Background: Children in industrialized and developing countries have a higher tendency to
present earlier signs of puberty. One hypothesis includes the hormonal effects of
phytoestrogens found in soy products.
Objective: to examine the association between consumption of soy-based food in early infancy
and childhood and the incidence of early or precocious puberty and overweight in school-aged
Methods: the study population for this case control study is randomized from a prospectively
followed cohort of all babies born at Assaf Haroffeh medical center and followed for milk
allergy signs and food intake until the age of 3 years (A nested cohort). It is divided to
those who were allergic to milk, and thus consumed only soy based formula and food during
infancy and childhood (soy group) and a randomized control group who consumed non-soy based
intake. For both groups data are available of food habits during infancy and collected from 3
days food diaries during the current study. Physical examination, including weight , height,
blood pressure and Tanner Pubertal Staging will performed annually.