The acquisition of radial mineral density was evaluated in relation to anthropometric
characteristics, menarche status, calcium intake and physical activity in a healthy
young female population (200 girls and 100 women, respectively aged 11 - 16 yrs and
20 - 24 yrs) living in an area of Southern Italy. We performed bone mineral density
(BMD) by dual energy X-ray absorptiometry on the ultradistal and middistal radius.
Dietary calcium intake was evaluated by a detailed Food Frequency Questionnaire and
confirmed by a 3-day record. A questionnaire on energy expenditure was used to assess
physical activity in each participant. Morning blood samples were drawn from fasting
girls to measure 25-hydroxycalciferol (25 OH-D). We found current calcium above the
levels reported by Recommended Dietary Allowances (RDA) in only 31% of women and 6%
of girls. BMD steadily increased up to the age of 16 and was increased in postmenarcheal
girls compared to premenarcheals of the same pubertal stage. Bone density was also
significantly related to age, weight and height in postmenarcheal adolescents, while
in girls before and after menarche, no relation was observed between radial BMD and
calcium intake or physical activity. In the presence of comparable calcium-intake
values recorded in pre- and in postmenarcheal girls, the latter subgroup displayed
a marked increase of 25 OH-D serum levels. Our study revealed a calcium intake lower
than the RDA in a large percentage of healthy girls and young women, and emphasized
the importance of menarche occurrence in bone mass acquisition during pubertal development.
Key words
BMD - Calcium Intake - Puberty - 25 OH-D - Physical Activity
