Age at menarche in Korean adolescents: trends and influencing factors

Table 2 Average age at menarche and percentage of girls who had experienced menarche by age

	Total 2001–2011		II 2001		III 2005		IV 2007–2009		V 2010/2011		p-value
Average age at Menarche
Mean SE	12.71 ± 0.03		13.40 ± 0.06		13.08 ± 0.06		12.38 ± 0.04		12.38 ± 0.05		<0.0001
Number of total respondents
	3409		680		576		1299		854
Number of respondents experienced menarche
	2402		460		389		926		627
Percentage of girls who experienced menarche
Age (y)	n	%	n	%	n	%	n	%	n	%
10.0–10.9	461	8.0	91	8.8	79	5.1	174	7.5	117	10.3	0.6429
11.0–11.9	446	26.7	84	21.4	76	15.8	176	29.0	110	34.6	0.0084
12.0–12.9	410	60.0	78	42.3	68	63.2	174	65.5	90	62.2	0.0036
13.0–13.9	422	85.3	79	76.0	82	80.5	148	87.8	113	92.0	0.0018
14.0–14.9	403	95.8	76	94.7	68	95.6	161	95.7	98	96.9	0.4384
15.0–15.9	347	98.0	75	97.3	59	96.6	133	100.0	80	96.3	0.4801
16.0–16.9	331	98.8	65	98.5	53	98.1	125	99.2	88	98.9	0.6114
17.0–17.9	341	99.4	77	100.0	54	98.2	114	99.1	96	100.0	0.9318
18.0–18.9	248	99.2	55	100.0	37	97.3	94	98.9	62	100.0	0.9071

Data are expressed as mean ± SE
n: the total number of girls at each age who had answered the status of menarche
%: the percentage of girls who had experienced menarche among girls who had answered the status of menarche question

ISSN: 1742-4755