If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
To quantify changes in sport-related concussion and traumatic brain injury claims in New Zealand during the first two years of the COVID-19 pandemic (i.e., 2020 and 2021).
Design
Population-based cohort study.
Methods
This study included all new sport-related concussion and traumatic brain injury claims that were registered with the Accident Compensation Corporation in New Zealand during 1 January 2010 to 31 December 2021. Annual sport-related concussion and traumatic brain injury claim rates per 100,000 population from 2010 to 2019 were used to fit autoregressive integrated moving average models, from which forecast estimates with 95 % prediction intervals for 2020 and 2021 were derived and compared against corresponding observed values to obtain estimates of absolute and relative forecast errors.
Results
Sport-related concussion and traumatic brain injury claim rates were 30 % and 10 % lower than forecasted in 2020 and 2021, respectively, equating to an estimated total of 2410 fewer sport-related concussion and traumatic brain injury claims during the two-year period.
Conclusions
There was a large reduction in sport-related concussion and traumatic brain injury claims in New Zealand during the first two years of the COVID-19 pandemic. These findings highlight the need for future epidemiological studies examining temporal trends of sport-related concussion and traumatic brain injury to account for the impact of the COVID-19 pandemic.
There was an estimated total of 2410 fewer sport-related concussion and traumatic brain injury claims in New Zealand during the first two years of the COVID-19 pandemic.
•
Compared to forecasts, sport-related concussion and traumatic brain injury claim rates decreased by 30 % in 2020 and 10 % in 2021.
•
Future epidemiological studies investigating temporal trends in the incidence of sport-related concussion and traumatic brain injury should employ appropriate analysis methods that account for changes related to the COVID-19 pandemic.
1. Introduction
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide, costing the global economy an estimated US$400 billion every year.
Given the large societal burden of TBI, it is important to monitor trends over time. The best available population-based data on sport-related concussion and TBI in New Zealand are both outdated and limited in scope. King and colleagues
reported on sport-related concussion entitlement claims made to the Accident Compensation Corporation (ACC), New Zealand's national taxpayer-funded no-fault injury compensation system, during 2001 to 2011.
In addition to being more than a decade old, these data are also limited because they included only moderate to severe entitlement claims pertaining to seven sporting activities. Bastos Gottgtroy and colleagues
examined mild TBI claims made to the ACC during the two-year period from September 2016 to September 2018; however, with its short study period, this study was not designed to examine trends over time. Thus, it would be useful to provide a more comprehensive overview of recent trends in sport-related concussion and TBI in New Zealand.
The World Health Organization declared the novel coronavirus disease (COVID-19) a global pandemic on 11 March 2020.
On 21 March 2020, the New Zealand government introduced a four-tiered alert level system (i.e., [1] prepare, [2] reduce, [3] restrict, and [4] lockdown).
Subsequent elevations to alert level 3 or 4 occurred during the second half of 2020 and in 2021 (Fig. 1). Community sport was cancelled, indoor exercise and recreation facilities were closed, and outdoor exercise and recreation was limited to individual physical activity in local neighbourhoods during alert levels 3 and 4. Whilst physical activity generally decreased at the population-level during COVID-19 restrictions,
the impact on the incidence of sport-related concussion and TBI is yet to be determined. Thus, this study aimed to quantify changes in sport-related concussion and TBI claims in New Zealand during the first two years of the COVID-19 pandemic (i.e., 2020 and 2021).
Fig. 1Timeline of New Zealand COVID-19 alert levels during 2020 and 2021.
This population-based cohort study included all new sport-related concussion and TBI claims that were registered with the ACC in New Zealand during 1 January 2010 to 31 December 2021. New claims are based on the date the claim was lodged with ACC, not the date of injury. The annual number of sport-related concussion and TBI claims by sex, age group, and region was obtained from publicly available statistics published by the ACC.
Because reliable population-based data on sport participation in New Zealand were not available for the study period, general population estimates were used as denominator for calculating sport-related concussion and TBI claim rates. The estimated resident population by year, sex, age group, and region was obtained from Stats NZ via their online Infoshare platform (https://infoshare.stats.govt.nz/).
Annual sport-related concussion and TBI claim rates per 100,000 population were calculated with 95 % confidence intervals (CIs). Time series forecasting involved fitting autoregressive integrated moving average models of annual sport-related concussion and TBI claim rates per 100,000 population from 2010 to 2019 using the methods described by Hyndman and Athanasopoulos.
Forecast estimates with 95 % prediction intervals for 2020 and 2021 were derived from the autoregressive integrated moving average models and compared against the observed values for 2020 and 2021. The absolute and relative differences between forecasted and observed values were used as measures of absolute and relative impact of the COVID-19 pandemic on annual sport-related concussion and TBI claim rates. All statistical analyses were conducted using R, version 4.2.1 (R Foundation for Statistical Computing, Vienna, Austria) and the forecast package.
A total of 77,057 new sport-related concussion and TBI claims were registered with the ACC during 1 January 2010 to 31 December 2021, with males and females accounting for 71.5 % (n = 55,068) and 18.5 % (n = 21,989) of claims, respectively. Young people aged 10–29 years accounted for more than three-quarters the claims (i.e., 10–19 years: 53.8 %, n = 41,449; 20–29 years: 23.5 %, n = 18,124; respectively), whilst the remaining age groups accounted for less than 10 % each (i.e., 0–9 years: 5.5 %, n = 4233; 30–39 years: 7.7 %, n = 5926; 40+ years: 9.5 %, n = 7.325).
Overall, the forecasted and observed sport-related concussion and TBI claim rates per 100,000 population were 147.1 (95 % PI 130.0–164.2) and 112.7 (95 % CI 109.8–115.7) for 2020, and 147.1 (95 % PI 122.9–171.2) and 134.1 (95 % CI 130.9–137.3) for 2021, respectively (Fig. 2). The relative difference between forecasted and observed sport-related concussion and TBI claim rates per 100,000 population was −30 % and −10 % for 2020 and 2021, respectively. This equated to an estimated 1746 and 644 fewer sport-related concussion and TBI claims than forecasted for 2020 and 2021, respectively.
Fig. 2Time series with observed and forecasted sport-related concussion and traumatic brain injury claim rates per 100,000 population, New Zealand, 2010–2021.
The forecasted and observed sport-related concussion and TBI claim rates per 100,000 population by sex and age group are depicted in Fig. 3, Fig. 4, respectively, and an overview of absolute and relative differences is presented in Table 1. The relative difference between forecasted and observed sport-related concussion and TBI claim rates per 100,000 population for males and females was −34 % and −28 % for 2020 and −12 % and −14 % for 2021, respectively. The relative difference between forecasted and observed sport-related concussion and TBI claim rates per 100,000 population ranged from −39 % for those aged 10–19 years to 2 % for those aged 40+ years for 2020, and from −24 % for those aged 0–9 years to 10 % for those aged 40+ years for 2021.
Fig. 3Time series with observed and forecasted sport-related concussion and traumatic brain injury claim rates per 100,000 population by sex, New Zealand, 2010–2021.
Fig. 4Time series with observed and forecasted sport-related concussion and traumatic brain injury claim rates per 100,000 population by age group, New Zealand, 2010–2021.
Table 1Forecasted and observed sport-related concussion and traumatic brain injury claim rates per 100,000 population by year and subgroup, New Zealand, 2020 and 2021.
The observed sport-related concussion and TBI claim rates per 100,000 population were lower than forecasted in all regions in 2020, with the relative difference ranging from −79 % to −7 % (Fig. 5; Table 1). For 2021, the observed sport-related concussion and TBI claim rates per 100,000 population were lower than forecasted in ten regions (relative difference ranging from −32 % to −4 %) and higher than forecasted in six regions (relative difference ranging from 3 % to 20 %).
Fig. 5Choropleth map of relative difference between forecasted and observed sport-related concussion and traumatic brain injury claim rates per 100,000 population by region, New Zealand, 2020 and 2021.
This study found a large reduction in sport-related concussion and TBI claims in New Zealand during the first two years of the COVID-19 pandemic. In 2020 and 2021, sport-related concussion and TBI claim rates were 30 % and 10 % lower than forecasted, respectively, equating to an estimated total of 2410 fewer sport-related concussion and TBI claims during the two-year period. These findings highlight the need for future epidemiological studies examining temporal trends of sport-related concussion and TBI to account for the impact of the COVID-19 pandemic.
The reduction in sport-related concussion and TBI claims in New Zealand during the COVID-19 pandemic is consistent with observed decreases in the incidence of sport-related injuries in other countries.
For instance, studies have demonstrated that lockdowns and restrictions related to the COVID-19 pandemic resulted in significant declines in sport-related injuries presenting to Emergency Departments and level 1 paediatric trauma hospitals in the United States.
There were also fewer sport-related injuries seen in outpatient settings during the COVID-19 pandemic, and most of these injuries occurred outside of organised sports settings.
Naturally, the magnitude of the reduction in incidence varies depending on the level and duration of government-imposed restrictions across countries and regions. In New Zealand, alert level 3 or 4 was imposed for 14 % and 6 % of 2020 and 2021, respectively, whilst the estimated reductions in sport-related concussion and TBI claims were 30 % and 10 % for 2020 and 2021, respectively. This apparent discrepancy is to be expected because the impact of government lockdowns and restrictions on organised sports extends beyond the periods of alert level 3 or 4. That is, it takes time for community sports to organise and re-start their activities after lockdown periods.
There was considerable variation in relative differences in observed versus forecasted claim rates across regions in both 2020 (range −79 % to −7 %) and 2021 (range −32 % to 20 %). The specific reasons for this variation are not clear. It is tempting to assume that the variation can be explained by differences in duration and severity of COVID-19 social restrictions across regions; however, whilst this explanation fits for the Auckland region, the correlation across all regions is poor. This is illustrated by the variation across regions on the South Island, despite these regions having essentially identical lockdown periods (Fig. 5). Perhaps regional differences in attitudes toward or compliance with COVID-19 social restrictions or COVID-19 disease burden would offer more explanatory power, but the unavailability of such data in the present study precluded further exploration of those possibilities.
Marked reductions in the incidence of sport-related injuries during periods of lockdowns and restrictions on organised sporting activities may be offset by a relative increase in injury risk during post-lockdown periods. For instance, there is evidence suggesting that professional football and rugby athletes experienced increased injury incidence rates during post-lockdown periods.
Prolonged restricted training, fixture congestion and player rotation: what the COVID-19 pandemic taught us about injury risk in professional collision sport.
Influence of the COVID-19 lockdown and restart on the injury incidence and injury burden in men’s professional football leagues in 2020: the UEFA elite club injury study.
Two main potential explanations have been offered. Firstly, extended lockdown and restrictions can lead to deterioration in training quality and volume, and subsequent deconditioning can lead to increased risk of injury.
Secondly, to make up for lost time, there may be considerable match congestion when resuming competition post-lockdown. That is, playing the same number of matches in fewer days can significantly increase the risk of injury,
Prolonged restricted training, fixture congestion and player rotation: what the COVID-19 pandemic taught us about injury risk in professional collision sport.
Influence of the COVID-19 lockdown and restart on the injury incidence and injury burden in men’s professional football leagues in 2020: the UEFA elite club injury study.
The changes wrought by the COVID-19 pandemic have major implications for future epidemiological studies investigating temporal trends and changes over time in the incidence of sport-related injuries. Future epidemiological studies are strongly recommended to employ analysis methods that can account for pre-pandemic temporal trends in incidence rates, as well as the impact of the COVID-19 pandemic. One alternative is interrupted time series analysis, which involves segmented regression modelling whereby the regression coefficients estimate the pre-event slope (i.e., trend in outcome before the event), the level change (i.e., change in level of the outcome at the time of the event), and the change in slope (i.e., difference between pre-event and post-event slopes).
It should be noted that the independence assumption is unlikely to hold for time series of counts data or derivative incidence rates, with year-on-year observations very likely to be correlated. Because serial correlation can result in underestimation of standard errors and p-values, it may be necessary fit regression models that can handle autocorrelated observations (e.g., autoregressive moving average models).
Influence of the COVID-19 lockdown and restart on the injury incidence and injury burden in men’s professional football leagues in 2020: the UEFA elite club injury study.
Major strengths of this study were it being population-based and thus subject to minimal selection bias; it using a mature claims database with routinely collected and good quality data; and it using robust statistical methods to generate forecasting error estimates to quantify the impact of the COVID-19 pandemic on the incidence of sport-related concussion and TBI claims. The true incidence of sport-related concussion and TBI is likely under-enumerated as it is possible that not all people with a sport-related concussion or TBI will lodge a claim with the ACC. It is also worth noting that a concussion must be diagnosed by a medical doctor to be compensable under the ACC. That is, individuals with concussion or TBI who present solely to an allied health practitioner (e.g., physiotherapist, osteopath, chiropractor, strength and conditioning coach) without being referred to a medical doctor will not be able to claim from the ACC. However, such under-enumeration is unlikely to vary much from year to year and thus unlikely to have affected the estimated relative changes in incidence of sport-related concussion and TBI presented in this study. Another limitation of the ACC dataset used in this study was that it did not provide disaggregated numbers of claims for concussion and other TBI; however, the ACC has indicated elsewhere that about 80 % of all TBI claims were for concussion or mild TBI.
This study was also limited by the lack of available data to further examine potential factors that might explain the observed differences across regions and age groups (e.g., attitudes toward and compliance with COVID-19 social restrictions, COVID-19 disease burden, and proportion of subpopulation participating in activities that were less impacted by COVID-19 social restrictions). Lastly, the findings may not be generalisable beyond New Zealand because the magnitude of the impact of the COVID-19 pandemic on the incidence of sport-related concussions and TBIs depends on the level and duration of government-imposed restrictions and countermeasures.
5. Conclusion
There was a large reduction in sport-related concussion and TBI claims in New Zealand during the first two years of the COVID-19 pandemic. Sport-related concussion and TBI claim rates decreased by 30 % and 10 % in 2020 and 2021, respectively, with an estimated total of 2410 fewer sport-related concussion and TBI claims during the first two years of the COVID-19 pandemic. These findings highlight the need for future epidemiological studies examining temporal trends of sport-related concussion and TBI to account for the impact of the COVID-19 pandemic.
Funding information
No funding was received for conducting this research or developing this manuscript.
Confirmation of ethical compliance
This research was exempted from human research ethics review as it involved analysis of non-identifiable aggregate data that are freely and openly available in the public domain.
CRediT authorship contribution statement
Reidar P. Lystad: Conceptualization, Methodology, Formal analysis, Visualization, Writing – original draft, Writing – review & editing.
Declaration of interest statement
The author declares that there are no competing interests.
Acknowledgements
The author would like to acknowledge and thank the sources and copyright holders of the data used in this study. Non-identifiable, aggregate claims data were obtained from the Accident Compensation Corporation in New Zealand. The estimated resident population data were obtained from Stats NZ, and their reuse has been licenced by Stats NZ under the Creative Commons Attribution 4.0 International licence.
References
Maas A.I.R.
Menon D.K.
Manley G.T.
et al.
Traumatic brain injury: progress and challenges in prevention, clinical care, and research.
Prolonged restricted training, fixture congestion and player rotation: what the COVID-19 pandemic taught us about injury risk in professional collision sport.
Influence of the COVID-19 lockdown and restart on the injury incidence and injury burden in men’s professional football leagues in 2020: the UEFA elite club injury study.
00044-0&id=gr1.jpg){kind=link}
00044-0&id=gr2.jpg){kind=link}
00044-0&id=gr3.jpg){kind=link}
00044-0&id=gr4.jpg){kind=link}
00044-0&id=gr5.jpg){kind=link}