Indirect calcium effects on bone growth in girls
Some studies indicate an interaction between calcium intake
and the age of the beginning of menarche. Calcium intake
in prepubertal girls may accelerate the initiation of puberty
and signifi cantly reduce the age at which menarche begins
[34,44,45]. It has been observed that premenarcheal girls
with an average calcium consumption of 420 mg/day experienced
the menarche at 12.8 years (Tanner maturation
stage 4.1), whereas a similar group with a calcium intake
of 839 mg/day experienced menarche at 11.9 years of age
(Tanner 3.5) [44]. It can be hypothesized, therefore, that
low calcium consumption is related to a low adrenal androgen
secretion and may affect adrenal steroidal enzymes,
thereby delaying the commencement of menarche [34,44].
The delay during female pubertal growth may result in
reduced endocortical apposition, resulting in a normal or
larger bone with a thinner cortex and larger medullar diameter
[46]. However, biomechanical consequences of delayed
puberty may be worse in boys than in girls, because boys
reduce their bone size [46].