According to the International Osteoporosis Foundation (IOF), 4.28 million fragility fractures occurred in 2019 as a result of bone loss (osteoporosis). This figure is expected to increase to more than 5.34 million by 2034 – an increase of 24%.2

According to the International Osteoporosis Foundation, 4.28 million fragility fractures occurred in 2019 as a result of bone loss (osteoporosis).

The expected increase is largely due to the growing elderly (>75 years) population. IOF data indicate that the number of men and women >75 years will increase by 42.6% and 29.6%, respectively by 2034.2

It is estimated that one in three women and one in five men aged >55 years will suffer from osteoporosis in their lifetime. Osteoporosis is defined as a metabolic bone disease ‘characterised by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk’.1,3

Treatment gap

One of the challenges in preventing fragility fractures is the lack of effective treatment. In 2010 only 55% of patients who suffered a fragility fracture were initiated on treatment. This number increased substantially to 71% in 2019, but much still needs to be done to close the treatment gap, cautions the IOF.2

Can bone loss be prevented?

According to the IOF, osteoporosis prevention should start in childhood. A bone-healthy diet and plenty of exercise can help children achieve their highest possible peak bone mass.4

This is important because the more bone mass you have when you reach adulthood, the less likely you are to have weak and breakable bones at an older age. For women, early prevention is especially important. Bone loss accelerates rapidly after menopause when the protective effect of oestrogen is lost.4

The IOF recommends a healthy diet, which includes enough calcium, protein (two key nutrients for bone health) as well as vitamin D – especially for people >65 years.4

Role of calcium

Calcium is the most abundant mineral in the body. About 1.2kg is present in the human body, with 99% located in the bones and teeth. Calcium is also present in body fluids and soft tissues.1

Calcium is a key raw material for the building of bone. Together with phosphate, it makes up the mineral component of bone, which is laid down within the collagen scaffold constructed by the osteoblasts.1

Calcium is extremely important for the cellular structure, intercellular and intracellular metabolic function, signal transmission, muscle contractions (including the heart muscle), nerve function, activities of enzymes and the normal clotting of blood.1

Role of vitamin D

Low vitamin D status is associated with an increased risk of falling and a variety of other health outcomes and is an area that requires urgent attention. Vitamin D deficiency is common in older people. When present, it impairs muscle strength and possibly neuromuscular function.1,5

Vitamin D deficiency is usually the result of low sunlight exposure (eg in frail older people, those who are veiled, those with dark-skin living at higher latitudes). The good news is that it is reversible.5

Vitamin D stimulates bone matrix formation and bone maturation. It also enhances osteoclastic activity and there are some data to suggest that it may influence differentiation of bone cell precursors. Together with parathyroid hormone, it regulates calcium and phosphate metabolism and promotes calcium absorption from the gut and kidney tubules.1

The metabolite of vitamin D (1,25-dihydroxycholecalciferol) stimulates calcium transport across the intestinal cells by inducing the production of a calcium-binding protein. This process occurs within the villus cells through the normal process of receptor binding, DNA interaction and messenger RNA production. Hence, vitamin D is critical for effective calcium absorption.1

Role of vitamin K

Vitamin K is an essential vitamin for bone health, taking part in the carboxylation of many bone-related proteins, regulating genetic transcription of osteoblastic markers, and regulating bone reabsorption.5

Vitamin K deficiency may occur as a result not only of an inadequate dietary supply but also because of many health problems, including liver disease, biliopancreatic disturbances, cystic fibrosis, alcoholism, or enteric diseases that may cause malabsorption (eg inflammatory bowel disease, short bowel syndrome). Most importantly, some medications are also a cause of vitamin K depletion.5

Reduced ability to absorb vitamins can be addressed with supplementation

Unfortunately, with age, the body’s ability to absorb vitamins and minerals may be reduced. Therefore the IOF recommends calcium and vitamin D supplementation when dairy consumption is low, and little time is spent outdoors.4

The American Geriatrics Society/British Geriatrics Society Clinical Practice Guideline supports the use of combined calcium and vitamin D3 supplementation to reduce fracture rates in older people. Recommendations are based on the findings of several meta-analyses and randomised controlled trials (RCTs) in older people in long-term care, which have shown a beneficial effect of vitamin D supplementation in fall prevention distinct from its effect on bone health. Some of these trials have also shown benefit even in older persons with normal serum vitamin D levels.6

Given the low number needed to treat (15) and the evidence of significant fall risk reduction, as well as the fact that vitamin D is safe and inexpensive, older persons with suspected vitamin D deficiency should be routinely offered supplementation to reduce fall risk. Moreover, vitamin D supplementation at appropriate levels should also be considered for all older adults.6

Vitamin D (800 IU) is recommended as a daily supplement for all older adults at risk of falls.

Vitamin D is also recommended for all older adults with known vitamin D deficiency and should be considered for those suspected of having vitamin D deficiency. There is strong evidence for vitamin D supplementation (800 IU/d) in patients residing in long-term care who have known vitamin D deficiency. Vitamin D supplementation should also be considered for those with problems of gait or balance or who are otherwise at risk for falls residing in long-term care.6

Yao et al assessed the risks of fracture associated with differences in concentrations of 25-hydroxyvitamin D (25[OH]D) in observational studies and the risks of fracture associated with supplementation with vitamin D alone or in combination with calcium.7

In a meta-analysis of 11 observational studies (39 141 participants, 6278 fractures, 2367 hip fractures), each increase of 10.0ng/mL in 25 (OH)D concentration was associated with an adjusted relative risk (RR) for any fracture of 0.93 and an adjusted RR for hip fracture of 0.80.

A meta-analysis of 11 RCTs (34 243 participants, 2843 fractures, 740 hip fractures) of vitamin D supplementation alone (daily or intermittent dose of 400-30 000IU, yielding a median difference in 25[OH]D concentration of 8.4ng/mL) did not find a reduced risk of any fracture or hip fracture, but these trials were constrained by infrequent intermittent dosing, low daily doses of vitamin D, or an inadequate number of participants.

In contrast, a meta-analysis of six RCTs (49 282 participants, 5449 fractures, 730 hip fractures) of combined supplementation with vitamin D (daily doses of 400-800IU, yielding a median difference in 25[OH]D concentration of 9.2ng/mL) and calcium (daily doses of 1000-1200mg) found a 6% reduced risk of any fracture and a 16% reduced risk of hip fracture.

The authors concluded that intermittent nor daily dosing with standard doses of vitamin D alone was associated with reduced risk of fracture, but daily supplementation with both vitamin D and calcium was a more promising strategy.7

Adequate intake

Adequate intake of vitamin D and calcium is essential. To maintain adequate levels, the Spanish Society for Bone and Mineral Metabolism Research, the Spanish Society of Rheumatology (SER) and the Spanish Society of Endocrinology and Nutrition recommend an intake of 400-1000 IU/day of vitamin D and 500-1200mg/day. In the case of patients with osteoporosis and vitamin D deficit, SER recommends a daily intake of 800-2000IU of vitamin D supplements, depending on their baselines.8

According to De Paz and Lizán supplementation/fortification with vitamin D and calcium seems to be cost-effective from the 70-80 year age range in the general public. In the case of people with osteoporosis, this intervention could be cost-effective from 60-70 years of age, and in people with a high risk of fracture, from 50-60 years. Regarding sex, the assessed strategies were even more cost-effective in women, except for the case of those men with high risk of fracture.8