THE EPIDEMIOLOGY OF INFLAMMATORY BOWEL DISEASE

Transcription

1 Journal of the Royal Army Medical Corps , THE EPIDEMIOLOGY OF INFLAMMATORY BOWEL DISEASE COLONEL D M ROBERTS, MD, FRCP(Ed), MRCP(Lond) Royal Army Medical College, London The epidemiological study of infiamma1tory bowel disease (!BD) is made difficult by problems of case ascertainment although, in developed oountries, hospital admission mtes are probably acoeptable as eviidence (Evans and Acheson 1 ). Many epidemiological surveys of U'lcerative collitis (UC) were done before Crohn's colitis and ischaemic col:itis were recognised as sepamte entities and are therefore of dubious quality. This artiole therefore concent,raites on the more recently published work in whioh acceptable criteria for ascertainment and diagnosis have been used. Because of possilible confusilon due to special forms of acute ileitis such as rtlose due to Yersinia entei'oodlri,tioa (Winblad et at") and the fish nematode larva Anisakis (lshikum and Hayasa']m 3) surveys whi,ch include the syndrome of acute regional enteritis have been excluded. Geographical variations in incidence Ulcerative colitis Table I shows the incidence 'Of UC in various parts of the wodd, grouped into broad geographical areas. U1cemtive oolitis appears to be most common in NOl1them EUlpe but much less so in Southern Europe, with Eastern Europe occupying anintermedi'ajte pos1ition. On the Amel'ican Oontinent, too, the incidence is higher in the north than in the south. Litde is known of the incidence in Africa and Asia. Table I Ulcerative colitis ~ incidence! 0,000 I year Area Year!s Incidence Copenhagen Oxford NORTHERN EUROPE Malmo Finland Norway Hamburg Rumania EASTERN EUROPE Yugos'lavia (S[ovenia) Yugoslavia (Celje) Seville 1%6 0.4 SOUTHERN EUROPE Vienna Iran Tel Aviv Baltimore OTHERS New Zealand Japan Chile Mexico

2 78 The Epidemiology of Inflammatory Bowel Disease Crohn's disease Table Il shows the inoidence of CD in various parts of the world. No gross geogra,phlioal variations seem to occur, although the high figure reported from Malmo is interesting. Crohn's disease - Table n incidence / 0,000 / year Area Year/s Incidence Clydesdale Gloucester UNITED KINGDOM London NO'ttingham & Oxford North East ScO'tland Avemge 1.5 Oopenhagen Finland SCANDINAVIA Norway Sweden ~Oent]1al) Sweden (Malmo) Average 1.98 OTHERS Baltimore Basel Regional variations in incidence Few data are avlailabie, but regional varia!1:!ions probably occur, as demonstrated by the Hosiljirba'l ln~pattient Enquiry DaJta for shown in Table III (Barker and Gardner 4 ). It may be signrficant that, in women,at least, the VC and CD rates are correlated, East Anglia having the lowest rate for both and South East Wales the highest. Table III Female discharge rates ;(Hospital In-patient Enquiry!Data) Inflammatory bowel disease Region Rate CROHN'S DISEASE East Anglia 40/million South East Wales 79/million ULCERATIVE COLITIS East Ang!1ia 66/million I South East Wales 155/million Sex and age Both VC and CD are predominantly diseases of young adults as typified by the dam on OD from Malmo (Brahme et ap) and on VC from Tel A viv (Gilat et 0.[6) (Figures 1 and 2).

3 fn"idence 15.0 PER 0, PER YEAR SMALL INTESTINE ---- COLON -TOTAL :!~ctg:~g~';7;m::b;!~ I I I I I I I I I I I I I I 01/1/1/1/1/1/1/1 ~~t-iw(l')(i')""'ii)"'coco"""" AGE OF ONSET (YEARS) Fig. 1. Incidence of Crohn's disease in Malmo (Brahme et at 1975). D M Roberts NO OF PATIENTS.0 to TOTAl. Fig. 2. Incidence of Ulcerative colitis in Tel Aviv (Gilat et ai1974). Several reports (Bmhme et a/ 52 Evans and Acheson l, Kyle 7, Lindenand Moller 8, Norten et al s, Smith et a[1o, Tresadern et al ll ) suggest that for both diseases there may be a "seoondary peak" in old age as shown in Figure 3 for Chicago NO OF PATIENTS o Femall ffij "all AGE OF ONSET (YEARS) Fig. 3. Incidence of Ulcerative colitis in Chicago showing "secondary peak" in old age {Rogers et al ). (Rogers et a[i2). For CD there is some evidence that the "secondary peak" is caused largely by an increased incidence in colonic disease which also tends to affect more women than men.

4 80 The Epidemiology of Inflammatory Bowel Disease Figures 4 and 5 show the relative sex incidence of the two diseases in various areas. For both diseases female preponderance seems to be most marked in the United Kingdom. CHICAGO FINLAND TEL AVIV GLOUCESTER MALMO CLEVELAND N. ZEALAND NOTTINGHAM CLYDESDALE N.E. SCOTLAND 59'6% 61% 63% Fig. 4. The sex incidence of Crohn's disease in various areas. TEL AVIV FINLAND CHICAGO GREECE OXFORD MALE 53'8% 55 5% ~iii!iii 50 45% 48'3% Fig. 5. The sex incidence of Ulcerative colitis in various areas. Race 'It is often difficult to determine that differences apparently due to race are not in fact due to envlironme~tal factors. NeveJ1theless, the weight of the evidence strongly suggests that both diseases are approxiiill\!tely four-fold more common in Je~s and five-rom less common in Negroes than in other ethnic groups (Brahme et a[5, EVlans et all, Monk et a1 13, Mosbeoh 14, Novis et a[15, Rogers et a[12). The exitraordinary thing-~if one accepts that epidemio'logical trends reflect aetidlogical factors--jis that the raciail pattern for the two diseases appears to be the same. Effects of other demographic factors Both VC and OD seem to be more common in urban than in rural areas (Oouchman and Wigley16, Unden and M6~ller8, K)Ale 7, Monk et al 13 ) the same phenomenon was probably observed in Ohicago (Rogers et a[12) where both diseases were found to be less oommon among farmej1s than others. No suoh difference, however, was noted for OD in Centrnil Sweden (Norten et ai 9 ). Evidence on the effect of sooial status or occupation is sparse and conflicting (K~le7, Monk et al 13 ). Some repot1ts(rogers et a[12, Monk et al 13 ) have suggested that IBD may be more common among those of higher educational attainment, but these data are open to sevel'a'l other poss:ihle interpretations. Is the incidence of inflammatory bowel disease changing? For OD, the only reliable information comes from EUl'Ope and is summarised in Figure 6. In both NotitJingham and NOI1th East Sootland the reported increase in females greartly exceeds that in ma<les Whereas the reverse is true for Central Sweden. In Sco~land there was a remarkable 12-fold increase in the incidence of colonic disease. In Clydesdale, compared with a 33 per cent increase in small bowel cases, there was a 0 per cent incj1ease in purely large bowel cases with a marked female predominance (specrallyover the age of 50 years, when the sex ratio was eight females to one male).

5 D M Roberts 81 Overall, the incidence of CD is increasing at a rate of 250 per cent per decade. The little reliable information ahout the changing inoidence of VC is rep resent'ed in Figure 7. The incidence may be on the increase in most areas. INCIDENCE 6 PER 0, _. 0, Sweden (central).2. Basel.3. Copenhagen.4. Sweden (Malmo)'.5. N.E. Scotland.6. Clydesdale.7. Nottingham 8. Norway 7 I 4 a 2 -' ti80 15tH Cktord 2. Fin_nd.3. Copenhagen.4. Sweden (M.lmi)) 5. NOfWGV' 4 Fig. 6. The changing incidence of Crohn's disease in Europe. Fig 7. The changing incidence of Ulcerative colitis in Europe. Arguments vhajt!these increases may be more apparent than real are difficult to completely refute but (although space does not permit any elahomtion) they are unlikely to account for large assessment errors. Other possible epidemiological clues a. Miller et al 17 looked for "time-space clustering" as evidence for an linefective a'etiology of OD jn!the No1Jti:ngham area and found none. b. Gll!rdner and James 1B reporlted 1!hait pll!tlients with OD ate signi1ficantly more cornflakes and wheat than cont11ols. c. Table IV shows the w,ide geographical variation in the incidence of other conditions known to be associll!ted with Vc. The significance of these variations is obscure.

6 82 The Epidemiology of Inflammatory Bowel Disease Ulcerative colitis - Table IV incidence of extracolonic manifestations Manifestation Area Percentage Australia 14.0 Czechosl'Ovakia 9.1 LIVER DISEASE England 7.4 Israel 3.2 ''O? Spain 2.4 Turkey 20.0 Great Brimin (vari'ously 7.4 rep'orted) AR'J1HROPATHY Czech'Oslovakia 5.2 (including ankylosing sp'ondylitis) Israel 4.8 Spain 11.5 Turkey 8.3 EYES DISEASES (Approximate) 0.5 SKIN DISEASES (Approx:imate) 2.5 REFERENCES 1. EVANS, J G AND ACHESON, E id (1965). An epidemi'01'ogicai study 'Of ulcerative colitis and relgi'onal enitel'itis in t,he Oxf'Ord Area. Gut 6, WINBLAD, S, NIHLEN, B AND STERNBY, N H (1966). Yersinia enterocoliiltica {pasteurella X) in human enlteric linfecti~s. British Medical Journal ii ISHlKURA, HAND HAYASAKA, H (1967). Acuite regi'onal ilei,tis at Iwanai and H'Okkaid'O, with special reference t'o iilltelsitlinal AniSlakfa's.is. Sapporo Medical Journal 32, BARKER, D J AND GARDNER, M J (1974). Epidemiol'Ogy 'Of Orohn's Disease. Lancet H BRAHME, IF, ILINDSTROM, C AND WENCKERT, A :(197'5). CJ1'Ohn's 'Di,sease nn a defined p'opulati'on. Gastroenterology 69, GILLAT, T, et al (1974). Ulcerative colitis in the Jewish popuja!ti'on 'Of Tel Aviv Iat'O. Gastroenterology 66, 33' KYLE, J (197'l). An epidemji'ologioal study of Cl1Ohn',s dise:asei in Nor,~h RaSlt Scotland. Gastroenterology 61, '3).. 8. LINDEN, G AND MOLLER, C (1971). Ulcerative cohl1is in!finland. Diseases of the Colon and Rectum 14, NORTEN, B J, KRAUSE, U AND BERGMAN, IL (1970). An epidemiolo~ioall Sltudy 'Of Crohn's disease. Scandinavian Journal of Gastroenterology 5, SMITH, I S et al ~1975). Bpidemiol'OglicaI aspects 'Of Cr'Ohn's disease in Olydesda,le Gut 16, TRESADERN, J,C, GEAR, im W IL AND NICOL, A (1973). An epidemiological rstudy 'Of 'regional enter:<tis in'~e G1ouceSlterArela. British Journal of Surgery 60, ROGERS, B H G, CLARK, L M and KIRSNER, J B ('1971). The epidemi'ol'ogical and demographic oharaoteristiios of inflammatory bowl disease: an analysis 'Of a o'ompute!1ised file of 14,000 patients. Journal of Chronic Diseases 24,743'-7'7' MONK, M et al C1969). An epidemiol'ogical Sltudy of u1cer8jtive collitirs and regi'onal enteritis among adults,in lbajltlimore. Gastroemerology 56, MosBEcH, J (1960). MortaJiity from ulcerative o'olhis in Denmark. Gastroenterology 39, NOVIS et al (1975). Incidence 'Of Cmhn's disease at Groote Schuur HospiJtJal du!1ing South African Medical Journal 49, COUCHMAN, K G AND WIGLEY, R D ~197il). The distl1iburti'on of the systemic connective tissue diseases, ulceravive coliitis land Crohn's disea,se in New ZeIa,land :an Analysis of hospital aldmiss,ion statistics. New Zealand Medical Journal 74, 23: MILLER et al ~197'5). Crohn's dlj'sease in Nottingham: 'a search for time-space clustering Gut. 16, GARDNER, M J and JAMES, A IH (1977). BreraUas't and Ci1Ohn's dise'ase. Journal ii, 826"8~7. British Medical