The objectives of the present study were to evaluate the preconceptual, prenatal, and postnatal environmental factors as possible etiologic agents of childhood neoplasms. An exploratory case-control study was conducted on parents of children less than 15 yr of age with acute lymphocytic leukemia (ALL). Data were obtained on 147 identified cases by interview from their mothers and by mail questionnaire from their fathers. Hospital control cases were matched by sex and age, while population control cases were matched by place of residence, and sex. The following results were obtained.
1) As for the occupation of the parents, more fathers of the cases were engaged in occupations related to agriculture, medicine, and science than those of the controls, and more mothers of the cases were engaged in agriculture than those of the controls.
2) No significant relation could be demonstrated between ALL and occupations related to hydrocarbon and ionizing radiation.
3) The results of multivariate analysis showed that in comparison with the hospital control cases the preconceptual exposure to chemicals and the prenatal exposure to pesticides of the fathers and the prenatal exposure to benzine and spray pesticides of the mothers were risks of high significance. In comparison with population control cases, the prenatal exposure of benzine and exposure to paints of the mothers prior to disease onset were risks of high significance.
The foregoing results suggest that exposure to occupational and environmental factors of the parents may play an etiologic role in childhood leukemia.

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Musculoskeletal symptoms in pear and apple orchard workers were studied in relation to working postures, particularly arm elevation and head extension. The same forty-six female workers were examined three times; in May while thinning pears, in June while bagging pears, and in July while bagging apples. Musculoskeletal symptoms in the neck and shoulders were predominant in thinning and bagging pears when compared with bagging apples. When thinning pears, there was a significantly higher prevalence of complaints of stiffness and pain in the neck and shoulders, pain in the upper and lower back, muscle tenderness in the shoulders and forearm, and decreased back muscle power. When bagging pears, there was a significant difference in complaints of stiffness and pain in the neck and shoulders, muscle tenderness in the shoulders, and pain in motion of the neck joint. Pear tasks require more arm elevation and head extension than apple tasks. The working postures of arm elevation and head extension were considered to be a dominant causative factor in shoulder-neck disorders of the workers examined. The low back pain from thinning pears may be related with continuous backward bending of the back associated with the thinning work.

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The amount of water supply in Japan was 16 billion ton as of 1989. Water from rivers and other sources is purified, sterilized and then supplied to the residents through conduits. When conduits are accidentally damaged, they must be repaired by the workers of the Waterworks Bureau of the local government. In this task, the workers are exposed to airborne dust which develops while digging and filling the ground and cutting the conduit and the concrete covering the road. The purpose of the present study was to estimate the airborne dust exposure level among the workers and to investigate its effect on their respiratory organs. First, we measured the total dust exposure concentration of 20 conduit repair workers and the total dust concentration in 10 office rooms. Second, we conducted a self-administered questionnaire survey to estimate the prevalence of respiratory symptoms among the employees of 119 Waterworks Bureaus. The subjects of the analysis were 322 conduit repair workers and as their controls 345 clerical/engineering workers. The results can be summarized as follows:
1) The average daily total dust exposure while repairing conduits ranged from 0.27 to 5.05 mg/m³ (mean=0.91 mg/m³), while that while exchanging water meters from 0.23 to 0.52 mg/m³ (mean 0.41 mg/m³). These values were 4.6 and 2.1 fold higher than the total dust concentration in office rooms (mean=0.20 mg/m³).
2) With the use of fluorescent X-ray method, iron and aluminum were detected in all samples collected while repairing conduits and the intensity of X-ray increased with increase in weight of collected dust. Iron exposure concentration ranged from 0.006 to 0.095 mg/m³, which is much higher than the levels in the air in urban areas. Iron and aluminum could not be detected by fluorescent X-ray method in most of the samples collected in office rooms. These findings indicate that the main element in the dust collected while repairing conduits is soil, while that in office rooms is tobacco smoke.
3) Among the smokers, the prevalence of cough and phlegm was significantly higher in conduit repair workers than in clerical/engineering workers. A similar tendency was observed among ex-smokers and non-smokers, but the difference was not significant.
These results suggest the possibility in conduit repair workers who are current smoker that exposure to airborne dust during work affects their respiratory organs.

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