Hair dye use and other risk factors for leukemia and pre-leukemia: a case-control study. Italian Leukemia Study Group

Smoking and myelodysplastic syndromes

The purpose of this case-control study was to investigate tobacco smoking as a risk factor for myelodysplastic syndromes, emphasizing karyotypic aberrations as markers for exposure and risk differentiation with respect to morphology. We obtained smoking history by interview of 330 cytogenetically investigated adult myelodysplastic syndrome cases and 337 controls, matched with respect to sex, year of birth, and county of living. Smoking for at least 1 year at some time 20 years or less before diagnosis was associated with an elevated relative risk (RR) for primary myelodysplastic syndromes (odds ratio (OR) 1.8; 95% confidence interval (CI) = 1.2-2.7). The results indicated a relation with intensity and duration of smoking as well as a decrease in risk a few years after cessation of smoking. Smoking was associated with an increased RR for primary myelodysplastic syndromes with chromosome 7 abnormalities (OR 5.0; 95% CI = 1.1-23). Elevated RRs were also seen for refractory anemia (OR 2.5; 95% CI = 1.2-5.6) and for refractory anemia with ringed sideroblasts (OR 3.2; 95% CI = 0.88-12). The findings suggest that smoking is a risk factor for myelodysplastic syndromes.

Tobacco and the risk of acute leukaemia in adults

Self-reported smoking histories were collected during face-to-face interviews with 807 patients with acute leukaemia and 1593 age- and sex-matched controls. Individuals who had smoked regularly at some time during their lives were more likely to develop acute leukaemia than those who had never smoked (odds ratio (OR) = 1.2, 95% confidence interval (CI) 1.0-1.4). The association was strongest for current smokers, defined here as smoking 2 years before diagnosis (OR = 1.4, 95% CI 1.1-1.7). With respect to the numbers of years smoked, risk estimates were raised in all groups except those who had smoked for fewer than 10 years. Similarly, the odds ratio decreased as the number of years 'stopped smoking' increased, falling to one amongst those who had given up smoking for more than 10 years. No significant linear trends were found, however, with either the numbers of years smoked or the numbers of years stopped smoking, and no significant differences were found between AML and ALL.

Gingival hemorrhage, myelodysplastic syndromes, and acute myeloid leukemia. A case report

Myelodysplasia syndrome (MDS) presenting as spontaneous gingival hemorrhage is described. Gingival hemorrhage is recognized as a symptom of MDS, a rare group of potentially fatal hematological disorders, but it has not previously been documented as a presenting sign. The diagnostic pitfalls are discussed with the case, and the need for careful interpretation of laboratory findings in conjunction with clinical signs is emphasized. Finally, the MDSs are defined, classified and discussed with respect to their relevance to the clinical periodontist, from a diagnostic, therapeutic, and management standpoint.

Occupational, environmental, and life-style factors associated with the risk of hematolymphopoietic malignancies in women

BACKGROUND

The etiology of lymphomas, leukemias, and multiple myeloma is still largely unknown. The known risk factors (ionizing radiation, solvent exposure, pesticide exposure, immunosuppression) explain only a small proportion of the cases that occur.

METHODS

We conducted a multicenter population-based case-control study on hematolymphopoietic malignancies in Italy and interviewed 2,011 women (1,183 cases and 828 controls).

RESULTS

There was a suggestion of a positive association between smoking and the risk of non-Hodgkin's lymphoma + chronic lymphocytic leukemia. A slight increased risk of leukemias was observed among women using permanent hair dye. Housewives were at increased risk for leukemia and multiple myeloma. The risk of non-Hodgkin's lymphomas + chronic lymphocytic leukemia, leukemias, multiple myeloma, and Hodgkin's disease increased among women employed as hairdressers and textile workers. Teachers were at increased risk for non-Hodgkin's lymphomas + chronic lymphocytic leukemia, leukemias, and Hodgkin's disease.

CONCLUSIONS

These results confirm previous associations and may provide additional clues to some determinants of hematolymphopoietic malignancies in women.

Human herpes virus-6 seroprevalence and leukaemias: a case-control study. GIMEMA (Gruppo Italiano Malattie Ematologiche dell' Adulto)

The relationships between acute myeloid leukaemia (AML), acute lymphocytic leukaemia (ALL), chronic myeloid leukaemia (CML) and refractory anaemia with excess of blasts (RAEB) and human herpes virus (HHV)-6 antibody level were investigated in a multicentre case-control study. An association between increased HHV-6 seropositivity and geometric mean titre ratio with AML was shown: P for trend = 0.022, adjusted odds ratio 1.20, 95% confidence interval 1.07-1.33 respectively. No association was found between HHV-6 and ALL, CML or RAEB.

Hair dye use and occupational exposure to organic solvents as risk factors for myelodysplastic syndrome

To investigate the relationships of personal hair dye use and environmental factors to myelodysplastic syndromes (MDS), we conducted a case-control study in Japan. A total of 111 MDS cases and 830 controls randomly selected from the residents in the same prefecture of cases using telephone directories responded to a health questionnaire. The odds ratio (OR) for ever having used hair dye was 1.99 (95% confidence interval (CI) 1.17-3.38) and there were statistically significant trends in risk with increasing duration and number of hair dye use. Occupational exposure to organic solvents was marginally associated with the risk of MDS (OR = 1.99; 95% CI 0.97-4.10).

Acute promyelocytic leukaemia: epidemiology and risk factors. A report of the GIMEMA Italian archive of adult acute leukaemia. GIMEMA Cooperative Group

Acute promyelocytic leukaemia (APL) exhibits peculiar epidemiological, clinical, cytogenetic and molecular features, compared to the other acute myeloid leukaemias (AML). Data on epidemiology and occupational risk factors for APL desumed from the GIMEMA archive are reported and compared with those of the other AML. An exploratory case-case study was designed on AML patients from 56 haematology centres in Italy. Overall, 4296 patients older than 15 yr with a new diagnosis of acute leukaemia were recorded between July 1992 and July 1997. Of these, 335 were classified as APL, and 2894 as other AML. The median age of APL patients was 43 compared to 59 yr for the other AML (p < 0.00001). In order to identify peculiar risk factors for APL development, different parameters were compared in the 2 groups. After adjusting by age no significant differences were observed with regard to education, lifetime prevalence of cancer among siblings and previous diseases in the patient's history. Occupational exposure as a possible risk factor for APL showed no increased risk compared to other AML among farmers, builders and leather workers. A significant association was found in electricians (OR=4.4, 95% CI=2.0-9.7) and a weak association was found in wood workers (OR=3.2, 95% CI=0.8-10.8). The proportion of APL with respect to other AML was significantly higher in the north east of Italy compared to the rest of the country (OR=1.7, 95% CI=1.3-2.2). These data confirm the younger age of APL patients compared to the other AML. A possible role of electromagnetic fields is suggested by the higher risk of APL in electrical workers and in the more industrialized areas of the country.

Adult myeloid leukaemia, geology, and domestic exposure to radon and gamma radiation: a case control study in central Italy

OBJECTIVES

To investigate whether indoor randon or gamma radiation might play a part in myeloid leukaemia as suggested by studies based on crude geographical or geological data for exposure assessment.

METHODS

For six months randon and gamma radiation was measured with solid state nuclear track detectors and thermoluminescent dosimeters in dwellings of 44 adult male cases of acute myeloid leukaemia and 211 controls (all subjects deceased). Conditional logistic regression ORs (ORs) and 95% confidence intervals (95% CIs) were estimated for quartiles of radon and gamma radiation and for municipality and dwelling characteristics.

RESULTS

The risk of leukaemia was associated with an increasing urbanisation index (p value for trend = 0.008). An increased OR was found among those living in more modern houses (OR 3.0, 95% CI 1.4 to 6.6). Confirming the findings of a previous study in the same area, geological features bore a positive association with myeloid leukemia, even by adjusting for level of urbanisation. Contrary to expectations from the previous study, however, no association appeared between myeloid leukaemia and radon and gamma radiation; for the highest quartiles of exposure, ORs were 0.56 (95% CI 0.2 to 1.4) and 0.52 (95% CI 0.2 to 1.4), respectively. Considering only subjects who had lived > or = 20 years in the monitored home and adjusting for urbanisation, there was still no effect of exposure to radiation.

CONCLUSIONS

In view of the limited numbers, the results do not in general refute a possible risk of myeloid leukaemia from exposure to indoor radon or gamma radiation, but decrease the credibility of such a relation in the area studied and also of other studies suggesting an effect without monitoring indoor radiation. Some other fairly strong determinants have appeared--that is, level of urbanisation and living in modern houses--that might need further consideration.

Increasing incidence of myelodysplastic syndromes: real or fictitious?

Over the past 10-20 years, there has been a growing interest in the myelodysplastic syndromes (MDS). Due to difficulties of diagnosis, classification and case recording, the epidemiological features of MDS are still poorly defined. Recently, a number of cancer registries have published data on the regional occurrence of MDS, suggesting that MDS are much more common than previously thought. The crude incidence of MDS in these studies was 3.5-12.6 per 100,000 population per year. In people over the age of 70 years, incidence rates varied between 15 and 50 per 100,000 per year. Contrary to the assumption of most hematologists, cancer surveys usually failed to demonstrate a rising incidence of MDS. In those studies showing a significant increase in MDS, the rising number of cases was probably due to increased physician awareness and extended use of invasive diagnostic procedures in elderly people. Differences in incidence figures between regional studies may be attributed to several causes, including regional variations in disease incidence, small and ill-defined reference populations, bias due to patient referral patterns, varying intensity of diagnostic procedures and different observation periods. Because of the paucity of clinical symptoms and insignificance of morphological bone marrow changes particularly in early stage MDS, the currently available incidence figures are likely to underestimate the true incidence of MDS. Large-scale epidemiological studies are required for obtaining truly representative statistics on the incidence and prevalence of the MDS. In industrialized countries, a dramatic increase in these disorders can be expected over the next few decades due to the 'greying' of the population.

Hematopoietic and lymphatic malignancies in vehicle mechanics

Although it is generally acknowledged that benzene causes leukemia, especially acute myeloid leukemia, considerable divergences persist in the assessment of the leukemia risk due to occupational low-level benzene exposure. Specifically, the risk for vehicle mechanics is considered by some authors as being nondetectable with epidemiologic methods, whereas others calculated that the incidence rate of leukemia (all types) in vehicle mechanics is increased more than 60 times. The purpose of this review is to examine the publications on this topic in light of criteria for causal inference and to discuss the possible role of bias, confounding factors, and chance. The results of this analysis reveal that there are surprisingly few epidemiologic observations supporting an increased incidence of leukemia in vehicle mechanics. Apparently, publications suggesting a leukemogenic effect of low-level benzene exposure in garage mechanics are more often quoted than their negative counterparts, although they are not better designed.

Risk factors for essential thrombocythemia: A case-control study. Italian Leukemia Study Group

BACKGROUND

Very little information is presently available regarding risk factors for essential thrombocythemia (ET).

METHODS

A case-control study was performed to study the possible association between ET and selected behavioral, occupational, and environmental exposures.

RESULTS

Thirty-nine patients aged 20 years or older and 156 controls were enrolled in 2 Italian Hematology Departments located in Rome and Pavia. Controls were recruited among outpatients seen in the same hospitals and matched 4:1 to the patients after stratification by age and sex. Odds ratio (OR) estimates suggest an association between ET and hair dye use (in particular the use of dark hair dye for periods longer than 10 years: OR - 5.3; 95% confidence interval [CI], 1.4-19.9), living in houses built with tuff (a material with a high concentration of gamma-emitting radionuclides and radon) for longer than 9 years (OR = 5.1; 95% CI, 1.2-22.1), and selected occupations (electrical worker and shoemaker, OR +infinity and 2.7; 95% CI, 0.5-16 respectively).

CONCLUSION

Behavioral exposures such as hair dyes, living in a tuff house, and working as an electrician are significantly associated with ET development. The data are consistent with those observed in acute leukemias.

Epidemiologic perspectives on myelodysplastic syndromes and leukemia

The ICD classification of the myelodysplastic syndromes (MDS), and the four main features of the descriptive epidemiology of the condition are discussed. MDS is: (1) a rare disease; which may be, (2) on the increase; (3) which primarily affects the elderly; and (4) which predominantly affects men. We reviewed four causal models pertaining to the relationship between MDS and leukemia. These models may be described as: (1) non-biological correlates; (2) biological correlates; (3) early phase; and (4) interactive cause. Each model is described and the evidence in support of or against each is presented.