Musculoskeletal Failure

Abstract

Osteoarthritis, osteoporosis, and sarcopenia are prevalent musculoskeletal disorders that significantly impact the aging population’s health and quality of life. Osteoarthritis, characterized by joint inflammation, leads to pain, stiffness, and reduced mobility. Osteoporosis, a condition marked by bone density loss, increases fracture susceptibility, especially in postmenopausal women and older adults. Sarcopenia, the age-related loss of muscle mass and function, contributes to frailty and an increased risk of falls. Combined, osteoarthritis, osteoporosis and sarcopenia constitute “Musculoskeletal Failure.” These 3 conditions share common risk factors like aging, genetics, and hormonal changes, as well as unhealthy lifestyle behaviors resulting in systemic chronic inflammation. Healthy lifestyle behaviors, including regular physical activity and a nutritious diet across the lifespan play a crucial role in the prevention and management of musculoskeletal failure. Awareness of the relationship between lifestyle behaviors, systemic chronic inflammation and the development and progression of these 3 common conditions is a key step in prevention, early detection and are essential for addressing the complex interplay of these musculoskeletal disorders. As the global population ages, understanding and effectively preventing and managing osteoarthritis, osteoporosis, and sarcopenia become paramount for promoting healthy aging and mitigating the societal and economic burden associated with these conditions.

“Dietary intake is an important source of Vitamin D, primarily through fortified dairy products.”

E.D. is an 87-year-old female with osteoporosis and osteoarthritis. She had a knee replacement 20 years ago, has suffered 2 broken hips, and has fractured her pelvis 3 times. The resultant trauma—both physical and psychological—has led to her being wheelchair-bound. Consequently, her inactivity has contributed to significant muscle loss—sarcopenia. The resultant loss of muscle mass and musculoskeletal control predisposes her to falls, and the cycle starts all over again. This is musculoskeletal failure.

Musculoskeletal failure is largely a consequence of lifestyle behaviors, physical inactivity and inadequate nutrition leading to insufficient development of skeletal muscle and bone mass, as well as the premature loss of both, while setting the stage for falls and fractures, loss of independent living, and premature mortality. The manifestations of musculoskeletal failure are significant at an individual, population, and public health level. Amongst older adults, the 1-year mortality rate following non-operative management of hip fracture, or its surgical repair is 14.4% and 29.8%, respectively. ¹ Survivors of a hip fracture are more likely to face impairment in their mobility, reduction in overall health and quality of life, and higher rates of institutionalization compared to age-matched controls. ²

Osteoporosis typically manifests in older adulthood, affecting 8.4% of 50–64-year-olds, compared to 17.7% aged 65 and older. ³ Women are 4 times more likely to have osteoporosis and 2 times more likely to have osteopenia compared to men. ⁴ However, the foundations of osteoporosis are manifested much earlier in life. Ninety percent of adult bone mass is accumulated by age 18. ⁵ meaning, that efforts to optimize bone health through sufficient dietary intake of calcium, adequate vitamin D, and weight bearing physical activity throughout childhood and adolescence are essential.

Osteoarthritis is estimated to affect 32.5 million U.S. adults. Although osteoarthritis can affect people of any age, it’s incidence and prevalence increase with age, and like osteoporosis, affects women more than men. ⁶ Several factors increase the risk of developing osteoarthritis including obesity, diabetes, joint injury, and family history of osteoarthritis. ⁶ Osteoarthritis commonly affects the hip and knees joints, which combined with osteoarthritis symptoms such as joint pain, swelling, and stiffness, decreased mobility, and a decline in physical activity, increases the likelihood of falls—the risk of which increases with the number of joints affected by osteoarthritis. ⁷

Sarcopenia is the third leg of the musculoskeletal failure stool. Sarcopenia is defined as the involuntary loss of skeletal muscle mass and strength. It is estimated that by the 8^th decade of life, nearly 50% of skeletal muscle mass has been lost. ⁸ The cause of sarcopenia is multifactorial, including physical inactivity, poor nutrition, and underlying inflammatory conditions. ⁸ People with sarcopenia have significantly higher odds of falling and sustaining a fracture compared to non-sarcopenic individuals. ⁹

Notably, there are common and potentially modifiable causes of musculoskeletal failure, specifically lifestyle behaviors including physical inactivity, poor nutrition, smoking, and alcohol consumption^10–12; and these behaviors are also associated with the development of systemic chronic inflammation. ¹³ According to data from the 2020 National Health Interview Survey, only 28% of adults met the combined guidelines for aerobic and muscle strength training, ¹⁴ and the percentage of older adults (65 years and older) meeting guidelines is even lower (15%). ¹⁵ Regular physical activity is associated with a decreased incidence of each component of musculoskeletal failure—osteoporosis, ¹⁶ osteoarthritis, ¹⁷ sarcopenia, ¹⁸ and falls. ¹⁹ Additionally, physical activity interventions have been shown to improve bone mineral density in women with osteoporosis, ²⁰ reduce symptoms of osteoarthritis, ¹⁷ and reduce falls. ¹⁹

Inadequate nutrition can contribute to musculoskeletal failure throughout life, starting in childhood and adolescence. Insufficient calcium intake has been observed in low-income populations in the U.S., as well as in women over the age 50 regardless of economic status. ²¹ Other groups at risk for low calcium intake include those who are lactose intolerant or avoid dairy as part of food-restricted diets. ²¹ Calcium supplementation has not been observed to objectively improve bone health in otherwise healthy adolescents and young adults; rather the recommendation is to optimize dietary intake of calcium rich foods. ²²

Vitamin D is another significant component of healthy bone. Vitamin D helps to absorb dietary calcium and phosphorus from the gastrointestinal tract, and suppresses the release of parathyroid hormone, preventing bone loss. ²³ Vitamin D is produced in the skin as the result of sunlight exposure, although there is considerable variability in production based on age, skin pigmentation, underlying medical problems, and season of the year. ²⁴ Dietary intake is an important source of Vitamin D, primarily through fortified dairy products. As a fat-soluble vitamin, people with medical conditions such as celiac disease and inflammatory bowel disease or who have undergone metabolic bariatric surgery are at increased risk of Vitamin D deficiency. ²⁵

Smoking and alcohol consumption contribute to musculoskeletal failure in many ways. Both are known to increase inflammatory biomarkers (IL-6, CRP) associated with osteoporosis, osteoarthritis and sarcopenia. ¹³ Tobacco smoking also exerts direct effects on bone through many pathophysiologic processes that inhibit bone formation and increase bone resorption, ²⁶ and is associated with a greater than 2-fold risk of sarcopenia. ²⁷ With respect to alcohol, a 2022 meta-analysis of 19 studies including nearly 300,000 individuals found that heavy alcohol intake (3 drinks or more per day) was associated with lower bone mineral density at the spine and hip, higher risk of hip fracture, and a trend toward higher risk of any osteoporotic fracture. ²⁸ The relationship between alcohol intake and sarcopenia in humans remains incompletely defined. While 2 meta-analyses have demonstrated no or a slightly positive relationship between alcohol intake and muscle mass, investigators conclude that it is probable that excessive alcohol intake is a risk factor for the development of sarcopenia; the amount and frequency of alcohol intake necessary to result in sarcopenia have not yet been identified. ²⁹

Underpinning osteoporosis, osteoarthritis and sarcopenia is systemic chronic inflammation. The hallmarks of chronic inflammation are the infiltration of inflammatory cells, producing pro-inflammatory cytokines and enzymes that result in tissue damage. These same inflammatory cytokines (TNF-α, IL-1, IL-6, IL-7, IL-8, IL-11, IL-15, IL-17, and IL-20) ³⁰ have also been implicated in bone resorption, uncoupling the balance of bone homeostasis toward bone resorption and osteoporosis. ³¹ Although osteoarthritis is classified as a “degenerative” arthritis, chronic, low-grade inflammation can be a major driver of joint damage. Following overstress or overuse joint injury, the development of chronic inflammation in osteoarthritis can result in a pernicious cycle of local tissue damage, inflammation, and repair. ³² Sarcopenia is likewise, a consequence of chronic low-grade inflammation leading to loss of muscle mass, strength, and function. Pro-inflammatory cytokines (CRP, IL-6, TNF-α) are observed in sarcopenic elderly and are thought to be involved in the progression of age-related muscle wasting and are associated with measurable decreases in both muscle mass and strength. ³³ While acute inflammation is a necessary and protective mechanism to address injury and pathogens, low-grade systemic chronic inflammation is harmful, and contributes significantly to musculoskeletal failure.

Aside from the devastating individual costs of musculoskeletal failure, falls and fractures result in exorbitant direct healthcare costs. Hospitalizations and cost associated with osteoporotic fractures in women exceed that of breast cancer, myocardial infarction and stroke combined. ³⁴

We commonly hear and read about congestive heart failure, end stage renal disease, and liver failure, all devastating diseases with significant human and healthcare costs. They are part of community discussions and popular culture. However, the concept of musculoskeletal failure has eluded discussion in the medical and public health literature and throughout the communities we are part of; this despite the prevalence, consequences and costs associated with the triumvirate of osteoporosis, osteoarthritis, and sarcopenia. Modifiable risk factors underly all 3 of these conditions, notably physical inactivity, and inadequate nutrition. These behaviors as well as bone, joint and muscle health must be regularly addressed by primary and specialty care providers starting in childhood and throughout adulthood to prevent the devastating and often life-changing consequences. Even more so, the concept of musculoskeletal failure and the behaviors that prevent it and many other chronic medical conditions must be part of everyday conversations.