{'fraction_non_alphanumeric': 0.021835826930853213, 'fraction_numerical': 0.01900525677315002, 'mean_word_length': 4.932853717026379, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Respiratory disability in ex-cotton workers.

SIR,-Elwood and his colleagues (1986;43:580-6) observed a small permanent effect on respiratory function from past exposure to dust among ex-cotton workers. There are two reasons, however, why their survey is likely to underestimate the real extent of any permanent disability. Firstly, their population included 472 ex-cotton workers, but only 116 were from the card room, the group most heavily exposed to dust; the 22 men in this group had on average spent 14 years and the 94 women 15 years in the card room. Disabling byssinosis of at least moderate severity is generally seen in cotton workers with much longer exposures. 3 Secondly, workers are affected unequally. In a survey of Lancashire textile workers, mostly from card rooms, more than 75% did not have work related symptoms.4 Individuals exposed to similar dust concentrations have widely different acute responses. FEV losses range from almost zero to nearly 0-5 6 To avoid bias, Elwood et al did not question subjects about work related symptoms but their study must have included mainly people without byssinosis. Their lung function results are expressed as mean values for each occupational group. Means obscure the heterogeneity of response, which is well recognised in relation to occupational exposures. The authors take account very roughly of each individual's degree of exposure by multiplying arbitrary dust scores based on another survey7 by number of years exposed. Regression coefficients for exposure show significant increases in adverse effect on FEV1 (p < 0O01) and FVC (p < 0-001) for men and FVC (p < 005) for women. The authors conclude that the effect is real but small and that even after prolonged exposure to the worst dust conditions the loss is comparable with that associated with light smoking. These findings are to be expected in a population which has only 22 male card room workers, the most heavily exposed group, and even fewer with exposures long enough to be likely to lead to moderately severe disability. The overall results of this survey of ex-cotton workers do not provide any evidence to contradict previous clinical and epidemiological observations that cotton workers with heavy and lengthy exposures are at risk of developing pronounced loss of lung function and accompanying disability.'38 It would have been better to undertake a prospective survey of workers who are now employed in the cotton industry References