A. E. Bennett

Factors Influencing the Onset of Chronic Respiratory Disease

To investigate the effect of different environmental and personal factors on ventilatory function 10,971 children resident and going to school in four areas of Kent were examined. Details of past respiratory illnesses were obtained by a questionary completed by the parents; the examination included measurement of height, weight, and peak expiratory flow. Area of residence, social class, family size, and a past history of pneumonia, bronchitis, or asthma were found to be associated with differing levels of peak expiratory flow. These four factors acted independently, and the effects were additive. It is suggested that environment in the early years of life can produce adverse changes which may exist throughout life and contribute to the development of chronic respiratory disease.

Chronic disease and disability in the community: a prevalence study.

A two-stage prevalence survey of disability (defined as the inability to perform unaided defined activities essential to daily life) used questionnaires on a random sample of the population living in north Lambeth. The central estimates of the prevalence of disability in those aged 35-74 are 7·2% for men and 9·7% for women. Among the disabled population locomotor impairments were more common in women; internal impairments were more common in men. For men and women together chronic respiratory disease, mainly bronchitis, was shown to be the single most common condition associated with disability. Though for women there may be an association between low social class and disability and between marital break-up and disability, these associations, though statistically significant, are weak. The data are therefore considered to be more widely relevant for the planning of health and welfare services.

The use of hospitals by a defined population. A community and hospital study in North Lambeth.

This present study is an attempt to estimate the hospital utilization of people living in a defined urban area. Results are presented of a house-tohouse enquiry into hospital usage. An attempt has been made to estimate the response errors of such an enquiry and to indicate how the results of a hospital survey by the Bailey method might be expected to differ from the results of a house-tohouse survey.

Computers, Mathematics and Medicine

Summary The concept of a modern digital computer as a machine solely designed for the high speed manipulation of numbers in mathematical calculation is much too limited. Particularly is this true in medicine where applications range from analysis of physiological signals to record linkage. As in other fields, the computer has stimulated a more detailed examination of systems than has previously been undertaken. The application of mathematical methods has advanced and perhaps no single area has received as much attention as diagnosis. However, up to the present, only partial success can be accorded to the various techniques tried. In the near future, computers will become increasingly available for use in medicine, both in terms of available time and of ease of access. It is very possible that the next series of advances in medical knowledge will be derived from advancing techniques in the collection, handling and analysis of information.

Value of Multiple Screening

SIR,-Professor Richard Scott and Dr. P. D. Robertson (15 June, p. 643) describe the organization and methodology of a multiple screening programme in general practice. They make the valid point that within the context of our health care organization the logical place for screening is in, or in conjunction with, general practice. They pose the question as to what is the short-term or long-term effect of screening on the health of the patient. It must be regretted, however, that this question is not given more prominence, nor will the design of their study allow any answer to be obtained. Numerous examples of screening programmes have been reviewed by Wilson and Jungner.1 All of these, as well as Scott and Robertson, show that they can find a substandal amount of morbidity. There is no evidence, however, in any of these publications that in terms of subsequent morbidity and mortality the individual shown to have one or more of the conditions screened for has benefited. For many of the conditions for which screening is performed there is still little evidence that methods of treatment used improve prognosis. At this stage of our knowledge it is of great importance to assess the value of screening examinations by properly controlled trials. Any general practitioner who wishes to embark on a screening programme must be urged to plan his study in such a way that he will be able to evaluate his findings rather than simply present a list of conditions discovered.--We are, etc., W. W. HOLLAND. A. E. BENNETT. M. H. TREVELYAN. Department of Clinical Epidemiology and Social Medicine, St. Thomass Hospital Medical School, London S.E.l. U. M. P. KROLL. I. N. MANSER. J. D. PAULETT.