The effects of vitamin D deficiency in athletes

Sarcopenia: how to determine and manage

BACKGROUND

Understanding sarcopenia is becoming increasingly important as society ages. This comprehensive review covers the definition, epidemiology, causes, pathogenesis, diagnosis, prevention, management, and future directions for the management of sarcopenia, and the major issues related to sarcopenia in the knee joint.

MAIN TEXT

Sarcopenia, a condition related to aging, is characterized by decreased muscle mass and strength, which significantly affects physical function. Its prevalence may vary by region and age, with reports of up to 50% prevalence in the elderly population. The potential causes of sarcopenia include neurodegeneration, poor nutrition, changes in hormonal effects, elevated levels of proinflammatory cytokines, and reduced activation of muscle satellite cells. Various pathogeneses, such as apoptosis, proteolysis, and inhibition of the signaling for increasing muscle mass, contribute to the development of sarcopenia. Generally, the diagnostic criteria for sarcopenia are based on reduced muscle mass, reduced muscle strength, and decreased physical performance, and can be assessed using various equipment and clinical tests. A healthy lifestyle consisting of a balanced diet, sufficient protein intake, and regular exercise is recommended to prevent sarcopenia. The management of sarcopenia involves resistance exercise, proper nutrition, and deprescribing from polypharmacy. In the future, pharmacological treatment and personalized nutrition may become alternative management options for sarcopenia. Finally, since sarcopenia can be associated with knee osteoarthritis and poor outcomes after total knee arthroplasty, appropriate management of sarcopenia is important for physicians treating knee-related conditions.

CONCLUSIONS

Sarcopenia is a significant pathological condition that needs to be recognized, especially in the older population. Although sarcopenia is common as aging occurs, it can be prevented by a healthy lifestyle. Currently, there are no approved drugs for sarcopenia; however, resistance exercise and proper nutritional supplementation are essential methods for managing sarcopenic conditions. Given its diverse causes, a personalized approach may be necessary to effectively manage sarcopenia. Finally, appropriate management of sarcopenia can contribute to the prevention and effective treatment of knee osteoarthritis.

Assessment of Micro- and Macronutrient Intake in Male Competitive Athletes Using the Epic-Norfolk Food Frequency Questionnaire

This study aimed to investigate diet quality in a population of male competitive athletes by comparing their total energy and macro- and micronutrients intake assessed by a food frequency questionnaire (FFQ) to current nutritional recommendations for this specific population. An additional goal was to assess athletes' sodium-to-potassium (Na-to-K) ratio. This cross-sectional study involved 31 healthy competitive male athletes. Subjects' body mass index, body composition, arterial blood pressure, as well as red blood count (RBC) and serum lipid profile measurements showed that all subjects were lean and normotensive and had normal RBC and serum lipid levels. All subjects completed a cross-culturally adapted, translated, and validated EPIC-Norfolk FFQ. The total energy intake reported in the FFQ was below the recommended values; however, 71% of subjects were classified as low energy reporters (LERs). Energy intake from proteins was within and from carbohydrates was below the recommended interval, while the total energy intake from fats (and also saturated fatty acids) exceeded the recommendations. Suboptimal intakes of vitamin D and folate were observed, indicating the necessity for monitoring (and supplementing) in this population. High Na intake, which despite adequate K intake resulted in a higher Na-to-K ratio, highlighted concerns over excessive salt consumption, but also accentuated the need for monitoring sodium (and potassium) intake in competitive athletes with consideration for sweat-related losses.

Running Low: A Seasonal Analysis of Micronutrient Deficiencies on External-Load Measures in Elite Female Rugby League Players

Iron and vitamin D are essential for physiological mechanisms underpinning physical capacities characterizing team-sport performance. Yet, the impact of iron deficiency on physical capacities beyond endurance is not clear.

PURPOSE

The purpose of this study was to assess variations in seasonal micronutrient concentrations and how iron deficiency impacts external-load measures in elite female rugby league players.

METHODS

Iron and vitamin D status were measured in 28 players (age 24 [4] y, body mass 76 [11] kg) across 3 time points of the 17-week National Rugby League Women's season. Physical demands were evaluated using external-load measures (eg, total distance, PlayerLoad) for training and competition. Linear mixed-effects models were employed to assess the effect of change in serum ferritin concentration on external-load measures. Effect sizes with 95% CIs were calculated to interpret the magnitude of difference in change in indices and performance outcomes between iron-deficient and iron-sufficient players.

RESULTS

Iron-deficiency prevalence ranged from 26% to 57% across the season, and <22% of players were vitamin D deficient at each time point. Weak to strong positive associations (R2 = .3-.6) were observed between all external-load measures and moderating variables (serum ferritin, week, position, and athlete). However, these associations were largely attributable to the contribution of week and position. Differences in load measures between iron-deficient and iron-sufficient players were mostly trivial to small.

CONCLUSIONS

Iron status of elite female rugby league players had little effect on most workload measures within this cohort. However, longitudinal monitoring is warranted to identify how external-load measures are affected individually in response to fluctuations in serum ferritin.

The Prevalence of Low Vitamin D in Elite Para-Athletes: A Systematic Review

BACKGROUND

Vitamin D insufficiency (25OHD, 50-75 nmolˑl- 1) is a common issue within healthy adults and elite athletes and is associated with decreased musculoskeletal health and performance. However, few studies have identified the prevalence and risk factors associated with vitamin D insufficiency within elite Para-Athletes.

METHODS

An electronic search was completed on the 5th January 2023 and updated on the 21st June 2024, searching Web of Science, PubMed, Scopus, Cochrane Library and EASY (originally OpenGrey). To meet the eligibility criteria, retrieved studies were required to include at least one baseline measure of a vitamin D biomarker from elite Para-Athletes performing at national or international levels and therefore all quantitative study designs could be included. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist (8-item) for analytical cross-sectional studies. Data from the eligible studies was extracted and charted, with a supporting narrative synthesis.

RESULTS

The search strategy retrieved 3083 articles, of which ten studies met the inclusion criteria. In total there were n = 355 Para-Athletes, 69.6% of which comprised of males in the included studies. Across the ten included studies, n = 546 samples were taken from n = 355 Para-Athletes across different seasons and based upon the 25(OH)D insufficiency and deficiency thresholds set by each individual study 43.2% of the samples were considered insufficient and 28.1% deficient. During the winter months vitamin D insufficiency was at its most prevalent at 74.1%, compared to 57.1% in summer of the 25(OH)D samples measured in Para-Athletes. Wheelchair athletes who competed in indoor sports were also more susceptible to low vitamin D.

CONCLUSION

This review has highlighted that vitamin D insufficiency and deficiency is highly prevalent in elite level Para-Athletes, all year, across both summer and winter months. Therefore, this review highlights the need for education, treatment, and preventative measures in elite Para-Athletes throughout the year.

REGISTRATION

The following systematic review was prospectively registered through PROSPERO International prospective register of systematic reviews (PROSPERO registration ID number: CRD42022362149).

Characteristics of Vitamin D Concentration in Elite Israeli Olympic Athletes

BACKGROUND

The prevalence of vitamin D deficiency has been a growing concern in recent years. Vitamin D is important in many of the body's physiological systems, such as the musculoskeletal, cardiovascular and immune functions. A deficiency of vitamin D in athletes may negatively impact both muscle functions and recovery and, thus, affect performance and increase the risk of injury. Many studies assessed the prevalence of vitamin D deficiency in athletes; however, as of today, there are no official recommendations/protocols for screening vitamin D levels in athletes, and only a few studies were performed in male and female elite athletes (i.e., Olympic level), in different sport disciplines.

METHOD

We investigated the prevalence of vitamin D deficiency among athletes entering the Israeli Olympic team. A total of 761 samples of Vitamin D(OH)25 from 334 athletes were analyzed. For this analysis, we used the first test the athlete had performed when joining the Olympic team. The prevalence of vitamin D deficiency (<50 nmol/L, as defined by the Endocrine Society Committee) was investigated according to gender, types of sports and outdoor vs. indoor sports through the different seasons of the Israeli Olympic team athletes.

RESULT

Twenty-five athletes (7.5%) were diagnosed with vitamin D deficiency. One hundred and thirty-one athletes (39.2%) had insufficient levels of vitamin D (50-75 nmol/L). The highest incidence of vitamin D deficiency was found amongst gymnastics and combat sport athletes. A significant difference was also found in vitamin D concentration between seasons. Vitamin D average concentration in the winter was 74.1 nmol/L compared to 86.4 nmol/L in the Summer (p < 0.0005).

CONCLUSIONS

Due to the importance of vitamin D to athletic performance and the high prevalence of deficiency and insufficiency, we suggest careful and frequent monitoring of groups at risk, including elite athletes, especially in susceptible sports and during the winter. Future studies are necessary to investigate the effectiveness of Vitamin D supplementation in athletes with low baseline vitamin D levels.

Effects of vitamin D3 supplementation on strength of lower and upper extremities in athletes: an updated systematic review and meta-analysis of randomized controlled trials

Background

Coaches and athletes are increasingly interested in understanding athletes' serum vitamin D levels, their impact on strength, physical performance, and athletic outcomes. Previous meta-analyses were reported with limited sample size and no significant overall effect was found. Hence, it is crucial to conduct a thorough and up-to-date systematic examination and meta-analysis to elucidate the potential advantages of supplementing with vitamin D3 in enhancing muscle strength for athletes.

Methods

We performed a thorough investigation, spanning three databases (PubMed, EBSCO, and Cochrane Library), seeking randomized controlled trials (RCTs) in all languages. These trials delved into the influence of vitamin D3 supplementation on the changes of pre- and post-intervention muscle strength in healthy athletes. Our systematic examination and meta-analysis took into account serum 25(OH)D levels exceeding 30 ng/mL as a marker of adequacy.

Results

Ten RCTs, comprising 354 athletes (185 in the vitamin D3 group and 169 in the placebo group), fulfilled the inclusion criteria. During the study, 36 athletes were lost to follow-up, leaving 318 athletes (166 in the vitamin D3 group and 152 in the placebo group) with documented complete results. In comparison with the placebo group, there is a significant increase between the changes of pre- and post-intervention serum 25(OH)D levels among athletes following a period of vitamin D3 supplementation (MD 14.76, 95% CI: 8.74 to 20.77, p < 0.0001). Overall effect of four strength measurements including handgrip, one repetition maximum Bench Press (1-RM BP), vertical jump, and quadriceps contraction was not significantly improved (SMD 0.18, 95% CI: -0.02 to 0.37, p = 0.08), but there was a significant increase in quadriceps contraction (SMD 0.57, 95% CI: 0.04 to 1.11, p = 0.04).

Conclusion

This updated meta-analysis indicates the potential benefits of vitamin D supplementation for enhancing muscle strength in athletes when analyzing its quantitatively synthesized effects. With limited available studies for the quantitative synthesis, it cannot warrant significant overall enhancements in muscle strength when athletes attain adequate serum 25(OH)D levels through supplementation.

Vitamin D Supplementation Influences Ultramarathon-Induced Changes in Serum Amino Acid Levels, Tryptophan/Branched-Chain Amino Acid Ratio, and Arginine/Asymmetric Dimethylarginine Ratio

Exercise affects serum levels of amino acids and their metabolites, with important metabolic consequences. Since vitamin D impacts skeletal muscle protein degradation, we hypothesised that it would also impact exercise-induced changes in serum amino acid levels and the serum levels of arginine metabolites, influencing the body's ability to synthesise NO. Accordingly, we analysed the effect of a single high-dose vitamin D supplementation on the serum levels of various amino acids in ultramarathon runners. Thirty-five male amateur runners were assigned to the supplemented group, administered 150,000 IU vitamin D in vegetable oil 24 h before the run (n = 16), or the control (placebo) group (n = 19). Blood was sampled 24 h before, immediately after, and 24 h after the run. Changes in the serum levels of some amino acids were distinct in the two groups. The asymmetric dimethyl arginine levels were significantly decreased immediately after the run and increased 24 h later and were not affected by the supplementation. The symmetric dimethyl arginine levels were increased after the run in both groups but were lower in the supplemented group than in the placebo group 24 h after the run. The dimethylamine levels increased significantly in the supplemented group as compared to the placebo group. In conclusion, vitamin D impacts exercise-induced changes in serum amino acids and methylated arginine metabolites.

Impaired Bone Microarchitecture at Distal Radial and Tibial Reference Locations Is Not Related to Injury Site in Athletes With Bone Stress Injury

BACKGROUND

Bone stress injuries (BSIs) are common sports injuries that occur because of an imbalance between microdamage accumulation and removal through bone remodeling. The underlying bone phenotype has been assumed to be a contributing factor. However, the bone microarchitecture of athletes with BSI is not well characterized, and no study has investigated whether impaired bone microarchitecture is associated with bone composition or anatomic site of injury.

PURPOSE/HYPOTHESIS

This cross-sectional study characterizes the bone microarchitecture at distal radial and tibial reference locations in athletes with BSI. Based on previous dual-energy X-ray absorptiometry (DXA) findings, the aim was to compare anatomic injury sites, hypothesizing that athletes with BSIs in bones with greater trabecular composition show impaired bone microarchitecture parameters compared with those with BSIs in bones with greater cortical composition.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Athletes who had presented to our outpatient clinic because of a high-grade BSI (ie, stress fracture) were retrospectively included. Blood and urine samples were collected. Areal bone mineral density (aBMD) was assessed by DXA at the lumbar spine and both hips. Bone microarchitecture was analyzed by high-resolution peripheral quantitative computed tomography (HR-pQCT) at the distal radius and tibia. HR-pQCT parameters were expressed in relation to available sex-, age-, and device-adjusted reference values and compared with a cohort of 53 age- and sex-matched controls.

RESULTS

In total, 53 athletes had a BSI of the foot (n = 20), tibia/fibula (n = 18), pelvis (n = 9), femur (n = 5), or sternum (n = 1). Based on DXA measurements, a Z-score of -1.0 or lower was found in 32 of 53 (60.4%) of the athletes, of whom 16 of 53 (30.2%) had a Z score -2.0 or lower. While an impairment of cortical area (P = .034 and P = .001) and thickness (P = .029 and P < .001) was detected at the distal radius and tibia in the BSI cohort compared with controls, no differences in BMD or bone microarchitecture were observed between anatomic injury sites. Furthermore, no difference was revealed when BSIs were grouped into cortical- and trabecular-rich sites.

CONCLUSION

Reduced aBMD and impaired cortical bone microarchitecture were present in a considerable number of athletes with BSI. Neither aBMD nor bone microarchitecture was related to the injury site, highlighting the multifactorial etiology of BSI.

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

PURPOSE

The aim of this review was to discuss the effects of vitamin D on physical performance and musculoskeletal injuries in athletes and provide information on the field applications of vitamin D.

METHODS

A systematic review was conducted to identify studies on vitamin D in athletes that assessed serum vitamin D levels, vitamin D and physical performance, vitamin D and musculoskeletal injuries, and practical guidelines for supplementation of vitamin D.

RESULTS

Several studies reported that a high proportion of athletes had vitamin D insufficiency or deficiency. Low serum levels of vitamin D in athletes were more pronounced in winter than in other seasons, and indoor athletes had lower serum vitamin D levels than outdoor athletes. Low vitamin D levels have been demonstrated to have negative effects on muscle strength, power, and endurance; increase stress fractures and other musculoskeletal injuries; and affect acute muscle injuries and inflammation following high-intensity exercises. Therefore, periodic assessment and monitoring of vitamin D levels are necessary in athletes; the recommended serum level of 25(OH)D is &gt; 32 ng/mL and the preferred level is &gt; 40 ng/mL (-1). In those with low levels of vitamin D, exposure to sunlight and an improved diet or supplements may be helpful. Particularly, 2000-6000 IU of supplemental vitamin D3 can be consumed daily.

CONCLUSION

Vitamin D is a potential nutritional factor that can significantly affect physical performance and musculoskeletal injuries in athletes. The importance and role of vitamin D in athletes should be emphasized, and the current levels of vitamin D should be assessed. Therefore, it is essential to periodically evaluate and monitor serum vitamin D levels in athletes.

The impact of vitamin D supplementation on body fat mass in elite male collegiate athletes

BACKGROUND

Whether vitamin D supplementation has any effect on body fat percentage, especially among elite athletes, remains unclear. The aim of this study was to evaluate the effect of vitamin D supplementation on serum vitamin D level in elite male collegiate athletes and to analyze its effect on body fat percentage.

METHODS

We enrolled a total of 42 elite male collegiate athletes in this prospective cohort study. In March 2020, body composition monitoring and blood test were performed. All athletes were provided with vitamin D3 supplement tablets of 25 μg/day. The use of the supplement was dependent on athletes' preference. During the study period, their club activities were stopped for 2 months due to the coronavirus disease 2019 outbreak. A second examination, similar to the first one, was performed after approximately 3 months. Supplement usage by each athlete was also confirmed. The participants were divided into a non-supplement group (without supplementation, n = 15) and a supplement group (with supplementation, n = 27).

RESULTS

Regarding baseline data at initial examination, the non-supplement and supplement groups showed significant differences in the mean body fat percentage (9.0% and 12.1%, respectively; P = 0.03) and serum 25(OH)D level (22.7 and 18.5 ng/mL, respectively, P = 0.02). At the time of the second examination, there were no significant differences in the results of both the groups. In terms of mean change value from the first to the second examination, there were significant differences in body fat percentage (1.9 and 0.2%, respectively, P = 0.02) and serum 25(OH)D level (1.7 and 7.2 ng/mL, respectively, P < 0.001) between the two groups. A significant negative correlation was observed between the change ratio of body fat percentage and change value of serum 25(OH)D level (r =  - 0.37, P = 0.02).

CONCLUSIONS

Vitamin D supplementation of 25 μg/day significantly increased the serum 25(OH)D level in elite male collegiate athletes. Vitamin D supplementation may play a role in maintaining athletes' body fat percentage under circumstances where sports activity has decreased.

Sarcopenia and Vitamin D Deficiency in Patients with Crohn's Disease: Pathological Conditions That Should Be Linked Together

Sarcopenia is a prevalent condition in patients with Crohn’s disease (CD), representing an independent predictor factor for the development of major postoperative complications. Thus, a proper assessment of the muscle strength, by using different validated tools, should be deemed an important step of the clinical management of these patients. Patients with CD are frequently malnourished, presenting a high prevalence of different macro- and micro-nutrient deficiencies, including that of vitamin D. The available published studies indicate that vitamin D is involved in the regulation of proliferation, differentiation, and regeneration of muscle cells. The relationship between vitamin D deficiency and sarcopenia has been extensively studied in other populations, with interesting evidence in regards to a potential role of vitamin D supplementation as a means to prevent and treat sarcopenia. The aim of this review was to find studies that linked together these pathological conditions.

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

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.

Prevalence of Vitamin D Insufficiency and Deficiency in Young, Female Patients With Lower Extremity Musculoskeletal Complaints

BACKGROUND

Low levels of vitamin D have well-known impacts on bone health, but vitamin D also has a more global role throughout many tissues, including skeletal muscle. The high prevalence of hypovitaminosis D and the vast physiological features of vitamin D have led researchers to examine the influence of vitamin D on physical performance and injury. Because of the critical role of vitamin D in maintaining musculoskeletal health and function, a high rate of hypovitaminosis D among female patients with a variety of musculoskeletal issues could be of high clinical relevance.

HYPOTHESIS

There is a high prevalence of low vitamin D in female patients with both acute and overuse sports-related issues of both soft tissue and bone.

STUDY DESIGN

Prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Female patients, aged 16 to 40 years, presenting with lower extremity injury diagnosed within the past 4 weeks, no use of multivitamin or vitamin D supplement, and no history of malabsorption syndrome met the inclusion criteria. Vitamin D levels were assessed and categorized as normal (≥32 ng/mL) and low, which includes insufficient (20.01-31.9 ng/mL) and deficient (≤20 ng/mL).

RESULTS

Of the 105 patients enrolled, 65.7% had low vitamin D. Within the low vitamin D cohort, 40.6% were deficient and 59.4% were insufficient. Injuries were grouped into overuse or acute with 74 overuse injuries and 31 acute injuries, exhibiting low vitamin D prevalence of 60.8% and 77.4%, respectively. Patients with ligamentous/cartilaginous injuries exhibited the highest percentage of low vitamin D (76.5%), followed by those with patellofemoral-related complaints (71.0%), muscle/tendon injuries (54.6%), and bone stress injuries (45.5%). In univariable analysis, older age, non-White race, less physical activity, less high-intensity interval training days, less endurance training days, and more rest days showed an association with low vitamin D, but none showed an independent association in multivariable analysis.

CONCLUSION

The prevalence of low vitamin D in female patients with various musculoskeletal complaints was high. Clinicians should evaluate for low vitamin D in both acute and overuse injuries.

CLINICAL RELEVANCE

In addition to screening, this study suggests that clinicians should evaluate for low vitamin D levels beyond bone stress injuries in the setting of acute and overuse injuries.

Association of Serum Vitamin D Levels and Stress Fractures in Collegiate Athletes

Background

Low vitamin D levels along with high-intensity athletic training may put an athlete at increased risk for a stress fracture.

Purpose

To assess whether supplementation with vitamin D is associated with a reduced risk of stress fractures in college athletes. We also assessed differences in vitamin D levels among athletes participating in outdoor versus indoor sports.

Study Design

Cohort study; Level of evidence, 2.

Methods

The study participants included 802 National Collegiate Athletic Association Division I intercollegiate athletes (497 men and 305 women) on a sports team for at least 1 semester from 2012 to 2018. All athletes who had a baseline vitamin D level in their medical record were included. Athletes with vitamin D levels <40 ng/mL were given vitamin D supplements. We assessed differences in the rate of stress fracture among those who maintained or improved vitamin D levels to ≥40 ng/mL and those who did not, as well as differences in average baseline vitamin D levels by sport type (indoor vs outdoor).

Results

The rate of stress fracture was 12% higher (95% CI, 6-19; P < .001) for those who remained low in vitamin D compared with those who were low at baseline but improved their vitamin D status to ≥40 ng/mL. The rate of stress fracture was also 12% higher (95% CI, 5-18; P < .001) for those who had low vitamin D levels compared with those who maintained normal levels. The mean baseline vitamin D values were significantly higher for men participating in outdoor sports versus indoor sports. For men, the mean vitamin D level was 5.7 ng/mL higher (95% CI, 0.9-10.5; P = .01) in outdoor athletes. For women, the mean vitamin D level was 3.7 ng/mL higher (95% CI, -0.58 to 8.03; P < .04) for outdoor versus indoor sports.

Conclusion

Study results indicated that correcting low serum vitamin D levels reduces the risk of stress fracture. This study also presented evidence that athletes who participate in indoor sports may be at greater risk for vitamin D deficiency than those who compete in outdoor sports.

Vitamin D and the athlete-patient: state of the art

Vitamin D deficiency is common in athletes. The conventional measurement of vitamin D levels provides a general indicator of body stores. However, there are nuances in its interpretation as values of 25(OH)D do not correlate absolutely with the amount of 'bioavailable' vitamin to the cells. Vitamin D should be regarded as a hormone and influences between 5% and 10% of our total genome. Determining the precise effect of the vitamin, isolated from the actions of other cofactors, is not straightforward and restricts our complete understanding of all of its actions. Deficiency has harmful effects on not only bone and muscle but also wider areas, including immunity and respiratory and neurological activities. More caution should be applied regarding the ability of supranormal vitamin D levels to elevate athletic performance. Hopefully, future research will shed more light on optimal levels of vitamin D and supplementation regimes, and improved understanding of its intracellular control of our genetic mechanisms and how extrinsic influences modify its activity.

Assessing the impact of a mushroom-derived food ingredient on vitamin D levels in healthy volunteers

BACKGROUND

Prevalence of vitamin D insufficiency/deficiency has been noted in athletic populations, although less is known about recreationally active individuals. Biofortification of natural food sources (e.g. UV radiated mushrooms) may support vitamin D status and is therefore of current scientific and commercial interest. The aim of this study was to assess the impact of a mushroom-derived food ingredient on vitamin D status in recreationally active, healthy volunteers.

METHODS

Twenty-eight participants were randomly assigned to either: 25 μg (1000 IU) encapsulated natural mushroom-derived vitamin D₂; matched-dose encapsulated vitamin D₃ or placebo (PL) for 12 weeks. Venous blood samples were collected at baseline, week 6 and 12 for analysis of serum 25(OH)D₂ and 25(OH)D₃ using liquid chromatography mass spectrometry. Habitual dietary intake and activity were monitored across the intervention.

RESULTS

Vitamin D status (25(OH)D_TOTAL) was significantly increased with vitamin D₃ supplementation from 46.1 ± 5.3 nmol·L^- 1 to 88.0 ± 8.6 nmol·L^- 1 (p < 0.0001) across the intervention, coupled with an expected rise in 25(OH)D₃ concentrations from 38.8 ± 5.2 nmol·L^- 1 to 82.0 ± 7.9 nmol·L^- 1 (p < 0.0001). In contrast, D₂ supplementation increased 25(OH)D₂ by + 347% (7.0 ± 1.1 nmol·L^- 1 to 31.4 ± 2.1 nmol·L^- 1, p < 0.0001), but resulted in a - 42% reduction in 25(OH)D₃ by week 6 (p = 0.001). A net + 14% increase in 25(OH)D_TOTAL was established with D₂ supplementation by week 12 (p > 0.05), which was not statistically different to D₃. Vitamin D status was maintained with PL, following an initial - 15% reduction by week 6 (p ≤ 0.046 compared to both supplement groups).

CONCLUSIONS

The use of a UV radiated mushroom food ingredient was effective in maintaining 25(OH)D_TOTAL in healthy, recreationally active volunteers. This may offer an adjunct strategy in supporting vitamin D intake. However, consistent with the literature, the use of vitamin D₃ supplementation likely offers benefits when acute elevation in vitamin D status is warranted.

Malnutrition in Orthopaedic Sports Medicine: A Review of the Current Literature

CONTEXT

Malnutrition is well-studied in various aspects of the orthopaedic literature, most commonly in relation to arthroplasty, spine surgery, and trauma. However, the management of nutritional deficiencies is commonly overlooked among orthopaedic sports medicine providers. The purpose of this article is to analyze the available sports medicine literature to review the associations between malnutrition and the management of orthopaedic sports medicine patients from a treatment and performance standpoint.

EVIDENCE ACQUISITION

PubMed was searched for relevant articles published from 1979 to 2019.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Few studies exist on the implications of macronutrient deficiencies specific to orthopaedic sports medicine procedures. Interestingly, micronutrient disorders-namely, hypovitaminosis D and iron deficiency-have been well studied and may lead to worse postoperative outcomes, injury rates, and athletic performance. Nutritional supplementation to correct such deficiencies has been shown to mitigate these effects, though further study is required.

CONCLUSION

Nutritional deficiencies are highly prevalent in orthopaedic sports medicine patients, and practitioners should be aware of their potential effects on treatment and performance outcomes. Management of such deficiencies and their effect on surgical patients remain an area of potential future research. Future studies are warranted in order to explore the potential therapeutic role of nutritional supplementation to prevent complications after common orthopaedic sports medicine procedures, improve athletic performance, and reduce injury rates.

Nutrition and Athlete Bone Health

Athletes should pay more attention to their bone health, whether this relates to their longer-term bone health (e.g. risk of osteopenia and osteoporosis) or their shorter-term risk of bony injuries. Perhaps the easiest way to do this would be to modify their training loads, although this advice rarely seems popular with coaches and athletes for obvious reasons. As such, other possibilities to support the athletes’ bone health need to be explored. Given that bone is a nutritionally modified tissue and diet has a significant influence on bone health across the lifespan, diet and nutritional composition seem like obvious candidates for manipulation. The nutritional requirements to support the skeleton during growth and development and during ageing are unlikely to be notably different between athletes and the general population, although there are some considerations of specific relevance, including energy availability, low carbohydrate availability, protein intake, vitamin D intake and dermal calcium and sodium losses. Energy availability is important for optimising bone health in the athlete, although normative energy balance targets are highly unrealistic for many athletes. The level of energy availability beyond which there is no negative effect for the bone needs to be established. On the balance of the available evidence it would seem unlikely that higher animal protein intakes, in the amounts recommended to athletes, are harmful to bone health, particularly with adequate calcium intake. Dermal calcium losses might be an important consideration for endurance athletes, particularly during long training sessions or events. In these situations, some consideration should be given to pre-exercise calcium feeding. The avoidance of vitamin D deficiency and insufficiency is important for the athlete to protect their bone health. There remains a lack of information relating to the longer-term effects of different dietary and nutritional practices on bone health in athletes, something that needs to be addressed before specific guidance can be provided.

Bioactive Lipid Signaling in Cardiovascular Disease, Development, and Regeneration

Cardiovascular disease (CVD) remains a leading cause of death globally. Understanding and characterizing the biochemical context of the cardiovascular system in health and disease is a necessary preliminary step for developing novel therapeutic strategies aimed at restoring cardiovascular function. Bioactive lipids are a class of dietary-dependent, chemically heterogeneous lipids with potent biological signaling functions. They have been intensively studied for their roles in immunity, inflammation, and reproduction, among others. Recent advances in liquid chromatography-mass spectrometry techniques have revealed a staggering number of novel bioactive lipids, most of them unknown or very poorly characterized in a biological context. Some of these new bioactive lipids play important roles in cardiovascular biology, including development, inflammation, regeneration, stem cell differentiation, and regulation of cell proliferation. Identifying the lipid signaling pathways underlying these effects and uncovering their novel biological functions could pave the way for new therapeutic strategies aimed at CVD and cardiovascular regeneration.

Actual Nutrition and Dietary Supplementation in Lithuanian Elite Athletes

Background and objectives: Health is partly determined by the state of one's nutrition; it stimulates the body's functional and metabolic adaptations to physical strain and helps one prevent sports injuries and get in shape in terms of body composition. This study aims to investigate the actual nutrition and dietary supplements taken by elite Lithuanian athletes and to identify the relationship between the dietary intake, dietary supplementation and body composition of elite athletes. Materials and Methods: The research subjects were 76.7% of Lithuanian elite athletes (N = 247). The actual diet was investigated using the 24 h recall dietary survey method. Dietary supplementation was studied applying the questionnaire method. Measurements of body composition were performed using the BIA (bioelectrical impedance analysis) tetra-polar electrodes and measuring resistivity with 8-12 tangent electrodes at different frequencies of signal: 5, 50 and 250 kHz. Results: Results indicate that among the athletes, 62% use too few carbohydrates and 77% use too much fat. Although the 3.5% increase in lean body mass (95% CI: -0.107, 7.070) helps gain an increased protein intake with food (p = 0.057), 38% of athletes consume too little protein with food. The athletes mostly use carbohydrates (86%), vitamins (81%), protein supplements (70%), and multivitamins (62%). We did not determine the impact (p > 0.05) of individual or complex supplement use on the lean body mass (%) or fat mass (%) values of athletes. Conclusions: Athletes consume insufficient carbohydrates, vitamin D, calcium, polyunsaturated fatty acids, omega-3 and omega-6 fatty acids and too much fat, saturated fatty acids, cholesterol, and they use proteins irrationally. Sport nutritionists should also focus on the risk of malnutrition for female athletes. Nutritional supplements partially offset macronutrient and micronutrient deficiency. Nevertheless, the effect of food supplements on the body composition of athletes is too small compared to the normal diet. Athletes ought to prioritize the formation of eating habits and only then use supplements.

25-Hydroxyvitamin D, Vitamin D Binding Protein, Bioavailable 25-Hydroxyvitamin D, and Body Composition in a Diverse Sample of Women Collegiate Indoor Athletes

Women athletes are at higher risk for bone diseases; yet, information on vitamin D status ((25(OH)D), vitamin D binding protein (VDBP), and bioavailable 25(OH)D is limited. Collegiate athletes (n = 36) from volleyball (WVB), basketball (WBB), and track and field (WTF) were measured for (25(OH)D), VDBP, and bioavailable 25(OH)D; body composition and bone mineral density (BMD); and skin pigmentation. Participants self-reported daily vitamin D intake and sun exposure. One-way analysis of variance analyzed mean differences in measures across sports. Linear regression examined relationships between 25(OH)D; VDBP; bioavailable 25(OH)D; and whole body, hip, and spine BMD. Participants' (mean ± SD, 19.4 ± 1.4 years, 172.75 ± 8.21 cm, 70.9 ± 13.2 kg, and 22.9 ± 4.1% body fat) overall mean 25(OH)D was 70.5 ± 32.25 nmol/L, and 28% of participants were deemed inadequate and 61% below thresholds identified as sufficient for athletes. Although WBB athletes consumed higher (p = 0.007) dietary vitamin D (760.9 ± 484.2 IU/d) than WVB (342.6 ± 257.8) and WTF (402.3 ± 376.4) athletes did, there were no differences across sport in serum 25(OH)D. WVB and WTF had higher bioavailable 25(OH)D than WBB. No relationships existed between vitamin D status and body composition. Vitamin D inadequacy was identified among 1/3 of women indoor sport athletes. Consistent monitoring of vitamin D status and diet are recommended to sustain athlete health and sport performance.

Vitamin D3 Supplementation and Stress Fractures in High-Risk Collegiate Athletes - A Pilot Study

INTRODUCTION

Vitamin D is paramount to bone health and little is known about vitamin D's role in the prevention of stress fractures in high-risk athletes. This study consists of a prospective, cross-sectional analysis accompanied by a retrospective review for control comparison of vitamin D3 supplementation in high-risk athletes. Our hypothesis is that supplemental vitamin D3 treatment will decrease the occurrence of stress fractures in high-risk collegiate athletes.

MATERIALS AND METHODS

A total of 118 NCAA Division I athletes were recruited from 6 high-risk collegiate teams. Blood draws in August and February established baseline 25(OH)D levels. Subjects with serum 25(OH)D <30 ng/mL were supplemented with 50,000 IU of vitamin D3/week for 8 weeks. Treated subjects were re-tested to ensure serum 25(OH)D levels rose to sufficient status. All enrolled subjects were monitored for the development of stress fractures. A 5-year retrospective chart review of athletes from the same sports teams was conducted to determine the incidence of any reported stress fractures in the past.

RESULTS

Prospective: 112 of the 118 enrolled subjects were tested in August. Sixty-one demonstrated vitamin D sufficiency (40.2 ng/mL ±8.28) and 51 were either insufficient or deficient (22.7 ng/mL ±4.89). Of the 118 enrolled subjects, 104 were tested in February. Fifty-six demonstrated vitamin D sufficiency (40.7 ng/mL ±9.47) and 48 were insufficient or deficient (21.6 ng/mL ±5.87). Two stress fractures were diagnosed amongst our cohort of 118 student athletes (1.69%). Retrospective: 34 stress fractures were diagnosed in 453 subjects from 01/2010-05/2015 (7.51%). Amongst our athletic teams, the cross-country team specifically demonstrated a statistically significant decrease in stress fracture incidence (p<0.05). We also found a statistically significant reduction in stress fracture incidence amongst the current overall cohort compared to our retrospective cohort (p<0.05).

CONCLUSION

In our population, almost half of the tested athletes proved to be vitamin D deficient. Hypovitaminosis D was prevalent throughout the winter months compared with the summer. With vitamin D3 supplementation, the stress fracture rate in our overall cohort demonstrated a statistically significant decrease from 7.51% to 1.65% (p=0.009).

Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends

We are currently experiencing a vitamin D (VITD) deficiency pandemic across the world. Athletes have the same predisposition to low levels of vitamin D, the majority of its concentrations being below 20 ng/mL in a wide range of sports, especially in the winter months. Vitamin D is important in bone health, but recent research also points out its essential role in extraskeletal functions, including skeletal muscle growth, immune and cardiopulmonary functions and inflammatory modulation, which influence athletic performance. Vitamin D can also interact with extraskeletal tissues to modulate injury recovery and also influence the risk of infection. The data presented in this paper has triggered investigations in relation to the importance of maintaining adequate levels of vitamin D and to the possible positive influence supplementation has on immune and musculoskeletal functions in athletes, benefiting their performance and preventing future injuries. The objective of this review is to describe the latest research conducted on the epidemiology of vitamin D deficiency and its effects on sports performance and musculoskeletal health.

Effects of vitamin D3 supplementation on serum 25(OH)D concentration and strength in athletes: a systematic review and meta-analysis of randomized controlled trials

Background

The purpose of this systematic review and meta-analysis is to investigate the effects of vitamin D3 supplementation on skeletal muscle strength in athletes. Vitamin D3 supplements or vitamin D3 fortified foods always have claims for bringing people health benefits including bone and muscle health. An up-to-date rigorous systematic review and meta-analysis is important to better understand the effect of vitamin D3 supplementation on muscle strength.

Methods

English written randomized controlled trials (RCTs) that looked at effects of vitamin D3 supplementation on muscle strength in healthy athletes were searched using three databases (PubMed, Embase and Cochrane Library). Serum 25(OH)D above 30 ng/mL is considered to be sufficient in this systematic review and meta-analysis.

Results

Five RCTs with 163 athletes (vitamin D3 n = 86, placebo n = 77) met inclusion criteria. Fourteen athletes were lost to follow-up and 149 athletes (vitamin D3 n = 80, placebo n = 69) were documented with complete result. Among athletes with baseline serum 25(OH)D values suggesting insufficiency, vitamin D3 daily dosage at 5000 IU for over 4 weeks led to a serum 25(OH)D concentration of 31.7 ng/mL. Athletes with sufficient serum 25(OH)D level at baseline were recruited in only one study, and the participants of which were assigned to either vitamin D3 at a daily dosage of 3570 IU or placebo for 12 weeks, their serum 25(OH)D sufficiency (VD: 37.2 ± 7.6 vs. 45.6 ± 7.6; PL: 38 ± 6.8 vs. 32 ± 8.4) was well maintained above the cut-off boundary. One repetition maximum Bench Press (1-RM BP) was not improved significantly (SMD 0.07, 95% CI: − 0.32 to 0.47, P = 0.72) and there was no significant increase in maximal quadriceps contraction (SMD -2.14, 95% CI: − 4.87 to 0.59, P = 0.12). Furthermore, there was no significant overall effect of vitamin D3 intervention on muscle strength in this meta-analysis (SMD -0.75, 95% CI: − 1.82 to 0.32, P = 0.17).

Conclusion

Although, serum 25(OH)D concentrations after supplementation reached sufficiency was observed, muscle strength did not significantly improve at this point of current meta-analysis. Additional well-designed RCTs with large number of participants examined for the effect of vitamin D3 supplementation on serum 25(OH)D concentrations, muscle strength in a variety of sports, latitudes and diverse multicultural populations are needed.

Vitamin D Deficiency and Sarcopenia in Older Persons

Vitamin D deficiency is a common health problem worldwide, in particular among older people. Vitamin D regulates and modulates the physiology and function of multiple human systems, including the skeletal muscle. The effect of vitamin D on the muscle has been widely investigated, suggesting that this hormone can stimulate the proliferation and differentiation of skeletal muscle fibers, maintaining and improving muscle strength and physical performance. Older persons have a higher prevalence of low Vitamin D levels as a consequence of low dietary intake and reduced ultraviolet irradiation of the skin. Therefore, older people with vitamin D deficiency might be at risk of sarcopenia, a geriatric syndrome characterized by the progressive loss of skeletal muscle mass and strength often complicated by adverse events, such as falls, disability hospitalization and death. Several randomized clinical trials have been conducted to investigate the effect of oral vitamin D supplementation in older patients to prevent or treat sarcopenia, but results are still controversial. In this narrative review we summarize the biological, clinical and epidemiological evidence supporting the hypothesis of a causal association between Vitamin D deficiency and an increased risk of sarcopenia in older people.

Vitamin D, Skeletal Muscle Function and Athletic Performance in Athletes-A Narrative Review

The active form of vitamin D (calcitriol) exerts its biological effects by binding to nuclear vitamin D receptors (VDRs), which are found in most human extraskeletal cells, including skeletal muscles. Vitamin D deficiency may cause deficits in strength, and lead to fatty degeneration of type II muscle fibers, which has been found to negatively correlate with physical performance. Vitamin D supplementation has been shown to improve vitamin D status and can positively affect skeletal muscles. The purpose of this study is to summarize the current evidence of the relationship between vitamin D, skeletal muscle function and physical performance in athletes. Additionally, we will discuss the effect of vitamin D supplementation on athletic performance in players. Further studies are necessary to fully characterize the underlying mechanisms of calcitriol action in the human skeletal muscle tissue, and to understand how these actions impact the athletic performance in athletes.

Current concepts in vitamin D and orthopaedic surgery

INTRODUCTION

Vitamin D plays an important role in the musculoskeletal system of the human body. Here, we review the most current literature on vitamin D as it relates to orthopaedic surgery and the musculoskeletal system, focusing largely on non-fracture applications.

MATERIALS AND METHODS

A literature review was performed on the basic science of vitamin D metabolism, epidemiology of vitamin D levels, role of vitamin D within the musculoskeletal system, and the correlation of vitamin D with injuries and orthopaedic surgical outcomes.

RESULTS

The existing literature suggests vitamin D plays multiple roles in the musculoskeletal system. Recent research has shed light on the importance of vitamin D in the setting of soft tissue healing and recovery in addition to affecting postoperative outcomes after common orthopaedic procedures.

CONCLUSIONS

Given the widespread prevalence of vitamin D deficiency, orthopaedic surgeons should be aware of the current evidence regarding clinical implications in patients with musculoskeletal complaints.

Sport Nutrigenomics: Personalized Nutrition for Athletic Performance

An individual's dietary and supplement strategies can influence markedly their physical performance. Personalized nutrition in athletic populations aims to optimize health, body composition, and exercise performance by targeting dietary recommendations to an individual's genetic profile. Sport dietitians and nutritionists have long been adept at placing additional scrutiny on the one-size-fits-all general population dietary guidelines to accommodate various sporting populations. However, generic "one-size-fits-all" recommendations still remain. Genetic differences are known to impact absorption, metabolism, uptake, utilization and excretion of nutrients and food bioactives, which ultimately affects a number of metabolic pathways. Nutrigenomics and nutrigenetics are experimental approaches that use genomic information and genetic testing technologies to examine the role of individual genetic differences in modifying an athlete's response to nutrients and other food components. Although there have been few randomized, controlled trials examining the effects of genetic variation on performance in response to an ergogenic aid, there is a growing foundation of research linking gene-diet interactions on biomarkers of nutritional status, which impact exercise and sport performance. This foundation forms the basis from which the field of sport nutrigenomics continues to develop. We review the science of genetic modifiers of various dietary factors that impact an athlete's nutritional status, body composition and, ultimately athletic performance.

Effects of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D Concentrations and Physical Performance in Athletes: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

There is currently no systematic review examining the effects of vitamin D supplementation among athletes. A rigorous systematic review and meta-analysis is important to provide a balanced view of current knowledge on the effect of vitamin D on serum 25-hydroxyvitamin D [25(OH)D] concentrations and physical performance.

OBJECTIVES

This systematic review of randomized controlled trials (RCTs) evaluated the effects of oral vitamin D supplementation on serum 25(OH)D concentrations and physical performance in athletes.

METHODS

Multiple electronic databases were searched, and study eligibility, methodological quality assessment, and data extraction were completed independently and in duplicate. Studies were stratified by baseline vitamin D sufficiency, season, and latitude. A cut-off of 30 ng/ml (75 nmol/l) of 25(OH)D was used for sufficiency. Absolute mean differences (AMDs) between vitamin D and placebo using random effects analysis, and heterogeneity using Q statistic and I ² index, were calculated. AMD with 95% confidence interval (CI), p value, and I ² are reported.

RESULTS

In total, 13 RCTs (2005-2016) with 532 athletes (vitamin D 311, placebo 221) were eligible. A total of 433 athletes (vitamin D 244, placebo 189) had complete outcome data. Among athletes with baseline values suggesting insufficiency, vitamin D supplementation led to significant increases from 3000 IU (AMD 15.2 ng/ml; 95% CI 10.7-19.7, p < 0.0001, I ² = 0%) and 5000 IU (AMD 27.8 ng/ml; 95% CI 16.9-38.8, p < 0.0001, I ² = 78%) per day at >45° latitudes. Both doses led to sufficiency concentrations during winter months. Among athletes with baseline vitamin D suggesting sufficiency, serum 25(OH)D sufficiency was maintained from different doses at both latitudes. Of 13 included trials, only seven measured different physical performances and none demonstrated a significant effect of vitamin D supplementation during 12 weeks of follow-up.

CONCLUSION

Despite achieving sufficiency in vitamin D concentrations from ≥3000 IU supplementation, physical performance did not significantly improve. Between-study heterogeneity was large, and well-designed RCTs examining the effect of vitamin D supplementation on serum 25(OH)D concentrations, physical performance, and injuries in different sports, latitudes, ethnicities, and vitamin D status are needed.

Case report: ischial stress fracture non-union in a college football player

Stress fractures are common injuries associated with repetitive high-impact activities, often in high-level athletes and military recruits. Although predominantly occurring in the lower extremities, stress fractures may occur wherever there is a sudden increase in frequency or intensity of activity, thereby overloading the yield point of the local bone environment. Ischial stress fractures are a rarely diagnosed cause of pain around the hip and pelvis. Often, patients present with buttock pain with activity, which can be misdiagnosed as proximal hamstring tendonitis or avulsion. Here, we report a case of a college football player who was diagnosed with an ischial stress fracture which went on to symptomatic non-union after extensive conservative management. We treated his ischial non-union with open reduction internal fixation utilizing a tension band plate and screws. This interesting case highlights an uncommon cause of the relatively common presentation of posterior hip pain and describes our technique for addressing a stress fracture non-union in the ischium.

Case Study: The Effect of Nutritional Intervention on Body Composition and Physical Performance of a Female Squash Player

The body composition of a squash player may affect athletic performance as carrying excessive body fat may increase injury risk and impair agility and speed. This case study outlines the effect of a nutritional intervention on body composition, vitamin D status, and physical performance of a female squash player. A structured, 6-week, moderate energy-restricted diet (70-78% of estimated energy requirement of 2,300 kcal) was implemented with weekly support. A daily supplement of vitamin D, omega-3 fatty acids, and a multivitamin and whey protein was used. Full blood count, vitamin D status, body composition, and physical performance assessments were carried out at baseline and Week 6 of intervention. Body composition changes were measured using the BOD POD™ and skinfold calipers. Body fat was 23% at baseline and 22% at Week 6. Mean sum of eight skinfolds was 127.4 ± 2.2 mm at baseline and 107.3 ± 0.4 mm at Week 6. Lean body mass-to-fat mass ratio improved from 3.4 at baseline to 3.7 at Week 6. The greatest increments compared with baseline in serum markers were 25-hydroxyvitamin D3 (68%), ferritin (31%), eosinophils (20%), and triglycerides (16%). All physical performance measures improved, with reactive strength index (4.8%), and on-court repeated speed (6.0%) showing the greatest improvements from baseline. This intervention demonstrates that structured energy restriction alongside appropriately structured strength and conditioning training is an effective way to gradually reduce the body fat and improve the body composition of a female athlete.

Vitamin D Insufficiency Among Professional Basketball Players: A Relationship to Fracture Risk and Athletic Performance

Background:

Vitamin D is believed to play a role in influencing fracture risk and athletic performance. Insufficiency of vitamin D affects an estimated three-quarters of the United States population. Hypovitaminosis D has also been demonstrated to be quite common among professional basketball players in the National Basketball Association (NBA).

Purpose:

To determine whether a relationship exists between vitamin D levels and fracture risk and athletic performance (as measured by NBA draft status) among elite basketball players.

Study Design:

Descriptive epidemiology study.

Methods:

Data were obtained from the NBA regarding combine participants from 2009 through 2013. This information included vitamin D level, demographic information, fracture history, and NBA draft status. The data were analyzed to determine associations between vitamin D level and fracture risk and NBA draft status.

Results:

Vitamin D levels were measured for 279 players at the NBA Combine from 2009 through 2013. Vitamin D deficiency (<20 ng/mL) was seen in 32.3% of athletes, vitamin D insufficiency (20-30 ng/mL) was seen in 41.2%, and sufficient levels of vitamin D (>30 ng/mL) were present in only 26.5%. A total of 118 players had a history of at least 1 fracture. Vitamin D level was not predictive of fracture risk. Contrary to our hypothesis, players with a history of stress fracture had a significantly greater mean vitamin D level than those without such history (30.7 vs 25.1 ng/mL; P = .04). A majority (79.6%) of participants were selected in the NBA draft. Players with deficient vitamin D levels had a significantly lower rate of being drafted into the NBA (P = .027). The NBA draft rate was found to increase with increasing levels of vitamin D (P = .007).

Conclusion:

Hypovitaminosis D is quite common among NBA Combine participants, affecting 73.5%. While no significant relationship was found between vitamin D level and fracture history, patients with a history of stress fracture had significantly greater mean vitamin D levels. Additionally, participants with greater vitamin D levels were more likely to be drafted into the NBA. This information supports the potential role of vitamin D in influencing athletic performance.

Editorial Commentary: Is Vitamin D the New Wheaties? Preventing Muscle Fatigue Could Keep Athletes in the Game

Vitamin D deficiency is an oft overlooked and underevaluated condition that is widespread in patient-athletes, including the elite and professional. Although the symptomatology of this deficiency is well known in the general population (osteoporosis and increased risk of fracture), the symptom of muscle fatigue is not. It is only recently that the association between vitamin D deficiency and muscle fatigue in professional athletes has been placed in the spotlight. However, vitamin D deficiency should be of increasing concern for orthopaedists in regard to all athletes. In the elite collegiate/professional ranks, this condition may lead to detrimental injuries with career-altering effects. Although this condition may not affect career and financial well-being for most patients, modifications in athletic performance and lifestyle are still of utmost value to any athlete. Although I do not condone ordering vitamin D levels as a screening tool, nor broadly prescribing supplements to all patient-athletes, I do believe that it is warranted if certain "high-risk" criteria are met.

The Association of Vitamin D Status in Lower Extremity Muscle Strains and Core Muscle Injuries at the National Football League Combine

PURPOSE

To evaluate the association between serum vitamin D level and the prevalence of lower extremity muscle strains and core muscle injuries in elite level athletes at the National Football League (NFL) combine.

METHODS

During the 2015 NFL combine, all athletes with available serum vitamin D levels were included for study. Baseline data were collected, including age, race, body mass index, position, injury history specific to lower extremity muscle strain or core muscle injury, and Functional Movement Screen scores. Serum 25-hydroxyvitamin D was collected and defined as normal (≥32 ng/mL), insufficient (20-31 ng/mL), and deficient (<20 ng/mL). Univariate regression analysis was used to examine the association of vitamin D level and injury history. Subsequent multivariate regression analysis was used to examine this relation with adjustment for collected baseline data variables.

RESULTS

The study population included 214 athletes, including 78% African American athletes and 51% skilled position players. Inadequate vitamin D was present in 59%, including 10% with deficient levels. Lower extremity muscle strain or core muscle injury was present in 50% of athletes, which was associated with lower vitamin D levels (P = .03). Athletes with a positive injury history also showed significantly lower vitamin D levels as compared with uninjured athletes (P = .03). African American/black race (P < .001) and injury history (P < .001) was associated with lower vitamin D. Vitamin D groups showed no differences in age (P = .9), body mass index (P = .9), or Functional Movement Screen testing (P = .2). Univariate analysis of inadequate vitamin D levels showed a 1.86 higher odds of lower extremity strain or core muscle injury (P = .03), and 3.61 higher odds of hamstring injury (P < .001). Multivariate analysis did not reach an independent association of low vitamin D with injury history (P = .07).

CONCLUSIONS

Inadequate vitamin D levels are a widespread finding in athletes at the NFL combine. Players with a history of lower extremity muscle strain and core muscle injury had a higher prevalence of inadequate vitamin D.

LEVEL OF EVIDENCE

Level IV, retrospective study-case series.

Tarsal navicular stress fractures

PURPOSE OF REVIEW

Navicular stress fractures are common in athletes and management is debated. This article will review the evaluation and management of navicular stress fractures.

RECENT FINDINGS

Various operative and non-operative adjunctive treatment modalities are reviewed including the relevance of vitamin D levels, use of shock wave therapy and bone marrow aspirate concentrate (BMAC), and administration of teriparatide. Surgical treatment may be associated with earlier return to sports. The author's preferred treatment algorithm with corresponding images is presented which allows for safe and rapid return to activities in the athletic patient. Future research is needed in evaluating the preventative effects of vitamin D and use of other adjunctive treatments to increase the healing rates of this fracture.

Prevalence of Vitamin D Insufficiency in Professional Hockey Players

Background:

Vitamin D is a fat-soluble hormone that plays a role in bone health, muscle function, and athletic performance. Studies have shown that low levels of vitamin D can lead to slower muscle recovery and function, increased rates of stress fractures, and even poorer athletic performance. Insufficient vitamin D levels have been demonstrated in professional basketball and football players, however, there have been no studies to date reviewing vitamin D insufficiency in professional hockey players.

Purpose/Hypothesis:

The purpose of this study was to perform a cross-sectional review to determine the prevalence of vitamin D deficiency and insufficiency in professional hockey players. The hypothesis was that there would be a high percentage of players with vitamin D insufficiency.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

The preseason serum 25-hydroxy (OH) vitamin D laboratory test results of 105 professional hockey players were retrospectively reviewed. All players on 3 National Hockey League (NHL) teams were included. Player parameters evaluated included age, height, weight, body mass index, and 25(OH) vitamin D level. Players were divided into 4 groups based on serum vitamin D levels: deficient (<20 ng/mL), insufficient (20-31.9 ng/mL), sufficient (≥32 ng/mL), and ideal (≥40 ng/mL). Descriptive statistics were performed, in addition to 2-group and 3-group comparisons.

Results:

The average 25(OH) vitamin D level of 105 players was 45.8 ± 13.7 ng/mL (range, 24-108 ng/mL). No players in the study were considered deficient. A total of 14 players (13.3%) were considered insufficient, while 91 players (86.7%) were considered sufficient. However, only 68 players (64.8%) were considered ideal. When comparing groups, athletes with sufficient vitamin D levels were older than athletes with insufficient vitamin D levels (25.9 vs 23.1 years; P = .018). All other player parameters demonstrated no significant difference between groups.

Conclusion:

Despite playing a winter sport and spending a great deal of time training indoors, professional hockey players have low levels of vitamin D insufficiency.

Bone Health in Athletes

CONTEXT

The health of the skeletal system is important for athletes young and old. From the early benefits of exercise on bones to the importance of osteoporosis prevention and treatment, bone health affects the ability to be active throughout life.

EVIDENCE ACQUISITION

PubMed articles dating from 1986 to 2016 were used for the review. Relevant terms such as keywords and section titles of the article were searched and articles identified were reviewed for relevance to this article.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Levels 1 through 4 evidence included.

RESULTS

There is strong evidence that exercise benefits bone health at every age and is a critical factor in osteoporosis prevention and treatment. Vitamin D, calcium, and hormones play vital roles in ensuring optimal bone health. When there is an imbalance between exercise and nutrition, as seen in the female athlete triad, bone health is compromised and can lead to bone stress injuries and early osteoporosis. Both of these can lead to morbidity and lost time from training and competition. Thus, early recognition and appropriate treatment of the female athlete triad and other stress fracture risk factors are vital to preventing long-term bone health problems.

CONCLUSION

To optimize bone health, adequate nutrition, appropriate weightbearing exercise, strength training, and adequate calcium and vitamin D are necessary throughout life.

Acute Effects of Vitamin D3 Supplementation on Muscle Strength in Judoka Athletes: A Randomized Placebo-Controlled, Double-Blind Trial

OBJECTIVE

Indoor athletes have been shown to be prone to vitamin D3 deficiency. The aim of the study was to examine the acute effects of vitamin D supplementation on muscle function using isokinetic dynamometry.

DESIGN

Randomized placebo-controlled, double-blind study.

SETTING

Institutional.

PARTICIPANTS

Adult male white national level judoka athletes (n = 22) who were involved in full-time training. Exclusion criteria were vitamin supplementation, overseas travel to sunny climes, and/or an injury incurred during the last 3 months before testing.

INTERVENTIONS

Subjects were randomly allocated to the treatment (150 000IU vitamin D3) or placebo and given blinded supplements by an independent researcher. Participants were tested twice, 8 days apart, on a Monday morning before the start of judo training and after 2 days of rest. A 5 to 7 mL of blood sample was collected followed by isokinetic concentric quadriceps and hamstring muscle function assessments on the right leg at 30 and 200°·s.

MAIN OUTCOME MEASURES

Repeated-measures analysis of variance was used to analyze isokinetic muscle force and serum 25(OH)D3. Regression to the mean was used to examine changes in 25(OH)D3 levels over the study period.

RESULTS

The treatment group demonstrated a significant increase in serum 25(OH)D levels (34%, P ≤ 0.001) and muscle strength (13%, P = 0.01) between days 1 and 8. No significant differences were found for the placebo group for the same period.

CONCLUSIONS

A single bolus of 150 000IU vitamin D3 had a significant positive effect on serum 25(OH)D levels and muscle function in vitamin D insufficient elite indoor athletes.

CLINICAL RELEVANCE

Serum 25(OH)D3 levels of indoor athletes should be monitored throughout the year and especially during winter months. Beneficial responses, in muscle strength and serum 25(OH)D3, to 1 dose of vitamin D3 supplementation can be observed within 1 week of ingestion. Muscle strength is linked to serum 25(OH)D levels.

Plasma vitamin D metabolites and C-reactive protein in stage-stop racing endurance sled dogs

Background

Dogs are a unique model for examining the effects of exercise on vitamin D status because of their lack of vitamin D synthesis by UV exposure. In addition, the inflammatory response may be associated with hypovitaminosis D.

Objectives

To investigate the effects of several days of endurance exercise on plasma vitamin D (25‐(OH)D₃, 24,25‐(OH)D₃ and 1,25(OH)D₃) and serum C‐reactive protein (CRP) concentrations in stage‐stop racing sled dogs.

Animals

12 racing sled dogs and 8 control dogs.

Methods

Blood was collected before the race and immediately after racing on days 2 and 8. Plasma vitamin D metabolites and serum CRP concentrations were measured.

Results

Racing dogs showed a significant increase in 25(OH)D₃ on day 2 (P = .027) and day 8 of the race (P < .001), whereas no increases were observed in control dogs. The plasma concentration of 24,25(OH)D₃ showed a significant increase by day 8 (P < .001). There were no significant changes in 1,25(OH) D₃ concentrations across all time points and groups. Racing dogs had significantly increased CRP concentrations by day 2 (39.3 ± 30.1 μg/mL; P < .001).

Conclusions and Clinical Importance

Increases in vitamin D metabolites as well as increases in CRP concentrations were observed in racing sled dogs. This finding was contrary to the hypothesis that decreases in vitamin D status in athletes may be related to the acute phase inflammatory response during exercise. In addition, the increased 24,25(OH)D₃ concentrations compared to what is observed in other species suggests metabolic variations in dogs that lead to enhanced disposal of vitamin D.

Effects of vitamin D and quercetin, alone and in combination, on cardiorespiratory fitness and muscle function in physically active male adults

Introduction

Vitamin D and the antioxidant quercetin, are promising agents for improving physical performance because of their possible beneficial effects on muscular strength and cardiorespiratory fitness.

Purpose

The purpose of this study was to determine the effects of increased intakes of vitamin D, quercetin, and their combination on antioxidant status, the steroid hormone regulators of muscle function, and measures of physical performance in apparently healthy male adults engaged in moderate-to-vigorous-intensity exercise training.

Methods

A total of 40 adult male participants were randomized to either 4,000 IU vitamin D/d, 1,000 mg/d quercetin, vitamin D plus quercetin, or placebo for 8 weeks. Measures of cardiorespiratory fitness and muscle function, blood markers for antioxidant and vitamin D status, and hormones 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) and testosterone were measured pre- and postsupplementation.

Results

At enrollment, 88.6% of participants were vitamin D sufficient (serum 25-hydroxyvitamin D >50 nmol/L) and had normal serum testosterone levels. Supplementation with vitamin D significantly increased serum 25(OH)D concentration (by 87.3% in the vitamin D group, P<0.001) and was associated with an increasing trend of testosterone concentration. There were no changes in concentration of 1,25(OH)₂D₃ and markers of antioxidant status associated with vitamin D or quercetin supplementation. No improvements in physical performance measures associated with vitamin D and quercetin supplementation were found.

Conclusion

The findings obtained demonstrate that long-term vitamin D and quercetin supplementation, alone or in combination, does not improve physical performance in male adults with adequate vitamin D, testosterone, and antioxidant status.

Prevalence of vitamin D inadequacy in athletes: a systematic-review and meta-analysis

BACKGROUND

Vitamin D is essential for maintaining optimal bone health. The prevalence of vitamin D inadequacy in athletes is currently unclear.

OBJECTIVE

The objective of this study is to determine the prevalence of vitamin D inadequacy in athletes.

METHODS

We conducted a systematic review and meta-analysis. Multiple databases were searched and studies assessing serum 25-hydroxyvitamin D [25(OH)D] status in athletes were identified. Serum 25(OH)D is measured to clinically determine vitamin D status. Reviewers independently selected the eligible articles, assessed the methodological quality, and extracted data. Disagreements were resolved by consensus. Weighted proportions of vitamin D inadequacy [serum 25(OH)D <32 ng/mL] were calculated (DerSimonian-Laird random-effects model) and compared using Chi-squared (χ (2)) test. Subgroup analyses were conducted and risk ratios (RRs) with 95 % confidence intervals (CIs) were reported.

RESULTS

Twenty-three studies with 2,313 athletes [mean (standard deviation) age 22.5 (5.0) years, 76 % male] were included. Of 2,313 athletes, 56 % (44-67 %) had vitamin D inadequacy that significantly varied by geographical location (p < 0.001). It was significantly higher in the UK and in the Middle East. The risk significantly increased for winter and spring seasons (RR 1.85; 95 % CI 1.27-2.70), indoor sport activities (RR 1.19; 95 % CI 1.09-1.30), and mixed sport activities (RR 2.54; 95 % CI 1.03-6.26). The risk was slightly higher for >40°N latitude [RR 1.14 (95 % CI 0.91-1.44)] but it increased significantly [RR 1.85 (1.35-2.53)] after excluding the Middle East as an outlier. Seven studies with 359 athletes reported injuries. The prevalence of injuries in athletes was 43 % (95 % CI 20-68) [bone related = 19 % (95 % CI 7-36); muscle and soft-tissue = 37.5 % (95 % CI 11.5-68.5)].

CONCLUSION

Despite the limitations of the current evidence, the prevalence of vitamin D inadequacy in athletes is prominent. The risk significantly increases in higher latitudes, in winter and early spring seasons, and for indoor sport activities. Regular investigation of vitamin D status using reliable assays and supplementation is essential to ensure healthy athletes. The prevalence of injuries in athletes is notable but its association with vitamin D status is unclear. A well-designed longitudinal study is needed to answer this possible association.

Low Serum Vitamin D Is Not Correlated With the Severity of a Rotator Cuff Tear or Retear After Arthroscopic Repair

BACKGROUND

Despite the essential role of vitamin D in muscle function, the prevalence of vitamin D deficiency has been reported to be very high. Recently, low vitamin D level was found to correlate with fatty degeneration of the rotator cuff tendon in humans and to negatively affect early healing at the rotator cuff repair site in an animal study. However, the effects of vitamin D level on severity of rotator cuff tear and healing after surgical repair have not been documented.

PURPOSE

To evaluate (1) the prevalence of vitamin D deficiency among patients who underwent arthroscopic repair for a full-thickness rotator cuff tear, (2) the relationship of vitamin D level with severity of the rotator cuff tear, and (3) surgical outcomes after repair.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A consecutive series of 91 patients (age, 50-65 years) who underwent arthroscopic rotator cuff repair for full-thickness, small-sized to massive tears were evaluated. Preoperative serum vitamin D levels (25-hydroxyvitamin) were analyzed to detect correlations with the features of a preoperative rotator cuff tear as well as postoperative structural and functional outcomes. All patients were followed clinically for a minimum of 1 year.

RESULTS

Preoperative vitamin D levels were deficient (<20 ng/mL) in 80 subjects (88%), insufficient (20-30 ng/mL) in 8 subjects (9%), and normal (>30 ng/mL) in 3 subjects (3%). No correlation was found between preoperative tear size (P = .23), extent of retraction (P = .60), degree of fatty infiltration of each cuff muscle (P > .50 each), or the global fatty infiltration index (P = .32). Similarly, no correlations were detected between vitamin D level and postoperative Sugaya type (P = .66) or any of the functional outcome scores (P > .50 each).

CONCLUSION

Low serum vitamin D level was not related to tear size, extent of retraction, or the degree of fatty infiltration in cuff muscles. It also had no significant relationships with postoperative structural integrity and functional outcomes after arthroscopic repair. The results suggest that low serum vitamin D level is not a significant risk factor for the severity of rotator cuff tear or poor healing after repair.

A review and clinical summary of vitamin D in regard to bone health and athletic performance

The large amount of scientific literature regarding vitamin D can be overwhelming and confusing. Some organizations have made specific guidelines and recommendations regarding optimal blood levels of vitamin D. In the sports medicine literature, new information about the effects of vitamin D on performance and bone health abound. Most of these articles seem to raise more questions than they answer. Are athletes at increased risk of vitamin D deficiency? Does vitamin D deficiency affect athletic performance? Should athletes be tested for deficiency? What is the optimal goal for vitamin D levels in athletes and is this different from the general population? The goal of this article is to provide clinical insight and clarity, both for those practicing in the primary care setting as well as for those taking care of athletes.

Vitamin D profile in National Football League players

BACKGROUND

By maintaining phosphate and calcium homeostasis, vitamin D is critical for bone health and possibly physical performance. Hence, vitamin D is important to athletes. Few studies have investigated vitamin D levels in relation to fractures and performance in athletes, and no published study has included a multiracial sample of professional American football players.

PURPOSE

To assess vitamin D levels, including the prevalence of vitamin D deficiency/insufficiency, in professional American football players and to evaluate the association of vitamin D levels with race, fracture history, and the ability to obtain a contract position, which may be a marker for athletic performance.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Serum vitamin D levels of 80 professional football players from a single team in the National Football League were obtained during the 2011 off-season (mean age, 26.5±3.7 years; black, n=67 [84%]). These levels were used to compare injury reports from the 2011-2012 and 2012-2013 seasons. Statistical analyses were performed to test if vitamin D levels were related to race, fracture history, and the ability to obtain a contract position.

RESULTS

Mean vitamin D level was 27.4±11.7 ng/mL, with significantly lower levels for black players (25.6±11.3 ng/mL) versus white players (37.4±8.6 ng/mL; F 1,78=13.00, P=.001). All athletes who were vitamin D deficient were black. When controlling for number of professional years played, vitamin D levels were significantly lower in players with at least 1 bone fracture when compared with no fractures. Players who were released during the preseason because of either injury or poor performance had significantly lower vitamin D levels than did players who played in the regular season.

CONCLUSION

Black professional football players have a higher rate of vitamin D deficiency than do white players. Furthermore, professional football players with higher vitamin D levels were more likely to obtain a contract position in the National Football League. Professional football players deficient in vitamin D levels may be at greater risk of bone fractures.

The pathophysiology, diagnosis, and management of foot stress fractures

INTRODUCTION

There is an increasing prevalence of osteoporosis, and with it a rise in the diagnosis of stress fractures. Postmenopausal women are particularly at risk of stress fractures. This review article describes the pathophysiology of foot stress fractures and the latest diagnostic and treatment strategies for these common injuries.

DISCUSSION

There are numerous risk factors for stress fractures that have been identified in the literature. Reduced bone mineral density is an independent risk factor for delayed union. Prevention of stress fractures with training periodization and nutritional assessment is essential, especially in females. Diagnosis of stress fractures of the foot is based on history and diagnostic imaging, which include radiographs, ultrasound, therapeutic ultrasound, computed tomography, and bone scans; however, magnetic resonance imaging is still the gold standard. Treatment depends on the bone involved and the risk of nonunion, with high-risk fractures requiring immobilization or surgical intervention. Patients presenting with underlying bone mineral deficiency treated without surgery require a longer period of activity modification. Training rehabilitation protocols are described for those with low-risk stress fractures.

RESULTS

A useful algorithm is presented to guide the clinician in the diagnosis and management of such injuries.

Knowledge and attitudes to vitamin D and sun exposure in elite New Zealand athletes: a cross-sectional study

Background

Sun safety and vitamin D status are important for prolonged health. They are of particular interest to those working with athletes for whom for whom safe sun practices maybe limited.

The aim of this cross-sectional study was to describe the attitudes of elite New Zealand athletes to both vitamin D and sun exposure.

Methods

110 elite New Zealand outdoor athletes volunteered to participate in an interview with a trained interviewer. The interviewer asked the athletes questions on their Vitamin D knowledge, attitudes and practices regarding sun exposure as well as their concerns about skin cancer.

Results

Athletes were more concerned about their risk of skin cancer (66%) than their vitamin D status (6%). Although the majority (97%) were aware of Vitamin D and could identify the sun as a source (76%) only 17% could name another source of Vitamin D.

Only 10 (9%) reported always applying sunscreen before going out in the sun. No athlete reported reapplying sunscreen every hour and 25 suggesting that they never reapply sunscreen.

Conclusions

Athletes are concerned about skin cancer however, their use of sunscreen is not optimal suggesting reapplication of sunscreen could be targeted in order to reduce the risk of sun cancer. Awareness of sources of Vitamin D other than the sun may also need to be improved potentially through educational interventions and possibly in conjunction with sun smart messages.

Incidence of Vitamin D Insufficiency in Coastal South-Eastern US Patient Population With Cardiovascular Disease

Background

Vitamin D insufficiency is increasingly gaining prominence as an associated cardiovascular disease (CVD) risk factor, often thought to be an issue in colder climates and higher altitudes. The intent of this study was to ascertain vitamin D levels in the southern Alabama gulf-coast region that has a high number of sunny days along with an annual average elevated UV ray index.

Methods

An observational retrospective study of 204 patients with established CVD treated at the University of South Alabama’s Heart Center from January 2007 through January 2013 was undertaken. One-way ANOVA analyses were performed to determine any significant difference in the mean 25-hydroxyvitamin D (25(OH)D) serum based on gender and also based on race/ethnicity. Further, odds ratio (OR) was computed to ascertain if there was a relationship between vitamin D insufficiency and elevated body mass index (BMI).

Results

Out of 204 patients, 53.4% (n = 109) were found to have vitamin D insufficiency (25(OH)D = 20.1 ng/mL), while 46.6% (n = 95) were within the normal range (25(OH)D = 37.8 ng/mL). The mean 25(OH)D of the entire group was 28.3, indicating a general trend of vitamin D insufficiency for patients treated at the cardiology clinics.

Conclusion

This study established the prevalence of vitamin D insufficiency in the hot and high UV ray index climate of the coastal south-eastern United States. Also, it revealed the relationship of increased BMI with low 25(OH)D serum level. More extensive studies should be conducted in similar climates to further assess vitamin D insufficiency.

Vitamin D and exercise performance in professional soccer players

Aim

The current study had two aims. The primary purpose was to examine the association between serum vitamin D levels and the ergometric evaluation of muscle strength, aerobic capacity, and speed in professional soccer players. The secondary aim was to evaluate the effects of the soccer off-season period on serum vitamin D levels.

Methods

Sixty-seven Caucasian male soccer players (age 25.6±6.2 and height 1.81±0.08 m), members of two Greek Superleague Soccer teams and one Football-league championship team participated in this study. Exercise performance testing for the determination of squat jump (SJ), countermovement jump (CMJ), 10 (10 m) and 20 meters (20 m) sprint performance, maximal oxygen consumption (VO₂max), anthropometry, and blood sampling were performed before (pre) and after (post) the six-week off-season period.

Results

Analysis of our results showed the following: (a) a significant correlations between serum vitamin D levels and performance parameters in both pre (SJ; P<0.001, CMJ; P<0.001, VO₂max; P<0.001, 10 m; P<0.001, and 20 m; P<0.001) and post (SJ; P<0.001, CMJ; P<0.001, VO₂max; P = 0.006, 10 m; P<0.001, and 20 m; P<0.001) experimental sessions. (b) Vitamin D concentration increased significantly (P<0.001) following the six-week off-season period compared to baseline, while at the same time all measured performance parameters decreased (SJ; P<0.001, CMJ; P<0.001, 10 m; P<0.001, 20 m; P<0.001, VO₂max; P<0.001).

Discussion

Our findings suggest that vitamin D levels are associated with the ergometric evaluation of muscle strength, as expressed by SJ and CMJ, sprinting capacity, and VO₂max in professional soccer players, irrespective the levels of performance. Furthermore, our data reaffirm the importance of UVB on serum vitamin D levels. Moreover, reductions in exercise training stress may also have beneficial effects on vitamin D levels, suggesting a possible association of its levels and the training-induced stress. Our results indicate a possibly bidirectional interaction between soccer performance indices and vitamin D levels.

Intravenous bisphosphonates and vitamin D in the treatment of bone marrow oedema in professional athletes

INTRODUCTION

The goal of this retrospective study was to evaluate the safety and efficacy of ibandronate for bone marrow oedema (BMO) syndrome and stress fracture cases, and to demonstrate an additional field of therapeutic importance-the high-performance athlete.

PATIENTS AND METHODS

This retrospective study included twenty-five high-performance athletes. Sixty per cent of the athletes were European soccer players and 40.0% other high-class international athletes (3 women and 22 men with an average age of 25.0±4.2), with BMO of the lower trunk or extremity diagnosed by magnetic resonance imaging (MRI). The treatment regimen consisted of high-dose vitamin D supplementation and intravenous ibandronate therapy.

RESULTS

The time between the onset of pain and proper diagnosis of BMO was 106.3±104.1 days. Excellent pain reduction (pain at rest and under strain) and improved mobility was reported within the first two weeks after the first ibandronate administration by sixteen patients (64%). The time from first treatment until return to competition (RTC) was on average 102.6±65.2 days in total. If the time from onset of pain until diagnosis was within 40 days, the RTC was significantly reduced (p≤0.05) to almost 50% (63.8±48.1 days) when compared to the athletes with later diagnosis (124.4±63.2 days).

CONCLUSIONS

The here-applied therapy regimen of intravenous BPs application and vitamin D supplementation in BMO syndrome has a beneficial effect for high-performance athletes. An early diagnosis and rapid treatment start can reduce the RTC significantly. An optimal bone metabolism with sufficient daily calcium and vitamin D intake is crucial and should not only be strived for the professional but also for the recreational athlete.