Importance of thyroid abnormalities detected at US screening: a 5-year follow-up.

PURPOSE: To clarify the natural history and frequency of thyroid echo abnormalities in a random adult population by performing a 5-year follow-up study of subjects of a previous thyroid ultrasonographic (US) screening study. MATERIALS AND METHODS: In the original survey, 253 randomly selected adults were screened by means of thyroid US. US abnormalities were detected in 69 subjects (27%). In the follow-up study, 57 (83%) of those 69 subjects who had abnormalities were reexamined by means of thyroid US, fine-needle aspiration biopsy (FNAB), blood tests, and clinical examination. RESULTS: Of 34 individual nodules, 12 (35%) had grown. Biopsy was performed in 10 of them. Nine were benign. One was equivocal, was excised, and proved to be an adenomatous nodule. Eight nodules (24%) had diminished or disappeared. Seven new focal lesions were found in seven subjects (12%). Biopsy was performed in five of these lesions, and they were benign. At 5-year follow-up, no thyroid malignancies were detected among subjects with echo abnormalities at the primary US screening. CONCLUSION: Thyroid US abnormalities occurring in a random adult population are predominantly benign and clinically unimportant.

Chemical exposures and respiratory cancer among Finnish woodworkers.

A case-control study of respiratory cancer, nested within a cohort of male woodworkers, was updated in Finland. The update extended the initial follow up of 3805 workers from 19 plants to 7307 workers from 35 plants. Each case of respiratory cancer (n = 136) diagnosed between 1957 and 1982 within the cohort was matched by year of birth with three controls (n = 408) from the cohort. Chemical exposures were assessed for the cases and the controls by a plant and period specific job exposure matrix. An excess of respiratory cancer was associated with phenol. Concomitant exposures to several other agents occurred as well, however, and no exposure-response relation for phenol was seen. An excess risk and an increasing exposure-response relation were found for engine exhaust from petrol and diesel driven factory trucks. The excess risk associated with pesticides was lower than in our previous study, an indication of qualitative and quantitative differences in exposure between the initial and augmented cohorts. Slightly increased risks were found for terpenes and mould spores, which may be due to chance although the contribution of occupational exposure cannot be ruled out. Exposure to wood dust, mainly from pine, spruce and birch, at a level of about 1 mg/m3, was not associated with lung cancer, upper respiratory cancer, or adenocarcinoma of the lung.

Respiratory cancers and chemical exposures in the wood industry: a nested case-control study.

A cohort of 3805 men who had worked for at least one year in the particleboard, plywood, sawmill, or formaldehyde glue industries between 1944 and 1965 was followed up until 1981. From within the cohort the 57 patients with verified "respiratory" cancer (ICD 7 codes: 160-162.1, 141, 143-8) were defined as "cases," and 171 men without respiratory cancer from within the cohort were matched on birth year and used as controls. The comparison of exposures was carried out according to work histories and job exposure matrices for each plant. The odds ratio for exposure to wood dust was 1.03 (32 exposed cases) without provision for any latent period, and 0.97 (27 exposed cases) when provision for a minimum latent period of ten years was applied. The odds ratios were 1.60 and 1.68, respectively, when smoking was controlled by stratification. These results did not differ significantly from unity. The estimated average level of exposure to wood dust among the exposed was 1-2 mg/m3 and the mean duration of exposure about ten years. Significantly (one sided test, 5% level) raised odds ratios were observed for exposure to pesticides and phenol. No single pesticide could be identified as "causative" because of frequent multiple exposures. The raised odds ratios for phenol were partly explained by smoking and exposure to pesticides which confounded the observed associations for phenol exposure. Exposure to terpenes and other heating products of coniferous woods was significantly associated with a risk of respiratory cancer when the duration of exposure exceeded five years.

Observations by scanning electron microscopy of normal and pathological human gall bladder epithelium.

Thirteen gall bladders presenting normal findings, cholesterolosis, chronic cholecystitis, mucosal hyperplasia and adenomyomatosis were studied by scanning and light microscopy. In the bladder of patients with cholesterolosis the mucosal folds were clearly dilated, but the individual epithelial cells had preserved their normal hexagonal structure. In the gall bladder of one patient with cholesterolosis, goblet-like cells were seen in the epithelium. The greatest changes were seen in material from patients with chronic cholecystitis, in which the mucosal folds were clearly flattened and the cell boundaries indistinct and small polypoid structures were seen on the surface of the epithelium. No special changes were seen in material obtained from patients with adenomyomatosis or mucosal hyperplasia.