Is calcium supplementation the only way to treat osteoporosis?

Many middle-aged and elderly people, especially postmenopausal women, often seek medical treatment for waist and back pain and are diagnosed with osteoporosis. In severe cases, a fall may result in a fracture. When people mention osteoporosis, their first reaction is often calcium deficiency. Can osteoporosis really be cured by calcium supplementation?

1What is osteoporosis? Osteoporosis (OP) is the most common bone disease. It is a systemic bone disease characterized by low bone mass, damaged bone tissue microstructure, increased bone fragility, and susceptibility to fractures. Clinical manifestations include fragility fractures, unexplained chronic low back pain, dwarfing, or spinal deformity. With the aging of the population, osteoporosis has gradually become a global health problem for men and women aged 50 and above. It can lead to fragility fractures and even disability. In Western societies, from the age of 50, one-third of women and one-fifth of men will suffer from osteoporotic fractures[1]. The absolute number of OP cases in my country is showing a clear upward trend. It is estimated that by 2050, the number of patients with osteoporosis or low bone density in China will reach 212 million[2].

2 Osteoporosis and Calcium Supplementation Calcium is one of the essential elements for the formation of bones. Calcium supplements can effectively increase bone density and are also the basic medicine for the prevention and treatment of OP. Adequate calcium supplementation plays an important role in maintaining bone health [3]. Other studies have shown that taking a certain amount of calcium can increase the body's calcitonin level, resist hypersecretion of parathyroid hormone, inhibit bone resorption, reduce blood calcium, and reduce the risk of fractures [4]. The recommended daily calcium intake for adults is 800 mg, and the recommended daily calcium intake for people aged 50 and above is 1000-1200 mg [5].

However, calcium supplementation alone is not enough. The consensus of experts at home and abroad is that vitamin D can promote intestinal absorption and utilization of calcium, maintain normal serum calcium concentration, and regulate neuromuscular and cellular functions. Therefore, calcium and vitamin D supplementation is a basic measure for preventing and treating osteoporosis[6]. The recommended vitamin D intake for adults is 400 IU (10 μg)/d, and the recommended vitamin D intake for people aged 65 and above is 600 IU (15 μg)/d. When vitamin D is used to prevent and treat osteoporosis, the dosage can be 800-1200 IU (20-30 μg)/d, and the maximum tolerable intake is 2000 IU (50 μg)/d[5].

3 Other treatment measures for osteoporosis 3.1 Adjusting lifestyle ① Scientific diet: Eat more foods with high calcium and vitamin D content. Selectively eat more milk, beans, seafood, sesame, vegetables, etc. to prevent osteoporosis. Pay attention to quitting smoking, limiting alcohol, and avoid excessive drinking of coffee and carbonated beverages [5, 7]. ② Adequate sunlight: In addition to food, vitamin D is also synthesized by ultraviolet rays in the sun irradiating the skin. ③ Reasonable exercise: Middle-aged people should take aerobic exercise as the basis, combined with whole-body muscle strength training, 3 to 7 times a week, and gradually increase the amount of exercise; the elderly can choose walking, jogging, dancing, cycling and other moderate-intensity exercises.

3.2 Drug treatment ① Active vitamin D and its analogs

Active vitamin D calcitriol [1,25 (OH) 2 vitamin D] or active vitamin D analogue alfacalcidol (1α-hydroxyvitamin D) are commonly used in clinical practice. After the latter is hydroxylated at the 25 position in the liver, it can be converted into active 1,25 (OH) 2 vitamin D, activate vitamin D receptors in target cells, and then exert biological effects [8].

② Bisphosphonates

Bisphosphonates are bone resorption inhibitors that inhibit bone resorption by osteoclasts, thereby promoting osteoclast apoptosis and inhibiting osteoclast formation. They can be used to prevent fractures caused by osteoporosis. Alendronate sodium is the most commonly used in clinical practice. It should be taken in the morning on an empty stomach (at least 30 minutes apart from breakfast) with at least 200 ml of warm water. Do not lie flat within 30 minutes after taking the medicine to reduce irritation to the esophagus.

③Salmon calcitonin

Calcitonin is one of the important hormones that regulate calcium metabolism in the body. It is also a bone resorption inhibitor used to treat osteoporosis with bone pain and hypercalcemia. Salmon calcitonin is currently available in two dosage forms: injection and nasal spray. Intranasal preparations have become a superior method of administration to parenteral routes. Nasal sprays are more convenient and less invasive for patients. They can also reduce the common side effects of salmon calcitonin injections, such as nausea and vomiting, and have good tolerability and compliance [9].

④New drugs for the treatment of osteoporosis

In addition to the commonly used clinical drugs mentioned above, a variety of new drugs have been launched on the market, such as the RANKL inhibitor denosumab, the cathepsin K inhibitor onakinumab, and the humanized sclerostin antibody romosuzumab [10]. Only a small number of these new drugs have been approved for marketing in China, and their safety and efficacy in the Chinese population still need more data to confirm.

References

[1] Lorentzon M, Johansson H, Harvey NC, et al. Osteoporosis and fractures in women: the burden of disease[J]. Climacteric, 2021:1-7.

[2] Bai Bihui, Xie Xingwen, Li Dingpeng, et al. Current status of epidemiological research on osteoporosis in my country in the past five years[J]. Chinese Journal of Osteoporosis, 2018, 24(2): 253-258.

[3] Chinese Medical Association Osteoporosis and Bone Mineral Disease Branch. Guidelines for the diagnosis and treatment of primary osteoporosis (2017)[J]. Chinese Journal of Osteoporosis, 2019, 25(3): 281-309.

[4] Jiang Hui, Yan Yunfei. Analysis of risk factors for osteoporosis in the elderly in Nanjing[J]. Chinese Journal of Osteoporosis, 2012, 18(7): 641-643.

[5] China Health Promotion Foundation, Expert Consensus Committee on Osteoporosis Diagnosis and Treatment in Primary Medical Institutions. Expert Consensus on Osteoporosis Diagnosis and Treatment in Primary Medical Institutions (2021)[J]. Chinese Journal of Osteoporosis, 2021, 27(07):937-944.

[6] Zhou Qi, Zhou Jianlie. The value of vitamin D in the clinical application of calcium supplementation to prevent osteoporosis[J]. Chinese Journal of Osteoporosis, 2006, 12(4): 405-408.

[7] Kong X, Tang L, Ma X, et al. Relationship between mild-to-moderate chronic kidney disease and decreased bone mineral density in Chinese adult population[J]. Int Urol Nephrol, 2015,47(9):1547-1553.

[8] Xia Weibo, Zhang Zhenlin, Lin Hua, et al. Consensus on the clinical application of vitamin D and its analogs[J]. Chinese Journal of Osteoporosis and Bone Mineral Diseases, 2018, 11(01): 1-19.

[9] Srinivasan A, Wong FK, Karponis D. Calcitonin: A useful old friend[J]. J Musculoskelet Neuronal Interact,2020,20(4):600-609.

[10] Liu Yuhang, Wang Jianhua. Advances in drug treatment of osteoporosis[J]. Journal of Qiqihar Medical College, 2021, 42(09): 792-795.