Evidence for a downward secular trend in age of menarche in a rural Gambian population

Figures & data

Table I. Table showing subject numbers by age, at three time points and percentage of subjects that recorded a ‘yes’ response to having achieved menarche.

Age	Age centre	1989		2000		2008
		Number of subjects (n = 239)	% Yes	Number of subjects (n = 346)	% Yes	Number of subjects (n = 339)	% Yes
10	10.5	33	0	39	0	30	3
11	11.5	32	3	32	0	40	3
12	12.5	23	0	54	5	39	8
13	13.5	28	0	35	8	27	11
14	14.5	29	14	41	33	30	40
15	15.5	25	32	30	52	26	69
16	16.5	23	57	35	91	44	84
17	17.5	18	89	32	100	27	89
18	18.5	12	100	20	100	14	88
19	19.5	8	100	17	100	18	100
20	20.5	8	100	11	100	14	100

Figure 1. Percentage of girls in a rural Gambian population at three time points who had reached menarche by age.

Table II. Median age of menarche in a rural Gambian population at three time points.

Time point	Median age at menarche (95% CI)	Standard deviation of age at menarche (95% CI)
1989	16.06 (15.67–16.45)	1.47 (1.15–1.88)
2000	15.03 (14.76–15.30)	1.20 (0.98–1.47)
2008	14.90 (14.52–15.28)	2.00 (1.68–2.37)