HAIR DYES AND CANCER: ANOTHER CONFOUNDING FACTOR?

HAIR DYES AND CANCER: ANOTHER CONFOUNDING FACTOR?

536 ACTH AND &bgr;-ENDORPHIN ascertained deaths from all causes over 21 years up to 1969 among 480 adult Mexicans who had been examined in 1948 and ...

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536 ACTH AND

&bgr;-ENDORPHIN

ascertained deaths from all causes over 21 years up to 1969 among 480 adult Mexicans who had been examined in 1948 and given hair-greyness scores; after relating mortality to greyness, allowing for sex and age, they concluded that the results indicated a possible association between greyness and mortality. They also noted that age at greying was related to race. I am not suggesting a direct association between cancer and early greying, but rather that, on present knowledge, the possibility cannot be excluded and should not be ignored. Surely the design of any study of hair-dye use among cancer patients should take account of possible case/control differences in natural hair colour and age at greying among both dye users and non-users.

RECORDED BEFORE, DURING, AND AFTER ELECTROACUPUNCTURE: MEAN ±SD

(N=10)

*Time 0 refers

to

the basal

conditions, times 9, 15, 18 min during elec-

troacupuncture, and 30, 60 and 80 min after electroacupuncture.

Division of Epidemiology, Institute of Cancer Research, Sutton, Surrey SM2 5PX

der certain experimental conditions p-endorphin can increase in the peripheral blood system, but not in the brain.5,6 The physiological significance of peripheral &bgr;-endorphins is not yet known. E. MALIZIA Antiveleni Centre,

University of Rome, and Medical Clinic V,

University of Rome, Policlinico Umberto I,

Rome, Italy

HOW MANY LEGIONNAIRES?

G. ANDREUCCI D. PAOLUCCI F. CRESCENZI A. FABBRI F. FRAIOLI

SIR,-The’properties of a second strain of Legionella pneumophila (Cambridge 2) recently isolated in Cambridge draw attention to current aspects of the microbiology of legion-

HAIR DYES AND CANCER: ANOTHER CONFOUNDING FACTOR?

SiR,—The possible carcinogenicity of hair dyes is a topic of and research, especially with regard to breast

current concern

Kinlen et aLl found no difference in usage between breast-cancer cases and controls, but Shore et awl. reported that when confounding variables had been controlled, regular dyeing was positively associated with breast cancer if frequency and length of use were taken into account; this applied particularly to women aged over fifty at diagnosis. Hennekens et al. did not consider that their results indicated an association between hair-dye use and breast cancer. The authors of these three papers discuss possible confounding variables such as social class, smoking, and age at first pregnancy, and clearly recognise their importance, but another possible confounding factor is not mentioned in any of the papers and does not seem to have been covered by the questionnaires-namely, natural hair colour. After the age of about forty the prevalence of regular hair dyeing among any group of women is likely to be related to the prevalence of grey hair among them, and the use of dyes by younger women must surely be related to hair colour (and perhaps also to hair texture). If, for some genetic or other reason, early greying or another relevant hair characteristic was more prevalent among women who later developed breast cancer this might account for more of them becoming regular dye users; the same argument could apply to any cancer site. A literature search back to 1973 revealed only one paper relating hair greying to subsequent disease. Laker and Kaplan44 cancer.

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5. Rossier J, French ED, Rivier C, Ling N, Guillemin R, Bloom FE. Foot-shock induced stress increases beta-endorphin levels in blood but not in the brain. Nature 1977; 270: 618-20. 6. Cheung AL, Goldstein A. Failure of hypophysectomy to alter brain content ofopioid peptides. Life Sci 1976; 23: 1480-85. 1. Kinlen LJ, Harris R, Garrod A, Rodriguez K. Use of hair dyes by patients with breast cancer: a case-control study. Br Med J 1977; ii: 366-68. 2. Shore RE, Pasternack BS, Thiessen EU, Sadow M, Forbes R, Albert RE. A case-control study of hair dye use and breast cancer. J Nat Cancer Inst

1979; 62: 277-83. 3. Hennekens CH, Rosner B, Belanger C, Speizer FE, Bain CJ, Peto R. Use of permanent hair dyes and cancer among registered nurses. Lancet 1979; i: 1390-93. 4. Lesker GW, Kaplan B. Graying of the hair and mortality. Soc Biol 1974; 21: 290-95.

JOAN M. DAVIES

naires’disease. The Cambridge 2 strain was isolated from a woman aged 76 with chronic lymphatic leukaemia who had been on 10 mg prednisolone/day until April 20, 1979, when the dosage was increased to 20 mg/day. Her respiratory illness began on May 4 with fever, unproductive cough, shortness of breath, and pain in her right arm, although she was able to play the violin on the day before she was admitted to hospital on May 7. On admission she had pneumonia with left-lower-lobe consolidation ; her condition deteriorated rapidly and she died suddenly on May 8. She had no serological evidence of L. pneumophila infection in immunofluorescence tests with antigens of serogroups 1-4’ or Cambridge 2. Post-mortem lung smears fixed with acetone and stained for L. pneumophila by direct immunofluorescence with anti-serogroup 1 conjugate, provided by Dr A. G. Taylor of the Standards Laboratory, Public Health Laboratory Service, failed to give any staining. Indirect immunofluorescence staining with rabbit antisera to serogroups 1-4 gave specific staining with antisera to serogroups 3 and 4 only. Dilutions of lung homogenate were cultured on cysteinecontaining and other media2,3 and a heavy growth was obtained of an organism identical with L. pneumophila in morphology, staining, and growth requirements. Subsequently it was further confirmed to be L. pneumophila by the lipid profile in gas-liquid chromatography (Dr R. M. McKinney, Center for Disease Control, Atlanta). However, when smears of the isolate were fixed with acetone and stained with direct conjugates of antisera to serogroup 1 (provided by Dr Taylor) and serogroups 1, 2, and 3 (provided by Dr R. J. Fallon) there was complete absence of specific staining. No staining was achieved with a further set of direct conjugates to serogroups 1-4 in the hands of Dr McKinney. When rabbit antisera prepared against serogroups 1-4 were used for indirect immunofluorescence the organisms were stained to some extent by all of the sera, especially those against serogroup 1 and the Oxford serogroup 3 (provided by ,

Dr J. O’H. Tobin). These results suggest that Cambridge 2 may be sufficiently distinct to be a new serogroup or it may be an example ofantigenic variation of a known serogroup; and they emphasise the 1. McKinney RM, et al. Four serogroups of legionnaires’ disease bacteria defined by direct immunofluorescence. Ann Intern Med 1979; 90: 621-24. 2. Nagington J, Smith DJ, Wreghitt TG. Isolation of legionnaires’ disease organism in Cambridge. Lancet 1978; ii: 1144-45. 3. Greaves PG, Sharp G, Macrae AD. Isolation of Legionella pneumophila. Lancet 1979; i: 551-52. 4.

Nagington J, Wreghitt TG, Tobin JO’H, Macrae AD. The antibody response in legionnaires’ disease. J Hyg Camb (in press).