Childhood leukemia and parents' occupational and home exposures.

A case-control study of children of ages 10 years and under in Los Angeles County was conducted to investigate the causes of leukemia. The mothers and fathers of acute leukemia cases and their individually matched controls were interviewed regarding specific occupational and home exposures as well as other potential risk factors associated with leukemia. Analysis of the information from the 123 matched pairs showed an increased risk of leukemia for children whose fathers had occupational exposure after the birth of the child to chlorinated solvents [odds ratio (OR) = 3.5, P = .01], spray paint (OR = 2.0, P = .02), dyes or pigments (OR = 4.5, P = .03), methyl ethyl ketone (CAS: 78-93-3; OR = 3.0, P = .05), and cutting oil (OR = 1.7, P = .05) or whose fathers were exposed during the mother's pregnancy with the child to spray paint (OR = 2.2, P = .03). For all of these, the risk associated with frequent use was greater than for infrequent use. There was an increased risk of leukemia for the child if the father worked in industries manufacturing transportation equipment (mostly aircraft) (OR = 2.5, P = .03) or machinery (OR = 3.0, P = .02). An increased risk was found for children whose parents used pesticides in the home (OR = 3.8, P = .004) or garden (OR = 6.5, P = .007) or who burned incense in the home (OR = 2.7, P = .007). The risk was greater for frequent use. Risk of leukemia was related to mothers' employment in personal service industries (OR = 2.7, P = .04) but not to specified occupational exposures. Risk related to fathers' exposure to chlorinated solvents, employment in the transportation equipment-manufacturing industry, and parents' exposure to household or garden pesticides and incense remains statistically significant after adjusting for the other significant findings.

Cigarette smoking, obesity, diuretic use, and coffee consumption as risk factors for renal cell carcinoma.

One hundred sixty incident cases of renal cell carcinoma under the age of 55 years and an equal number of age-(within 5 yr), race-, and sex-matched neighborhood controls were interviewed. Cigarette smoking was a risk factor for renal cell carcinoma in males [relative risk (RR) = 2.1, one-sided P = .02] but not in females (RR = 1.1, P = .50). Obesity was a significant risk factor in both males and females: The RR for a 4th quartile compared to a 1st quartile Quetelet's Index 10 years ago was 2.5 for males and 3.3 for females. Additional risk factors in females were diuretic use (RR = 4.5, P = .002) and daily coffee consumption (RR = 2.3, P = .06).

An 11-year longitudinal study of the occupational dust exposure and lung function of polyvinyl chloride, cement and asbestos cement factory workers.

Standardized questionnaires and lung function tests were administered in 1973, 1980, and 1984 to 126 workers occupationally exposed to polyvinyl chloride (PVC) dust, to cement dust, or to asbestos cement dust until 1974-1978 and to PVC thereafter. The workers in the last group were assigned to two asbestos exposure categories (heavy and slight). The decline in forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1.0) was analyzed with regard to the length of time since the data of first employment. After adjustment for age, height, and smoking status at the date of first employment, the decline in FVC and FEV1.0 among the nonsmokers-light smokers was slightly accelerated with length of employment in the PVC and slight asbestos exposure groups and markedly accelerated with time since first employment in the heavy asbestos exposure group. The heavy smokers in all the exposure groups had FVC and FEV1.0 predicted values that were lower than those of the nonsmokers-light smokers; these differences remained constant with length of employment. Cessation of asbestos exposure for about 10 years did not seem to change lung function decline.

Blood lead levels in children living in three communities, at different risks of lead pollution.

We carried out a survey on blood lead levels in children living in three different communities in Umbria, Italy: Corciano, a small community (12,500 inhabitants), free of lead-using factories and with light traffic; Perugia, a medium-sized city (146,500 inhabitants); Deruta, a small community (7500 inhabitants) whose economy is based mainly on the production of artistic pottery, mostly in small home-operated factories. The study sample was made up of 539 children (275 boys and 264 girls); 156 of them attended nursery school (aged 3-6) and 383 primary school (aged 6-11). The mean blood lead level was significantly higher in Deruta than in Corciano (9.7 vs 8.3 micrograms/dl); Deruta children whose parents were occupationally exposed to lead had significantly higher blood lead levels than children of lead-unexposed parents (10.7 vs 9.0 micrograms/dl). The mean blood lead level was higher in Perugia than in Corciano children. On the average boys had higher blood lead levels than girls in all of the groups. We conclude that blood lead levels were low in the groups of children studied. Nevertheless children of ceramic workers and children living in a medium-sized city had greater lead absorption than children living in the control area.

Effects of low doses of lead on children's health.

An investigation has been carried out of the blood lead levels of children resident in three different municipalities of Umbria: Corciano, selected as a control area; Perugia, the largest town in Umbria (approx. 150,000 inhabitants), with intense automobile traffic; and Deruta a town in which there is a flourishing ceramic industry. The mean blood lead levels were found to be higher in children in Perugia (96 micrograms/l) and Deruta (97 micrograms/l) with respect to Corciano (83 micrograms/l); in Deruta the mean blood levels were raised in those children whose families are occupationally exposed to lead (107 micrograms/l). The concentration of lead in the air in Deruta was higher than in Corciano (0.19 vs 0.11 microgram/m3, respectively). The lead concentrations in house dust were higher in Deruta (2.8 micrograms/m2) than in Corciano (0.8 microgram/m2) and the difference was greater in the houses were the inhabitants were exposed to lead in factories (2.7 micrograms/m2) or in workshops which were adjacent to the houses (4.7 micrograms/m2). The blood lead levels of children included in this study have been compared with those obtained during a similar investigation in 1978. Over the last eight years primary school children in Corciano and Deruta have shown a marked reduction in blood lead levels (greater than 50%). This improvement should not lead to false optimism: in fact, it is impossible to establish the blood lead level at which no adverse effects are induced, especially in children. Numerous studies suggest that even sub-clinical levels of lead can cause alteration in heme synthesis, peripheral nervous system, kidney, immune system, skeleton and growth. Furthermore, with regard to the central nervous system, low blood lead levels can provoke neuropsychological deficits, which can result above all, in a decreased I.Q., and behavioural alterations.

Lung function among asbestos cement factory workers: cross-sectional and longitudinal study.

Ventilatory capacity tests and standardized respiratory questionnaires were used in 1973 and in 1980 to measure the effect of mixed dust exposure in the asbestos cement industry on respiratory symptoms and lung function in 65 exposed workers and 30 controls (exposed to polyvinyl chloride but not to asbestos). Workers exposed to asbestos had 1) a higher prevalence of breathlessness and chest pain, and a higher incidence of breathlessness; 2) lower 1980 values of forced vital capacity (FVC) (0.27-0.83 liters) and forced expiratory volume in 1 sec (FEV1) (0.23-0.62 liters); and 3) a faster decline (nearly 40 ml/year) in FVC and FEV1 between 1973 and 1980. The FVC annual decrease was 52.5 ml in the subjects with more than 15 years since first asbestos exposure, whereas it was 24.3 ml in those with less than 15 years, suggesting a faster decline after 15 years of exposure. The effect of asbestos exposure and smoking habits was less than additive as regards pulmonary function.

Occupational asbestos exposure and mesothelioma risk in Los Angeles County: application of an occupational hazard survey job-exposure matrix.

We evaluated the newly available National Institute for Occupational Safety and Health (NIOSH) National Occupational Hazard Survey (NOHS) job exposure matrix (JEM) by considering mesothelioma risk from asbestos exposure. We applied this system (NOHS-JEM) to the Los Angeles County Cancer Surveillance Program (CSP) to see how many cancer cases could be assigned asbestos exposure and how asbestos exposure affected mesothelioma risk. Using the same CSP data, our "experts" classified asbestos exposure simply by occupation and industry. Both exposure classifications were divided into low and high; the NOHS-JEM by the number of exposed people per couplet, and ours by judgements of intensity. Odds ratios (OR) for mesothelioma risk for low and high asbestos exposure for the NOHS-JEM were 2.0 (95% C.I. 1.2-3.4) and 2.5 (95% C.I. 1.2-4.8). For ours, corresponding risks were 1.6 (95% C.I. 1.1-2.4) and 6.3 (95% C.I. 2.5-15.1). Our system was able to assign more cases to couplets then the NOHS-JEM (35,895 to 22,369). Three limitations of the NOHS-JEM were that many occupation-industry couplets were not classified at all, many couplets associated with past asbestos exposure (before the 1972-1974 NOHS survey) were not classified as asbestos exposure, and no assessment of intensity was made. These limitations may apply to other exposures and should be carefully considered before the NOHS-JEM is applied to other case-control studies.

Mortality from cancer and chronic respiratory diseases among workers who manufacture carbon electrodes.

OBJECTIVES: To investigate the risk of cancer and non-neoplastic respiratory diseases among workers who manufacture carbon electrodes, as this industry entails exposure to mixtures of polycyclic aromatic hydrocarbons. METHODS: A historical cohort study was carried out of 1006 male workers employed for at least 1 year between 1945 and 1971 in a carbon (graphite) electrode production plant in central Italy, who were followed up for mortality between 1955 and 1996. The ratio of observed to expected deaths (standardised mortality ratios, SMRs) was computed from both national and (for the period 1964-96) regional age and period specific mortalities. A multivariate Poisson regression analysis was performed to investigate the relative risk (RR) of death according to duration of employment and time since first employment in the factory. RESULTS: A total of 424 workers had died, 538 were still alive, and 44 were lost to follow up. Mortalities from all causes, all cancers, and respiratory tract cancer were in line with the regional figure. An excess was found over the expected deaths from skin cancer including melanoma (SMR 3.16, 95% confidence interval (95% CI) 0.65 to 9.23) and from non-neoplastic respiratory diseases (SMR 1.58, 95% CI 1.16 to 2.11). Poisson regression analysis including age as a covariate showed an increased risk of dying from gastric cancer with increasing duration of employment, and an increase in the RR of dying from lung cancer and from non-neoplastic respiratory diseases with increasing time since first employment, although the linear trend was not significant. CONCLUSION: This study supports previous findings that working in the carbon electrode manufacturing industry may not increase the risk of dying from respiratory cancer. However, a possible association with non-malignant respiratory diseases cannot be excluded.