Biological monitoring of low-level exposure to benzene.

INTRODUCTION: Conflicting opinions exist about the reliability of biomarkers of low-level exposure to benzene. We compared the ability of the urinary excretion of trans,trans-muconic acid (t,t-MA), s-phenilmercapturic acid (s-PAMA) and urinary benzene (U-Benz) to detect low level occupational and environmental exposure to benzene. METHODS: We monitored airborne benzene by personal air sampling, and U-Benz, s-PMAI, t,t-MA and cotinine (U-Cotinine) in spot urine samples, collected at 8 am and 8 pm, in 32 oil refinery workers and 65 subjects, randomly selected among the general population of urban and suburban Cagliari, Italy. Information on personal characteristics, diet and events during the sampling day was acquired through in person interviews. RESULTS: The median concentration of airborne benzene was 25.2 microg/m3 in oil refinery workers, and 8.5 microg/m3 in the general population subgroup. U-Benz in morning and evening samples was significantly more elevated among oil refinery workers than the general population subgroup (p = 0.012, and p = 7.4 x 10(-7), respectively) and among current smokers compared to non-smokers (p = 5.2 x 10(-8), and p = 5.2 x 10(-5) respectively). Benzene biomarkers and their readings in the two sampling phases were well correlated to each other. The Spearman's correlation coefficient with airborne benzene was significant for U-Benz in the evening sample, while no correlation was seen with t,t-MA and s-PMA readings in either samplings. The two benzene metabolites were frequently below limit of detection (LOD), particularly among the general population study subjects (17-9% and 39%, for t,t-MA and s-PMA respectively). Morning U-Cotinine excretion showed a good correlation with U-Benz in the morning and in the evening sampling (p < 0.001), and with s-PMA in the evening sample (p < 0.001), but not with t,t-MA in either samplings. t,t-MA in the evening sample was the only biomarker showing a moderate inverse correlation with BMI (p < 0.05). The multiple regression analysis adjusting by BMI and number of cigarettes smoked during the day confirmed the results of the univariate analysis. DISCUSSION: Our results suggest that unmetabolized U-Benz would allow a more reliable biomonitoring of low-level exposure to benzene than s-PMA and t,t-MA.

[Risk of major lymphoma subtypes and use of mobile phones]. / Rischio dei principali sottotipi di linfoma associato all'uso di apparati di telefonia mobile.

INTRODUCTION: We explored the association between use of mobile phones and lymphoma risk in a case-control study. METHODS: We conducted unconditional logistic regression analysis in 322 lymphoma cases and 446 population controls, adjusting by age, gender and education. RESULTS: Risk of lymphoma (all types; OR = 1.5; 95% CI 1.0 - 2.1), and chronic lymphocytic leukaemia (OR = 1.8; 95% CI 1.0 - 3.4) was elevated in subjects reporting use of mobile phones, but it decreased with duration of use, and years from first purchase. CONCLUSIONS: Our contradictory findings would not support the aetiological nature of the observed associations.

Dust exposure, respiratory symptoms, and longitudinal decline of lung function in young coal miners.

OBJECTIVES: To study the role of dust exposure on incidence of respiratory symptoms and decline of lung function in young coal miners. METHODS: The loss of lung function (forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow (MEF), carbon monoxide transfer factor (TLCO)) with time and the incidence of respiratory symptoms in 909 Sardinian coal miners (followed up between 1983 and 1993 with seven separate surveys) has been compared with the past and current individual exposures to respirable mixed coal dust. Multiple linear and logistic regression models were used simultaneously controlling for age, smoking, past occupational exposures, and other relevant covariates. RESULTS: According to the relatively low dust exposures experienced during the follow up few abnormal chest x ray films were detected. In the cross sectional analysis of initial data, significant associations between individual cumulative exposure to dust, decrements in FEV1 and MEFs, and increasing prevalence of respiratory symptoms were detected after allowing for the covariates included in the model. The yearly decline of FVC, FEV1, and single breath carbon monoxide transfer factor (TLCO/VA) was still significantly related to the individual exposure to dust experienced during the follow up, even after allowing for age, smoking, initial cumulative exposure to dust, and initial level of each functional variable. In logistic models, dust exposure was a significant predictor of the onset of respiratory symptoms besides age and smoking. CONCLUSIONS: The results show that even moderate exposures to mixed coal dust, as in our study, significantly affect lung function and incidence of symptoms of underground miners. Although the frequency of chest x ray examination might be fixed at every three or four years, yearly measurements of lung function (spirometry, MEFs, and TLCO) are recommended for evaluation of the respiratory risk from the coal mine environment to assess the need for further preventive interventions.

Glucose-6-phosphate dehydrogenase deficiency and cancer in a Sardinian male population: a case-control study.

A case-control study was conducted to test the hypothesis whether the genetic condition of glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with a reduced risk of cancer. One hundred and eighty seven male cancer patients admitted to hospitals in Cagliari (Sardinia, Italy), between November 1984 and March 1986, were compared with 186 male patients with other diseases, except hemolytic anemia, admitted to the same hospitals in the same period. In contrast to previous reports, our study found no reduction of cancer risk in G6PD-deficient subjects. The study had sufficient statistical power to detect a 0.5-fold decrease in the risk of cancer. The recent suggestion from other studies that tumoral cells of G6PD-deficient subjects can produce their own G6PD, seems to be consistent with this negative finding. Among those subjects presenting some level of erythrocyte G6PD activity, the average enzyme activity was significantly higher in cancer patients than in controls. This finding is consistent with previous experimental studies suggesting a positive correlation between cell proliferation and G6PD activity.

[Polychlorobiphenyl content in adipose tissue of subjects not exposed professionally]. / Contenuto di PCB nel tessuto adiposo di soggetti non esposti professionalmente.

Polychlorinated biphenyl (PCB) levels were determined in 52 samples of adipose tissue removed during surgery from patients residing in a central region of Sardinia who had no previous occupational exposure. The average PCB value of the whole group was 0.72 microgram/g (range 0.11-2.81 micrograms/g); in males the average value (means = 0.97 microgram/g) was significantly higher than in females (means = 0.60 microgram/g). A positive correlation was observed between age and PCB levels in adipose tissue. This analysis could be usefully performed in occupationally exposed subjects so as to better assess the exposure level.