Expired air carbon monoxide, smoking, and other variables. A community study.

Analysis of the carbon monoxide content of expired air is now a frequently used technique in population studies. Its close correlation with the blood concentration of carboxyhaemoglobin was first demonstrated by Jones, Ellicott, Cadigan, and Gaensler in 1958. Studies in the United Kingdom (Tyrer, 1964) and the United States (Ringold et al., 1962; Goldsmith, Schuette, and Novick, 1963) have shown that it is also associated with cigarette smoking as well as exposure to atmospheric pollution with carbon monoxide. The carbon monoxide in cigarette smoke, present in concentrations of 2% or more, can give rise to carboxyhaemoglobin levels of up to 12% of total haemoglobin in individuals smoking 15 or more cigarettes per day (Goldsmith and Landaw, 1968). There is some evidence that carboxyhaemoglobin levels greater than 5% may have adverse effects on fine visual and aural discrimination (Macfarland, Roughton, Halperin, and Niven, 1944; Beard and Wertheim, 1967; Schulte, 1963). It has been suggested recently that the effect of carbon monoxide might also be involved in the relationship between cigarette smoking and ischaemic heart disease (Goldsmith and Landaw, 1968; Goldsmith, 1969; Astrup, Kjeldsen, and Wanstrup, 1967; Astrup, 1969) and in the relationship between smoking in pregnancy and low birth weight (Astrup, Trolle, Olsen, and Kjeldsen, 1972). This paper is based on the results of a community study of cardiorespiratory disease in Lambeth in 1967, in which various cardiorespiratory tests were carried out, including carbon monoxide levels of expired air (Holland and Waller, 1971). It gives the experimental details of the latter test and describes the relationship between carbon monoxide levels in expired air, smoking, ischaemic heart disease, and other factors.