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Short Communication I Summar) In a case-control stud\. of 8-1 multiple mkeioma patlents and 168 age- and sex-matched controls I uith turnours at other sites. reported prior allergies were associated with an elesated risk of m>eloma I RR = 3. I . P < 0.001). In addition. more myeloma patients than controls reported prior m!xocdema I R R = 5.0. i P=O.O1). History of agricultural work was associated with d n elevated risk of mheloma [ R R = I . 2 . P =O.OI). I Jlrhougn no detailed information was available on the typr o i farmlng in which the subjects were engaged. More detailed studies are required to confirm and further delineate these findings. I Incidence rates for multiple myeloma in British Columbia are - 3.4 and 2.1. per 100.000 in males and females respectively (B.C. .Ministry of Health. 1976). A recent study has indicated that the incidence has been increasing over the last 30 years (Velez er al.. 1983). The highest reported incidence in the world is in U.S. black males (Waterhouse et al.. 1976). Several occupational risks have been demonstrated. with Milham showing elevated mortality for myeloma among farmers. woodworkers. smeltermen and forgemen (Milham. 1976). Several studies have shown nuclear workers to be at high risk for myeloma (Dolphin. 1976: Lewis, 1963: Cuzick. 198I ). Schafer and Miller in a study of 153 patients showed elevated risks of prior biliary disease and peptic ulcer in patients with I& myeloma when compared to patients with all other myeloma types (Schafer & Miller 1979). and Allen found an elevated frequency among myeloma patients of individuals with group A blood (Allen, 1970). Familial Occurrence of myeloma has been reported in spouses (Kyle er ai.. 1976) and in blood relatives (Maldonado & Kyle 1974). Other suspected risk factors are summarized in the excellent review of Blattner. (1980). To assess the impact of a variety of environmental and medical factors on risk of myeloma in British Columbia. a case-control epidemiological study was initiated in 1979. Correspondence: R.P Gallagher. Division of Epidemiology & Biometry: Cancer Control Agency of Bntish Columbia. # 7 W 8 6 West Broadway. Vancouver. B.C V5Z IGI Canada Received 28 March 1983. accepted 6 September 1983 Methods A total of Q4 myeloma patients, 49 males and 35 females, were interviewed. In order to maximize the number of responses available, all myeloma patients seen at the A. Maxwell Evans Clinic (AMEC) in Vancouver between 1972 and 1978 and surviving to the start of the study in 1979 were interviewed (total. 32 patients). The remaining 52 patients were newly incident cases referred to the AMEC from 1979-1981. These incident and prevalent cases were grouped for most of our analyses. The 84 patients represent -20,.b of the 410 myeloma patients treated at the AMEC from 1972 to 1981. Virtually all of the patients not included in the study had died before our interviewer contacted them. None of the patients contacted for the study refused interview. Two groups of controls were selected. The first group comprised 84 patients with head and neck tumours, and the second group were patients with other cancers which did not appear to be smoking or alcohol related. Actual site distribution included 26 neoplasms of the digestive system, 10 basal cell skin carcinomas, 27 breast and female genital tumours, 7 male genital turnours, 1 brain and 13 haematopoietic tumours. All controls were diagnosed from 1977 to 1980 and were treated as patients at the AMEC. Myeloma cases were matched to a single control from each group by sex and by age within a 5 year age group. as well as by year of diagnosis within 5 years. Initial comparisons revealed that marital status and edicational level of the myeloma cases and non-head and neck controls were similar. The head and neck control group. however, appeared to have a lower educational level. indicating lower socioeconomic status than that of the other groups. For analysis of most factors, the control groups were I The Macmillan Press Ltd.. 1983 854 R.P.GALLAGHER F I al. combined. giving two controls per myeloma patient. but for a few variables. notably alcohol and tobacco use, only the non-head and neck control group was used, as head and neck tumours are known to be associated with these variables. Cases and controls were interviewed by a trained interviewer using a standardized questionnaire covenng medical. dental. occupational and residential history; smoking and alcohol use, dietary patterns, and history of drug taking. A total of I19 different variables were examined in the interview. Special emphasis was placed on prior exposure to ionizing radiation and the presence of autoimmune diseases. The study was conducted as an initial overview of a rare tumour, and a large number of possible aetiological factors were examined. However. because of limitations on interview time with ill patients, relatively little detail on individual variables was collected. The data were analysed using a conditional logistic regression model for matched data sets (Breslow & Day, 1980). Results The median age at diagnosis of the myeloma patients was 61 years (range 34-81 years) for the males. and 63 years (range 48-83 years) for the females. Of the 84 patients. 13 were diagnosed as having IgA myelomas. -14 had IgG disease. and 2': had other elevated immune globulin component5 including IgD. IgE. light chain components o r Bence-Jones protein only. '-1 Ilergies Myeloma patients reporrcd siynilicantl? more allergies than controls ( R R =3.1. P<O.OOI) as jhoun in Table I . In addition. significantl> more m)eloma patient? also reported dlt.r=. treatrncn ts (injections. special diets. drugs) ( R R = 3.5. P =0.02) than did controls. The character of the allergies also appeared to differ between cases and controls. Nearly one-halt' of the allergies repored by controls were described as breathing difticulties. L+ hile Table 1 Medical factors in myeloma Allergies Allergy t restment Myoedema 2.6 13.1 7.I I I 3 3.1 <0.001 11.6. 6.31 4.2 3.5 0.02 ( 1 . 1 . 10.6) 1.2 5.0 O.w (1.0. 3 . 7 ) <lOo/o of myeloma patients uith allergies reported this symptom. Myeloma patients described the symptoms mainly as skin rashes. swellings and hives. Specific information on alle- :n> was unfortunately not available. No difference between the prevalent and incident groups of myeloma patients for the association with allergies was found. Other medical factors A significantly greater proportion of myeloma patients reported prior pnmary myoedema than controls (RR=5.0. P =0.04) as shown in Table I. .A number of other medical factors were reviewed to see if various diseases were associated with myeloma. N o relationship was found for pnor kidney disease. hyper-cholesterolaemia. tuberculosis. osteomyelitis. infectious hepatitis. or serum hepatitis. Autoimmune rheumatoid diseases were not elevated in myeloma patients. no relationship being found with systemic lupus erythematosis. rheumatoid arthritis. osteoarthritis. or ankylosing spondylitis. In addition. no association was found with prior scleroderma. hyperthyroidism. diabetes. h! pertension. or prior tonsillecromy. lnforrnation on blood group was unabailable for the majority ot' the cases and controls. so we were unable to examine distribution of this factor. There \vas no difference between myeloma cases and controls with regard to frequency of medical X-rays. .-lgriciiiwul exposure Occupational information was recorded for each job held by a subject for one hear or more. m d . in addition. each respondent uas questioned using a ciieck list of karious industriss and occupations common within the province o i British Columbia. \nal>sis of the detailed occupational data j :,>sed a n slevatcd risk at rn)clonia in subjects uvrking in agriculture r R R = 1 . 3 . P =0.01) as i r dicated in Table 11. \o Jsjociation was found .-b.:tween length of time spent in asriculture and risk fc m>elorna. Further %inal!\ib hho\reJ the rciationship with farming io be prirnaril! in the ir-cident myeloma case group. with little or no a,sociation in the pretalent m\rlorna group. While this difference may be iirnpl! due to the small n x n b e r 1321 ot' prevalcnL rn!clorn;i c a w s . t h r relationship betucen m!clnniJ And a p x l t u r s slivuld be interpreted ! t h ;;lullon. U n ~ ~ ~ r t u n a r e l ) d.,ta \\ere not cc~llecteu o n the [!pes ot' farming most strongly asbociated u i t h m)elorna. Esposure tc, processed grain as recorded an tiic occupational checklist showed m increased but non-significant association with myeloma ( R R = 2.4. P =0.09 as indicated in Table 11). ~~~~ ~ ALLERGIES A N D .4GRICULTURAL EXPOSURE IN MULTIPLE MYELOMA 857 ANDERSON. ti.. BACHMANN. R. & HALLEPU'. J. (19661. Frequency of pathological proteins iM-components) in 6995 sera from an adult population. Acra .Ued. Scand.. 179, 235. ASELSON. 0 . DAHLGREN. E.. J.ANSSOS. C . D & REHNLUND. S.O. (1978). Arsenic exposure and mortality. a case referent study from a Swedish copper smelter. Br. J . Ind. .Wed., 35. 8. B C M I N I S T R I ~OF HEALTH (1976). Cancer in Bntish Columbia, 1969-73 Ministrv of Health. B.C. BLAlTNER. W.A. (1980). Epidemiology of multiple myeloma and related plasma cell disorders: an analytic re\ieu. In Progress in .tfjeloma (ed. Potter, EIseLier Sorth-Holland. Neu York. p. 65. BRESLOW. N.E. & DAY. N.E. (1980). Srarisrical .Merho& in Cancer Research C'ol I IARC Scientific Publication No. 32. Lyons. BRILTOh. L A . . STONE. B.J.. BLOT. W.J.& FRAUMENI. J F. (1976). Nasal Cancer in U.S. furniture industry counties. Lancer.. ii, 628. BURMEISTER. L.F. (1981). Cancer Mortality among Iowa Farmers. 1971-1978. J . :Vat1 Cancer Inst.. 66.461. CLZICK. ! (I981 1. Radiation induced myelomatosis, :V. Engl. J . Med.. 304,204. .DECOUFFLE. P STANISLAWEZYK. HOUTEN. L.. BROSS. 1.D.J & VIADANA, E. (1977). A Reirospecrive Survey of Cancer in Relation io Occupation. DHEW (NIOSH) Publ. 30.77-178 Washington D.C. DOLPHIN. G.W (1976). A comparison of the observed and the expected cancers of the haematopoietic and lymphatic systems among workers at Windscale: a first report. Nail Radiol. Plot. Board, (NRPB-RjJ) Hawell. KYLE. R.4.. HEXDERSOX. ES., RANDOLPH. V.L. & BUDGE. W R (1976). Multiple myeloma. acute leukaemia and Hodgkin's Disease occurrence in three of four family members. Cancer, 37, 1496. KYLE. R.A.. F U N K E L S T E I N . S., ELVEBACK, L.R. & KL'RLAND, L.T. (1972). Incidence of monoclonal proteins in a Minnesota community with a cluster of multiple myeloma. Blood, 40. 719. KRUPP. M A & CHATTON. M.J (1982). Current Medical Diagnoses and Treatmenr Large Medical Publications, Los Altos. Ca. LEWIS. E.B. 119631. Leukaemia multiple myeloma and aplastic anaemia in American radiologists. Science. 142. 1492. MALDONADO. J.E & KYLE. R..A. (1974). Familial myeloma. Report of eight families and a study of serum proteins in their relatives. Am. J .Wed.. 57, 875 MILH.4M. S. ( 1976). Occuparrond Vnrraliry in U'LZ Srare. 1950-1971. DHEW Publication (NIOSH) No. 76-1 7'5. Washington. D.C. MILH.AM. S (1971). Leukaemia and multiple myeloma in farmers. .4m.J . Eptdemiol.. 94. 30' PRIESTER. W .A. & MASON. T J I 1974). Human cancer mortalit) in relation to poultr) population. b! county. in I O Southeastern states. J . .Vat! Cancer Insr.. 53, 45. REGISTRAR GENERAL'S DECENSIAL SUPPLEMENT ( 1978). Occuparional .Uortalirj. England and Wales 1970-1972. HMSO. London. ROBERTSOS. M.A.. HARRINGTON. J.S & BR.ADSH.AW. E. ( 1971). The cancer pattern in African gold miners. Br. J . Cancer. 25. 395. SCHAFER. A.1. & MILLER. J.B. (1979). Association of IgA multiple myeloma with pre-existing disease. Br. J . Haemarol.. 41, 19. VALEZ. R.. BERAL. V. & CtiZICK. J. (1982). Increasing trends of multiple myeloma mortality in England and Wales: 1950-79: Are the changes real? J . .Varl Cancer Insi.. 69. 387. WATERHOCSE. J & MCIR. C. eds. (19761. Cancer Incidence in Five Conrinenrs. I.A.R.C.. Lyon 19'6. WINTROBE. W.. THORN. G.. ADAMS. R.. BRALSWALD. E.. ISSELBACHER. K.J. & PETERSDORF. R G. (1974). Harrison '.r Principles of Infernal Medicine 7th Edition, McGraw Hill. New York. E 856 R.P GALLAGHER er ai. associations emerged. however, because of the number of factors examined. it is possible that some of them might be due to chance. Further research will be needed to confirm the risks. The elevated risks for myeloma in farmers has been detected in several mortality studies (Burmeister, 1981; Agu et af.. 1980; Milham. 1971). None of these studies were able to specify the type of farming associated with multiple myeloma. although a further study of mortality in Southeastern United States found an excess of myeloma in poultry farmers (Priester & Mason 1974). It should be noted, however, that the association Seems to appear only in North American farmers, as no such risk has been seen in British fanners (Registrar General's Decennial Supplement. 1978). Our study confirms the elevated risk of myeloma among individuals engaged in farming, and, in addition. demonstrates an elevated but nonsignificant risk of myeloma in those working with grains. Our study found both an increase in reported allergies in myeloma patients. and an increase in treatments for allergies. An association between allergies and risk of myeloma has not been reported before. and must be treated with caution. Our myeloma patients were of higher socio-economic status than the controls. The higher status of the patients might have given them better access to medical care and hence account for the differences in allergy treatment between the myeloma patients and controls. It seems unlikely. however. that socioeconomic status could account for the difference in simple reported allergies between the two groups. though a bias resulting from more complete recall of minor allergies by cases than controls remains a possibility. However. the myeloma patients seemed to report a different pattern of allergies from the controls. with skin rashes and hives predominating. rather than breathing difficulties. The findings of a n increased risk of myeloma among individuals with allergies implies that hyprrsensitivity may play a role in the genesis o i It is well known that the incidence of benign monoclonal gammapathies (BMG) in the general population rises with age. A Swedish study showed that among individuals over the age of 50. 1 . 7 r ~ had single immunoglobulin spikes. either IgA. IgG or IgM (Anderson rr al.. 1966). A survey carried out in Minnesota in residents aged 50 and over. showed a prevalence of 1.25Ok of benign 1g.M spikes, with a rate of 1.89'0 in the 80t age group (Kyle et ul.. 1972). Although the manifestation of allergies results from abnormal IgE production. with release of histamine from mast cells lining the respiratory and gastrointestinal tract (Wintrobe er af., 1974). perhaps the immune system of patients with allergies are also predisposed to other plasma cell abnormalities. The finding of an increased risk of myeloma among individuals employed in agriculture 'may indicate that some group of compounds associated with farming may act in conjunction with the natural tendency for an increased risk of developing BMG with age. I t seems clear. however. that agricultural exposure may not be unique in this regard. as a number of jtudifj have implicated asbestos (Robertson rr ul.. 19711. wood dusr (Bnnton rf ul.. 1976: Decouffle cr 01.. 1977). leather dust (Decouffle er al.. 1977) and heav? metal exposure (Decouffle t i al., l9--: Axelson rr ul., 1978) as factors with possible associations a.ith myeloma. Further work is indicated on the relationship of allergies and myeloma. In parricular. future studies should focus on separating the different types of hypersensitivity and better investigating the seventy of allergies. and the allergens responsible for them. In addition. specific information on jocio-cconomic status of the subjects is required to eliminate possible confounding b> this \anable. Future aetiological studies Should also jpecifically address the possible association between m>cloma and farming by collecting detaiied data on [hi. type of agnculture in nhich the respondenrj ilre cngaged. Referewes .4GC. V U.. CHRISTENSEN. B L. & BL'FFLER. P A . (1980). Geographic patterns of multiple myeloma: racial and industrial correlates. State of Texas. 1969-71. 1.Xurl Cancer Inst.. 65. 735. .ALLEN. T.M. (1970). A B 0 blood groups and myelomatosis. Br. .Wed. 1..4. 1-8. .ALLERGIES AND AGRICL'LTURAL EXPOSL'RE IN MULTIPLE MYELOMA 855 Table I I Occupational f x i o r s . i l I ~ r z i t -miel dcviL iiirio.< The relationship betwen m)eioma and dllergiss and farming %as further examined. There was no significant association betueen allergies and farming. Twelve percent of indi\iduals who worked in farming at least one year had allergies. and 19'6 of those without farming exposure had allergies. Theri. appears to be an increased risk of mLeloma among farmers aiter controlling for allerpirs (RR=2.6. P=O.OU3). Orher oc.c.upurioncil :.\-posicres '4s myeloma patients showed slightly elevated but non-significant nskj for a number of occupations entailing exposure to dusts (grain work. asbestos work. textile work). a separate analysis was done for dust? en\'ironmentj. .An index of occupational dust exposure u a s d r a u n up. in which each job dtscrtprion was reviewed. and values were assigned to each for overall dust exposure. The exposures were totalled for each respondent. While myeloma patients appeared to have greater exposure to dusty conditions than controls ( R R = 2. I , P = 0.02). the relationship disappeared when farming was removed from the anal!.sis. The checklist of substances encountered in ;he workplace was reviewed for each respondent. y o significant relationships were found with asbestos. textiles. metal fumes. wood dusts. coal. si1ica.m other rock dusts. No relationship between occupational exposare to ionizing radiation was detected. probably because there is virtually no nuclear industry in Bntish Columbia. and consequently no reporrs. of exposure. Dirruri parrerns X n examination of dietnr) factors shoned no d~ffeerencebetween m)eloma patients and combined control patients for consumption of meats. tish. [ea. coffee. or spic! foods Socio-ec.onornic fucrors. including deeriral histor>. bl>eloma patients and controls showed differences in dental histor>. which appear likely to be related 10 socio-economic difference.; between the groups. Signilicanrl! rcucr ni!clonia patients had dentures :hun did the control> I R R = O . i S . P =O.OJ). 4l!eioma patients here more likel! to have had orthodontic work than controls. and less likely to have had 5 or more teeth extracted ~t one time. Neither of these relationships usre significant. In addirion. myeloma pausnts reportea more pricr nose and throat operations. other than ton~illcctornics. than thc controls t R R =2.9. P=O.O?). Since J nunibcr ol' these procedures were reported 3s cosmetic nose operitions. the relationship is iikel! to be a n artefact due to the higher socio-economic status of the myeloma patients. S t ~ k i t d~tlgti ilicdroi ICTC Due t o the k n o w n association of smoking and alcohol use with head and neck turnours. myeloma patients were compared with the non-head and neck controls only for these factors. Myeloma cases appeared to smoke less than controls ( RR =0.48. P =0.08). although the difference was not signiticant. There was no difference betueen cases and controls for alcohol :onsumption. Discussion The iacr that only ~ O O Oof the cases seen at .A.MEC from 1973-1981 were interviewed for the study raises the possibility that sampling biases have been introduced. In fact, the 32 prevalent cases, diagnosed between 1972 and 1978 were different from the other cases diagnosed during those years by virtue of the fact that they had survived to the time of the interview. This may mean that their disease process was less severe and they did not develop medical complications leading to a fatal outcome. or that they responded better to therapy. As described earlier. the relationship between myeloma and farming appears to be centered in the incident caseload diagnosed from 1979-198I and absent in the prevalent group of cases. The relationship between myeloma and allergjes is present in both the prevalent and incident case groups. I t would appear. then. that the possible biases introduced by the small sample of cases diagnosed from 1972- I97S who were actually interviewed could only have the effect of decreasing the strength o l the associations detected in our study. In spite of the relativel) small number of cases interviewed for the stud!. several significant ALLERGIES AND AGRlCULTLR4L EXPOSC'RE IN MULTIPLE MYELOMA 855 Table I1 Occupational Iacrors .-Jli~~r:ie,m.~ i d c v i c uiriir, The relationship between rn>eloma and alleryrs and farming uas further examined. There *as no signiiicant association becueen allergies and farming. Twelve percent of indibiduais who worked in farming a[ least one year had allergies. and 19"; of those without rarming exposure had allergies. There appears to be an increased risk of rn>elorna among farmers after controlling for allergies tRR=1.6. P =O.iN?). Orher l J ~ ~ i ' l i p U l l ~ J n.'(.lY/ posurc's A s myeloma patien ts showed slightly elevated but non-significant nsks for a number of occupations entailing exposure to dusts (grain work. asbestos work. textile work). a separate analysis was done for dust! environments. .An index of occupational dust txposure * a s draun up. in which each job dcwiprion was :ewewed. and values were assigned to each for overall dust exposure. The exposures were totalled for each respondent. While myeloma patients appeared 10 have greater exposure to dusty conditions than zontrols ( R R = 2. I , P =0.02). the relationship disappeared when farming was removed from the analysis. ,. The checklist of substances encountered in the workplace was reviewed for cach respondent. ;Yo significant relationships were found with asbestos. textiles. metal fumes. wood dusts. coal. silica,dr other rock dusts. No relationship between occupational exposure to ionizing radiation was detected. probably because there is virtually no nuclear industr. in Bntish Columbia. and consequently no reports. of exposure. Dierun puirerns An examination o i dietar! factors shoaed no difference between myeloma patients and combined control pdiients for consumption of meats. fish. tea. col'fee. or sp~c)foods Socio-ec.onnrnic Ibcrorq. inchiding deriral liisror!. 4f>eloma patients and controls showed differences in dental historb. which appear likel! 10 be related to socio-economic difference.: berween the groups. Signiticanrl! I;.ucr m>elonia patients had dentures than did the conrrols i R R = 0 . 4 5 . P=O.O4). M ~ e i n m apatients here more likel! to have had orthodontic work than controls. and less likely to have had 5 or more :eeih extracted at one time. Neither o i thcse relationships uere significant. In addition. m>eloma patients reportea more prior n o w 2nd throat opcrations. other than ionsillcctumic's. than thc controis ( R R =2.9. P = 0 . 0 2 1 . Since 2 number 01' these procedures were reporied as cosmetic nose oper2tions. the relationship is like]! to be a n arteiact due to the higher socio-economic status of the myeloma parients. st?7Okrne unti til( o / i i i [ i i w Due to the h n o u n dssocidiion of smoking and alcohol use uith head And neck turnours. myeloma patients Rere compared with the non-head and neck controls onl) for these factors M ~ e l o m acases appeared to smoke less than controls ( R R = O 48. P = 0 0 8 ) . although the difference was not significant The-e uas no difference betusen cases and controls for alcohol consumption. Discussion The Px! that only 20*0 of the cases seen at .A.MEC from 19;'-1981 were interviewed for the study raisss the possibility that sampling biases have been introduced. In fact. the 32 prevalent cases. diagnosed berween 1973 m d 19% were different irom the other cases diagnosed during those years by virtue of the fact that they had survived to the time of the interview. This may mean that their disease process was less severe and they did not develop medical complications leading to a fatal outcome. or that they responded better to therapy. As descnbed earlier. the relationship between myeloma and farming 3ppears to be centered in the incident caseload diagnosed from 1979-1981 and absent in the prevalent group of cases. The relationship between myeloma and allergies is present in both the prevalent and incident case groups. I t would appear. then. that the possible biases introduced bc the small sample of cases diagnosed from 1Y2-1978 who were actually interviewed could onl! have the effect of decreasing the strength of the associations detected in our stud. In spite of the relativel! small number of cases inter\.iewsd for the study. several significant ALLERGIES AND AGRICULTL'R;\L EXPOSURE IN .MULTIPLE MYELOMA 855 . - ! l I t * r y i r ~mrti dgric u1iio.t The relationship betwen mbeloma and allerzies and farming *as further examined. There was no significant association between allergies and farming. Twelve percent or indi\iduals who worked in farming at least one year had allergies. and 19"b of those without farming exposure had allergies. Therc appears to be an increased r!sk of myeloma among farmers after controlling for allergies (RR=2.6. P=O.UU?). Other oc~cxpotronrrl:.\-ppo.rures As myeloma patients showed slightly elevated but non-significant risks for a number of occupations entailing exposure to dusts (grain work. asbestos work. textile work). a separate analysis was done for dust! en\.ironments. .An index of occupational dust exposure <was draun up. in which each job description uas reviewed. and values were assigned to each for overall dust exposure. The exposures were totalled for each respondent. Whiie myeloma patients appeared to have greater exposure to dusty conditions than controls ( RR = 1.I , P =0.02). the relationship disappeared when farming was removed from the analysis. I The checklist of substances encountered in the workplace was reviewed for each respondent. Sjo significant relationships were found with asbestvs. textiles. metal fumes. wood dusts. coal. silicabdr other rock dusts. No relationship between occupational exposare to ionizing radiation was detected. probably because there i s virrually no nuclear industry in Bntish Columbia. and consequently no reports. of exposure. h r u n pairern3 An examination of dietar! factors showed no difference between myeloma patients and combined control pdiients for consumption of meats. fish. tea. coffee. or spic! foods Sncin-ri.onomic factors. mcliidinR Jetiraf /iIsrorr .Lt>elorna patients and controls showed differences in dsntal histor:. which appear likely to be related to socio-economic difference5 between the groups. Signiticunti! fet4t.r ni!t.lonia patients had dentures than did the control> iRR=iI.45. P=O.OJ). .Ll!eloma patients mere more likel) IO have had orthodontic work than controls. and less likely to have had 5 or more teeth extractcd at one time. Neither of these relationships were significant. In addition. myeloma parients reportea more prior nose and throat operations. other than ronliillcctumit.s. than thc controls ( R R =2.9. P=0.011. Since a number 01' these procedures were reported as cosmetic nose operations. the relationship is likel! to be a n artefact due to the higher jocio-economic Status of the myeloma patients. Soiokirir unti ~ii~rilrioiis(~ Due t o the known association of smoking and alcohol use with head and neck turnours. myeloma patients were compared with the non-head and neck controls onl!. ior these factors. .M>eloma cases appeared to smoke less than controls t R R s 0 . 4 8 . P =0.08r. although the difference was not significant. There was no difference between cases and controls for alcohol zonsurnption. Discussion The f x t that only 20"h of the cases seen Jt AMEC from 1972-1981 were interviewed for the study raises the possibility that sampling biases have been introduced. In fact. the 32 prevalent cases, diagnosed between I972 and 1975 were different from the other cases diagnosed during those years by virtue of the fact that they had survived to the time of the inten'iew. Th:s may mean that their disease process was less severe and they did not develop medical complications leading to a fatal outcome. o r that they responded better to therapy. As described earlier. the relationship between myeloma and farmin_e appears to be centered in the incident caseload diagnosed from 1979-1981 and absent in the prevalent group or cases. The relationship between myeloma and allergies is present in both the prevalent and incident case groups. I t would appear. then. that the possible biases introduced by the small sample of cases diagnosed from 1972-1978 who were actually interviewed could only have the effect of decreasing the strength of the associations detected in our study. I n spite of the relativel! small number of cases interviewed for the study. several significant