Conflict of interest: None declared. References 1 Cornfield J, Haenszel W, Hammond EC, Lilienfeld AM, Shimkin MB, Wynder EL. Smoking and lung cancer: recent evidence and a discussion of some principles. J Natl Cancer Inst 1959;22:173–204. Reprinted Int J Epidemiol 2009;38:1175–91. 2 Cochran WG. The planning of observational studies of human populations (with discussion). J R Stat Soc A 1965;128...

n engl j med 355;14 www.nejm.org october 5, 2006 1500 large thrombus burden. Indeed, a recent study comparing clinical and procedural characteristics among hospitals, mostly regarding elective percutaneous coronary intervention, invariably reported a contrast volume of more than 200 ml.5 Finally, the difference in the primary end point and the other clinical end points between the two N-acetylc...

PURPOSE To evaluate the age-related change in contrast sensitivity seen in a middle-aged to elderly Japanese population. METHODS Contrast sensitivity and visual acuity were measured in subjects aged 40 to 79 years randomly recruited from a community in Aichi prefecture near Nagoya, Japan. Contrast sensitivity tests were performed using the Vistech contrast sensitivity test chart (VCTS 6500). ...

A standard approach to analyzing n binary matched pairs being usually represented in n 2× 2 tables is to apply a subject-specific model; for the simplest situation it is the so-called Rasch Model. An alternative population-averaged approach is to apply a marginal model to the single 2 × 2 table formed by n subjects. For the situation of having an additional stratification variable with K levels...

introduction : the aim of this quantitative systematic review/meta-analysis was to compare the treatment outcomes of mineral trioxide aggregate (mta) and calcium hydroxide (ch) in pulpotomy of human primary molars. the focused pico question was “in case of pulp exposure in vital primary molars, how does mta pulpotomy compare to ch in terms of clinical/radiographic success?” methods and material...

OBJECTIVES The aim of the study was to investigate the effects of age and/or surgical approach on perioperative wound complication following ovariohysterectomy (OHE). METHODS A retrospective search of perioperative monitoring records from a shelter desexing program was conducted to identify cats that underwent OHE between 1 June 2010 and 31 December 2012 inclusive. A wound complication was de...

BACKGROUND HIV/AIDS treatment programs are currently being mounted in many developing nations that include palliative care services. While measures of palliative care have been developed and validated for resource rich settings, very little work exists to support an understanding of measurement for Africa, Latin America or Asia. METHODS This study investigates the construct validity of measur...