Immediate physiological effects of acute electronic cigarette use in humans: A systematic review and meta-analysis.

BACKGROUND: Electronic cigarettes (e-cigs) are widely used devices that were initially created to aid in smoking cessation. However, their acute physiological effects are unclear and there have been a number of E-cig and Vaping Acute Lung Injury (EVALI) events reported. RESEARCH QUESTION: What are the immediate physiological effects (i.e. cardiovascular, respiratory or blood-based responses) of acute e-cig usage in humans? STUDY DESIGN AND METHODS: PubMed, Web of Science, Cochrane and Scopus databases were searched for English or French peer-reviewed articles published until May 20, 2021 and measuring at least one physiological parameter before and after using an e-cig. The study followed PRISMA guidelines and assessed article quality using the Downs and Black checklist. Independent extraction was conducted by two reviewers. Data were pooled using random-effect models. Sensitivity analysis and meta-regressions were performed to explore heterogeneity. MAIN OUTCOMES: Systolic and diastolic blood pressure, heart rate, augmentation index (AIx75), fraction of exhaled nitric oxide (FeNO), and spirometry were the most frequently assessed parameters and were therefore chosen for meta-analyses. RESULTS: Of 19823 articles screened, 45 articles were included for the qualitative synthesis, and 27 articles (919 patients) were included in meta-analyses. Acute use of nicotine e-cig was associated with increased heart rate(SMD = 0.71; 95%CI 0.46-0.95), systolic blood pressure (SMD = 0.38; 95%CI 0.18-0.57), diastolic blood pressure (SMD = 0.52; 95%CI 0.33-0.70), and augmentation index AIx75 (SMD = 0.580; 95%CI 0.220-0.941), along with decreased FeNO (SMD = -0.26; 95%CI -0.49 to -0.04). E-cig exposure wasn't associated with significant changes in any spirometry measure. INTERPRETATION: Acute use of nicotine e-cigs was associated with statistically significant cardiovascular and respiratory responses. These devices have a physiological impact that could be clinically relevant, especially in terms of cardiovascular morbidity. However, the direct consequences of long-term e-cig use needs to be further explored.

Physical Maturity and Concussion Symptom Duration among Adolescent Ice Hockey Players.

OBJECTIVE: To investigate the association between physical maturity and risk of prolonged concussion symptoms in adolescent ice hockey players. STUDY DESIGN: Prospective cohort study of 145 patients ages 13-18 years with concussion referred to 3 hospital-affiliated sports medicine clinics between September 1, 2012 and March 31, 2015. Concussion evaluations included Post Concussive Symptom Score, neurologic examination, and postinjury computerized neurocognitive testing. Pubertal development at initial visit was assessed by the Pubertal Developmental Scale. Duration of concussion symptoms (days) was the main outcome. Statistical comparisons were conducted using Student t test, Wilcoxon rank sum, and logistic regression. RESULTS: Mean symptom duration was 44.5 ± 48.7 days. Nearly one-half (48.3%) of all players enrolled had prolonged concussion symptoms (≥ 28 days); most (86.9%) had symptom resolution by 90 days. Among males, less physically mature adolescents took longer to recover than more physically mature players (54.5 days vs 33.4 days; P = .004). "Early" Pubertal Category Score was the strongest predictor of prolonged symptoms (OR = 4.29, 95% CI 1.24-14.85; P = .021) among males. Among females, heavier weight increased the odds of experiencing prolonged symptoms (OR 1.07, 95% CI 1.00-1.14; P = .039). CONCLUSIONS: Among adolescent ice hockey players, early-pubertal stage is independently associated with longer recovery from concussion in males, and heavier weight is associated with longer concussion recovery in females. Until further studies determine valid physical maturity indicators, peripubertal collision sport athletes should compete in leagues grouped by relative age and be discouraged from "playing up" on varsity teams.