Question 1

The WHO's definition of osteoporosis is a BMD greater than _____ standard deviations below the mean for healthy 20- to 29-year-old adults.

Accepted Answer

Compared with the mean BMD of 20- to 29-year-old adults, the World Health Organization defines osteoporosis as a BMD greater than 2.5 standard deviations below the standard.

Question 2

Which of the following female patients is at risk for osteoporosis?

Accepted Answer

Risk factors for the development of osteoporosis include being a woman of European or Asian descent, being underweight or sarcopenic, having experienced menopause or oophorectomy, lack of exercise, cigarette smoking, excessive alcohol or caffeine use, and limited intake of calcium and vitamin D.

Question 3

Which of the following bone measurements is more appropriate for individuals from late adolescence to the elderly years?

Accepted Answer

After peak bone mass is achieved by about 30 years of age, bone mineral density is the term used to describe bone throughout the rest of life.Bone mineral content is used to describe the amount of bone accumulated before the end of growth (usually in height).Alkaline phosphatase measured in the blood is a marker of bone formation.

Question 4

When is the peak bone mass of a female typically achieved?

Accepted Answer

Peak bone mass occurs by about 30 years of age.Through adolescence, the opportunity exists to increase bone mineral density by promoting calcium intake, maintaining weight-bearing activity, and limiting use of alcohol and cigarettes.Around the age of 40 years, BMD gradually declines.After menopause, the rate of loss averages from 1% to 2% per year.

Question 5

Which of these is NOT a risk factor for developing osteoporosis?

Accepted Answer

People of European and Asian ethnicity experience more osteoporotic fractures than Blacks or Hispanics, who usually have a greater bone density.Cigarette smoking is a risk factor, probably because of toxic effects on bone.Young women with the female athlete triad of disordered eating, amenorrhea, and low BMD are at increased risk of having fractures.

Question 6

What does uncoupling of bone remodeling mean?

Accepted Answer

The uncoupling of bone remodeling explains why after peak bone mass is achieved, throughout the rest of the life cycle, bone mass declines.Normal bone remodeling involves first bone resorption and then bone formation.However, when uncoupling occurs, more resorption than formation occurs.This results in bone loss.

Question 7

Which of the following is NOT a risk associated with excessive calcium supplementation?

Accepted Answer

Increased calcium intake has been associated with lowered blood pressure.In susceptible individuals, excessive calcium supplementation may result in urinary tract stones.Excessive calcium supplementation may cause constipation and can interfere with the absorption of other divalent cations.

Question 8

Which of the following is necessary for the maturation of osteocalcin?

Accepted Answer

Vitamin K is involved in the posttranslational carboxylation process or maturation of osteocalcin.Vitamin D's role in bone formation is in regard to the adequate absorption of calcium from the gastrointestinal tract as well as the stimulation of osteoblast activity.Adequate vitamin A intake is necessary for the promotion of bone growth and maintenance.Vitamin E does not have a direct role in bone formation.

Question 9

Which of the following is associated with the bone tissue at the end of the long bones?

Accepted Answer

Trabecular bone is the spongy bone that is found in the knobby ends of the long bones.Cortical bone, which consists of osteons or Haversian systems, is found in the shaft regions of the long bones.

Question 10

Bone tissue consists of the mineral phase and the organic _____ phase.

Accepted Answer

The organic matrix or osteoid phase of bone consists mostly of collagen, which provides both the strength and flexibility of the bone.Osteocalcin and osteopontin are two proteins that occur in the osteoid phase.Cartilage is the connective tissue that occurs at the epiphyseal ends of bone.

Question 11

Which of the following is NOT a characteristic of hormone-related (type I) osteoporosis?

Accepted Answer

Although decreased dietary calcium intake is a risk factor for osteoporosis, it is not specific to either type of osteoporosis.Type I osteoporosis in women results after menopause when estrogen production ceases.The BMD of women with postmenopausal osteoporosis may fall as low as 25% to 40% of that of age-matched women without osteoporosis.Type I osteoporosis is associated with "crush" fractures of the wrists and lumbar vertebrae.

Question 12

Which of the following changes related to nutrition and bone metabolism does NOT occur in elderly subjects?

Accepted Answer

Although an excessive sodium intake may contribute to an increased renal excretion of calcium, aging itself does not result in this physiologic change.Aging is associated with decreased intestinal absorption of calcium through alterations in the gastrointestinal mucosa and in vitamin D biosynthesis and metabolism.In contrast to osteoblast activity, osteoclast activity increases because of the uncoupling of bone remodeling.

Question 13

Which of the following statements about exercise and bone is TRUE?

Accepted Answer

Use of upper body strength activities has been shown to improve the BMD of the femur.Regular weight-bearing exercise seems to have little influence on BMD of older persons but is beneficial during periods of bone accumulation.Walking and swimming similarly do not provide benefit to bone health in elderly adults.

Question 14

Bisphosphonates treat osteoporosis by

Accepted Answer

Alendronate sodium, risedronate sodium, and zoledrosonic acid, which are bisphosphonates, are approved for the prevention of osteoporosis, especially for postmenopausal women.The bisphosphonates act as inhibitors on osteoclasts to reduce bone resorption.

Question 15

A chronic elevation of which circulating hormone typically leads to an increase in bone resorption and bone loss?

Accepted Answer

Vitamin D deficiency is associated with secondary hyperparathyroidism.This results in excessive parathyroid hormone secretion, which then stimulates bone resorption to maintain serum calcium concentrations.Excessive use of thyroid hormone or corticosteroids as medications can also contribute to bone loss.Glucagon has not been associated with risk of osteopenia.

Question 16

Which of the following is a characteristic of type II, or age-related, osteoporosis?

Accepted Answer

Type II osteoporosis, or age-related osteoporosis, usually occurs after 65 years of age and affects both men and women.Type II osteoporosis affects both trabecular and cortical bone.Fractures of the hip and vertebrae are the most common to occur with this type of osteoporosis.Because of the latter, a loss of height, spinal deformity, and dowager's hump occur.

Question 17

Which of the following dietary variables is NOT related to low bone mass?

Accepted Answer

Bone mass is maintained by adequate vitamin D and calcium intake and adequate phosphorus to maintain the serum calcium-to-phosphate ratio.Too much phosphorus in relation to calcium stimulates parathyroid hormone, resulting in loss of bone.Oral doses of potassium bicarbonate by postmenopausal women neutralize endogenous acids that may contribute to bone resorption.

Question 18

What is the most beneficial type of exercise to include in an exercise program for a patient at risk for osteoporosis?

Accepted Answer

Weight-bearing activities place stress on the skeleton and stimulate osteoblast activity during the developmental periods of bone accretion.Swimming, regular walking, and isometrics do not place as much stress on the skeleton and are not associated with improvements in BMD.

Question 19

Which of the following are bone-forming cells?

Accepted Answer

Osteoblasts are the cells responsible for the formation of bone tissue.Osteocytes are formed by osteoblasts and are incorporated into the mineralized bone.Osteoclasts are responsible for the resorption or breakdown of bone.Osteocalcin is a matrix protein of bone.

Quiz 24: Nutrition and Bone Health