Occupational lung disease

Prevalence of occupational asthma and respiratory symptoms in foundry workers

This cross-sectional study was conducted in a foundry factory to assess the prevalence of respiratory symptoms and occupational asthma in foundry workers. Physical examination, spirometric evaluation, chest radiograph, and a questionnaire related to respiratory symptoms were performed. Monitoring of peak expiratory flow rates, spirometric reversibility test, and high-resolution computed tomographies were performed for the participants having respiratory symptoms and/or impaired respiratory function test. A total of 347 participants including 286 workers from production department and 61 subjects who worked in nonproduction departments were enrolled in this study. It is found that phlegm (n: 71, 20.46%) and cough (n: 52, 14.98%) were the most frequent symptoms. The other symptoms were breathlessness (n: 28, 8.06%), chest tightness (n: 14, 4.03%), and wheezing (n: 7, 2.01%) . The prevalence of occupational asthma was found to be more frequent among the subjects who worked in the production department (n: 48, 16.78% ) than the other persons who worked in the nonproduction department (n: 3, 4.91%) by chi-square test (P: 0.001). To prevent hazardous respiratory effects of the foundry production, an early diagnosis of occupational asthma is very important. Cessation of cigarette smoking and using of protective masks during the working time should be encouraged.

Anti-lactoferrin toxicity and elevated iron: The environmental prerequisites which activate susceptibility to tuberculosis infection?

The maintenance and multiplication of Mycobacteria tuberculosis (TB) and many other species of parasitic pathogen are dependent to varying, largely unidentified degrees upon a source of free iron within the host tissues. To combat these infections, the mammalian biosystem expresses an iron binding exocrine protein, lactoferrin, which scavenges and competes for free iron, thereby starving the parasite of its vital iron supply. TB mycobacteria are naturally endemic in the external environment, and once a latent, low level TB infection is established within the host tissues, a full blown proliferation of the mycobacteria population can be activated as soon as the levels of free iron are elevated within the host tissues. The increase in iron can be induced by several environmental and/or eco-genetic prerequisites that operate either singly or in a synergistic combination; factors such as iron rich water/foods, increased iron uptake/retention in the host tissues or an environmental/genetic induced reduction in the turn over of iron binding lactoferrin mediated immune defence against TB. Susceptibility to the full blown proliferation of TB pathogenesis is markedly increased as a result. This paper proposes that the recent dramatic increase in the incidence of bovine/badger TB across the UK can be correlated to the overall increase in acidification of the agricultural ecosystem, which, in turn, has induced a substantial elevation of soluble iron within the farm foodchain, thereby exacerbating susceptibility to TB infection within any mammalian species that is dependent upon these high iron ecosystems. The problem is further compounded by the routine use of 'anti-lactoferrin' levamisole based cattle wormers, which 'sensitise' the levamisole's target receptors, thereby down regulating the secretion of the iron binding lactoferrin molecule, which causes a reduction in the host's main line of defence against TB infection.

Costs of occupational COPD and asthma

OBJECTIVE

To estimate the number of annual deaths, as well as the direct and indirect costs of occupational COPD and asthma, in the United States in 1996.

DESIGN

Aggregation and analysis of national data sets collected by the National Center for Health Statistics, the Health Care Financing Administration, and other government bureaus and private firms. To assess mortality, we reviewed data from national surveys and applied a population attributable risk (PAR) of 15% for both asthma and COPD. We use a lower age limit of 35 years for occupational COPD and 20 years for occupational asthma. To calculate costs, we use the human capital method that decomposes costs into direct categories, such as medical expenses, as well as indirect categories, such as lost earnings and lost home production. We calculated proportionately adjusted costs for other plausible PARs.

RESULTS

The 15% PARs result in costs of $5.0 billion for COPD and $1.6 billion for asthma. For COPD, 56% of costs were direct and 44% were indirect; for asthma, 74% were direct and 26% indirect. These estimates are conservative since we ignored costs associated with pain and suffering as well as the value of care rendered by family members. The proportionately adjusted costs for 10 to 20% PARs are $3.3 to $6.6 billion for COPD and $1.1 to $2.1 billion for asthma.

CONCLUSIONS

The estimated $6.6 billion cost of occupational COPD and asthma in 1996 is likely to rise with the increasing prevalence of these diseases and warrants preventive intervention.