Team illness prevention strategy (TIPS) is associated with a 59% reduction in acute illness during the Super Rugby tournament: a control-intervention study over 7 seasons involving 126 850 player days.

OBJECTIVES: To determine whether a team illness prevention strategy (TIPS) would reduce the incidence of acute illness during the Super Rugby tournament. METHODS: We studied 1340 male professional rugby union player seasons from six South African teams that participated in the Super Rugby tournament (2010-2016). Medical staff recorded all illnesses daily (126 850 player days) in a 3-year control (C: 2010-2012; 47 553 player days) and a 4-year intervention (I: 2013-2016; 79 297 player days) period. A five-element TIPS was implemented in the I period, following agreement by consensus. Incidence rate (IR: per 1000 player days; 95% CI) of all acute illnesses, illness by main organ system, infectious illness and illness burden (days lost due to illness per 1000 player days) were compared between C and I period. RESULTS: The IR of acute illness was significantly lower in the I (5.5: 4.7 to 6.4) versus the C period (13.2: 9.7 to 18.0) (p<0.001). The IR of respiratory (C=8.6: 6.3 to 11.7; I=3.8: 3.3 to 4.3) (p<0.0001), digestive (C=2.5: 1.8 to 3.6; I=1.1: 0.8 to 1.4) (p<0.001), skin and subcutaneous tissue illness (C=0.7: 0.4 to 1.4; I=0.3: 0.2 to 0.5) (p=0.0238), all infections (C=8.4: 5.9 to 11.9; I=4.3: 3.7 to 4.9) (p<0.001) and illness burden (C=9.2: 6.8 to 12.5; I=5.7: 4.1 to 7.8) (p=0.0314) were significantly lower in the I versus the C period. CONCLUSION: A TIPS during the Super Rugby tournament was associated with a lower incidence of all acute illnesses (59%), infectious illness (49%) and illness burden (39%). Our findings may have important clinical implications for other travelling team sport settings.

Match injury incidence during the Super Rugby tournament is high: a prospective cohort study over five seasons involving 93 641 player-hours.

OBJECTIVES: To determine the incidence and nature of injuries in the Super Rugby tournament over a 5-year period. METHODS: 482 male professional rugby union players from six South African teams participating in the Super Rugby tournament were studied (1020 player-seasons). Medical staff of participating teams (2012-2016 tournaments) recorded all time loss injuries (total injuries and match injuries) and exposure hours (93 641 total playing hours; 8032 match hours). Injury incidence, injured player proportion, severity (time lost), anatomical location, tissue type and activity/phase during which injury occurred are reported. RESULTS: The overall incidence of match injuries (per 1000 player-hours; 95% CI) for each year was as follows: 2012 (83.3; 69.4-99.2); 2013 (115.1; 98.7-133.5); 2014 (95.9; 80.8-113.1), 2015 (112.3; 96.6-129.9) and 2016 (93.2; 79.9-107.9). The injured player proportion for each year was as follows: 2012 (54.6%); 2013 (49.4%); 2014 (52.0%); 2015 (50.0%); and 2016 (39.8%). The thigh, knee, head/face and shoulder/clavicle are the most frequently injured locations, and muscle/tendon and joint/ligament injuries account for the majority of injuries. Most injuries (79%) occur in contact situations, in particular during a tackle (54%). CONCLUSION: The incidence of match injuries and the injured player proportion in South African teams competing in the Super Rugby tournament is high. Match injury incidence is consistently higher than previously reported for senior male rugby players at elite/professional level. Targeted risk management strategies are therefore needed in the Super Rugby tournament to manage risk of injury.

Inflammatory and apoptotic signalling pathways and concussion severity: a genetic association study.

The objective was to investigate the relationship between IL-1B rs16944, IL-6 rs1800795, and CASP8 rs3834129 genetic polymorphisms and concussion severity. Rugby players from high school, senior amateur, and professional teams completed a concussion severity questionnaire and donated a DNA sample. Participants (n = 163) were split into symptom severity groups around the median number and duration of symptoms. The frequency of participants with high symptom counts (more than five symptoms) increased across the IL-1B (C/C: 35%; C/T: 51%; T/T: 56%; P = 0.047) and the IL-6 (C/C: 31%; C/G: 44%; G/G: 58%; P = 0.027) genotypes. The C-C inferred interleukin allele construct frequency, created from combining the IL-1B and IL-6 genotype data, was lower in participants reporting a high symptom count (18%), compared to those with a low symptom count (fewer than six symptoms, 36%, P = 0.002). Similarly, the C-C inferred interleukin allele construct frequency was lower in those reporting prolonged symptom duration (more than one week, 16%), as opposed to short symptom duration (less than one week, 34%, P = 0.015). This study provides evidence of novel inflammatory pathway genetic associations with concussion severity, which supports the hypothesis implicating neuroinflammation in the development of concussion symptoms.

The association between COMT rs4680 and 5-HTTLPR genotypes and concussion history in South African rugby union players.

The objective was to investigate the relationship between Catechol-O-methyltransferase (COMT) rs4680 and serotonin-transporter-linked polymorphic region (5-HTTLPR) genotypes with concussion history and personality traits. Rugby players ("all levels": n = 303), from high schools ("junior", n = 137), senior amateur, and professional teams ("senior", n = 166), completed a self-reported concussion history questionnaire, Cloninger's Tridimensional Personality Questionnaire, and donated a DNA sample. Participants were allocated into control (non-concussed, n = 140), case (all) (previous suspected or diagnosed concussions, n = 163), or case (diagnosed only) (previous diagnosed concussion, n = 140) groups. COMT rs4680 Val/Val genotypes were over-represented in controls in all levels (P = 0.013, OR:2.00, 95% CI:1.15-3.57) and in juniors (P = 0.003, OR:3.57, 95% CI:1.45-9.09). Junior Val/Val participants displayed increased "anticipatory worry" (P = 0.023). The 5-HTTLPR low expressing group was under-represented in controls when all levels were considered (P = 0.032; OR:2.02, 95% CI:1.05-3.90) and in juniors (P = 0.021; OR:3.36, 95% CI:1.16-9.72). Junior 5-HTTLPR low and intermediate expressing groups displayed decreased "harm avoidance" (P = 0.009), "anticipatory worry" (P = 0.041), and "fear of uncertainty" (P < 0.001). This study provides preliminary indications that personality associated genetic variants can influence concussion in rugby.

Associations between habitual sleep characteristics and cardiometabolic disease risk in corporate executives.

OBJECTIVES: Corporate executive job demands may lead to poor sleep habits, increasing their risk for cardiometabolic disease. This study aimed to describe and explore associations between objectively measured habitual sleep characteristics and cardiometabolic disease risk of corporate executives, while accounting for occupational, psychological, and lifestyle factors. METHODS: Habitual sleep was measured using wrist-worn actigraphy and a sleep diary over seven consecutive days in 61 (68.3% men) corporate executives aged 46.4 ± 8.7years. A composite cardiometabolic disease risk score was determined using body mass index, waist circumference, blood pressure and fasting glucose and lipid concentrations. Prediction models were built using a backward stepwise selection approach to explore associations between sleep characteristics and cardiometabolic disease risk factors adjusting for occupational, psychological, and lifestyle covariates. RESULTS: Average total sleep time was 6.60 ± 0.75 hours, with 51.7% of participants reporting poor sleep quality and 26.2% extending their weekend sleep. Adjusted models showed that lower sleep efficiency (ß = -0.25, 95%CI: -0.43; -0.08, P = .006), shorter weekday total sleep time (ß = -1.37, 95% CI: -2.41, -0.32; P = .011) and catch-up sleep (ß = 0.84, 95%CI: 0.08, 1.60, P = .002) were associated with higher cardiometabolic disease risk scores. Adjusted models also found that shorter average time-in-bed (ß=-2.00, 95%CI: -3.76; -0.18, P = .031), average total sleep time (ß=1.98, 95%CI: -3.70; -0.25, P = .025) and weekday total sleep time (ß = -2.13, 95%CI: -3.56; -0.69, P = .025) as well as catch-up sleep (ß = 1.67, 95% CI: 0.52; 2.83; P = .012) were all associated with a higher body mass index. CONCLUSION: Corporate executives who compromise sleep duration during the working week may increase their risk for obesity and future cardiometabolic disease.

Toxic tau: The TAU gene polymorphisms associate with concussion history in rugby union players.

OBJECTIVES: Concussion is a brain injury that occurs when biomechanical forces are transmitted to the head region resulting in neurological deficits. The accumulation of tau protein in autopsies of athletes with multiple concussions implicates tau in concussion-associated neurodegeneration. The TAU rs2435211 (C>T) and rs2435200 (G>A) polymorphisms are involved in pathological tau expression and neurodegenerative disease risk. The aims of this study were to investigate the associations of TAU (rs2435211, rs2435200) polymorphisms with concussion history and sustaining multiple concussions in rugby. DESIGN: In total, 140 non-concussed controls and 163 previously concussed participants (all cases group, N=163; clinically diagnosed, N=140; multiple concussed, N=87) were recruited from high school (N=135, junior), club and professional rugby teams (N=166, senior). METHODS: Participants were genotyped for TAU rs2435211 and rs2435200 polymorphisms. RESULTS: In seniors, the rs2435200 AA genotype was significantly over-represented in the control group compared to the multiple concussed subgroup (P=0.033, control: 25%, N=16, multiple concussed: 11%, N=6; OR: 0.34, 95% CI 0.12-0.96). While the AG genotype was significantly under-represented in the control compared to multiple concussed (P=0.024, control: 45%, N=29, multiple concussed: 63%, N=36; OR: 2.34, 95% CI 1.11-4.95). The inferred TAU (rs2435211 C>T-rs2435200 G>A) T-G haplotype was significantly under-represented in the control (19%, N=12) compared to the all cases group (30%, N=28, P=0.031). CONCLUSIONS: The TAU-associated neurodegenerative pathway was implicated as a potential pathophysiological mechanism underlying concussion in seniors. In future, the identification of TAU polymorphisms associated with concussion risk may assist clinical management and reduce risk of severe complications.

Unravelling the interaction between the DRD2 and DRD4 genes, personality traits and concussion risk.

BACKGROUND: Concussion occurs when biomechanical forces transmitted to the head result in neurological deficits. Personality may affect the balance between safe and dangerous play potentially influencing concussion risk. Dopamine receptor D2 (DRD2) and dopamine receptor D4 (DRD4) genetic polymorphisms were previously associated with personality traits. OBJECTIVES: This case-control genetic association study investigated the associations of (1) DRD2 and DRD4 genotypes with concussion susceptibility and personality, (2) personality with concussion susceptibility and (3) the statistical model of genotype, personality and concussion susceptibility. METHODS: In total, 138 non-concussed controls and 163 previously concussed cases were recruited from high school (n=135, junior), club and professional rugby teams (n=166, senior). Participants were genotyped for DRD2 rs12364283 (A>G), DRD2 rs1076560 (C>A) and DRD4 rs1800955 (T>C) genetic variants. Statistical analyses including structural equation modelling were performed using the R environment and STATA. RESULTS: The rs1800955 CC genotype (p=0.014) and inferred DRD2 (rs12364283-rs1076560)-DRD4 (rs1800955) A-C-C allele combination (p=0.019) were associated with decreased concussion susceptibility in juniors. The rs1800955 TT and CT genotypes were associated with low reward dependence in juniors (p<0.001) and seniors (p=0.010), respectively. High harm avoidance was associated with decreased concussion susceptibility in juniors (p=0.009) and increased susceptibility in seniors (p=0.001). The model showed that a genetic variant was associated with personality while personality was associated with concussion susceptibility. CONCLUSION: These findings highlight the linear relationship between genetics, personality and concussion susceptibility. Identifying a genetic profile of 'high risk' behaviour, together with the development of personalised behavioural training, can potentially reduce concussion risk.

An association between polymorphisms within the APOE gene and concussion aetiology in rugby union players.

OBJECTIVES: Concussion refers to changes in neurological function due to biomechanical forces transmitted to the head. The APOE ε4 allele is associated with brain injury severity. The objective was to determine if APOE gene variants are associated with concussion history and severity in rugby players. DESIGN: In total, 128 non-concussed controls and 160 previously concussed participants (all cases N=160; diagnosed N=139) were recruited from high school (junior, N=121), club (N=116) and professional rugby teams (N=51). METHODS: Participants were genotyped for rs405509 (G>T), rs429358 (T>C) and rs7412 (C>T) APOE variants. Statistical analyses were performed using the R environment. RESULTS: The rs405509 TT genotype was over-represented in controls compared to all cases (P=0.043; control: 29%, all cases: 18%; odds ratio: 0.55, 95% confidence interval 0.31-0.98). The APOE-ε isoform frequencies were not significantly different between groups (P>0.05). Additionally, the inferred APOE (rs405509-ε2/ε3/ε4) T-ε3 haplotype was over-represented in controls (41%) compared to diagnosed (32%, P=0.042). The G-ε3 haplotype was under-represented in controls (36%) compared to all cases (44%, P=0.019) and diagnosed (44%, P=0.021). The TT genotype was significantly associated with rapid recovery (P=0.048, <1 week: 51%, N=70, ≥1 week: 36%, N=29; odds ratio: 0.55, 95% confidence interval 0.30-1.01). CONCLUSIONS: These findings support the further elucidation of the APOE gene or closely-related genes in concussion aetiology. Although similar preliminary results were found when juniors were separately analysed, the under-powered sample size for junior subgroup requires future investigation in larger cohorts of junior-level athletes.

The association between harm avoidance personality traits and self-reported concussion history in South African rugby union players.

OBJECTIVES: Personality traits have been proposed to affect the risk of sports concussion, but evidence is limited. Cloninger's Tridimensional Personality Questionnaire (TPQ) measures novelty seeking, harm avoidance (HA), and reward dependence traits. The aim of this study was to investigate the relationship between TPQ scores and concussion history in rugby union players. DESIGN: Cross-sectional study. METHODS: Rugby players from high schools, senior amateur clubs, and professional teams provided a self-reported concussion history and completed the TPQ. Participants reporting no previous concussions formed the control group, while participants reporting concussion formed the case group. A one-way analysis of covariance, with age as a covariate, was used to examine the differences in TPQ scores between groups. RESULTS: Of the 309 participants, 54% reported a minimum of one concussion (junior: 47%; amateur: 52%; professional: 72%). HA scores were significantly higher in junior players without a history of concussion compared to cases (p=0.006). Specifically, the junior control group had higher "anticipatory worry" (p=0.009) and "fear of uncertainty" (p=0.008). In contrast, the professional control group had lower HA scores than cases (p=0.009), while the amateur cohort displayed no differences between control and case groups. CONCLUSIONS: This study identified a novel association between HA and concussion in rugby players, adding evidence to the role of personality in a multifactorial risk-model of concussion. The findings suggest that lower HA may lead to increased dangerous play in youth rugby, influencing concussion susceptibility. Contrasting associations in the professional cohort suggest further research is required to understand the role of personality in concussion.