Correlation between vitamin D levels and hard-to-heal wounds: a systematic review

Hard-to-heal wounds are a major biological, psychological, social and financial burden on both individual patients and the broader health system, and are a threat to a patient's quality of life (QoL).^1,2 Some 30% of patients with hard-to-heal wounds experience depressive thoughts or anxiety related to the condition.² These thoughts are often associated with wound duration, odour, pain and immobility.² A study found that of the 8.2 million Medicare beneficiaries, 15% had a wound or wound infection. Total Medicare spending estimates were $28.1–96.8 billion on wounds alone. This included hospitalisations, outpatient treatments, infection costs and surgical interventions.³ With the rising cost and QoL impairment, there has been increasing interest in better understanding aetiology and treatment options for hard-to-heal wounds.

Hard-to-heal wounds are associated with a variety of comorbidities and have a complex aetiology, but are typically associated with nutritional deficiencies. Most of the research thus far has focused on protein, caloric intake, ascorbic acid, vitamin A and zinc.⁴ However, there has been limited research related to vitamin D status and wounds. Vitamin D is not abundant in the food supply; however, it is made endogenously upon exposure to ultraviolet B (UVB) rays in sunlight. The primary assessment of vitamin D status is a blood test measuring 25-hydroxyvitamin D levels.⁵ Many research studies have different guidelines on what is considered deficient versus sufficient. Table 1 lists the guidelines according to the National Institute of Health.⁶