academic years.Main Outcome Measure(s): Sport-related concussion counts, percentages, rates per 10 000 athlete-exposures (AEs), rate ratios (RRs), and injury proportion ratios (IPRs) were reported with 95% confidence intervals (CIs). Rate ratios and IPRs with 95% CIs not containing 1.0 were considered significant.Results: Overall, 2004 SRCs were reported among 27 high school sports, for a rate of 3.89 per 10 000 AEs. Football had the highest SRC rate (9.21/10 000 AEs), followed by boys' lacrosse (6.65/10 000 AEs) and girls' soccer (6.11/10 000 AEs). The SRC rate was higher in competition than in practice (RR ¼ 3.30; 95% CI ¼ 3.02, 3.60). Among sex-comparable sports, the SRC rate was higher in girls than in boys (RR ¼ 1.56; 95% CI ¼ 1.34, 1.81); however, the proportion of SRCs due to player-to-player contact was higher in boys than in girls (IPR ¼ 1.48; 95% CI ¼ 1.27, 1.73). Common symptoms reported among all athletes with SRCs were headache (94.7%), dizziness (74.8%), and difficulty concentrating (61.0%). Only 0.8% of players with SRCs returned to play within 24 hours. The majority of athletes with SRCs (65.8%) returned to play between 7 and 28 days. More players had symptoms resolve after 7 days (48.8%) than less than a week (40.7%).Conclusions: Our findings provide updated high school SRC incidence estimates and further evidence of sex differences in reported SRCs. Few athletes with SRCs returned to play within 24 hours or a week. Most injured players returned after 7 days, despite a smaller proportion having symptoms resolve within a week.Key Words: injury surveillance, traumatic brain injuries, return to play Key PointsPer 10 000 athlete-exposures, the rates of sport-related concussion were highest in football (9.21), boys' lacrosse (6.65), and girls' soccer (6.11). Among sex-comparable sports, the rate of sport-related concussion was 56% higher in girls than in boys. Most athletes with sport-related concussions returned to play after 7 days, despite resolution of symptoms in a smaller proportion within 1 week.

Background The Mental Health Continuum–Short Form (MHC-SF) is a measure of positive mental health and flourishing, which is widely used in several countries but has not yet been validated in Denmark. This study aimed to examine its qualitative and quantitative properties in a Danish population sample and compare scores with Canada and the Netherlands. Methods Three thousand five hundred eight participants aged 16–95 filled out an electronic survey. Both the unidimensional and multidimensional aspects of the Danish MHC-SF were studied through bifactor modelling. Cognitive interviews examined face validity and usability. Results The general score of the Danish MHC-SF was reliable for computing unit-weighted composite scores, as well as using a bifactor model to compute general factor scores or measurement models in an SEM context. Nonetheless, subscale scores were unreliable, explaining very low variance beyond that explained by the general factor. The participants of the qualitative interviews observed problems with wording and content of the items, especially from the social subscale. The general score correlated with other scales as expected. We found substantial variation in flourishing prevalence rates between the three cultural settings. Conclusions The Danish MHC-SF produced reliable general scores of well-being. Most of the issues observed regarding the subscale scores have been shown in previous research in other contexts. The further analysis of indices of the bifactor model and the inclusion of qualitative interviews allowed for a better understanding of the possible sources of problems with the questionnaire’s subscales. The use of subscales, the substantive understanding of the general score, as well as the operationalization of the state of flourishing, require further study.

This study presents nationally representative estimates of self-reported changes in alcohol and cannabis consumption since the onset of COVID-19 in Canada. We used data from the Survey on COVID-19 and Mental Health (collected from September to December 2020) to calculate the prevalence of self-reported change in alcohol and cannabis consumption. We found that 15.7% of respondents self-reported an increase in alcohol consumption and 5.4% in cannabis consumption since the start of the pandemic. Sociodemographic disparities were also observed, indicating that increased alcohol and cannabis consumption may be more prevalent among certain populations.

The 2019 edition of the Canadian Chronic Disease Indicators (CCDI) provides recent estimates of the burden of chronic conditions and measures of general health and associated determinants in Canada. Using data from the CCDI and 2017 Canadian Community Health Survey, we explored the relationship between sociodemographic factors and selfreported mental health. Our findings suggest that sex (males vs females: adjusted odds ratio [aOR] = 1.22); age (65–79 vs 35–49 year age group: aOR = 1.48); education (postsecondary graduate vs less than high school: aOR = 1.68); household income adequacy (highest quintile [Q5] vs lowest [Q1]: aOR = 2.25); and immigrant status (recent immigrants vs nonimmigrants: aOR= 2.29) were significantly associated with higher self-reported mental health.

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