Osteoporosis develops when more bone is lost (resorbed) than is replaced in the normal bone remodeling process. Several factors contribute to the development of osteoporosis, but the exact reason why the remodeling process becomes unbalanced is unknown. Factors that often lead to osteoporosis include aging, physical inactivity, reduced levels of estrogen, excessive cortisone or thyroid hormone, smoking, and excessive alcohol intake. Loss of bone calcium accelerates in women after menopause.

Bone loss occurs most frequently in the spine, lower forearm above the wrist, and upper femur or thigh, the site where hip fractures usually occur.

Standard Definitions for Osteoporosis Diagnosis

Osteopenia or low bone mass: A value for bone mineral density more than 1 standard deviation (SD) below the young healthy female adult mean, but less than 2.5 SD below this value.1

Osteoporosis: A value for bone mineral density 2.5 SD or more below the young healthy female adult mean.1

Young female adult mean and standard deviation (SD): For the femoral neck, the mean and SD were based on data for 20- to 29-year-old non-Hispanic white females from the Third National Health and Nutrition Examination Survey (NHANES III).2 For the lumbar spine, the mean and SD were based on data for 30-year-old white women from the dual-energy x-ray absorptiometry (DEXA) densitometer manufacturer.3

Other races: People from racial and ethnic groups other than non-Hispanic white, non-Hispanic black, or Mexican American. This group consists primarily of Hispanic descent other than Mexican American, Asian, Native American, and multiracial persons, among others.

Prevalence of Osteopenia and Osteoporosis

Prevalence estimates of osteoporosis or low bone mass at the femoral neck or lumbar spine (adjusted by age, sex, and race/ethnicity to the 2010 Census) for the non-institutionalized population age 50 years and older from the National Health and Nutrition Examination Survey 2005–2010 US Census population counts to determine the total number of older US residents with osteoporosis and low bone mass. There were over 99 million adults 50 years and older in the US in 2010. Based on an overall 10.3% prevalence of osteoporosis, the authors estimated that in 2010, 10.2 million older adults had osteoporosis. The overall low bone mass prevalence was 43.9%, from which they estimated 43.4 million older adults had low bone mass. Of these, 7.7 million were non-Hispanic white (prevalence of 10.2%), 0.5 million non-Hispanic black (prevalence of 4.9%), and 0.6 million Mexican American adults (prevalence of 13.4%) had osteoporosis and another 33.8 million, 2.9 million, and 2.0 million had low bone mass (prevalence 44.9%, 29.7%, and 43.2%), respectively. 4 (Reference Table 7B.5.1 PDF CSV)

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Healthcare Visits

Osteoporosis often is not the principal diagnosis code related to a healthcare visit because the condition is usually an underlying cause of another condition, particularly fragility fractures that often occur after a fall or other seemingly minor incident. Often in such healthcare visits, osteoporosis may not even be listed as a condition. Still, in 2015, primary osteoporosis was listed in 1.87 million hospital discharges and emergency department visits as a reason for the visit in the population aged 50 and over. Fragility fractures occurred in 1.48 million visits for people aged 50 years and older. (Reference Table 7B.5.1 PDF CSV)

Age is a factor in both primary osteoporosis diagnosis and in the occurrence of fragility fractures with most occurring in people after the age of 70. A prior fracture in women aged 50 years and older is the most important risk factor for hip fractures. More than three-fourths (76%) of primary osteoporosis diagnoses were for people ages 70 years and older. However, in 2013, 8% of osteoporosis diagnoses was for people aged 50 to 59 years, and 16% among those aged 60 to 69 years.

Among fragility fractures, 79% were for people aged 70 years and older, with the remainder split among those aged 50 to 69. The site of the fracture was particularly important with respect to age. The oldest group, those 70 years and older, were prone to fractures of the hip and vertebrae. Fractures of the wrist and ankle or foot occurred across all people over the age of 50. (Reference Table 7B.5.1 PDF CSV)

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Falls

Approximately 30% of older women will fall annually, and this risk may be higher in women with other chronic conditions.5^,6 Several studies have used survey data to analyze falls, while other studies have limited their analysis to falls seen in emergency departments, in older women, or falls that resulted in fracture or hip fracture.

Falls prevalence may vary by race/ethnicity. In a survey-based cross-sectional study of self- reported falls from 6,277 women 65–90 years of age. The independent association of race/ethnicity and recent falls was examined, adjusting for known risk factors. Compared to whites, Asian (OR 0.64, CI 0.50–0.81) and black (OR 0.73, CI 0.55–0.95) women were much less likely to have ≥1 fall in the past year, adjusting for age, comorbidities, mobility limitation and poor health status. Asians were also less likely to have ≥2 falls (OR 0.62, CI 0.43–0.88). This may contribute to their lower rates of hip fracture.7

Fractures

Fractures are associated with significant increases in health services utilization compared to pre-fracture levels. Relative to the prior 6-month period, rates of acute hospitalization are between 19.5 (distal radius/ulna) and 72.4 (hip) percentage points higher in the 6 months after fractures. Average acute inpatient days are 1.9 (distal radius/ulna) to 8.7 (hip) higher in the post-fracture period. Fractures are associated with large increases in all forms of post-acute care, including post-acute hospitalizations (13.1% to 71.5%), post-acute inpatient days (6.1% to 31.4%), home healthcare hours (3.4% to 8.4%), and hours of physical (5.2% to 23.6%) and occupational therapy (4.3% to 14.0%). Among patients who were initially community dwelling at the time of the initial fracture, 0.9% to 1.1% were living in a nursing home 6 months after the fracture. These rates rose by 2.4% to 4.0% one year after the fracture.8

Institutionalization

Since 1980, there has been a nearly 15% decrease in the prevalence of chronic disability and institutionalization among people aged 65 years and older. A reduction in disability translates directly into cost savings since it is seven times more expensive to care for a disabled senior versus a healthy one. Major activity limitations are a common cause of nursing home admissions. While the most common cause of limitations is arthritis, affecting nearly 50% of people older than 65 years and an estimated 60 million by 2020.9

Fractures and Mortality

Vertebral and hip osteoporotic fractures result in a 20% increase in mortality, usually observed in the 12 months after the fracture. Men, who are generally older at the time of the hip fracture, have a 30% mortality rate after the fracture. Moreover, comorbidities such as cardiovascular disease contribute to a higher mortality rate.

A population-based study in Olmsted County, MN, found that within the first seven days after hip fracture repair, 116 (10.4%) of participants experienced myocardial infarction and 41 (3.7%) subclinical myocardial ischemia. Overall, the 1-year mortality was 22%, with no difference between those with subclinical myocardial ischemia and those with no myocardial ischemia. One-year mortality for those with a myocardial infraction was significantly higher (35.8%) than for the other two groups.10 The relative mortality after vertebral fracture varies from 1.2 to 1.9 in different reports,3^,11 but the excess deaths occur late, rather than early, after vertebral fractures.12

• 1. a. b. World Health Organization. WHO Scientific Group on the assessment of osteoporosis at primary health care level. Summary Meeting Report, Brussels, Belgium, 5-7 May 2004. Page 2. http://www.who.int/chp/topics/Osteoporosis.pdf  Accessed November 29, 2019.
• 2. Kilgore ML, Morrisey MA, Becker DJ, et al.: Healthcare expenditures associated with skeletal fractures among Medicare beneficiaries, 1999–2005. J Bone Miner Res 2009;24(12):2050-2055.
• 3. a. b. Huddleston JM, Gullerud RE, Smither F, et al.: Myocardial infarction after hip fracture repair: A population-based study. J Am Geriatr Soc 2012;60(11):2020-2026.
• 4. Wright NC, Looker AC, Saag KG, et al. The recent prevalence of osteoporosis and low bone mass in the United States based on bone mineral density at the femoral neck or lumbar spine. JBMR 2014;29(11):2520-2526. DOI: 10.1002/jbmr.2269
• 5. Lord S. Falls. In: Halter JB, Ouslander JG, Studenski S, et al., eds. Hazzard's Geriatric Medicine and Gerontology. New York, NY: McGraw Hill Education; 2016.
• 6. Wildes TM, Dua P, Fowler SA, et al. Systematic review of falls in older adults with cancer. Journal of Geriatric Oncology 2015;6(1):70-83.
• 7. Geng Y, Lo JC, Brickner L, Gordon NP. Racial-Ethnic Differences in Fall Prevalence among Older Women: A Cross-Sectional Survey Study. BMC Geriatrics 2017;17(1):65.
• 8. Kilgore ML, Morrisey MA, Becker DJ, et al.: Health care expenditures associated with skeletal fractures among Medicare beneficiaries, 1999–2005. J Bone Miner Res 2009;24(12):2050-2055.
• 9. Kilgore{/fn] Hip fractures are a second source of immobility, and are projected to reach 289,000 in the year 2030, nearly all fall-related.National Academy on An Aging Society: Arthritis: A leading cause of disability in the United States. Chronic and Disabling Conditions. 2000;5. http://www.agingsociety.org/agingsociety/publications/chronic/index.html Accessed June 22, 2015.
• 10. Centers for Disease Control and Prevention: Hip Fractures Among Older Adults. http://www.cdc.gov/HomeandRecreationalSafety/Falls/adulthipfx.html Accessed June 22, 2015.
• 11. Kado DM, Browner WS, Palermo L, et al.: Vertebral fractures and mortality in older women: A prospective study. Arch Intern Med 1999;159(11):1215-1220.
• 12. Center JR, Nguyen TV, Schneider D, et al. Mortality after all major types of osteoporotic fracture in men and women: An observational study. Lancet 1999;353(9156):878-882.