Secular trends in age at menarche among Chinese girls from 24 ethnic minorities, 1985 to 2010

Figures & data

Fig. 1 The locations of 24 ethnic minorities sampled in China.

Table 1 The distribution and sample size of girls aged 9–18 among 24 ethnic minorities from 1985 to 2010

Ethnic minorities	Source province/region	Number (millions) (27)^a	Minority population ranking^a	1985	1991	1995	2000	2005	2010
Mongolian (urban)	Inner Mongolia	5.98	9	700	1,452	–	1,190	653	559
Mongolian (rural)	Autonomous Region			900	1,333	–	1,202	1,176	992
Mongolian (combined)				1,600	2,785	–	2,392	1,829	1,551
Hui (urban)	Ningxia Hui Autonomous	10.59	2	800	1,000	1,205	999	583	962
Hui (rural)	Region			694	1,000	1,193	1,000	1,462	1,185
Hui (combined)				1,494	2,000	2,398	1,999	2,045	2,147
Uighur (urban)	Xinjiang Uyghur	10.07	4	699	1,693	1,200	689	–	885
Uighur (rural)	Autonomous Region			700	1,700	1,200	312	–	1,008
Uighur (combined)				1,399	3,393	2,400	1,001	–	1,893
Kazakh (Hasake)		1.46	17	860	–	1,199	–	–	1,200
Kirghiz		0.19	31	449	–	1,200	500	–	1,225
Zhuang (urban)	Guangxi Zhuang	16.93	1	612	1,000	1,155	992	490	970
Zhuang (rural)	Autonomous Region			714	999	1,200	1,006	356	973
Zhuang (combined)				1,326	1,999	2,355	1,998	846	1,943
Yao		2.80	12	616	–	1,199	1,001	989	859
Korean (urban)	Jilin	1.83	14	800	998	1,199	981	395	1,034
Korean (rural)				1,100	984	1,198	989	474	1,117
Korean (combined)				1,900	1,982	2,397	1,970	869	2,151
Tibetan	Tibet Autonomous Region	6.28	8	769	994	1,197	1,144	999	1,047
Miao	Guizhou	9.43	5	696	982	1,101	1,720	999	992
Buyi	Guizhou	2.87	11	1,184	1,000	1,181	982	973	996
Dong	Guizhou	2.88	10	723	965	1,200	931	998	983
Tujia	Hunan	8.35	7	500	–	–	998	1,015	1,016
Bai	Yunnan	1.93	13	800	1,020	–	1,001	1,100	1,072
Hani	Yunnan	1.66	15	734	918	1,154	–	1,074	1,094
Dai	Yunnan	1.26	18	609	996	–	972	1,085	1,064
Lisu	Yunnan	0.70	20	728	–	1,106	–	1,087	1,027
Wa (Va)	Yunnan	0.43	24	613	–	1,090	–	1,098	1,076
Naxi (Nakhi)	Yunnan	0.33	26	700	1,018	1,200	–	1,096	1,094
Li	Hainan	1.46	16	700	999	1,200	909	–	865
Tu	Qinghai	0.29	28	1,103	583	600	1,001	1,059	1,085
Sala	Qinghai	0.13	34	224	574	600	999	1,051	1,072
Qiang	Sichuan	0.31	27	861	–	1,232	848	1,170	1,149
Yi	Sichuan	8.71	6	865	–	–	–	–	1,175
Total				21,739	23,186	27,145	24,319	21,382	31,711

^aAccording to the Sixth National Census in 2010.

Fig. 2 The clustering pattern of age at menarche among girls aged 9–18 from 24 ethnic minorities.

Table 2 Age at menarche (95% CI) of girls aged 9–18 among 24 ethnic minorities from 1985 to 2010

Ethnic minorities	1985	1991	1995	2000	2005	2010	Difference 1985 to 2010	Months of decline per decade
Mongolian (urban)	13.68 (13.50–13.87)	13.73 (13.32–14.15)	–	12.96 (12.76–13.44)	12.51 (12.02–12.94)	12.26 (12.06–12.46)	−1.42*	6.82
Mongolian (rural)	14.06 (13.90–14.25)	13.95 (13.56–14.35)	–	13.44 (12.00–14.66)	12.93 (12.76–13.09)	12.52 (12.36–12.68)	−1.54*	7.39
Mongolian (combined)	13.95 (13.82–14.07)	13.93 (13.53–14.35)	–	13.27 (12.47–14.01)	12.78 (12.51–13.04)	12.44 (12.03–12.84)	−1.51*	7.25
Hui (urban)	13.60 (13.42–13.79)	13.22 (12.98–13.46)	13.14 (12.92–13.35)	13.03 (12.88–13.25)	12.90 (12.70–13.10)	13.03 (12.46–13.56)	−0.57*	2.74
Hui (rural)	13.95 (13.83–14.07)	13.33 (13.02–13.65)	13.73 (13.53–13.94)	13.90 (13.47–14.30)	13.43 (13.12–13.73)	13.20 (11.88–14.68)	−0.75	3.60
Hui (combined)	13.73 (13.55–13.91)	13.38 (13.15–13.60)	13.46 (13.30–13.62)	13.44 (12.63–14.18)	13.28 (13.00–13.54)	13.09 (12.42–13.76)	−0.64*	3.07
Uighur (urban)	14.21 (14.04–14.38)	14.03 (13.84–14.22)	13.57 (13.36–13.78)	13.47 (13.26–13.72)	–	13.56 (12.92–14.12)	−0.65*	3.12
Uighur (rural)	14.44 (14.25–14.63)	14.29 (14.03–14.54)	14.49 (14.28–14.70)	13.48 (13.29–13.77)	–	13.78 (13.40–14.14)	−0.66*	3.17
Uighur (combined)	14.42 (14.29–14.54)	14.17 (14.00–14.35)	13.92 (13.77–14.08)	13.48 (13.30–13.80)	–	13.67 (13.34–13.99)	−0.75*	3.60
Kazakh (Hasake)	14.54 (14.39–14.69)	–	13.82 (13.64–14.02)	–	–	12.85 (12.70–13.00)	−1.69*	8.11
Kirghiz	14.72 (14.49–14.95)	–	14.65 (14.44–14.86)	13.86 (13.67–14.03)	–	13.40 (12.81–13.96)	−1.32*	6.34
Zhuang (urban)	13.35 (13.18–13.53)	12.97 (12.64–13.30)	13.11 (12.92–13.30)	12.58 (11.90–13.22)	13.02 (12.69–13.33)	12.26 (12.11–12.41)	−1.09*	5.23
Zhuang (rural)	13.20 (12.97–14.43)	13.12 (12.58–13.39)	14.68 (14.41–14.96)	13.12 (12.20–13.89)	12.42 (11.84–12.99)	12.79 (12.30–13.28)	−0.41*	1.97
Zhuang (combined)	13.21 (13.05–13.36)	13.02 (12.83–13.21)	13.83 (13.66–14.00)	12.86 (12.52–13.18)	12.71 (12.38–13.04)	12.52 (12.33–12.70)	−0.69*	3.31
Yao	14.43 (14.22–14.64)	–	13.59 (13.38–13.79)	13.54 (13.24–13.95)	12.67 (11.75–13.52)	13.41 (12.81–13.99)	−1.02*	4.90
Korean (urban)	13.22 (13.07–13.38)	12.92 (12.69–13.15)	12.92 (12.67–13.16)	12.30 (12.07–12.61)	12.25 (11.93–12.56)	11.94 (11.71–12.16)	−1.28*	6.14
Korean (rural)	13.56 (13.39–13.73)	13.34 (12.99–13.69)	12.50 (12.28–12.72)	12.87 (12.54–13.19)	12.43 (13.32–12.54)	11.65 (11.32–11.97)	−1.91*	9.17
Korean (combined)	13.36 (13.25–13.47)	13.14 (12.93–13.35)	12.75 (12.58–12.92)	12.59 (12.21–12.96)	12.35 (12.21–12.49)	11.79 (11.68–11.89)	−1.57*	7.54
Tibetan	13.63 (13.42–13.84)	13.73 (13.35–14.13)	13.72 (13.52–13.92)	13.04 (12.72–13.39)	13.42 (12.84–14.00)	13.12 (11.41–14.81)	−0.51	2.45
Miao	13.71 (13.53–13.89)	13.15 (12.78–13.54)	13.54 (13.33–13.75)	12.95 (12.43–13.39)	13.00 (12.83–13.18)	13.36 (12.99–13.72)	−0.35	1.68
Buyi	13.91 (13.68–14.13)	13.57 (13.15–14.01)	13.37 (13.08–13.66)	13.25 (12.93–13.69)	13.12 (10.70–15.60)	13.26 (13.01–13.51)	−0.65*	3.12
Dong	14.26 (14.07–14.45)	13.21 (12.95–13.47)	13.50 (13.31–13.68)	13.41 (13.08–13.80)	13.32 (13.16–13.48)	12.91 (12.48–13.34)	−1.35*	6.48
Tujia	14.05 (13.90–14.20)	–	–	13.63 (13.47–13.78)	11.90 (11.36–12.40)	13.02 (12.27–13.72)	−1.03*	4.94
Bai	13.91 (13.73–14.09)	13.15 (12.89–13.24)	–	13.44 (13.07–13.84)	12.89 (11.85–13.89)	12.79 (11.77–13.74)	−1.12*	5.38
Hani	14.42 (14.25–14.58)	17.17 (15.73–18.84)	13.40 (13.24–13.57)	–	13.37 (12.88–13.84)	13.12 (12.46–13.78)	−1.30*	6.24
Dai	14.27 (14.12–14.43)	13.43 (13.12–13.74)	–	13.39 (13.09–13.72)	13.24 (13.08–13.39)	12.73 (12.47–12.98)	−1.54*	7.39
Lisu	14.83 (14.66–14.99)	–	13.10 (12.88–13.34)	–	13.60 (13.43–13.76)	13.04 (12.39–13.68)	−1.79*	8.59
Wa (Va)	13.85 (13.63–14.08)	–	12.56 (12.34–12.78)	–	13.17 (11.77–14.58)	13.06 (12.91–13.20)	−0.79*	3.79
Naxi (Nakhi)	13.35 (13.20–13.51)	13.09 (12.88–13.31)	13.04 (12.86–13.22)	–	11.97 (11.83–12.11)	12.64 (12.48–12.79)	−0.71*	3.41
Li	13.10 (12.94–13.26)	13.02 (12.79–13.24)	13.04 (12.84–13.24)	13.23 (12.87–13.56)	–	12.95 (12.80–13.09)	−0.15	0.72
Tu	14.22 (14.02–14.43)	14.34 (13.83–14.86)	14.03 (13.80–14.26)	13.63 (13.46–13.81)	13.61 (12.89–14.33)	13.40 (12.76–13.99)	−0.82*	3.94
Sala	14.47 (14.18–14.76)	14.45 (14.09–14.81)	14.26 (13.87–14.67)	14.07 (13.82–14.31)	14.30 (14.15–14.44)	14.32 (14.02–14.61)	−0.15	0.72
Qiang	14.07 (13.91–14.23)	–	13.81 (13.63–13.99)	12.49 (11.67–13.11)	13.42 (13.28–13.56)	12.85 (12.71–13.00)	−1.22*	5.86
Yi	13.80 (13.60–14.01)	–	–	–	–	13.74 (13.47–14.00)	−0.06	0.29

*p<0.05 CI, confidence interval.

Fig. 3 The secular trends regarding age at menarche of girls aged 9–18 among 24 ethnic minorities from 1985 to 2010. (a) The clearly declining trend over time of the Mongolians, Koreans, Kazakhs (Hasake), Kirghiz, Dai, and Tu; (b) the relatively flat trend of the Yi, Sala, and Li; (c) the decreasing trend but with small upward fluctuations of less than 0.5 years displayed by the Lisu, Uighurs, Buyi, Dong, Hui, Bai, Tibetans, and Miao; and (d) the decreasing trend but with large upward fluctuations of more than 0.5 years exhibited by the Zhuang, Yao, Tujia, Hani, Wa (Va), Naxi (Nakhi), and Qiang.