The relationship of smoking cessation to coronary heart disease and lung cancer in the Multiple Risk Factor Intervention Trial (MRFIT).

Abstract

The impact of smoking cessation on coronary heart disease (CHD) and lung cancer was assessed after 10.5 years of follow-up in the 12,866 men in the Multiple Risk Factor Intervention Trial (MRFIT). Those men who died of lung cancer (n = 119) were either cigarette smokers at entry or ex-smokers; no lung cancer deaths occurred among the 1,859 men who reported never smoking cigarettes. The risk of lung cancer for smokers, adjusted for selected baseline variables using a Cox proportional hazards model, increased as the number of cigarettes smoked increased (B = 0.0203, SE = 0.0076). There was not the same graded response for CHD among smokers at entry. The risk of CHD death was greater among smokers than nonsmokers (RR = 1.57) (B = -0.0034, S.E. = 0.0048). After IntroductionIn the last two decades there have been continuing decreases in coronary heart disease (CHD) mortality rates in all United States populations'-3 while lung cancer mortality rates continue to increase in certain populations.4,5 Epidemiologic studies have consistently demonstrated a significantly higher relative risk for smokers compared to former smokers for each of these diseases." The beneficial effect of smoking cessation on CHD is rapid; as the period of cessation increases, the ex-smoker's relative risk approaches that of the never smoker.3 However, in one study this return occurred gradually over a 20-year period.8 The relative risk of developing lung cancer has been demonstrated to decrease as the period of cessation increases for smokers who have stopped smoking,6-8 but their relative risk is still significantly elevated after 10 to 20 years of cessation compared to lifetime never smokers and is related to both the duration of smoking and length of cessation.6-8In the available studies, the effect of smoking cessation on the risk of developing CHD and lung cancer was estimated either using data gathered retrospectively6-8 or by considering that smoking habits were unchanged over the period of follow-up.6,7 It is likely that during the course of these studies some ex-smokers became current smokers and vice versa. In

Body position and cardio-respiratory variables in older people

“…The cut off point of 20 years was chosen due to studies reporting the reduced risk of coronary heart disease and lung cancer gradually returns towards normal over a 20 year period [26].…”

Psychosocial Stress and Cardiovascular Disease: Pathophysiological Links

“…Traditional risk factors clearly play a role in promoting thrombus formation. Research data demonstrate that dyslipidemia, 44 diabetes, 45 and cigarette smoking 46 promote thrombus formation, probably through mechanisms mediated by platelets and some mechanisms not mediated by platelets. Preliminary studies suggest that psychosocial stress also plays a role in thrombus promotion.…”

Changes in adult cigarette smoking in the Minnesota Heart Health Program.

“…As many as one third of 35-year-old heavy smokers will die before age 85 of diseases caused by their smoking.3 Despite these health consequences, almost 50 million Americans continue to smoke.4 Cardiovascular diseases are the leading causes of death and disability in industrialized countries, and smoking is a major risk factor for these diseases. [5][6][7][8] Hundreds of studies have addressed smoking cessation methods, primarily at the level of the individual smoker.9""( Despite their strengths, these methods have little hope of producing major prevalence reductions in the general population.9"' Population risk should be amenable to change through communitywide strategies,' 2 and a number of community intervention research and demonstration projects are under way or have been completed in the United States and Europe. 'l-"8 One of the largest of these studies in the United States is the Minnesota Heart Health Program.'…”