Continuation: concepts and applications

OSTEOPOROSIS & MAXIMIZING BONE DENSITY

IN POSTMENOPAUSAL WOMEN

Maximizing bone density in postmenopausal women is dependent on adequate intakes of calcium, vitamin D, vitamin K, magnesium, fluoride, phosphorus, zinc and protein across the lifetime of the individual and since there is a known stage during which the effects of nutrition are most efficient and effective in the production of bone growth it is critical that nutrition during this stage be at focus in the effort to maximize the bones density in postmenopausal women.

Osteoporosis is a problem that has received much attention however, it has been little realized until only recently that women must prepare for this bone loss at an earlier stage in life than when the bone loss actually begins to occur. The work of Beck and Shoemaker (2000) states that according to the criteria of diagnosis for osteoporosis which the World Health Organization in a new study states that "70% of white American women over the age of 80 could be classified as osteoporotic. In fact, up to 30% of all postmenopausal women (an estimated 9.4 million in the United States) have osteoporosis according to WHO criteria, with another 54% (16.8 million) having osteopenia, or low bone mass." The work of Limpaphayom states that After the menopause, bone loss occurs predominantly in cancellous bone, which is found in the vertebral bodies and metaphyses of long bones, thus accounting for compression fracture of the vertebra and Colles' fracture in the early menopausal years. The loss of cortical bone occurs at a slower rate because there are fewer sites of remodeling in cortical bone. This senile decline in bone mass occurs in both sexes, although bone loss begins at a later age among men. Fractures that involve the site of primarily cortical bone occur at a later age." (2008) it is related that Oestrogens "can stop bone loss whether the woman is 50, 60, or 70 years old." Calcitonin is stated to "directly suppress the activity of oestoclasts and also inhibits their recruitment." (2008)

The American Association of Clinical Endocrinologists Medical Guidelines for Clinical Practice for the Prevention and Treatment of Postmenopausal Osteoporosis states that "...Postmenopausal osteoporosis is a condition characterized by the following features: (1) Low bone mass; (2) Microarchitectural deterioration of bone tissue, leading to bone fragility; and (3) a consequent susceptibility to fracture." It is additionally stated that Osteoporosis-related fractures "...may lead to diminished quality of life, disability, and even death." (American Association of Clinical Endocrinologists, 2003) Nutritional conditions cited as causes of Osteoporosis include: (1) malabsorption syndromes and malnutrition; (2) Chronic liver disease; (3) Gastric operations; (4) Vitamin D deficiency; (5) calcium deficiency; and (6) alcoholism." (2001)

I. OSTEOPOROSIS FACTS

The work of Beck and Shoemaker relates that bone loss during the lifetime is "a normal consequence of aging; however, some people are more predisposed to developing osteoporosis and sustaining associated fractures than others." (2000) the risk of osteoporosis can be reduced in the following ways: (1) maximizing skeletal mass during the growing years, (2) consuming 1,000 to 1,500 mg of calcium per day, (3) participating in lifelong weight-bearing exercise, and (4) considering pharmacologic intervention at menopause. Pharmacologic options include calcium, vitamin D, estrogen, bisphosphonates, selective estrogen receptor modulators, and calcitonin. (Beck and Shoemaker, 2000) Diagnostic criteria for Osteoporosis as formulated by the World Health Organization is stated by Beck and Shoemaker (2000) as follows:

Bone Status Relationship of Patient to BMD to Mean Peak BMD

Normal < 1 SD below Osteopenia > 1 SD below but < 2.5 SD below Osteoporosis > 2.5 SD below Severe osteoporosis and fragility fracture > 2.5 SD below BMD = bone mineral density; SD = standard deviation

Beck and Shoemaker (2000) state that "calcium consumption alone is not considered adequate protection against osteoporosis" however calcium does play "an important role in the prevention and management of postmenopausal osteoporosis. " Optimal calcium intake as stated by the National Institutes of Health are those stated for the age and intake as follows:

Hormone Status Age in Years Recommended Daily Calcium Intake (mg)

Premenopausal 11-24 1,400

Premenopausal 25-50 1,000

Premenopausal, pregnant

or lactating 25-50 1,400

Postmenopausal, taking

Estrogen

Postmenopausal, not Taking estrogen >65 1,500

Calcium intake effectiveness is dependent upon the proper levels of calcium being absorbed by the human body. Vitamin D must be present in the body in sufficient levels in order for the body to absorb calcium. Sunlight results in the synthesis of vitamin D in the body however, even after exposure to sunlight, as the age of the individual increases the body's ability to synthesize vitamin D decreases. Beck and Shoemaker (2000) state that the adequate daily intake of vitamin D for the different ages of the individual are as follows:

Age Daily Vitamin D Intake

Age 50-200 IU (5 micrograms)

Age 51-70-400 IU (10 micrograms)

71+ 600 IU (15 micrograms)

Also important to combat osteoporosis is estrogen replacement therapy (ERT) and as well bisphosphonates including: (1) alendronate sodium; (2) etidronate disodium; (3) pamidronate disodium; and (4) risedronate sodium, also decrease bone resorbption. Of these, alendronate is stated to show the "greatest efficacy in increasing BMD and preventing fractures and is the only FDA-approved bisphosphate for osteoporosis." (Beck and Shoemaker, 2000) Prevention dose is stated at 5 mg and treatment of established osteoporosis dosage is stated at 10 mg.