Osteoporosis: Overview and Risk Factors

Osteoporosis is a metabolic disease characterized by progressive thinning of the bone matrix and cortex. Fractures may result from decreased bone strength, and hip fractures are a significant cause of morbidity and mortality for aging adults. Primary osteoporosis reflects an imbalance in the coupling of osteoblasts and osteoclasts and commonly reflects natural hormonal and metabolic changes. Secondary osteoporosis makes up 5% of cases and can be caused by hyperparathyroidism, hyperthyroidism, diabetes mellitus, chronic kidney disease, hepatic disease, malabsorption syndromes, pancreatic insufficiency, malignancy, and certain medications, such as corticosteroids, aluminum–containing antacids, and heparin.

Risk Factors

In general, whites are at greater risk than persons of Latin American or African heritage. African Americans have greater bone densities and a lower risk of fracture, compared with white Americans. African American women, however, have higher morbidity and mortality associated with fracture.¹ This example shows the importance of screening at–risk individuals independent of race, ethnic background, and gender.

Many risk factors are associated with osteoporosis. The following are among the most common:

Age. In postmenopausal women, fracture risk increases with age. Both men and women aged 70 and older have an increased risk of fracture.

Female gender. Primary osteoporosis is 6 times more common in women than in men. Also, osteoporosis begins earlier and tends to be more severe in women.

Body habitus. Persons with lower body mass have lower bone mineral density. Obesity reduces the risk of developing osteoporosis.

• Sedentary lifestyle.
• Genetic factors.
• Previous fracture.
• Smoking.
• Glucocorticoid, cyclosporine, and methotrexate treatment.
• Vitamin A, heparin, aluminum–containing antacids, and medroxyprogesterone increase risk, whereas thiazide diuretics, estrogen, and androgens are protective.
• High alcohol consumption. However, a moderate–to–low alcohol intake could be protective.²
• Elevated blood homocysteine concentration is associated with elevated risk.
• Nulliparity.
• Early onset of menopause.
• Calcium or vitamin D deficiency.
• Low peak bone density achieved in young adulthood.
• Dietary factors (see Nutritional Considerations).