traceptives, the rate increased more than sevenfold; and in those women who both smoked heavily and used oral contracep- tives the rate increased at least twentyfold

A study of male and female office workers found no sex difference in the relationship between carboxyhemoglobin (COHb) levels and daily consumption of cigarettes. However, women smoked fewer cigarettes on the average than men. The study found that the COHb levels in smokers were higher among the sedentary office workers than among physically active meat porters and that both had higher levels of COHb than pregnant women who smoked (12). The latter had COHb levels approximately three times higher than that of nonsmokers. Wald reported from a cross-sectional study that carboxyhemoglobin levels of smokers are a better indicator of the risk of atherosclerotic cardiovascular disease than a reported smoking history (48). The proportion of both men and women with atherosclerotic disease increased with increasing levels of COHb.