The Use of NSAIDs and Nutritional Supplements in Athletes with Osteoarthritis: Prevalence, Benefits, and Consequences

IL-17 in osteoarthritis: A narrative review

Osteoarthritis (OA) is a painful joint disease that is common among the middle-aged and elderly populations, with an increasing prevalence. Therapeutic options for OA are limited, and the pathogenic mechanism of OA remains unclear. The roles of cytokines and signaling pathways in the development of OA is a current research hot spot. Interleukin (IL)-17 is a pleiotropic inflammatory cytokine produced mainly by T helper 17 cells that has established roles in host defense, tissue repair, lymphoid tissue metabolism, tumor progression, and pathological processes of immune diseases, and studies in recent years have identified an important role for IL-17 in the progression of OA. This narrative review focuses on the mechanisms by which IL-17 contributes to articular cartilage degeneration and synovial inflammation in OA and discusses how IL-17 and the IL-17 signaling pathway affect the pathological process of OA. Additionally, therapeutic targets that have been proposed in recent years based on IL-17 and its pathway in OA are summarized as well as recent advances in the study of IL-17 pathway inhibitors and the potential challenges of their use for OA treatment.

Nonsteroidal Anti-Inflammatory Drug Prescriptions Are Associated With Increased Stress Fracture Diagnosis in the US Army Population

Stress fractures are common in military personnel and endurance athletes, and nonsteroidal anti-inflammatory drug (NSAID) use is widespread in these populations. NSAIDs inhibit prostaglandin synthesis, which blunts the anabolic response of bone to physical activity and could therefore increase risk of stress fracture. The objective of this study was to determine whether prescribed NSAIDs were associated with stress fracture diagnoses among US Army soldiers. We also aimed to establish whether acetaminophen, an analgesic alternative to NSAIDs, was associated with stress fracture risk. A nested case-control study was conducted using data from the Total Army Injury and Health Outcomes Database from 2002 to 2011 (n = 1,260,168). We identified soldiers with a diagnosis of stress fracture (n = 24,146) and selected 4 controls per case matched on length of military service (n = 96,584). We identified NSAID and acetaminophen prescriptions 180 to 30 days before injury (or match date). We also identified soldiers who participated in basic combat training (BCT), a 10-week period of heightened physical activity at the onset of Army service. Among these individuals, we identified 9088 cases and 36,878 matched controls. Conditional logistic regression was used to calculate incident rate ratios (RR) for stress fracture with adjustment for sex. NSAID prescription was associated with a 2.9-fold increase (RR = 2.9, 95% confidence interval [CI] 2.8-2.9) and acetaminophen prescription with a 2.1-fold increase (RR = 2.1, 95% CI 2.0-2.2) in stress fracture risk within the total Army population. The risk was more than 5-fold greater in soldiers prescribed NSAIDs (RR = 5.3, 95% CI 4.9-5.7) and more than 4-fold greater in soldiers prescribed acetaminophen (RR = 4.4, 95% CI 3.9-4.9) during BCT. Our results reveal an association between NSAID and acetaminophen prescriptions and stress fracture risk, particularly during periods of heightened physical activity. Prospective observational studies and randomized controlled trials are needed to support these findings before clinical recommendations can be made. © 2018 American Society for Bone and Mineral Research.

Evaluation of the effect of the administration of a glucosamine‑containing supplement on biomarkers for cartilage metabolism in soccer players: A randomized double‑blind placebo‑controlled study

A randomized double‑blind placebo‑controlled clinical study was conducted to evaluate the chondroprotective action of glucosamine on healthy subjects (soccer players) without joint disorders. Collegiate soccer players (n=43) without joint disorders were randomly assigned to receive a glucosamine (2 g/day)‑containing supplement (n=22, glucosamine group) or a placebo (n=21, placebo group) for 16 weeks, and cartilage metabolism was evaluated by analyzing markers for type II collagen degradation urine C‑terminal telopeptide‑II (CTX‑II) and serum collagen type II cleavage (C2C) and synthesis urine C-terminal type II procollagen peptide (CPII). In the initial analysis of all subjects, urine CTX‑II level substantially decreased in the glucosamine group, but not in the placebo group after the intervention for 16 weeks (P=0.05). Moreover, CTX‑II level in the glucosamine group was also significantly lower than that in the placebo group at week 16 during the intervention. In the second analysis, to make the effect of the test supplement more clear, 41 subjects with less variation of exercise loading were evaluated. The results revealed that urine CTX‑II level significantly decreased in the glucosamine group (n=21), but not in the placebo group (n=20) after the intervention (P<0.05). Moreover, CTX‑II levels in the glucosamine group significantly decreased compared with the placebo group after the intervention (P<0.05). Both in the initial and second analyses, serum C2C level significantly decreased in the glucosamine group, but not in the placebo group after the intervention (P<0.05). In contrast, urine CPII level was not significantly changed even after the intervention in both the placebo and glucosamine groups. Importantly, no test supplement‑related adverse events were observed. These observations suggest that oral administration of glucosamine (2 g/day for 16 weeks) exerts a chondroprotective action on healthy subjects (soccer players) without joint disorders. This effect was achieved by improving cartilage metabolism (suppressing type II collagen degradation but maintaining type II collagen synthesis), without causing apparent adverse effects.

Emerging Concepts in Treating Cartilage, Osteochondral Defects, and Osteoarthritis of the Knee and Ankle

The management and treatment of cartilage lesions, osteochondral defects, and osteoarthritis remain a challenge in orthopedics. Moreover, these entities have different behaviors in different joints, such as the knee and the ankle, which have inherent differences in function, biology, and biomechanics. There has been a huge development on the conservative treatment (new technologies including orthobiologics) as well as on the surgical approach. Some surgical development upraises from technical improvements including advanced arthroscopic techniques but also from increased knowledge arriving from basic science research and tissue engineering and regenerative medicine approaches. This work addresses the state of the art concerning basic science comparing the knee and ankle as well as current options for treatment. Furthermore, the most promising research developments promising new options for the future are discussed.

Evaluation of the effect of N-acetyl-glucosamine administration on biomarkers for cartilage metabolism in healthy individuals without symptoms of arthritis: A randomized double-blind placebo-controlled clinical study

The present study aimed to evaluate the effect of N-acetyl-glucosamine (GlcNAc) on the joint health of healthy individuals without arthritic symptoms. A randomized double-blind placebo-controlled clinical trial was performed to investigate the effect of oral administration of a GlcNAc-containing test supplement (low dose, 500 mg/day and high dose, 1,000 mg/day) on cartilage metabolism in healthy individuals with a mean age of 48.6±1.3 years (range, 23-64 years) by analyzing the ratio of type II collagen degradation to type II collagen synthesis using type II collagen degradation (C2C) and synthesis (PIICP) markers. The results indicated that the changes in C2C/PIICP ratios from the baseline were suppressed in the treated with low and high doses of GlcNAc, compared with the placebo group at week 16 during intervention. To further elucidate the effect of GlcNAc, subjects with impaired cartilage metabolism were evaluated. Notably, the changes in the C2C/PIICP ratios were markedly suppressed in the groups treated with low and high doses of GlcNAc at week 16. Finally, to exclude the effect of heavy body weight on joint loading, subjects weighing <70 kg with impaired cartilage metabolism were analyzed. Notably, the changes in the C2C/PIICP ratios were suppressed in the groups treated with low and high doses of GlcNAc at weeks 12 and 16. No test supplement-related adverse events were observed during or following the intervention. Together, these observations suggest that oral administration of GlcNAc at doses of 500 mg and 1,000 mg/day exhibits a chondroprotective effect on healthy individuals by reducing the C2C/PIICP ratio (relatively decreasing type II collagen degradation and increasing type II collagen synthesis) without any apparent adverse effects.

Medications and Nutritional Supplements in Athletes during the 2000, 2004, 2008, and 2012 FIFA Futsal World Cups

Objective. To examine the use of medications and nutritional supplements among top-level male futsal players during international tournaments. Materials and Methods. This retrospective survey of the four consecutive 2000 to 2012 FIFA (Fédération Internationale de Football Association) Futsal World Cup tournaments analyzes data about the use of medications and nutritional supplements by each player prior to every match. A total of 5264 reports on 1064 futsal players were collected from the 188 matches played. Results. A total of 4237 medications and 8494 nutritional supplements (0.8 and 1.6 per player per match, resp.) were prescribed, and 64% of the players used at least one type of medication over the four tournaments. The most frequently prescribed medication was nonsteroidal anti-inflammatory drugs (NSAIDs) (41.1%), whereby 45.7% of all players consumed at least one NSAID during the tournament and 27.4% did so prior to every match. Conclusions. The intake of medications, particularly of NSAIDs, is frequently high among top-level futsal players and follows a similar pattern to that found in FIFA Football World Cups. Campaigns should be instituted to understand this prescription practice by team physicians involving professional football players, with the aim to decrease its use and to prevent athletes from potential short- and long-term risks.

Prevalence of osteoarthritis in former elite athletes: a systematic overview of the recent literature

The aim of this study was to systematically review the recent scientific literature to explore the prevalence of osteoarthritis (OA) in former elite athletes from team and individual sports. A systematic review of observational studies was conducted. Based on three categories of keywords (and synonyms), a sensitive search strategy was built in order to search MEDLINE and SPORTDiscus from 2000 to 2014. The data from included studies presenting a prevalence rate of OA as an outcome measure were extracted using a standardised extraction form, and their methodological quality was described. Fifteen studies were identified through our search strategy, studies being rather heterogeneous with regard to their study population and to the definition and assessment of OA. Hip OA ranged from 2 to 60%, and knee OA from 16 to 95%. Prevalence rates of general, lower limbs or hip/knee OA ranged from 1 to 59%. Prevalence of neck, back, shoulder and ankle OA was reported only in single studies (16, 18, 33 and 3%, respectively). This study showed that prevalence of OA, especially in their lower limbs, seems to be high among former elite athletes from team and individual sports compared to the general population and other occupational sectors.

Evaluation of the effect of glucosamine administration on biomarkers of cartilage and bone metabolism in bicycle racers

In the present study, the effect of glucosamine administration (1.5 or 3 g/day) on cartilage and bone metabolism was investigated in bicycle racers, using cartilage‑ and bone‑specific biomarkers, including C‑terminal cross‑linked telopeptides of type II collagen (CTX‑II), C‑terminal propeptides of type II procollagen (CPII), N‑terminal telopeptides of bone‑specific type I collagen (NTx) and bone alkaline phosphatase (BAP). The results indicate that CPII (a marker of type II collagen synthesis) was not substantially changed, however, CTX‑II (a marker of type II degradation) was reduced by glucosamine administration, particularly at a dose of 3 g/day. Consistent with these observations, the ratio of CTX‑II/CPII was reduced by glucosamine administration and the effect of glucosamine was dose‑dependent. By contrast, the levels of NTx (a bone resorption marker) and BAP (a bone formation marker) were not altered by glucosamine administration. A previous study by this group reported that glucosamine exerts a chondroprotective action in soccer players by preventing type II collagen degradation but maintaining type II collagen synthesis. Together these observations indicate that glucosamine may exert a chondroprotective action by preventing type II collagen degradation in athletes of various sports, including soccer players and bicycle racers.

Effect of a chicken comb extract-containing supplement on subclinical joint pain in collegiate soccer players

Much of our focus of attention has been on sub-clinical or subtle joint pain experienced by healthy soccer players. The present study aimed to determine at which joint such subclinical pains are the most prominent, and to examine the pain-relieving effect of a chicken comb extract (CCE)-containing supplement product (test product) on these athletes. A total of 46 collegiate soccer players, consisting of 24 leading and 22 substitute players, belonging to a university soccer team were enrolled for measuring the pains at 4 different joints (ankle, knee, hip and shoulder) using 3 pain subscales of a 100-mm visual analog scale (VAS) ('pain at rest', 'pain on pressing' and 'pain on moving'), and participated in a prospective, double-blind, controlled study. A total of 23 subjects each received the test product (4,800 mg/day) (test group) and placebo (placebo group) for 12 weeks. VAS pain scores of individual joints were evaluated at baseline and following 4, 8 and 12 weeks of the intervention. VAS scores for the 'pain on moving' subscale in 46 enrolled subjects were highest at the ankle joint, and thus the values (abbreviated as 'pain scores') were used as a parameter for efficacy assessment of the test product. Compared to the baseline, the pain scores were significantly decreased for the dominant foot (but not for the non-dominant foot) in the total subpopulation (at week 4; p<0.01) and the leading player subpopulation (at week 4; p<0.01 and at week 12; p<0.05) in the test group (n=19 and 11, respectively). In comparison between the test product and placebo groups, the pain scores were significantly changed for the dominant foot (p<0.05) at week 4 in the total subpopulation and at week 12 in the leading player subpopulation in the test group. Thus, subclinical joint pain is most prominently observed at the ankle joint of the dominant foot in healthy young soccer players and may be improved by the daily intake of the CCE-containing supplement.

Articular Cartilage Injury in Athletes

Articular cartilage lesions in the athletic population are observed with increasing frequency and, due to limited intrinsic healing capacity, can lead to progressive pain and functional limitation over time. If left untreated, isolated cartilage lesions can lead to progressive chondropenia or global cartilage loss over time. A chondropenia curve is described to help predict the outcome of cartilage injury based on different lesion and patient characteristics. Nutriceuticals and chondroprotective agents are being investigated as tools to slow the development of chondropenia. Several operative techniques have been described for articular cartilage repair or replacement and, more recently, cartilage regeneration. Rehabilitation guidelines are being developed to meet the needs of these new techniques. Next-generation techniques are currently evaluated to optimize articular cartilage repair biology and to provide a repair cartilage tissue that can withstand the high mechanical loads experienced by the athlete with consistent long-term durability.

The effects of oral glucosamine on joint health: is a change in research approach needed?

OBJECTIVE

Oral glucosamine (GlcN) has been widely studied for its potential therapeutic benefits in alleviating the pain and disability of osteoarthritis (OA). Its popularity has grown despite ongoing controversy regarding its effectiveness vs placebo in clinical trials, and lack of information regarding possible mechanisms of action. Here, we review the state of knowledge concerning the biology of GlcN as it relates to OA, and discuss a framework for future research directions.

METHODS

An editorial "narrative" review of peer-reviewed publications is organized into four topics (1) Chemistry and pharmacokinetics of GlcN salts (2) Biological effects of GlcN salts in vitro (3) Therapeutic effects of GlcN salts in animal models of OA and (4) GlcN salts in the treatment of clinical OA.

RESULTS

Data reporting potent pleiotropic activities of GlcN in in vitro cell and explant cultures are discussed in the context of the established pharmacokinetic data in humans and animals. The available clinical trial data are discussed to place the patient in the context of controlled research on disease management.

CONCLUSIONS

Future research to determine therapeutic mechanisms of GlcN salt preparations will require use of standardized and clinically relevant in vitro assay systems and in vivo animal models for testing, as well as development of new outcome measures for inflammation and pain pathways in human OA.

Glucosamine administration in athletes: effects on recovery of acute knee injury

The main aim of this study was to examine the effects of 4 weeks of glucosamine administration on the functional ability and the degree of pain intensity in competitive male athletes after acute knee injury. This study was a randomized, double-blind parallel trial of glucosamine (1500 mg per day) or a placebo for 28 days, utilising 106 patients with an acute knee injury. Pain and functional ability were evaluated at the beginning of the study and at 7, 14, 21, and 28 days after starting treatment. Pain intensity at rest and while walking was assessed using a visual analog scale. Passive knee flexibility (flexion and extension) of the injured limb was measured using a modified goniometer, and the degree of knee swelling was measured and compared with the noninjured limb. No significant difference was found between the glucosamine, and placebo group in mean pain intensity scores for resting and walking, and degree of knee swelling at the 7-day, 14-day, 21-day, and 28-day assessment. There was no significant difference between passive knee flexibility at the 7-day, 14-day, and 21-day assessment. After 28 days of treatment the patients from the glucosamine group demonstrated significant improvement in knee flexion and extension as compared with the placebo group.

Prevalence of and factors associated with glucosamine use in Canada

OBJECTIVE

Glucosamine is commonly used for the treatment of osteoarthritis, and its use is increasing in the general population. The Canadian Multicentre Osteoporosis Study (CaMos) provided an opportunity to examine the prevalence of glucosamine use across age and gender groups, and to assess the factors associated with its use.

METHOD

CaMos is a random, population-based sample of 9423 Canadians. Baseline assessments took place in 1996-1997 and the 5-year follow-up assessments in 2001-2002. The primary outcome of this analysis was glucosamine use at year 5. Prevalence estimates were age- and sex-standardized to the Canadian population. A number of factors potentially associated with glucosamine use were identified from the literature. Multivariable logistic regression was used to identify variables associated with glucosamine use.

RESULTS

At 5 years, complete data were available for 7652 of the original 9423 participants (81.2%). For men, glucosamine use increased from 0.9% to 4.7% (weighted values), and for women, it increased from 1.3% to 8.2%. Glucosamine use was higher among older participants, those living in western Canada, and those with arthritis, back pain, higher calcium intake from supplements, physical activity and prior glucosamine use.

CONCLUSIONS

Glucosamine use increased substantially over 5 years, and its use is associated with a number of factors. Some may use glucosamine to manage pain and symptoms of arthritis and back pain, while others use it as a preventive measure to maintain health.

Dietary supplements for football

Physical training and competition in football markedly increase the need for macro- and micronutrient intake. This requirement can generally be met by dietary management without the need for dietary supplements. In fact, the efficacy of most supplements available on the market is unproven. In addition, players must be cautious of inadequate product labelling and supplement impurities that may cause a positive drug test. Nonetheless, a number of dietary supplements may beneficially affect football performance. A high endurance capacity is a prerequisite for optimal match performance, particularly if extra time is played. In this context, the potential of low-dose caffeine ingestion (2 - 5 mg . kg body mass(-1)) to enhance endurance performance is well established. However, in the case of football, care must be taken not to overdose because visual information processing might be impaired. Scoring and preventing goals as a rule requires production of high power output. Dietary creatine supplementation (loading dose: 15 - 20 g . day(-1), 4 - 5 days; maintenance dose: 2 - 5 g g . day(-1)) has been found to increase muscle power output, especially during intermittent sprint exercises. Furthermore, creatine intake can augment muscle adaptations to resistance training. Team success and performance also depend on player availability, and thus injury prevention and health maintenance. Glucosamine or chondroitin may be useful in the treatment of joint pain and osteoarthritis, but there is no evidence to support the view that the administration of these supplements will be preventative. Ephedra-containing weight-loss cocktails should certainly be avoided due to reported adverse health effects and positive doping outcomes. Finally, the efficacy of antioxidant or vitamin C intake in excess of the normal recommended dietary dose is equivocal. Responses to dietary supplements can vary substantially between individuals, and therefore the ingestion of any supplement must be assessed in training before being used in competition. It is recommended that dietary supplements are only used based on the advice of a qualified sports nutrition professional.

Medication and supplement use by athletes

Athletes are affected in various ways by medications and supplements. Physicians caring for athletes need to be aware of medicines that athletes are taking and how they may interact with performance, exercise, environment, and other medicines. Athletes may attempt to gain a performance advantage with the use of a variety of dietary supplements and performance enhancers. Physicians must be knowledgeable of these so that athletes are properly educated about potential benefits and risks and physical effects. This article first reviews common medicines that athletes use and their potential efficacy and interactions with exercise and environment, then reviews dietary supplements and the data on their efficacy for performance enhancement. Finally, current and future doping issues are discussed.