Calcium & vitamin D

Calcium

Calcium and vitamin D supplementation are widely used among older people to support bone health and prevent osteoporosis and fractures. While the optimal daily calcium requirement is not firmly established, most guidelines recommend a dietary intake of 1,000 to 1,300 mg per day [508, 509]. If dietary intake meets these requirements, supplementation is generally unnecessary. However, many individuals overestimate their daily calcium intake [510], making it important to evaluate actual intake, particularly in those with low bone mineral density. A practical tool for this assessment is an online calcium calculator, such as the International Osteoporosis Foundation Calcium Calculator (https://www.osteoporosis.foundation/educational-hub/topic/calcium-calculator) [508].

Vitamin D

Vitamin D plays a crucial role in calcium homeostasis, bone mineralisation, and various physiological functions, including immune system support [511]. In Australia, sunlight (ultraviolet) exposure is the primary source of vitamin D [512]. The amount of ultraviolet exposure required for adequate vitamin D synthesis depends on skin type, extent of skin exposure, and environmental factors such as geographic location, season, time of day, and cloud cover [511]. Generally, exposing approximately 15% of the body’s surface (e.g. hands, face, and arms) for around 10 minutes in the mid-morning or mid-afternoon on most days during summer is sufficient to maintain adequate vitamin D levels. Although sunscreen has been shown to block vitamin D synthesis in laboratory settings, its impact on vitamin D levels in real-world conditions appears minimal [509].

Vitamin D Production and Dietary Sources

Older people have a reduced ability to synthesise vitamin D due to age-related declines in skin capacity and metabolic changes [513]. They may require longer sun exposure to achieve the same level of vitamin D production as younger individuals. However, factors such as skin cancer concerns, limited mobility, being housebound, or residing in a residential aged care service can restrict sun exposure. In such cases, dietary sources, such as fatty fish (e.g. salmon), eggs, meats, and fortified dairy products can help maintain vitamin D levels [508, 509]. However, most individuals obtain less than 10% of their vitamin D requirements from diet alone [514], making supplementation necessary for some people.

Indicator of vitamin D status

Serum 25-hydroxyvitamin D (25[OH]D) is the standard biomarker for assessing vitamin D status, though optimal concentrations vary across guidelines [515]. Both low and excessively high 25(OH)D levels have been linked to adverse health outcomes, including cardiovascular diseases and tuberculosis [516]. Additionally, variability in analytical methods can affect the accuracy of 25(OH)D measurements [517].

Vitamin D deficiency is typically defined as a serum 25(OH)D concentration below 30 nmol/L, while levels between 30–50 nmol/L are considered insufficient. Healthy Bones Australia recommends maintaining a concentration of at least 50 nmol/L year-round [518]. Overscreening for vitamin D deficiency in healthy older people has led to concerns about unnecessary testing and overtreatment [519].

Refer to the narrative evidence summary, the GRADE Summary of Findings table in the guidelines, and the Technical Report for a complete presentation of the deprescribing evidence based on the GRADE framework (including other factors considered in developing the recommendations).

For frail older people living in residential aged care services, current guidelines recommend ongoing calcium and vitamin D supplementation, along with adequate protein intake, to prevent fracture [480]. If discontinuation of calcium and/or vitamin D is deemed appropriate, periodic monitoring of dietary intake and sunlight exposure (taking into consideration seasonal variation) is important to promptly detect any potential deficiency [480]. As part of a holistic approach to fall and fracture prevention, it is also essential to address modifiable risk factors through other strategies. These may include environmental modifications and participating in fall prevention exercise programs, which have been shown to significantly reduce fall-related injuries, including fractures [480].

Calcium

Calcium is generally well-tolerated, but excessive doses may increase the risk of renal calculi, constipation, and abdominal bloating [520]. Some studies have suggested a potential link between calcium supplementation and an increased risk of myocardial infarction (MI) and stroke, though the evidence remains inconclusive [521, 522]. Calcium supplementation alone has not been shown to significantly reduce the risk of fractures of any type [523, 524]. However, in older people living in a residential aged care service, combined calcium and vitamin D supplementation has demonstrated a reduction in fracture risk [525]. Calcium supplementation is recommended when daily dietary calcium intake is below 1,300 mg [526]. If supplementation is necessary, doses of 250-600 mg of elemental calcium daily are generally recommended, depending on dietary intake [509]. Other long-term indications that may require ongoing treatment include the use of calcium as a phosphate-lowering therapy for individuals with hyperphosphatemia and chronic kidney disease if appropriate [527]. However, its use requires caution due to the risk of hypercalcaemia [528].

Vitamin D

For individuals undergoing antiresorptive therapy for osteoporosis, vitamin D supplementation is recommended if serum 25(OH)D levels fall below 50 nmol/L. Most guidelines suggest daily doses of 600-800 IU of vitamin D for the general older population, with higher doses required for those with moderate-to-severe deficiency [508, 509]. Other long-term indications that may require ongoing treatment include the use of calcitriol for the management of mineral and bone disease in chronic kidney disease if appropriate, regardless of measured vitamin D levels [527]. However, its use requires caution due to the risk of [528].

Given the lack of clear evidence supporting the routine use of vitamin D supplementation in relatively healthy, community-dwelling older people, supplementation is generally not recommended for individuals with 25(OH)D levels between 30–50 nmol/L. In fact, high doses of vitamin D (e.g. > 60,000 IU monthly or > 1,000-4,000 IU daily) have been associated with an increased risk of falls in older adults [529, 530].

We identified one RCT related to calcium and vitamin D deprescribing [535], one RCT related to calcitriol deprescribing [423], and one prospective cohort study related to calcium deprescribing [536] from the systematic review and meta-analysis.

Overall, there are some reports that there may be a decline in BMD following discontinuation of calcium and/or vitamin D, especially in women. However, these reported outcomes are of very low to low certainty and are surrogate outcomes indicative of fracture risks. It is difficult to interpret the effects of deprescribing in the absence of a true active group for comparison. The evidence is of very low certainty and inadequate to inform evidence-based recommendations.