Bert also made a study of decompression sickness, suffered by deep-sea divers (who know its agonizing pain as "the bends") when they are brought too quickly to the surface from the great pressures of the depths.
Norwegian GPs have reported on their difficulty in assessing and communicating on function [ 23, 24], and in a study of Swedish sickness certificates, only one-third of GPs reported on patients' activity limitations despite the introduction of new guidelines and implementation strategies [ 14, 25].
The diagnostic groups used in this study are quite similar to the groups used in a recent study of sickness absentees in Madrid [ 15].
Virtanen and colleagues conducted an ethnographic study of sickness absence and whether absence could be understood as a practice, not only based on the individuals' health, but also on the rules of the community they belonged to [ 42].
However, in a study of the quality of sickness certificates [ 5], it was found that such documents more often lacked essential information when issued by specialists than when provided by those who were not yet specialists.
In a comprehensive quantitative study of sickness certification in general practice, mild mental disorders accounted for 40% of sickness absence and these disorders were particularly associated with claimants developing longer term sickness absence.
In a study of British civil servants, such sickness presenteeism was found to be associated with increased risk of myocardial infarction in men (90).
A study of the minority of physicians who state sickness certification tasks to a great extent being a work environment problem.
Knowledge about the West Nile virus dates from 1937, when a healthy 37-year-old woman from Omogo, Uganda, gave blood for a scientific study of sleeping sickness.
