Smoking and Smoking Cessation in Relation to Mortality in Women

Abstract

Context Smoking is associated with an increased risk of total and cause-specific death, but the rate of mortality risk reduction after quitting compared with continuing to smoke is uncertain. There is inadequate or insufficient evidence to infer the presence or absence of a causal relationship between smoking and ovarian cancer and colorectal cancer. Objective To assess the relationship between cigarette smoking and smoking cessation on total and cause-specific mortality in women. Design, Setting, and Participants Prospective observational study of 104 519 female participants in the Nurses' Health Study with follow-up from 1980 to 2004. Main Outcome Measure Hazard ratios (HRs) for total mortality, further categorized into vascular and respiratory diseases, lung cancer, other cancers, and other causes. Results A total of 12 483 deaths occurred in this cohort, 4485 (35.9%) among never smokers, 3602 (28.9%) among current smokers, and 4396 (35.2%) among past smokers. Compared with never smokers, current smokers had an increased risk of total mortality (HR, 2.81; 95% confidence interval [CI], 2.68-2.95) and all major cause-specific mortality. The HR for cancers classified by the 2004 surgeon general's report to be smoking-related was 7.25 (95% CI, 6.43-8.18) and 1.58 (95% CI, 1.45-1.73) for other cancers. Compared with never smokers, the HR for colorectal cancer was 1.63 (95% CI, 1.29-2.05) for current smokers and 1.23 (95% CI, 1.02-1.49) for former smokers. A significant association was not observed for ovarian cancer. Significant trends were observed for earlier age at initiation of smoking for total mortality (P=.003), respiratory disease mortality (P=.001), and all smoking-related cancer mortality (P=.001). The excess risk for all-cause mortality decreases to the level of a never smoker 20 years after quitting, with different time frames for risk reduction observed across outcomes. Approximately 64% of deaths among current smokers and 28% of deaths among former smokers were attributable to cigarette smoking. Conclusions Most of the excess risk of vascular mortality due to smoking in women may be eliminated rapidly upon cessation and within 20 years for lung diseases. Postponing the age of smoking initiation reduces the risk of respiratory disease, lung cancer, and other smoking-related cancer deaths but has little effect on other causespecific mortality. These data suggest that smoking is associated with an increased risk of colorectal cancer mortality but not ovarian cancer mortality.

Longitudinal Changes in Smoking Behaviors and Cancer-Related Mortality Risk in Middle-Aged Korean Women

“…The risk of cancer-related deaths increased from 1.6-fold in those with < 5 pack-years to 2-fold in those with more than ten pack-years, and the risk of lung cancer deaths increased from 2-fold to > 4-fold, respectively. Consistent with our findings, previous studies also found a dose-response relationship between the intensity of smoking, measured as either the number of smoked cigarettes [ 8 , 26 ] or smoking pack-years [ 27 ], and mortality risk in female smokers. A pooled analysis of Asian female smokers reported a higher risk corresponding to higher smoking pack-years, with a 1.6-fold increase in all-cause mortality in those with < 10 pack-years to a 2-fold increase in women with ≥ 20 packyears [ 27 ].…”

Smoking cessation and mortality among middle-aged and elderly Chinese in Singapore: the Singapore Chinese Health Study

“…Nevertheless, even with long-term quitting, former smokers were still at higher risk of lung cancer and COPD deaths compared with never-smokers, suggesting that ever-smokers may never completely recover from the damage to the lungs. This finding is consistent with the results from the study on insured U.S. veterans27 and the Nurses' Health Study,25 which found that >20 years might be needed before the full benefits of smoking cessation on lung cancer or COPD could be observed.…”

The hazards of death by smoking in middle-aged women

“…We find a three-fold mortality rate among current smokers compared with that of never smokers for cerebrovascular diseases and MI, similar to those displayed in the Nurses’ Health study [ 25 ]; and in the Million Women Study [ 13 ], while our mortality rate from COPD and from lung cancer was much lower than in the other two studies. The US study [ 25 ], had more than 12,000 deaths during a follow-up time of 24 years, while the UK study [ 13 ], had 66,000 deaths after 12 years. Both studies [ 25 ] had a RR of mortality from lung cancer of more than 20, while the mortality rate from COPD was 40 and 35, respectively.…”