Bone health age vs menopause
ANN ARBOR, Mich.Treating all middle-aged
women with identical bone-protection therapies risks viewing aging
and menopause as interchangeable conditions. A new study by the
University of Michigan examines the difference between aging and
menopause as they relate to women’s bones.
“What is interesting about this study is
that we took age out of the equation,” principal investigator
Jane Lukacs said. She is a Pfizer post-doctoral fellow and assistant
research scientist at the U-M School of Nursing. Lukacs will present
her findings at ENDO 2003, the Endocrine Society’s annual
meeting in Philadelphia June 19-22.
Studies involving hormone replacement therapy
have found improvement in bone density of post-menopausal women,
leading experts to infer that estrogen withdrawal at menopause is
a major risk factor for osteoporosis. The question of whether the
natural decline of estrogen after menopause causes bone loss has
not been definitively shown.
After Lukacs and her research team found that
aging-related bone loss has only a minor influence on bone function
as compared to the body’s natural estrogen withdrawal, which
affects a number of parameters of bone health, Lukacs concluded:
“Therapy should be different at different points in a woman’s
The U-M team studied a group of women aged 20-52,
and age-matched women who had and had not gone through menopause
for study purposesfor example, she examined a 47-year-old
woman still having regular menstrual cycles and compared her data
to a 47-year-old woman who had not had regular cycles for 12 months.
She excluded women who used any form of hormones
or regular prescription medication, and also eliminated smokers
and heavy drinkers. Study subjects were neither, as Lukacs describes
them, endurance athletes or couch potatoes.
Typically the rate of bone turnoverthat
is, the rate at which the body replaces old bone material with newaccelerates
as women reach menopause. Because the replacement of old bone with
new bone is not as efficient in menopause, a faster rate of turnover
should translate to bone loss. This study examined bone biomarkers
in the different groups of women to see when bone turnover increases
and if measured calcium in the blood would be elevated, suggesting
greater mineral loss from bones.
Most preventive bone therapies, given in the hope
of protecting women against osteoporosis, slow the rate of bone
turnover. But Lukacs’ numbers showed pre-menopausal women
did not have elevated bone turnover as they aged. “Why would
you want to slow a rate of bone turnover that’s normal?”
Thus, with women already nervous about hormone
replacement therapy, this study gives further reason to be cautious
about overprescribing hormone therapy or other conventional therapies
used to slow bone turnover when it might be unnecessary in middle-aged
women who still have regular menstrual cycles. Studies have shown
a possible connection between HRT and cancer, as well as dementia.
A two-year, $130,000 fellowship from Pfizer helped
fund Lukacs’ research.
of Nursing >
Endocrine Society >
Contact: Colleen Newvine
Phone: (734) 647-4411