01585nas a2200217   4500000000100000008004100001260001300042653001900055653001100074653002200085653001100107653001200118653001900130653001500149100001400164245007100178300001100249490000800260520108500268022001401353       2005                            d  c2005 Nov10aBone and Bones10aEurope10aHistory, Medieval10aHumans10aleprosy10aPaleopathology10aPrevalence1 aBoldsen J00aTesting conditional independence in diagnostic palaeoepidemiology.  a586-920 v1283 a<p>Leprosy was a well-known and dreaded disease in the Middle Ages. A substantial fraction of the adult population carried leprosy-related lesions. Previous research analyzed the occurrence and implications of seven such lesions in samples of medieval skeletons. These analyses were carried out under the assumption of conditional independence among lesion scores. The present paper examines this assumption by developing a test based on the odds ratios and applying the test to three rural medieval samples from Europe: Tirup from the 12th-14th century AD in Jutland, Denmark; Refshale from the 12th-14th century AD on the island of Lolland, Denmark; and Lauchheim from AD 460-680 in southern Germany. Signs of nonzero prevalence of leprosy at death were found in all three samples: Tirup, 25.5% (95% CI, 17.2-34.6%); Refshale, 39.1% (95% CI, 25.5-54.7%); and Lauchheim, 16.2% (95% CI, 10.0-22.9%). It is shown that when leprosy is the prime factor creating variation in the lesion scores in and between samples, the assumption of conditional independence cannot be rejected.</p>  a0002-9483