Retrospective data on age at menarche were collected for 832 Guatemala
ns 15-30 y in age to test whether exposure to a high energy and high p
rotein supplement (Atole: 163 kcals/682 kJ and 11.5 g protein per cup
or 180 mL) during childhood led to earlier menarche than did exposure
to a low energy, no protein supplement (Fresco: 59 kcals/247 kJ in 180
mL). Mean age at menarche was similar in Atole (13.75 +/- 1.22 y; mea
n +/- sD) and Fresco (13.74 +/- 1.36 y) groups. The corresponding valu
e for immigrants (n = 144), subjects not exposed to the supplements, w
as 13.55 +/- 1.20 y. Year of birth as well as socioeconomic status (SE
S) were associated with age at menarche. Age at menarche declined by 0
.69 y over the 15-y period and menarche occurred earlier in higher SES
households. Significant positive interactions between supplement type
and SES and between supplement type and year of birth were found, but
plausible explanations for them could not be advanced.