Vitamin D and Stress Fractures in Sport: Preventive and Therapeutic Measures—A Narrative Review

Abstract

There are numerous risk factors for stress fractures that have been identified in literature. Among different risk factors, a prolonged lack of vitamin D (25(OH)D) can lead to stress fractures in athletes since 25(OH)D insufficiency is associated with an increased incidence of a fracture. A 25(OH)D value of <75.8 nmol/L is a risk factor for a stress fracture. 25(OH)D deficiency is, however, only one of several potential risk factors. Well-documented risk factors for a stress fracture include female sex, white ethnicity, older age, taller stature, lower aerobic fitness, prior physical inactivity, greater amounts of current physical training, thinner bones, 25(OH)D deficiency, iron deficiency, menstrual disturbances, and inadequate intake of 25(OH)D and/or calcium. Stress fractures are not uncommon in athletes and affect around 20% of all competitors. Most athletes with a stress fracture are under 25 years of age. Stress fractures can affect every sporty person, from weekend athletes to top athletes. Stress fractures are common in certain sports disciplines such as basketball, baseball, athletics, rowing, soccer, aerobics, and classical ballet. The lower extremity is increasingly affected for stress fractures with the locations of the tibia, metatarsalia and pelvis. Regarding prevention and therapy, 25(OH)D seems to play an important role. Athletes should have an evaluation of 25(OH)D -dependent calcium homeostasis based on laboratory tests of 25-OH-D3, calcium, creatinine, and parathyroid hormone. In case of a deficiency of 25(OH)D, normal blood levels of ≥30 ng/mL may be restored by optimizing the athlete’s lifestyle and, if appropriate, an oral substitution of 25(OH)D. Very recent studies suggested that the prevalence of stress fractures decreased when athletes are supplemented daily with 800 IU 25(OH)D and 2000 mg calcium. Recommendations of daily 25(OH)D intake may go up to 2000 IU of 25(OH)D per day.

Vitamin D in athletes: focus on physical performance and musculoskeletal injuries

“…Furthermore, it suggested that inadequate vitamin D levels could increase the risk of hamstring injuries. Particularly, vitamin D deficiency has been demonstrated to increase the incidence of stress fractures among musculoskeletal injuries in athletes [ 43 - 45 ]. Knechtle et al [ 43 ] reported that vitamin D deficiency was a risk factor for stress fractures in athletes.…”

“…Particularly, vitamin D deficiency has been demonstrated to increase the incidence of stress fractures among musculoskeletal injuries in athletes [ 43 - 45 ]. Knechtle et al [ 43 ] reported that vitamin D deficiency was a risk factor for stress fractures in athletes. Shimasaki et al [ 45 ] demonstrated that fifth metatarsal stress fractures were 5.1 and 2.9 times higher in athletes with 25(OH)D levels of 10 and 20 ng/mL, respectively.…”

Stress Fractures among Paramilitary Trainee Visiting a Paramilitary Hospital of Nepal: A Descriptive Cross-sectional Study

“…Stress fractures are particularly a common type of bone injury, which occurs either as a result of excessive stress on the bone, 1 exceeding the bone's capacity to withstand and heal from those forces, 2 or as insufficiency fractures due to secondary osteoporosis. 1 Such fractures act as a source of significant morbidity in physically active people, from recreational exercisers to military recruits. 1,2 The paramilitary trainee represents a unique population exposed to intense physical stress, 3 characterized by excessive stress on the bone.…”

“…1 Such fractures act as a source of significant morbidity in physically active people, from recreational exercisers to military recruits. 1,2 The paramilitary trainee represents a unique population exposed to intense physical stress, 3 characterized by excessive stress on the bone. 1 Energy deficits, due to restrictive dietary patterns, in such personnel may reduce the muscle mass and bone strength needed for optimal performance, which makes them more susceptible to developing stress fractures.…”

Associations of Vitamin D Levels with Physical Fitness and Motor Performance; A Cross-Sectional Study in Youth Soccer Players from Southern Croatia

“…Specifically, vitamin D affects the regulation of the differentiation, proliferation, and growth of cells; hormone production; and immune, nervous, and muscle systems [ 7 ]. Regarding these functions, vitamin D is considered to play a role in optimal sports performance since it is involved in muscle physiology as muscles express a high number of vitamin D receptors, affects the transport of phosphate and calcium across muscle cell membranes, modulates phospholipid metabolism, and induces the expression of several myogenic transcription factors and myotubular sizes, which together affect the contractile filaments [ 8 , 9 , 10 ].…”