Background:High-intensity functional training (HIFT) is a new training modality that merges high-intensity exercise with functional (multijoint) movements. Even though others exist, CrossFit training has emerged as the most common form of HIFT. Recently, several reports have linked CrossFit training to severe injuries and/or life-threatening conditions, such as rhabdomyolysis. Empirical evidence regarding the safety of this training modality is currently limited.Purpose:To examine the incidence of injuries related to CrossFit participation and to estimate the rate of injuries in a large cross-sectional convenience sample of CrossFit participants from around the world.Study Design:Descriptive epidemiology study.Methods:A total of 3049 participants who reported engaging in CrossFit training between 2013 and 2017 were surveyed.Results:A portion (30.5%) of the participants surveyed reported experiencing an injury over the previous 12 months because of their participation in CrossFit training. Injuries to the shoulders (39%), back (36%), knees (15%), elbows (12%), and wrists (11%) were most common for both male and female participants. The greatest number of injuries occurred among those who participated in CrossFit training 3 to 5 days per week (χ2 = 12.51; P = .0019). Overall, and based on the assumed maximum number of workout hours per week, the injury rate was 0.27 per 1000 hours (females: 0.28; males: 0.26), whereas the assumed minimum number of workout hours per week resulted in an injury rate of 0.74 per 1000 hours (females: 0.78; males: 0.70).Conclusion:Our findings suggest that CrossFit training is relatively safe compared with more traditional training modalities. However, it seems that those within their first year of training as well as those who engage in this training modality less than 3 days per week and/or participate in less than 3 workouts per week are at a greater risk for injuries.

Diagnosis of pertussis remains a challenge, and consequently research on the risk of disease might be biased because of misclassification. We quantified this misclassification and corrected for it in a case-control study of children in Philadelphia, Pennsylvania, who were 3 months to 6 years of age and diagnosed with pertussis between 2011 and 2013. Vaccine effectiveness (VE; calculated as (1 - odds ratio) × 100) was used to describe the average reduction in reported pertussis incidence resulting from persons being up to date on pertussis-antigen containing vaccines. Bayesian techniques were used to correct for purported nondifferential misclassification by reclassifying the cases per the 2014 Council of State and Territorial Epidemiologists pertussis case definition. Naïve VE was 50% (95% confidence interval: 16%, 69%). After correcting for misclassification, VE ranged from 57% (95% credible interval: 30, 73) to 82% (95% credible interval: 43, 95), depending on the amount of underreporting of pertussis that was assumed to have occurred in the study period. Meaningful misclassification was observed in terms of false negatives detected after the incorporation of infant apnea to the 2014 case definition. Although specificity was nearly perfect, sensitivity of the case definition varied from 90% to 20%, depending on the assumption about missed cases. Knowing the degree of the underreporting is essential to the accurate evaluation of VE.

Air pollution from motor vehicle traffic remains a significant threat to public health. Using taxi inspection and trip data, we assessed changes in New York City’s taxi fleet following Clean Air Taxi legislation enacted in 2005–2006. Inspection and trip data between 2004–2015 were used to assess changes in New York’s taxi fleet and to estimate and spatially apportion annual taxi-related exhaust emissions of nitric oxide (NO) and total particulate matter (PM T ). These emissions changes were used to predict reductions in NO and fine particulate matter (PM 2.5 ) concentrations estimates using data from the New York City Community Air Survey (NYCCAS) in 2009–2015. Efficiency trends among other for-hire vehicles and spatial variation in traffic intensity were also considered. The city fuel efficiency of the medallion taxi fleet increased from 15.7 MPG to 33.1 MPG, and corresponding NO and PM T exhaust emissions estimates declined by 82% and 49%, respectively. These emissions reductions were associated with changes in NYCCAS-modeled NO and PM 2.5 concentrations (p<0.001). New York’s clean air taxi legislation was effective at increasing fuel efficiency of the medallion taxi fleet, and reductions in estimated taxi emissions were associated with decreases in NO and PM 2.5 concentrations.

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Extrinsic factors partially explained risk for neonatal colonization and infection. For P. aeruginosa, infection prevention efforts at locations with space for more equipment may lower future colonization.