Publications by authors named "L Kingma"
Background: Poor sleep quality and insomnia have been associated with the use of tobacco, alcohol, and cannabis, but it is unclear if there is a causal link. In this Mendelian Randomization (MR) study we examine if insomnia causes substance use and/or if substance use causes insomnia.
Methods: MR uses summary effect estimates from a genome-wide association study (GWAS) to create a genetic instrumental variable for a proposed 'exposure' variable and then identifies that same genetic instrument in an 'outcome' GWAS.
Purpose: To determine the interobserver variability among radiologists for computed tomography (CT) diagnosis of scaphoid fractures.
Methods: Four specialized musculoskeletal radiologists evaluated the CT scans of 150 consecutive patients who were clinically suspected of having sustained a scaphoid fracture but whose scaphoid-specific radiographs were normal. The radiologists were asked to determine the presence or absence of a scaphoid fracture and to localize the fracture.
Objectives: Some have suggested that MRI might be the best reference standard for a true fracture among patients with suspected scaphoid fractures. The primary aim of this study was to determine the rate of false-positive diagnosis of an acute scaphoid fracture in a cohort of healthy volunteers.
Methods: In a prospective study, 33 healthy volunteers were recruited and both wrists of each were scanned, except for 2 volunteers for whom only one wrist was scanned.