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Background: We examined prospectively the relation of time since stopping smoking with risk of coronary heart disease in middle-aged women. Methods: The study was based on 12 years' follow-up data (1976 through 1988) from the Nurses' Health Study, an ongoing prospective cohort study, in which information on smoking habits was updated every 2 years by a mailed questionnaire. The study population consisted of 117 006 female registered nurses aged 30 to 55 years in 1976 who were free of coronary heart disease, stroke, and cancer at baseline. The outcome measure used was incident coronary heart disease, defined as nonfatal myocardial infarction plus fatal coronary heart disease. Results: A total of 970 incident cases of coronary heart disease (215 among participants who never smoked, 214 among former smokers, and 541 among current smokers) occurred during 1.37 million person-years of follow-up. The multivariate relative risk of total coronary heart disease among current smokers compared with participants who never smoked was 4.23 (95% confidence interval, 3.60 to 4.96). Risk of coronary heart disease was highest among smokers who started smoking before the age of 15 years (relative risk, 9.25; 95% confidence interval, 5.27 to 16.23). The relative risk among former smokers was 1.48 (95% confidence interval, 1.22 to 1.79). On stopping smoking, one third of the excess risk of coronary heart disease was eliminated within 2 years of cessation. Thereafter, the excess risk returned to the level of those who never smoked during the interval 10 to 14 years following cessation. Conclusion: Women who stop smoking will experience an immediate benefit as well as a further longer-term decline in excess risk of coronary heart disease to the level of those who never smoked.

Background.--While some analytic studies have suggested that individuals in occupations representing higher compared with lower socioeconomic status have a decreased risk of coronary heart disease, it is unclear whether occupation itself has an etiologic role in the development of coronary heart disease or whether differences in as yet uncontrolled coronary risk factors may account for these differences in risk. Methods.--White-collar vs blue-collar occupation and risk of coronary heart disease was evaluated among 230 male patients hospitalized for a first myocardial infarction and 222 control subjects of the same age, sex, and neighborhood of residence. Information on coronary risk factors was obtained from home interviews, and blood specimens were drawn to test lipid and lipoprotein levels. Usual occupation was dichotomized into white-collar and blue-collar occupation according to the Edwards' classification. Results.--The relative risk of myocardial infarction of white-collar compared with blue-collar workers was 0.74 (95% confidence interval, 0.46 to 1.19) after controlling for age, cigarette smoking, family history of premature myocardial infarction, history of treatment for high blood pressure, body mass index, history of diabetes, alcohol consumption, type A personality, leisure-time physical activity, total calories, and percentage of calories consumed as saturated fat. However, there was no residual association after control for high-density lipoprotein cholesterol yielding a relative risk of 0.98 (95% confidence interval, 0.59 to 1.63). Conclusions.--These results suggest that white-collar occupation per se does not appear to protect from coronary heart disease. Any apparent protective effect on myocardial infarction that has been previously observed in white-collar compared with blue-collar workers may be attributable to differences in high-density lipoprotein cholesterol levels. (Arch Intern Med. 1992;152:2253-2257)

Diabetes has long been known to be a risk factor for cardiovascular disease, but the magnitude of that risk is unknown. Over 100,000 women enrolled in a long-term study known as the Nurses' Health Study were followed-up to determine the prevalence of diabetes and the rate of cardiovascular disease, specifically fatal and nonfatal heart attack and stroke. Women with maturity-onset diabetes were found to have six times the risk for heart attack of nondiabetic women. Their risk of stroke was four times greater than that of nondiabetics. Women whose diabetes was diagnosed before the age of 30 had a 12-fold greater than normal chance of developing heart disease, and a 10-fold greater than normal chance of having a stroke. Heart disease among diabetics was found to be even more prevalent in the presence of other known cardiac risk factors, such as smoking, high blood pressure, high cholesterol levels and obesity. Of the 100,000 women studied, diabetics accounted for 2 percent, yet they accounted for 14 percent of the cases of heart disease and 12 percent of strokes. Diabetes causes this increased risk of heart disease and stroke through a variety of mechanisms, such as causing platelets, blood-clotting cells, to become more 'sticky,' increasing the likelihood of blood clots, or causing damage to the small blood vessels of the heart and brain. Since some cases of adult-onset diabetes can be prevented merely by preventing obesity, these data underscore the need to do so. Further, once diabetes has developed, modifying the other risk factors, such as smoking and high blood pressure, becomes even more important. (Consumer Summary produced by Reliance Medical Information, Inc.)

• Lowering the intake of fat to decrease serum cholesterol levels has unknown effects on the proportion of cholesterol in low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Twenty normolipidemic nonvegetarians were given dietary instruction and supervision in a low-fat, semivegetarian diet for three months. Mean consumption of total fat, saturated fat, and cholesterol decreased, whereas intake of carbohydrate increased significantly on a low-fat diet. Plasma LDL levels decreased by 18% and HDL levels by 7% from prestudy baseline levels. The LDL/HDL ratio declined by 11%. Plasma triglyercide levels and body weight were unchanged. In individual subjects, the decrements in consumption of saturated fat and the increments in ingestion of polyunsaturated fat were each significantly correlated with decreases in LDL. One year after the subjects had returned to a self-selected diet, levels of dietary saturated fat and cholesterol and the plasma LDL/HDL ratio remained significantly below prestudy levels. This study and others suggest that a low-fat, high-carbohydrate diet favorably affects the plasma LDL/HDL proportion by decreasing LDL on a percentage basis 2½ to three times more than it decreases HDL.(Arch Intern Med 1986;146:1573-1577)