Sarcopenia is a Greek word means loss of muscles (sarx: flesh and penia: loss). This disease affects elderly people which can lead to physical disability, poor life quality, and death in some cases.
According to the Center of Disease Control (CDC), Sarcopenia is a condition that is responsible for 51% hospitalisations of elderly between 70-80 years old.
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High Risk Groups
Sarcopenia is shown to be higher in type II diabetes patients. Also, the prevalence of Sarcopenia and Sarcopenic Obesity is higher in patients with metabolic syndrome.
- The prevalence of Sarcopenia in US and Europe ranges 5-13% in patients of 60 –70 years, and 11% – 50% in those over 80 years.
- In New Mexico, a study showed that the prevalence of Sarcopenia is 15% in males and 24% in females at 65-70 years, and 50% in both sexes over 80 years.
- In the Asian countries, it has been seen that the incidence ranges from 8 – 22% in females and 6 – 23% in males.
Causes of Sarcopenia
Primary Sarcopenia is age-related degeneration of the lean body mass and overall musculoskeletal system. Following factors trigger and lead to progression of the age related Sarcopenia.
- Decrease number of muscle satellite cells and motor neurons.
- Decrease in hormonal secretions as growth hormone and sex hormones.
- Decrease in mitochondrial functions.
- Increase production of inflammatory cytokines.
- Loss of appetite, weight loss, and decrease the ability of body to synthesize muscle proteins.
- Secondary Sarcopenia occurs due to inadequate physical activity and exercises which leads to muscle loss especially in lower extremities.
- It may also occur due to presence of diseases and other body disorders as:
- Major organ failure (kidney, liver, heart and brain)
- Malignant cancer
- Endocrine system disorder
- Nutritional disorders can also trigger development of Secondary Sarcopenia. Following factors are responsible:
- Low intake of proteins
- Lack of antioxidants and polyunsaturated fatty acids
Diagnosis of Sarcopenia
- Deuterated creatinine (D3-creatine) has been presented as a technique providing a quite direct quantification of muscle mass. It was shown that D3-creatinine was associated with physical performance and functional outcomes in older adults.
- Also, appendicular lean mass quantified by dual X-ray absorptiometry (DXA) has a modest association with functional outcomes.
- Diagnosis can also be done by using CT scan and MRI. This is through estimation of ratio between fat and free fat muscle mass.
- Dual X-ray Absorptiometry (DXA) may also be used for the diagnosis of the same by the measurement of the fat mass and the skeletal mass.
- The difference in the precision of the data obtained by means of DXA and CT or MRI is less than 5%.
The presence of Sarcopenia has been reported to result in a:
- Lower quality of life
- Higher risk of falls
- Higher risk of sustaining fractures after falling
- Decline of cognitive function
- Peripheral artery disease
Also, the risk of dyslipidemia and cardiovascular death was reported to be higher in people with Sarcopenia, especially in Sarcopenic obesity patients.
Management of Sarcopenia
Training sessions of aerobic or anaerobic exercise are useful for increasing muscle strength, muscle mass, and bone density.
Training sessions should be held for 30 minutes three to four times a week for 10 -12 weeks.
A study showed combination of exercise with fish oil in diet has improved muscle strength and size in Sarcopenic women.
- Low protein intake ≤ 0.45g/kg/day showed to have negative impact on lean muscle and physical performance.
- Studies suggested that 1.2-1.5 g/kg/day is adequate for elderly, 0.8 g/kg/day for middle age.
Protein Metabolism and Muscle Generation
- A recent study found the optimal amount of protein to be 25-30 g per meal and it should be equally distributed in all the meals of the day.
- Protein metabolism nearly plateaus after intake of 30 g per meal.
- So, addition of more proteins does not stimulate of protein synthesis in a muscle tissue.
Medication and Supplements
Vitamin D supplementation is important for patients with Sarcopenia. Studies are conducted to show its safety profile.
It has been studied that sex hormones as Tertosterone and Estrogen can help to increase the muscle strength to some extent due to their anabolic effects. However, side effects related to malignant growth or metabolic disorders were also observed with the use of hormones. Additionally, they were found to be ineffective in other studies.
Additionally, growth hormone has been studied to show positive effect on muscle growth and strength. Growth hormone decreases with age, hence replacement shows good results in some cases. However, it has also been studied to promote fluid retention and orthostatic hypotension as the side effects.
Sarcopenia: Mini Review, Orthopedics and Rheumatology Journal.
Chapter2 Epidemiology of Sarcopenia, Pages13, 14, 15.