Childhood asthma and household exposures to nitrogen dioxide and fine particles: a triple-crossover randomized intervention trial.

OBJECTIVE: Triple-crossover randomized controlled intervention trial to test whether reduced exposure to household NO2 or fine particles results in reduced symptoms among children with persistent asthma. METHODS: Children (n = 126) aged 5-11 years with persistent asthma living in homes with gas stoves and levels of NO2 15 ppb or greater recruited in Connecticut and Massachusetts (2015-2019) participated in an intervention involving three air cleaners configured for: (1) NO2 reduction: sham particle filtration and real NO2 scrubbing; (2) particle filtration: HEPA filter and sham NO2 scrubbing; (3) control: sham particle filtration and sham NO2 scrubbing. Air cleaners were randomly assigned for 5-week treatment periods using a three-arm crossover design. Outcome was number of asthma symptom-days during final 14 days of treatment. Treatment effects were assessed using repeated measures, linear mixed models. RESULTS: Measured NO2 was lower (by 4 ppb, p < .0001) for NO2-reducing compared to control or particle-reducing treatments. NO2-reducing treatment did not reduce asthma morbidity compared to control. In analysis controlling for measured NO2, there were 1.8 (95% CI -0.3 to 3.9, p = .10) fewer symptom days out of 14 in the particle-reducing treatment compared to control. CONCLUSIONS: It remains unknown if using an air cleaner alone can achieve levels of NO2 reduction large enough to observe reductions in asthma symptoms. We observed that in small, urban homes with gas stoves, modest reductions in asthma symptoms occurred using air cleaners that remove fine particles. An intervention targeting exposures to both NO2 and fine particles is complicated and further research is warranted. REGISTRATION NUMBER: NCT02258893.

Interpretation of 2002 Centers for Disease Control guidelines for group B streptococcus and evolving provider practice patterns.

We investigated if clinicians were altering their care of group B streptococcus (GBS)-positive women in labor to achieve 4 hours of intrapartum antibiotic prophylaxis based on their interpretation of the 2002 Centers for Disease Control (CDC) guidelines on prevention of perinatal GBS disease. We surveyed all clinicians with privileges on the labor floor at our institution about their interpretation and clinical application of the 2002 CDC guidelines. Seventy of 96 eligible clinicians (72.9%) completed our survey. In our survey, only 22.9% of clinicians reported not altering their management of labor in GBS-positive pregnancies that achieved less than 4 hours of prophylaxis. These alterations included "laboring down" or delaying pushing; turning off or decrease an oxytocin infusion; or delaying or avoiding artificial rupture of membranes. Clinicians are altering their management of labor to attempt to achieve 4 hours of intrapartum prophylaxis. The 2002 CDC guidelines do not specifically recommend prolonging labor and are being interpreted differently in the clinical setting than the authors may have intended. The effects and consequences of this interpretation are unknown.

Inferior Vena Cava Filters to Prevent Pulmonary Embolism: Systematic Review and Meta-Analysis.

BACKGROUND: Inferior vena cava (IVC) filters are widely used for prevention of pulmonary embolism (PE). However, uncertainty persists about their efficacy and safety. OBJECTIVES: The authors conducted a systematic review and meta-analysis of the published reports on the efficacy and safety of IVC filters. METHODS: The authors searched PubMed, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov through October 3, 2016, for randomized controlled trials (RCTs) or prospective controlled observational studies of IVC filters versus none in patients at risk of PE. Inverse variance fixed-effects models with odds ratio (OR) as the effect measure were used for primary analyses. Main outcomes included subsequent PE, PE-related mortality, all-cause mortality, and subsequent deep vein thrombosis (DVT). RESULTS: The authors' search retrieved 1,986 studies, of which 11 met criteria for inclusion (6 RCTs and 5 prospective observational studies). Quality of evidence for RCTs was low to moderate. Overall, patients receiving IVC filters had lower risk for subsequent PE (OR: 0.50; 95% confidence interval [CI]: 0.33 to 0.75); increased risk for DVT (OR: 1.70; 95% CI: 1.17 to 2.48); nonsignificantly lower PE-related mortality (OR: 0.51; 95% CI: 0.25 to 1.05); and no change in all-cause mortality (OR: 0.91; 95% CI: 0.70 to 1.19). Limiting the results to RCTs showed similar results. Findings were substantively similar across a wide range of sensitivity analyses. CONCLUSIONS: Very few prospective controlled studies, with limited quality of evidence, exist regarding the efficacy and safety of IVC filters. Overall, filters appear to reduce the risk of subsequent PE, increase the risk for DVT, and have no significant effect on overall mortality.

Duration of intrapartum prophylaxis for neonatal group B streptococcal disease: a systematic review.

OBJECTIVE: To examine published evidence regarding duration of intrapartum antibiotic prophylaxis administered to pregnant women colonized with group B Streptococcus (GBS) to reduce infant colonization with GBS and to prevent early-onset GBS sepsis. DATA SOURCES: A search was conducted in The Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2006), MEDLINE (1966 to January 2006), EMBASE (1980 to January 2006), CINAHL (1982 to January 2006), and in protocols and guidelines of the Centers for Disease Control and Prevention, American Academy of Pediatrics, and American College of Obstetrics and Gynecology. METHODS OF STUDY SELECTION: All randomized controlled trials and observational studies in which duration of intrapartum antibiotic prophylaxis is reported relative to subsequent neonatal GBS colonization or sepsis were considered. Case series and study designs using historical cohorts or controls for comparison were excluded. TABULATION, INTEGRATION, AND RESULTS: Three prospective cohort studies and one case-control study met inclusion criteria. Heterogeneity of study design and assembly of cohorts precluded meta-analysis. A systematic review of the individual studies was performed. All studies were rated as fair or poor validity with regard to their ability to evaluate duration of intrapartum prophylaxis and transmission of GBS to the newborn. All 4 studies were largely composed of women with existing risk factors for GBS disease of the newborn. One study supported more than 1 hour of prophylaxis, two studies supported more than 2 hours of prophylaxis, and one was inconclusive. CONCLUSION: Despite unequivocal clinical guidelines recommending at least 4 hours of intrapartum antibiotic prophylaxis, there are no well-designed studies examining duration of intrapartum antibiotic prophylaxis for prevention of early-onset GBS disease of the newborn. We recommend continuing to initiate intrapartum prophylaxis according to the American College of Obstetricians and Gynecologists guidelines; however, the transmission of GBS to neonates exposed to less than 4 hours of intrapartum prophylaxis and their subsequent management require further study.

Epidemiology as a liberal art: from graduate school to middle school, an unfulfilled agenda.

Calls by Lilienfeld, Fraser, and others some three decades ago to introduce epidemiology into undergraduate college education remain largely unfulfilled. Consideration of epidemiology as a "liberal art" has also led to exploring possibilities for introducing epidemiology into early education: to high and even middle schools. Adding epidemiology to school curricula should help educate the public to understand science-based evidence concerning the causes and treatments of disease, help inoculate them against a tsunami of biased and fraudulent media messaging, and permit advancing postgraduate education in epidemiology to even higher levels of scholarship.