Project: Research project

Project Details


This proposal is founded upon: 1) the recognition that bone density
acquired early in life is a predictor of osteoporosis risk, 2) recognition
that peak bone density in women is achieved during the second decade of
life, and 3) our current observation that 19 year old women who have been
menstrually irregular during their teenage years have significantly lower
trabecular bone density than their eumenorrheic classmates. Additional
findings which support the concept that maturational events during puberty
can affect women's health status decades later include: a documented
decrease in adolescent calcium intake, a decrease in adolescent exercise,
and linear premenopausa bone loss. Since premenopausal bone loss appears
to be influenced by sex steroid status, diet and exercise, we propose a
longitudinal study to determine the roles played during adolescence by
integrated estrogen status, calcium intake, and exercise upon the timing
and magnitude of peak bone density accretion in adolescent women.

We propose a five year study of 100 closely matched Caucasian school girls
who will be 11 years of age at entry. Fifty of the study group will be
given a 600 mg per day calcium supplement by a double-blind design. Each
subject will be seen every six months at which time integral vertebral and
cortical radial bone density will be measured. Investigations of
determinants of bone density in young women have been limited due to the
radiation exposure associated with previously available instrumentation
necessary to obtain quantitative measurement of ben density. A recent
advance in bone measurement technology, x-ray absorptiometry (XRA), in now
available and is well suited for studies involving children because of the
extremely low radiation used. Nutrition profiles will be obtained from
three day diet diaries and exercise patterns from activity surveys. We
will measure integrated estrogen exposure by evaluating pubertal
progression based on developmental landmarks in addition to sex steroid and
gonadotropin profiles obtained from urine specimens. Statistical analysis
of the continuous study variables will allow us to determine whether these
variables affect peak bone accretion in young girls independently or in a
concerted fashion. The results of this study will provide information to
be used in the prevention of osteoporosis in American women.
Effective start/end date1/1/9011/30/90


  • Eunice Kennedy Shriver National Institute of Child Health and Human Development

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