Contributors to caregiver burden, depression, and anxiety in the partners of professional American-style football players: a cross-sectional study

Introduction: American-style football (ASF) has been linked to chronic adverse health outcomes. The extent to which ASF players' careers impact their spouses' caregiver burden, depression, and anxiety remains unknown. In addition to conventional family stressors, ASF families may have specific concerns such as chronic traumatic encephalopathy (CTE; a condition that can only be established at autopsy), which may additionally contribute to caregiver burden and mood symptoms.

Methods: Family Experiences Managing Football Lives (FEM-FL) is a cross-sectional study developed under the Football Players Health Study at Harvard University. Eligible participants were partners of current and former professional ASF players who completed electronic surveys from 2021 to 2024. Data on age, race, family composition, income, employment status, caregiver help, personal health, marital satisfaction, player position, and number of relocations were collected. Participants were asked whether they believed their partner had “CTE.” Multivariable models measured associations between established and ASF-specific risk factors and caregiver burden (Zarit 4-item Burden Interview), and depression and anxiety symptoms (Patient Health Questionnaire-4).

Results: Among 153 partners of active and former professional ASF players, mean [SD] age was 48.1 [13.5], and 28.8% self-identified as Black. In models that adjusted for established risk factors and ASF-specific variables, poor health among partners was associated with a 1.6 point increase in depression score (95% CI = 0.90, 2.30; p < 0.001) and 1.87 point increase in anxiety (95% CI = 1.05, 2.69; p < 0.001). Models that controlled for established risk factors identified significant associations between increased marital satisfaction and a 5.87 reduction in caregiver burden score (95% CI= −7.32, −4.43; p < 0.001), 1.26 score reduction in depression score (95% CI = −1.75, −0.77; p < 0.001) and 1.32 reduction in anxiety score (95% CI = −1.89, −0.75; p < 0.001). CTE concerns were associated with a 2.90 increase in caregiver burden score (95% CI = 1.78, 3.99; p < 0.001) and a 0.44 increase in reported anxiety (95% CI = −0.01, 0.88; p = 0.05), but had no association with depression in adjusted models.

Discussion: Among partners of active and former professional ASF players, marital satisfaction, poor health, and concerns about CTE may play a role in caregiver burden and behavioral health. CTE concerns represents a potential novel risk factor for increased caregiver burden among partners of ASF players.

Introduction

Conditions and injuries associated with long-term disability and pain affect not only the individual but may also impact family members (Haines et al., 2024; Longo et al., 2020). For example, caregiver burden, defined as “the extent to which caregivers perceived their emotional, physical health, social life, and financial status as a result of caring for their relative” (Zarit et al., 1980) and adverse behavioral and physical health outcomes (Swartz and Collins, 2019) are more prevalent in the partners of individuals with dementia (Besser and Galvin, 2019; Chiari et al., 2021), Alzheimer's Disease (Croog et al., 2006), brain injuries (Brickell et al., 2018; Laratta et al., 2020), and orthopedic injuries (Ziran et al., 2009). Former American-style football (ASF) players represent a population at high-risk of repetitive head (Casson et al., 2010; Pellman et al., 2004) and orthopedic injuries (Chambers et al., 2017; Dodson et al., 2016) that have been linked to neuropsychiatric disease (Roberts et al., 2019), cardiovascular disease (Grashow et al., 2023b), and arthritis (Grashow et al., 2023a). However, the burden that caring for these players places on their long-term partners or spouses has not been investigated. Key risk factors for caregiver burden, depression, and anxiety in the general population include age (Tsai et al., 2021), marital satisfaction (Tough et al., 2017), income (Chou, 2000), family size (Liu et al., 2020), and caregiver health (Bekdemir and Ilhan, 2019; Chou, 2000). Caregiver burden in general populations is associated with (Unsar et al., 2021), although not identical to (Liu et al., 2017; Zhu and Jiang, 2018), mood symptoms like depression and anxiety.

Professional ASF players' experiences may also present unique stressors on their partners. For example, field position has been associated with differences in injury (Casson et al., 2010; Pellman et al., 2004) early aging (Grashow et al., 2023a), and has been shown to track by race (Marquez-Velarde et al., 2023), all of which may be related to caregiver burden, depression and anxiety. During active play, players and their families may experience numerous relocations, uprooting social ties, employment opportunities, and more. Finally, exposure to repetitive head injury has been linked to the neuropathological entity known as chronic traumatic encephalopathy (CTE) in deceased former ASF players (Daneshvar et al., 2023; McKee et al., 2023; Mez et al., 2017), yet has not been definitively linked to clinical premorbid symptoms. Despite being an autopsy-based diagnosis, mainstream media presentations and high-profile cases related to those diagnosed postmortem with CTE may have raised concerns among living players about CTE (Walton et al., 2022) and its research-based clinical correlate, traumatic encephalopathy syndrome (TES) (Katz et al., 2021). Given that two recent studies showed that ~35% of former players have concerns about CTE (Grashow et al., 2024; Walton et al., 2022), there may be a sizable number of families with concerns about long-term brain health.

Established and ASF-specific determinants of caregiver burden, depression, and anxiety among partners of ASF players have been incompletely characterized. The objectives of this study were to: (1) describe the Family Experiences Managing Football Lives (FEM-FL) cohort, a substudy of the Football Players Health Study at Harvard University (Zafonte et al., 2019) recruiting partners and spouses of current and former ASF players; (2) identify associations between established risk factors and ASF partner caregiver burden, depression, and anxiety; and (3) measure the extent to which ASF-specific stressors impact the outcomes of interest after adjusting for established risk factors. We hypothesized that established risk factors for caregiver burden would be relevant in a cohort of ASF partners and spouses, and that football-specific stressors would independently be associated with caregiver burden.

Materials and methods

Study participants

The Family Experiences Managing Football Lives (FEM-FL) study stands as an independent separate cohort that investigates the impact of ASF careers on spouses' physical, mental, and emotional health. Anyone currently partnered with an active or former ASF player was considered eligible. Both FPHS and FEM-FL utilize the community-based participatory research model (CBPR; Viswanathan et al., 2004) that prioritizes collaboration with the ASF family community, ASF partner organizations, clinicians, and researchers (Viswanathan et al., 2004) in study design, recruitment, and result presentation.

Recruitment

In accordance with CBPR principles, FEM-FL created a FEM-FL Advisory Board comprised of physicians, organizational leaders, and community members who were spouses and family members of ASF players. Recruitment was conducted in-person and remotely with promotional FEM-FL materials. Currently, there is no centralized list of partners and wives of active and former players. We therefore recruited through the Football Players Health Study at Harvard University (FPHS) (Zafonte et al., 2019) which was designed to investigate the health and wellbeing of former professional ASF players. Therefore, to maximize outreach to community members, FEM-FL invitations were printed in ASF family community publications, posted on social media, sent electronically to FPHS participants, and included in ASF community organization outreach. To be eligible for this study, participants had to be currently partnered with a former or active ASF player. There were no other exclusion criteria for recruitment. One hundred seventy-two participants enrolled in FEM-FL between February 2021 and March 2024. The study was approved by the Institutional Review Board of the Harvard T.H. Chan School of Public Health, and participants provided informed consent prior to enrollment. All research practices were performed in accordance with the Declaration of Helsinki.

Demographic measures

All FEM-FL participants identified as female. Demographic data were collected, including age, and self-identified race (Black/African American, White/Caucasian, American Indian/Alaskan Native, Native Hawaiian/Pacific Islander, Asian, Other, and missing). Body mass index (BMI) at the time of survey completion was calculated from self-reported weight (pounds) and height (inches). Alcohol consumption per week was calculated from: “In a typical week, how many days do you drink a beverage containing alcohol?” and “On a typical day that you drink, how many beverages containing alcohol do you usually have?” We queried the women on current smoking status. Questions on caregiver burden, participant depression, and participant anxiety were included. To determine marital satisfaction, participants were asked, “How satisfied are you with your marriage or romantic partnership?” with the option to select, “Very satisfied,” “Moderately satisfied,” “Slightly satisfied,” “Neutral,” “Slightly dissatisfied,” “Moderately dissatisfied,” or “Very dissatisfied.” Answers were categorized as “satisfied” and “dissatisfied”, “neutral” was included in “satisfied.” Approximate household net worth was classified as less than $5,000, $5,000–$49,000, $50,000–$169,000, $170,000–$499,000, $500,000–$999,000 and $1,000,000+, and then categorized into “$169,000 or less” and “$170,000 or more.” The question about health was phrased as “In general, would you say your health is…” with the option to select: “Excellent,” “Very good,” “Good,” “Fair,” or “Poor.” Answers were dichotomized into “Has poor health” and “Does not have poor health,” “Fair” was included in “Does not have poor health.” Participants were asked, “Which term best describes your primary work role?” with the option to select: “Employed for wages,” “Self-employed,” “Out of work and looking for work,” “Homemaker,” “Student,” “Military,” “Retired,” or “Unable to work.” Answers were dichotomized as “salaried worker” and “non-salaried” (i.e., out of work and looking for work, homemaker, retired, and unable to work). Lastly, for caregiver help, participants were asked “Do you currently employ or utilize any of the following for help with your partner, children, or older adults?” with the option to select all that applied: nanny, home health aide, help from another relative, other, and none. Answers were dichotomized as either “yes have help” or “no help.”

ASF-specific variables

Partners' ASF position was determined by asking, “To the best of your knowledge, what position did your partner primarily play while in the NFL?” Answers were dichotomized as either lineman or non-lineman. Number of relocations were asked with the phrasing, “How many times did you relocate based on your partner's NFL career?” Answers were dichotomized as being either below or equal to the mean, or above the mean. To assess participant CTE concerns, the survey asked “Do you believe your partner has Chronic Traumatic Encephalopathy?” No definition of CTE was provided for either question due to lack of clinical consensus on pre-mortem CTE (Lenihan and Jordan, 2015; Randolph, 2018; Taghdiri et al., 2024).

Outcome variables

The four-item Zarit Burden Interview (ZBI-4) assessed feelings of caregiver burden when supporting a partner's health (Higginson et al., 2010). Responses to the ZBI-4 include, “Never,” “Rarely,” “Sometimes,” “Often,” and “Nearly always.” Lower caregiver burden scores reflect less perceived stress associated with partner care. Scores may range from 0–16, and a score of eight is considered to reflect “severe” caregiver burden (Bédard et al., 2001). Depression and anxiety symptom severities over the past two weeks were assessed using the two-item Patient Health Questionnaire (PHQ-2; Löwe et al., 2005) and two item Generalized Anxiety Disorder (GAD-2; Delgadillo et al., 2012), respectively. Both the PHQ-2 and GAD-2 responses include “Not at all,” “Several days,” “More than half the days,” and “Nearly every day.” In the PHQ-2 and GAD-2, scores may range from 0–6, and a score of three is considered to be clinically depressed and clinically anxious, respectively (Staples et al., 2019).

Statistical analysis

Only participants who completed questions on the outcomes of interest (caregiver burden, depression, and anxiety) were included in analyses (N = 153). Bivariate associations were calculated between demographic, lifestyle, and current health variables and outcomes of concern [caregiver burden (less than eight, greater than or equal to eight), depression symptoms (less than three, greater than or equal to three), and anxiety symptoms (less than three, greater than or equal to three)] using Kruskal-Wallis rank sum tests for continuous variables and chi-square tests for categorical variables. For one participant missing age, age was imputed using multiple imputation by chained equations (MICE; Buuren and Groothuis-Oudshoorn, 2011) based on race, marital satisfaction, income, health, and having young children. Race was categorized as Black, White, and Other. Welch Two-Sample t-tests determined differences between levels of each predictor for caregiver burden, depression, and anxiety outcomes. We used linear regression to estimate associations and 95% confidence intervals between each risk factor and the three outcomes separately. Initial models adjusted only for demographics (age and race). Any established risk factor associated with any outcome of interest was included in final models that adjusted for ASF-specific exposures. To correct for multiple comparisons, we implemented a Benjamini-Hochberg correction in analyses that included multiple hypothesis testing (Benjamini and Hochberg, 1995). A post hoc power analysis was conducted for a sample size of 153 with an alpha level of 0.05. Based on these parameters, the minimum effect size (caregiver burden score) we had 80% power to detect was 0.95. Statistical significance was considered at p < 0.05 except where noted, and analyses were conducted using R Language for Statistical Computing (R Core Team, 2022).

Results

Among 172 FEM-FL participants (Supplementary Table 1), 153 completed all data on caregiver burden, depression, and anxiety (Table 1). The average ± SD age of the FEM-FL analytic cohort was 48.1 ± 13.5 years, and 93 self-identified as white (60.8%). Two participants reported being partnered to a current ASF player. Eighty-one (52.9%) participants reported body mass index (BMI) < 25.0, 82 (53.6%) reported not drinking alcohol, three (1.9%) reported current tobacco smoking, and 119 (77.77%) earned a bachelor's degree or higher. One hundred twenty-two (79.7%) reported marital satisfaction, and 14 (9.2%) reported having poor health. Among the 153 participants who provided data on CTE concerns, 60 (41.7%) endorsed believing their player-partner had CTE.

Table 1

Table 1. Characteristics of the FEM-FL cohort with complete questions on caregiver burden, depression, and anxiety.

Bivariate associations between demographic and family characteristics are shown in Figure 1. Marital satisfaction and race (white vs. Black) were associated with all three outcomes (Figures 1A–C). Income was significantly associated with caregiver burden (Figure 1A) and anxiety (Figure 1C), and poor health was significantly associated with depression (Figure 1B) and anxiety (Figure 1C).

Figure 1

Figure 1. (A) Caregiver burden, (B) depression, and (C) anxiety vs. demographic, health, and ASF-related characteristics. The dotted lines represent (A) a score of 8, which is defined as “severe” caregiver burden, (B) a PHQ-2 score of three in which an individual is considered “depressed,” and (C) a GAD-2 score of three in which an individual is considered to be “anxious.” *p < 0.05, **p < 0.01, ***p < 0.001.

We first investigated demographic (adjusted for age and race) models treating a single established risk factor as an independent variable and found that they were significantly associated with the three outcomes. In these age- and race-adjusted models for each non-football factor we saw significant associations between race, wealth, health, and marital satisfaction only (Supplementary Table 1). We then ran models that predicted each of the three outcomes of interest using all established risk-factors in the same model (Supplementary Table 2). The significant contributors from these models (age, poor health and marital satisfaction; Supplementary Table 2) were then incorporated into models with ASF-specific risk factors (number of relocations, and CTE concerns).

In models adjusted for age, poor health and marital satisfaction, CTE concerns were significantly associated with a 2.90 higher caregiver burden score (95% CI = 1.78, 3.99; p < 0.0001; Figure 2A; Supplementary Table 3), and 0.44 higher anxiety score (95% CI = −0.01, 0.88; p = 0.05; Figure 2C; Supplementary Table 3). CTE concerns were not significantly associated with depression or anxiety (Figure 2B; Supplementary Table 3). Partner lineman status showed no significant association with caregiver burden, depression, or anxiety in adjusted models (Supplementary Table 3); however, number of relocations was significantly associated with slightly increased anxiety (Figure 2C; Supplementary Table 3).

Figure 2

Figure 2. Effect estimates for (A) caregiver burden, (B) participant depression and (C) participant anxiety from models additionally adjusted with age and ASF-specific variables, such as lineman status, number of relocations, and CTE concerns. These analyses have been adjusted for multiple comparisons using Benjamini-Hochberg method. Parameter estimates that were significantly associated with any outcome are shown, with any outcome are shown, with output on all variables available in Supplementary material. *p < 0.05, ***p < 0.001. CTE, chronic traumatic encephalopathy.

Discussion

To our knowledge, FEM-FL is the first study of the spouses of active and former professional ASF players to investigate established and ASF-specific contributors to caregiver burden, depression, and anxiety in partners of ASF players. In fully adjusted models, marital satisfaction, poor health, and CTE concerns were associated with at least one of the outcomes of interest. Although CTE concerns were significantly associated with increased caregiver burden and anxiety, there was no association with depression. Although, among prior ASF players, CTE concern is likely inevitable due to the highly publicized link between ASF participation and subsequent brain disease (Bracken et al., 2023; Convery, 2023; Schwarz, 2007; Shpigel, 2022; Walton et al., 2022). This is the first study to investigate how the partners of these players may be affected by such concerns.

Previous studies have shown that caregiver burden is associated with negative mental and physical health outcomes in those with conditions such as dementia (Fauth et al., 2012; Schneider et al., 2002), stroke (Visser-Meily et al., 2004), cancer (Goldstein et al., 2004), and others (Janson et al., 2022). In a study of traumatic brain injury (TBI) patients, caregivers similarly experienced caregiver overload, depression, and anxiety (Mena-Marcos et al., 2024). Findings from this study suggest that caregiver burden is higher in participants who reported concerns about CTE their partners compared to those who do not. Interestingly, in this study, average total burden scores for participants with CTE concerns (7.5) were greater than averages measured using the ZBI-4 in caregivers of older family members (6.3; Alves et al., 2022), those with Parkinson's Disease (5.5; Hagell et al., 2017), dementia (6.1; Higginson et al., 2010), cancer (6.4; Higginson et al., 2010), and slightly less than acquired brain injury (7.9; Higginson et al., 2010). However, in a study of partners in a military household, the median ZBI-4 score was 10 (Shepherd-Banigan et al., 2020), approximately equivalent to participants with CTE concerns (median ZBI-4 = 9). Average depression scores (0.9) measured with the PHQ-2 were similar to scores reported by caregivers of dementia patients (1.1; Smolcic et al., 2016), and non-caregivers (0.97; Wicke et al., 2022), (1.0; Kroenke et al., 2009), but lower than those reported in caregivers of cancer patients (1.82; Sklenarova et al., 2015). Average anxiety scores measured by the GAD-2 (1.3) were similar to anxiety scores reported by cohorts of general participants (0.83; Wicke et al., 2022), (1.4; Kroenke et al., 2009), and less than reported scores from caregivers of cancer patients (2.15; Sklenarova et al., 2015). Amongst our cohort, depression and anxiety scores on average increased due to participant poor health and low marital satisfaction, reaching similar scores reported by caregivers of cancer patients (Sklenarova et al., 2015). These results may suggest that caregiver burden magnitude remains consistently high in partners of active and former ASF players and may approximate that of caregivers within military families, a population also at risk for repetitive head and orthopedic trauma. In contrast, depression and anxiety scores were on average close to scores reported by non-caregivers, but may be more significantly associated with other lifestyle factors.

After adjusting for ASF-specific characteristics in a model with significant established risk factors, number of relocations was significantly associated with depression and anxiety. CTE concerns among ASF partners were significantly associated with caregiver burden and anxiety, but not depression. Although tau-deposition consistent with CTE is a common autopsy finding among prior professional ASF players, current pre- and post-mortem tau deposition studies have not been definitively linked to proposed clinical attributes, such as depression, anxiety, suicidality, and cognitive dysfunction (Iverson et al., 2023; Mez et al., 2021; Stern et al., 2019). However, ASF players and their partners may experience concerns about CTE due to cognitive symptoms not attributed to other health conditions, and to mainstream media reports that implicate CTE as the underlying cause of neurocognitive dysfunction and psychiatric symptoms among former professional ASF players (Bracken et al., 2023; Convery, 2023; Schwarz, 2007; Shpigel, 2022). In a study of former ASF players, 39.5% of participants reported being “currently extremely concerned” about CTE (Walton et al., 2022), similar to another study which found 34.4% reported believing they have CTE (Grashow et al., 2024). This illustrates that although there is no direct pathophysiological mechanism linking previous football play and/or injuries sustained during football play with CTE, many athletes may perceive this risk. These numbers are approximately similar in that we identified that 41.2% of participants held concerns that their player partner had CTE.

This study has several limitations. First, these data were all self-reported by participants. Second, we cannot determine whether participant CTE concerns are due to the effects of underlying neuropathology, a misattribution of symptoms caused by alternative disease processes, another factor, or some combination. This represents an area of important future work which will only be possible when accurate tools to diagnose CTE in living players have been developed. Third, we do not have data on other conditions or symptoms the partner of the participant has been diagnosed with or is currently experiencing. Data from other studies have shown that those who reported being diagnosed with pre-mortem CTE (Grashow et al., 2020) were more likely to also report conditions associated with cognitive symptoms such as sleep apnea, low testosterone, hypertension, pain, and more. Fourth, we also have no way of determining whether the results described here can be generalized to the entire NFL partner population because there is currently no way to identify and reach all former and active ASF player spouses. We therefore acknowledge the possibility of a biased sample and that our findings may not apply to all partners of former and current ASF players. Finally, since this study only examined partners of former ASF players, results may not be generalizable to the partners of athletes of other professional sports.

In conclusion, one-third of partners of active and former professional ASF players report concerns about CTE. Data from this study established an association between participant CTE concerns and caregiver burden and anxiety. More research is needed to understand the risks associated with CTE concerns not only in former and current ASF players, but also in their partners and families.

These results should motivate future work that investigates the factors associated with concerns about CTE in former and active player's partners, and what interventions may be implemented to reduce caregiver burden and support the physical and mental health of partners and families of professional ASF players.

Data availability statement

The datasets presented in this article are not readily available because participant survey responses used in this study could be used to recognize the identities of participants, and are therefore under the protection of a Certificate of Confidentiality granted from the NIH. Questions regarding the datasets should be directed to cmdyYXNob3dAaHNwaC5oYXJ2YXJkLmVkdQ==.

Ethics statement

The studies involving humans were approved by the Institutional Review Board of the Harvard T.H. Chan School of Public Health. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

Author contributions

NK: Conceptualization, Data curation, Formal analysis, Methodology, Visualization, Writing – original draft, Writing – review & editing. PA: Conceptualization, Funding acquisition, Resources, Writing – original draft, Writing – review & editing. HD: Project administration, Writing – review & editing. ID: Project administration, Writing – review & editing. CB: Project administration, Writing – review & editing. KN: Project administration, Writing – review & editing. JB: Project administration, Writing – review & editing. VT: Project administration, Writing – review & editing. CG: Conceptualization, Investigation, Methodology, Writing – review & editing. LK: Methodology, Writing – review & editing. RT: Writing – review & editing. FS: Methodology, Writing – review & editing. RZ: Conceptualization, Writing – review & editing. HT: Conceptualization, Writing – review & editing. AB: Methodology, Writing – review & editing. MW: Conceptualization, Methodology, Supervision, Writing – review & editing. AW: Conceptualization, Investigation, Methodology, Supervision, Writing – review & editing. RG: Conceptualization, Data curation, Investigation, Methodology, Supervision, Writing – review & editing.

Funding

The author(s) declare that financial support was received for the research and/or publication of this article. This study was supported by Harvard Catalyst/The Harvard Clinical and Translational Science Center and the National Football League Players Association (NFLPA). The NFLPA had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Acknowledgments

We thank the study participants, advisors, and staff of the Football Players Health Study. We would also like to thank Dr. Mary Slavin for her valuable input and advice during the development of this manuscript.

Conflict of interest

AB has received funding from the National Institute of Health/National Heart, Lung, and Blood Institute, the National Football League Players Association (NFLPA), and the American Heart Association and receives compensation for his role as team cardiologist from the US Olympic Committee/US Olympic Training Centers, US Soccer, US Rowing, the New England Patriots, the Boston Bruins, the New England Revolution, and Harvard University. RZ reported receiving royalties from Springer/Demos publishing for serving as coeditor of the text Brain Injury Medicine; serving on the scientific advisory board of Myomo Inc, and onecare.ai Inc; evaluating patients in the Massachusetts General Hospital Brain and Body–TRUST Program, which is funded by the NFLPA; and receiving grants from the NIH. MW reported receiving grants from the NFLPA and the NIH during the conduct of the study. HT receives grant funding from the NFLPA, and serves as an advisor and consultant for Apple, Google, and Microsoft. LK has received private support on a clinical trial project with the company Mediwound. RG, HD, ID, CB, PA, and AW received grant funding from the NFLPA.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declare that no Gen AI was used in the creation of this manuscript.

Publisher's note

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Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpsyg.2025.1581239/full#supplementary-material

References

Alves, S., O'Caoimh, R., Ribeiro, O., Teixeira, L., Molloy, D. W., and Paúl, C. (2022). Screening for caregiver burden in the community: validation of the european portuguese screening version of the zarit burden interview (ZBI-4). Clin. Gerontol. 45, 525–537. doi: 10.1080/07317115.2020.1728807

PubMed Abstract | Crossref Full Text | Google Scholar

Bédard, M., Molloy, D. W., Squire, L., Dubois, S., Lever, J. A., and O'Donnell, M. (2001). The Zarit burden interview: a new short version and screening version. Gerontologist 41, 652–657. doi: 10.1093/geront/41.5.652

PubMed Abstract | Crossref Full Text | Google Scholar

Bekdemir, A., and Ilhan, N. (2019). Predictors of caregiver burden in caregivers of bedridden patients. JNR 27:e24. doi: 10.1097/jnr.0000000000000297

PubMed Abstract | Crossref Full Text | Google Scholar

Benjamini, Y., and Hochberg, Y. (1995). Controlling the false discovery rate: a practical and powerful approach to multiple testing. J. R. Stat. Soc. Ser. B Stat. Methodol. 57, 289–300. doi: 10.1111/j.2517-6161.1995.tb02031.x

Crossref Full Text | Google Scholar

Besser, L. M., and Galvin, J. E. (2019). Perceived burden among caregivers of patients with frontotemporal degeneration in the United States. Int. Psycho. 31, 1191–1201. doi: 10.1017/S104161021800159X

PubMed Abstract | Crossref Full Text | Google Scholar

Bracken, K., Branch, J., Laffin, B., Lieberman, R., and Ward, J. (2023). They started playing football as young as 6. they died in their teens and twenties with C.T.E. The New York Times. Available online at: https://www.nytimes.com/interactive/2023/11/16/us/cte-youth-football.html (accessed June 5, 2024).

Google Scholar

Brickell, T. A., French, L. M., Lippa, S. M., and Lange, R. T. (2018). Burden among caregivers of service members and veterans following traumatic brain injury. Brain Injury 32, 1541–1548. doi: 10.1080/02699052.2018.1503328

PubMed Abstract | Crossref Full Text | Google Scholar

Buuren, S., and Groothuis-Oudshoorn, K. (2011). Mice: multivariate imputation by chained equations in R. J. Stat. Softw. 45, 1–67. doi: 10.18637/jss.v045.i03

Crossref Full Text | Google Scholar

Casson, I. R., Viano, D. C., Powell, J. W., and Pellman, E. J. (2010). Twelve years of national football league concussion data. Sports Health 2:471. doi: 10.1177/1941738110383963

PubMed Abstract | Crossref Full Text | Google Scholar

Chambers, C. C., Lynch, T. S., Gibbs, D. B., Ghodasra, J. H., Sahota, S., Franke, K., et al. (2017). Superior labrum anterior-posterior tears in the national football league. Am. J. Sports Med. 45, 167–172. doi: 10.1177/0363546516673350

PubMed Abstract | Crossref Full Text | Google Scholar

Chiari, A., Pistoresi, B., Galli, C., Tondelli, M., Vinceti, G., Molinari, M. A., et al. (2021). Determinants of caregiver burden in early-onset dementia. Dement. Geriatr. Cogn. Dis. Extra.11, 189–197. doi: 10.1159/000516585

PubMed Abstract | Crossref Full Text | Google Scholar

Chou, K.-R. (2000). Caregiver burden: a concept analysis. J. Pediatr. Nurs. 15, 398–407. doi: 10.1053/jpdn.2000.16709

PubMed Abstract | Crossref Full Text | Google Scholar

Convery, S. (2023). NRL and Football Australia accept link between head trauma and CTE. The Guardian. Available onlie at: https://www.theguardian.com/sport/2023/mar/01/nrl-and-football-australia-accept-link-between-head-trauma-and-cte (accessed June 5, 2024).

Google Scholar

Croog, S. H., Burleson, J. A., Sudilovsky, A., and Baume, R. M. (2006). Spouse caregivers of alzheimer patients: problem responses to caregiver burden. Aging Ment. Health 10, 87–100. doi: 10.1080/13607860500492498

PubMed Abstract | Crossref Full Text | Google Scholar

Daneshvar, D. H., Nair, E. S., Baucom, Z. H., Rasch, A., Abdolmohammadi, B., Uretsky, M., et al. (2023). Leveraging football accelerometer data to quantify associations between repetitive head impacts and chronic traumatic encephalopathy in males. Nat. Commun. 14:3470. doi: 10.1038/s41467-023-39183-0

PubMed Abstract | Crossref Full Text | Google Scholar

Delgadillo, J., Payne, S., Gilbody, S., Godfrey, C., Gore, S., Jessop, D., et al. (2012). Brief case finding tools for anxiety disorders: validation of GAD-7 and GAD-2 in addictions treatment. Drug Alcohol Depend. 125, 37–42. doi: 10.1016/j.drugalcdep.2012.03.011

PubMed Abstract | Crossref Full Text | Google Scholar

Dodson, C. C., Secrist, E. S., Bhat, S. B., Woods, D. P., and Deluca, P. F. (2016). Anterior cruciate ligament injuries in national football league athletes from 2010 to 2013. Ortho. J. Sports Med. 4:2325967116631949. doi: 10.1177/2325967116631949

PubMed Abstract | Crossref Full Text | Google Scholar

Fauth, E., Hess, K., Piercy, K., Norton, M., Corcoran, C., Rabins, P., et al. (2012). Caregivers' relationship closeness with the person with dementia predicts both positive and negative outcomes for caregivers' physical health and psychological well-being. Aging Ment. Health 16, 699–711. doi: 10.1080/13607863.2012.678482

PubMed Abstract | Crossref Full Text | Google Scholar

Goldstein, N. E., Concato, J., Fried, T. R., Kasl, S. V., Johnson-Hurzeler, R., and Bradley, E. H. (2004). Factors associated with caregiver burden among caregivers of terminally ill patients with cancer. J. Palliat. Care, 20, 38–43. doi: 10.1177/082585970402000108

Crossref Full Text | Google Scholar

Grashow, R., Shaffer-Pancyzk, T. V., Dairi, I., Lee, H., Marengi, D., Baker, J., et al. (2023a). Healthspan and chronic disease burden among young adult and middle-aged male former American-style professional football players. Br. J. Sports Med. 57, 166–171. doi: 10.1136/bjsports-2022-106021

PubMed Abstract | Crossref Full Text | Google Scholar

Grashow, R., Tan, C. O., Izzy, S., Taylor, H. A., Weisskopf, M. G., Wasfy, M. M., et al. (2023b). Association between concussion burden during professional american-style football and postcareer hypertension. Circulation 147, 1112–1114. doi: 10.1161/CIRCULATIONAHA.122.063767

PubMed Abstract | Crossref Full Text | Google Scholar

Grashow, R., Terry, D. P., Iverson, G. L., DiGregorio, H., Dairi, I., Brown, C., et al. (2024). perceived chronic traumatic encephalopathy and suicidality in former professional football players. JAMA Neurol. 81, 1130–1139. doi: 10.1001/jamaneurol.2024.3083

PubMed Abstract | Crossref Full Text | Google Scholar

Grashow, R., Weisskopf, M. G., Baggish, A., Speizer, F. E., Whittington, A. J., Nadler, L., et al. (2020). Premortem chronic traumatic encephalopathy diagnoses in professional football. Ann. Neurol. 88, 106–112. doi: 10.1002/ana.25747

PubMed Abstract | Crossref Full Text | Google Scholar

Hagell, P., Alvariza, A., Westergren, A., and Årestedt, K. (2017). Assessment of Burden Among family caregivers of people with parkinson's disease using the zarit burden interview. J. Pain Symptom Manag. 53, 272–278. doi: 10.1016/j.jpainsymman.2016.09.007

PubMed Abstract | Crossref Full Text | Google Scholar

Haines, K., Lumpkin, S. T., Grisel, B., Kaur, K., Cantrell, S., Freeman, J., et al. (2024). Systematic literature review of health-related quality-of-life measures for caregivers of older adult trauma patients. J. Surgical Res. 297, 47–55. doi: 10.1016/j.jss.2024.01.011

PubMed Abstract | Crossref Full Text | Google Scholar

Higginson, I. J., Gao, W., Jackson, D., Murray, J., and Harding, R. (2010). Short-form Zarit caregiver burden interviews were valid in advanced conditions. J. Clin. Epidemiol. 63, 535–542. doi: 10.1016/j.jclinepi.2009.06.014

PubMed Abstract | Crossref Full Text | Google Scholar

Iverson, G. L., Kissinger-Knox, A., Huebschmann, N. A., Castellani, R. J., and Gardner, A. J. (2023). A narrative review of psychiatric features of traumatic encephalopathy syndrome as conceptualized in the 20th century. Front. Neurol. 14:1214814. doi: 10.3389/fneur.2023.1214814

PubMed Abstract | Crossref Full Text | Google Scholar

Janson, P., Willeke, K., Zaibert, L., Budnick, A., Berghöfer, A., Kittel-Schneider, S., et al. (2022). Mortality, morbidity and health-related outcomes in informal caregivers compared to non-caregivers: a systematic review. Int. J. Environ. Res. Public Health 10. doi: 10.1055/s-0042-1753689

PubMed Abstract | Crossref Full Text | Google Scholar

Katz, D. I., Bernick, C., Dodick, D. W., Mez, J., Mariani, M. L., Adler, C. H., et al. (2021). National institute of neurological disorders and stroke consensus diagnostic criteria for traumatic encephalopathy syndrome. Neurology 96, 848–863. doi: 10.1212/WNL.0000000000011850

PubMed Abstract | Crossref Full Text | Google Scholar

Kroenke, K., Spitzer, R. L., Williams, J. B. W., and Löwe, B. (2009). An ultra-brief screening scale for anxiety and depression: the PHQ−4. Psychosomatics 50, 613–621. doi: 10.1016/S0033-3182(09)70864-3

Crossref Full Text | Google Scholar

Laratta, S., Lucca, L. F., Tonin, P., and Cerasa, A. (2020). Factors influencing burden in spouse-caregivers of patients with chronic-acquired brain injury. BioMed Res. Int. 2020:e6240298. doi: 10.1155/2020/6240298

PubMed Abstract | Crossref Full Text | Google Scholar

Lenihan, M. W., and Jordan, B. D. (2015). The clinical presentation of chronic traumatic encephalopathy. Curr. Neurol. Neurosci. Rep. 15:23. doi: 10.1007/s11910-015-0541-5

PubMed Abstract | Crossref Full Text | Google Scholar

Liu, S., Li, C., Shi, Z., Wang, X., Zhou, Y., Liu, S., et al. (2017). Caregiver burden and prevalence of depression, anxiety and sleep disturbances in Alzheimer's disease caregivers in China. J. Clin. Nursing 26, 1291–1300. doi: 10.1111/jocn.13601

PubMed Abstract | Crossref Full Text | Google Scholar

Liu, Z., Heffernan, C., and Tan, J. (2020). Caregiver burden: a concept analysis. Int. J. Nursing Sci. 7, 438–445. doi: 10.1016/j.ijnss.2020.07.012

PubMed Abstract | Crossref Full Text | Google Scholar

Longo, U. G., Matarese, M., Arcangeli, V., Alciati, V., Candela, V., Facchinetti, G., et al. (2020). Family caregiver strain and challenges when caring for orthopedic patients: a systematic review. J. Clin. Med. 9:1497 doi: 10.3390/jcm9051497

PubMed Abstract | Crossref Full Text | Google Scholar

Löwe, B., Kroenke, K., and Gräfe, K. (2005). Detecting and monitoring depression with a two-item questionnaire (PHQ-2). J. Psycho. Res. 58, 163–171. doi: 10.1016/j.jpsychores.2004.09.006

PubMed Abstract | Crossref Full Text | Google Scholar

Marquez-Velarde, G., Grashow, R., Glass, C., Blaschke, A. M., Gillette, G., Taylor, H. A., et al. (2023). The paradox of integration: racial composition of NFL positions from 1960 to 2020. Sociol. Race Ethnic. 9, 451–469. doi: 10.1177/23326492231182597

Crossref Full Text | Google Scholar

McKee, A. C., Stein, T. D., Huber, B. R., Crary, J. F., Bieniek, K., Dickson, D., et al. (2023). Chronic traumatic encephalopathy (CTE): criteria for neuropathological diagnosis and relationship to repetitive head impacts. Acta Neuropathol. 145, 371–394. doi: 10.1007/s00401-023-02540-w

PubMed Abstract | Crossref Full Text | Google Scholar

Mena-Marcos, R., Sánchez-Romero, E. A., Navarro-Main, B., Lagares-Gómez-Abascal, A., Jiménez-Ortega, L., and Cuenca-Zaldívar, J. N. (2024). Assessment of the sentiments expressed by traumatic brain injury patients and caregivers: a qualitative study based on in-depth interviews. Heliyon 10:e39688. doi: 10.1016/j.heliyon.2024.e39688

PubMed Abstract | Crossref Full Text | Google Scholar

Mez, J., Alosco, M. L., Daneshvar, D. H., Saltiel, N., Baucom, Z., Abdolmohammadi, B., et al. (2021). Validity of the 2014 traumatic encephalopathy syndrome criteria for CTE pathology. Alzheimer's Demen. J. Alzheimer's Assoc. 17, 1709–1724. doi: 10.1002/alz.12338

PubMed Abstract | Crossref Full Text | Google Scholar

Mez, J., Daneshvar, D. H., Kiernan, P. T., Abdolmohammadi, B., Alvarez, V. E., Huber, B. R., et al. (2017). Clinicopathological evaluation of chronic traumatic encephalopathy in players of American football. JAMA 318, 360–370. doi: 10.1001/jama.2017.8334

PubMed Abstract | Crossref Full Text | Google Scholar

Pellman, E. J., Powell, J. W., Viano, D. C., Casson, I. R., Tucker, A. M., Feuer, H., et al. (2004). Concussion in professional football: epidemiological features of game injuries and review of the literature—part 3. Neurosurgery 54:81. doi: 10.1227/01.NEU.0000097267.54786.54

PubMed Abstract | Crossref Full Text | Google Scholar

R Core Team (2022). R: A Language and Environment for Statistical Computing [Computer software]. R Foundation for Statistical Computing. Available online at: https://www.R-project.org/ (accessed April 5, 2025).

Google Scholar

Randolph, C. (2018). Chronic traumatic encephalopathy is not a real disease. Arch. Clin. Neuropsychol. 33, 644–648. doi: 10.1093/arclin/acy063

Crossref Full Text | Google Scholar

Roberts, A. L., Pascual-Leone, A., Speizer, F. E., Zafonte, R. D., Baggish, A. L., Taylor, H., et al. (2019). Exposure to american football and neuropsychiatric health in former national football league players: findings from the football players health study. Am. J. Sports Med. 47, 2871–2880. doi: 10.1177/0363546519868989

PubMed Abstract | Crossref Full Text | Google Scholar

Schneider, J., Hallam, A., Murray, J., Foley, B., Atkin, L., Banerjee, S., et al. (2002). Formal and informal care for people with dementia: factors associated with service receipt. Aging Ment. Health 6, 255–265. doi: 10.1080/13607860220142486

PubMed Abstract | Crossref Full Text | Google Scholar

Schwarz, A. (2007). Expert Ties Ex-Player's Suicide to Brain Damage. The New York Times. Available online at: https://www.nytimes.com/2007/01/18/sports/football/18waters.html (accessed June 5, 2024).

Google Scholar

Shepherd-Banigan, M., Jones, K. A., Wang, K., DePasquale, N., Van Houtven, C., and Olsen, J. M. (2020). Mechanisms through which a family caregiver coaching intervention might reduce anxiety among children in military households. Matern. Child Health J. 24, 1248–1258. doi: 10.1007/s10995-020-02964-w

PubMed Abstract | Crossref Full Text | Google Scholar

Shpigel, B. (2022). What is C.T.E.? - The New York Times. Available online at: https://www.nytimes.com/article/cte-definition-nfl.html (accessed June 5, 2024).

Google Scholar

Sklenarova, H., Krümpelmann, A., Haun, M. W., Friederich, H.-C., Huber, J., Thomas, M., et al. (2015). When do we need to care about the caregiver? Supportive care needs, anxiety, and depression among informal caregivers of patients with cancer and cancer survivors. Cancer 121, 1513–1519. doi: 10.1002/cncr.29223

PubMed Abstract | Crossref Full Text | Google Scholar

Smolcic, E., Mavandadi, S., Streim, J. E., and Oslin, D. W. (2016). The association between caregiver-care recipient relationship and caregiver burden and depressive symptoms among community-dwelling older adults with dementia. Am. J. Geriatr. Psychiatry 24(3), S104–S105. doi: 10.1016/j.jagp.2016.01.105

Crossref Full Text | Google Scholar

Staples, L. G., Dear, B. F., Gandy, M., Fogliati, V., Fogliati, R., Karin, E., et al. (2019). Psychometric properties and clinical utility of brief measures of depression, anxiety, and general distress: the PHQ-2, GAD-2, and K-6. Gen. Hosp. Psychiatry, 56, 13–18. doi: 10.1016/j.genhosppsych.2018.11.003

PubMed Abstract | Crossref Full Text | Google Scholar

Stern, R. A., Adler, C. H., Chen, K., Navitsky, M., Luo, J., Dodick, D. W., et al. (2019). Tau positron-emission tomography in former national football league players. N. Engl. J. Med. 380, 1716–1725. doi: 10.1056/NEJMoa1900757

PubMed Abstract | Crossref Full Text | Google Scholar

Swartz, K., and Collins, L. G. (2019). Caregiver Care. Am. Fam. Physician 99, 699–706.

Google Scholar

Taghdiri, F., Khodadadi, M., Sadia, N., Mushtaque, A., Scott, O. F. T., Hirsch-Reinhagen, V., et al. (2024). Unusual combinations of neurodegenerative pathologies with chronic traumatic encephalopathy (CTE) complicates clinical prediction of CTE. Euro. J. Neurol. 31:e16259. doi: 10.1111/ene.16259

PubMed Abstract | Crossref Full Text | Google Scholar

Tough, H., Brinkhof, M. W., Siegrist, J., and Fekete, C. (2017). Subjective caregiver burden and caregiver satisfaction: the role of partner relationship quality and reciprocity. Arch. Phys. Med. Rehabil. 98, 2042–2051. doi: 10.1016/j.apmr.2017.02.009

PubMed Abstract | Crossref Full Text | Google Scholar

Tsai, C.-F., Hwang, W.-S., Lee, J.-J., Wang, W.-F., Huang, L.-C., Huang, L.-K., et al. (2021). Predictors of caregiver burden in aged caregivers of demented older patients. BMC Geriatr. 21:59. doi: 10.1186/s12877-021-02007-1

PubMed Abstract | Crossref Full Text | Google Scholar

Unsar, S., Erol, O., and Ozdemir, O. (2021). Caregiving burden, depression, and anxiety in family caregivers of patients with cancer. Euro. J. Oncol. Nurs. 50:101882. doi: 10.1016/j.ejon.2020.101882

PubMed Abstract | Crossref Full Text | Google Scholar

Visser-Meily, J. M. A., Post, M. W. M., Riphagen, I. I., and Lindeman, E. (2004). Measures used to assess burden among caregivers of stroke patients: a review. Clin. Rehabil. 18, 601–623. doi: 10.1191/0269215504cr776oa

PubMed Abstract | Crossref Full Text | Google Scholar

Viswanathan, M., Ammerman, A., Eng, E., Garlehner, G., Lohr, K. N., Griffith, D., et al. (2004). Community-Based Participatory Research: Assessing the Evidence: Summary. In AHRQ Evidence Report Summaries. Agency for Healthcare Research and Quality (US). Available online at: https://www.ncbi.nlm.nih.gov/sites/books/NBK11852/ (accessed August 3, 2024).

Google Scholar

Walton, S. R., Kerr, Z. Y., Mannix, R., Brett, B. L., Chandran, A., DeFreese, J. D., et al. (2022). Subjective concerns regarding the effects of sport-related concussion on long-term brain health among former NFL players: an NFL-LONG Study. Sports Med. 52, 1189–1203. doi: 10.1007/s40279-021-01589-5

PubMed Abstract | Crossref Full Text | Google Scholar

Wicke, F. S., Krakau, L., Löwe, B., Beutel, M. E., and Brähler, E. (2022). Update of the standardization of the patient health questionnaire-4 (PHQ-4) in the general population. J. Affect. Disord. 312, 310–314. doi: 10.1016/j.jad.2022.06.054

PubMed Abstract | Crossref Full Text | Google Scholar

Zafonte, R., Pascual-Leone, A., Baggish, A., Weisskopf, M. G., Taylor, H. A., Connor, A., et al. (2019). The football players' health study at harvard university: design and objectives. Am. J. Ind. Med. 62, 643–654. doi: 10.1002/ajim.22991

PubMed Abstract | Crossref Full Text | Google Scholar

Zarit, S. H., Reever, K. E., and Bach-Peterson, J. (1980). Relatives of the impaired elderly: correlates of feelings of burden1. Gerontologist 20, 649–655. doi: 10.1093/geront/20.6.649

PubMed Abstract | Crossref Full Text | Google Scholar

Zhu, W., and Jiang, Y. (2018). A meta-analytic study of predictors for informal caregiver burden in patients with stroke. J. Stroke Cerebrovasc. Dis. 27, 3636–3646. doi: 10.1016/j.jstrokecerebrovasdis.2018.08.037

PubMed Abstract | Crossref Full Text | Google Scholar

Ziran, B. H., Barrette-Grischow, M.-K., and Hull, T. (2009). Hidden burdens of orthopedic injury care: the lost providers. J. Trauma 66, 536–549. doi: 10.1097/TA.0b013e31817db0bf

PubMed Abstract | Crossref Full Text | Google Scholar