Documenting the evidence: the case of scurvy.

Abstract

Iain Milne & Iain Chalmers look at how James Lind's 1753 ground-breaking paper entitled "A treatise of the scurvy" helped to change the public health policy of his day and, in turn, improve public health. The authors describe how the Scottish naval surgeon recognized that there was widespread confusion over the diagnosis, prevention and cure of scurvy in the eighteenth century and how he sought to fill the knowledge gap with his paper. They review Lind's clinical experiments, methodology and conclusions as well as the effect of his work: within two years of ordering more generous provision of lemon juice scurvy had virtually disappeared from the ranks of the Royal Navy. In 1753, James Lind, a Scottish naval surgeon and medical graduate of Edinburgh University, published a 450-page, three-part Treatise of the scurvy (1). At that time, scurvy was killing thousands of people every year and was responsible for many more deaths of sailors in the Royal Navy than enemy action. Believing that one of the reasons there was so much confusion about the diagnosis, prevention and cure of scurvy was that "no physician conversant with this disease at sea had undertaken to throw light upon the subject", Lind set about filling this gap, with a clearly stated commitment to base his work on "observable facts" rather than on the theories that dominated medical decision-making at that time. Lind's Treatise is a classic for two main reasons: it is one of the earliest accounts so far identified of a prospectively organized controlled clinical trial, comparing six commonly used treatments for scurvy, and it is a systematic review of what had previously been published on the diagnosis, prognosis, prevention and treatment of scurvy. While serving in the Channel Fleet aboard HMS Salisbury in 1747, Lind reports having selected 12 sailors who were all at a clinically similar stage of scurvy, had the same basic diet, and were accommodated in the same part of the ship. He allocated two each to six of the many different treatments for scurvy then in use: a quart of cider daily; 25 gutts of elixir vitriol three times a day; two spoonfuls of vinegar three times a day; half a pint of seawater daily; a concoction of nutmeg, mustard and garlic three times a day; and two oranges and a lemon daily. "The most sudden and visible good effects", Lind reported, "were perceived from the use of oranges and lemons; one of those who had taken them being at the end of six days fit for duty ... The other was the best recovered of any in his condition; and being now deemed pretty well, was appointed nurse to the rest of the sick." Although Lind does not provide any information on how he allocated the sailors to the six treatments he compared, he is rightly celebrated for having taken care to compare like with like: his report shows his awareness of the need to guard against selection bias, noting that potential confounding factors--clinical condition, basic diet and environment--had been held constant. Although Lind is remembered for his controlled trial, his account of it fills only four pages in the book: the rest of it reports what had been published on the diagnosis, prognosis, prevention and treatment of scurvy. Lind's systematic review of the literature deserves greater recognition, particularly now that there is wide acceptance of the principle that decisions in health care and health policy should be informed by up-to-date, systematic reviews of reliable, relevant research. The year after Lind conducted his clinical experiment at sea, he left the Navy and returned to Enlightenment Edinburgh, where he graduated in medicine at the University, obtained a licence to practise, and became a fellow (and subsequently treasurer) of the Royal College of Physicians of Edinburgh. It was during this time, when his home was most probably an apartment in Paterson's Court off Edinburgh's Royal Mile (2), that Lind did the research that he reported in his Treatise. …