898
11	891	0·6	0·2	1·0	0·119
7–8	2372	0·9	1·0	0·7	0·461
9–11†	2923	0·3†	0·3†	0·4	0·363
Total	5295	0·6	0·6	0·6	0·936

Data are presented as number or percentage.

Anaemia was defined as Hb concentration <115 g/l, as proposed by WHO in 2001⁽¹⁾.

ID was defined by a multiple-index model, as proposed by the Chinese Medical Association in 2010⁽¹⁶⁾.

IDA was defined as the presence of both anaemia and ID⁽¹⁾.

^* P < 0·05, boys v. girls, assessed by the χ ² test for categorical variables.

^† P < 0·05, age 7–8 years v. 9–11 years, assessed by the χ ² test for categorical variables.