Age (years)                  Total no of girls              Socioeconomic status (SES)


at menarche                who have attained               High              Middle                 Low
                                        menarche                        No(%)            No(%)                  No(%)

10                                       0                                     0 (0.0)            0(0.0)                  0(0.0)
11                                       1                                    1(9.1)              0(0.0)                  0(0.0)
12                                      16                                  10(62.5)          6(37.5)                 0(0.0)
13                                       95                                 47(49.5)          38(40.0)               10(10.5) 
14                                      218                               106(48.6)         95(43.6)               17(7.8)
15                                      337                                31(9.2)            176(52.2)              130(61.4)
16                                      471                                 8(1.7)             143(30.4)              320(67.9)
17                                      313                                 2(6.5)             16(5.1)                  295(88.4)
18                                      112                                 0(0.0)             13(11.6)                99(88.4) 
19                                      62                                   0(0.0)              57(91.9)                5(8.1)
20                                      15                                   0(0.0)              12(80.0)                3(20.0)


Total                                1640                               205(12.5)         548(33.4)              887(54.1)

Mean age at
menarche                   13.44+1.32                         12.78+1.21a       13.42+1.18b         13.56+1.29c


(95% CI)                     (13.38-13.50)                   (12.61-12.95)        (13.32-13.52)      (13.42-13.59)

t-statistic                                                                a vs b=4.41          b vs c=2.08          a vs c=7.95

(p-value)                                                                    (<0.01)                (>0.05)                (<0.001)
Table 2: Socioeconomic status (SES)and mean age at menarche.