Statistical analysis in orthodontic journals: are we ignoring confounding?

AIM: To assess the prevalence of adjustment for confounding within statistical analysis and matching at the design stage in leading orthodontic journals and to explore potential associations between accounting for confounding and publication characteristics. MATERIALS AND METHODS: Twenty-four issues of four leading orthodontic journals with the highest impact factor were searched from July 2014 backwards. Confounding adjustment through statistical analysis and study characteristics including journal, study design, region of origin, number of authors, number of centres, involvement of a statistician, significance of results, and type of analysis were recorded. Reporting of matching at the design stage was also recorded. RESULTS: Of 426 studies identified, only 71 (17 per cent) accounted for confounding in the statistical analysis. There was evidence that journal, country of authorship, and involvement of a statistician (odds ratio = 3.91, 95 per cent confidence interval: 2.16-7.10; P < 0.001) were significant predictors of accounting for confounding at the analysis level. Reporting of matching at the design stage was identified in 111 of 426 (26 per cent) studies in which 9 studies adjusted for confounding at the analysis level. CONCLUSIONS: Appropriate adjustment for confounding in orthodontic literature either at the design or at the analysis stage was identified in less than half of studies overall (41 per cent), suggesting lack of expertise and awareness in design, conduct, analysis, and reporting of non-randomized studies in this field. This is a critical limitation that can potentially result in biased estimates and associations between examined exposures and outcomes.

Biometeorological and air quality assessment in an industrialized area of eastern Mediterranean: the Thriassion Plain, Greece.

Evidence that heat wave events are associated with poor air quality conditions and health hazards has become stronger in recent years. In this study, the impact of two heat wave episodes on human thermal discomfort and air quality is examined during summer 2007, in an industrial plain of eastern Mediterranean: the Thriassion Plain, Greece. For this purpose, two biometeorological indices-Discomfort Index (DI) and Heat Load (HL)-as well as an air quality index-Air Quality Stress Index (AQSI)-were calculated using data from seven measuring sites. A land-use map was procured in order to examine the effect of different land cover types on human thermal comfort. The results indicated high level of thermal discomfort and increased air pollution levels, while a significant correlation between the DI and the AQSI was identified.

Heat waves observed in 2007 in Athens, Greece: synoptic conditions, bioclimatological assessment, air quality levels and health effects.

Heat waves are considered to be increasing in frequency and intensity whereas they comprise a significant weather-related cause of deaths in several countries. Two heat waves occurred in Greece in summer 2007. These severe heat waves are assessed by analyzing the prevailing synoptic conditions, evaluating human thermal discomfort, through the Heat Load Index (HL), as well as investigating its interrelation of air pollutant concentrations, and the daily air quality stress index (AQSI), in the greater region of Athens (Attica), Greece. Furthermore, the relation of HL values and the number of heatstroke and heat exhaustion events recorded in public hospitals operating within the Greek National Health System is examined. Data included radiosonde measurements from the Athens airport station (LGAT), NCEP/NCAR reanalysis data in order to obtain the position of the Subtropical Jet Stream (STJ), GDAS meteorological data for back-trajectory calculation, 10-min meteorological data from 10 Hydro-Meteorological stations and mean hourly values of nitric dioxide (NO(2)), sulphur dioxide (SO(2)) and ozone (O(3)) concentrations, measured at 7 different sites, for the last 10-day period of June and July 2007. Spearman's rank correlation test was used to observe any possible correlation between HL values and air pollutant concentrations, and AQSI values. The results demonstrated different synoptic characteristics for the heat waves of June and July. In the heat wave of June, higher ambient temperatures were recorded and greater HL values were calculated. Extreme discomfort conditions were identified in both heat waves during both day-time and night-time hours. The air pollution analysis showed poor air quality conditions for the heat wave of July, while a significant correlation was found between HL values and average hourly concentrations of O(3), NO(2) and SO(2). The number of heat-affected patients reported during the June heat wave was larger.

Exposure to fine particulate matter in ten night clubs in Athens Greece: studying the effect of ventilation, cigarette smoking and resuspension.

The aim of the present work is to study the occupants' exposure to fine particulate concentrations in ten nightclubs (NCs) in Athens, Greece. Measurements of PM(1) and PM(2.5) were made in the outdoor and indoor environment of each NC. The average indoor PM(1) and PM(2.5) concentrations were found to be 181.77 microg m(-3) and 454.08 microg m(-3) respectively, while the corresponding outdoor values were 11.04 microg m(-3) and 32.19 microg m(-3). Ventilation and resuspension rates were estimated through consecutive numerical experiments with an indoor air quality model and were found to be remarkably lower than the minimum values recommended by national standards. The relative effects of the ventilation and smoking on the occupants' exposures were examined using multiple regression techniques. It was found that given the low ventilation rates, the effect of smoking as well as the occupancy is of the highest importance. Numerical evaluations showed that if the ventilation rates were at the minimum values set by national standards, then the indoor exposures would be reduced at the 70% of the present exposure values.