Quitting smoking improves survival comparable to never smokers: Study

 Smoking is a dangerous habit not only affecting the one smoking but also people around the person. It is the root cause of cancer, heart disease, stroke, lung diseases, diabetes, and chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis.

A new study in BMJ Journals, studied the health consequences of quitting smoking before age 43 by time since quitting, number of years smoked and cigarettes smoked per day in the Norwegian population. The study reports that the all-cause mortality, after adjustment for demographic factors and total cholesterol, triglycerides, physical activity among other covariates, was no higher in quitters than in never smokers. But it was 30% higher in quitters of less than 1 year, the quitter group with the highest risk. Ischaemic heart disease mortality, again after all adjustments for confounders, was no different in quitters than in never smokers.

Researchers designed a prospective study in the Norwegian counties. Study included men and women aged 40–43 years who participated in a national cardiovascular screening programme and who were followed from 1985 to 2018. Self-reports from questionnaire on time since quitting smoking, years smoked and number of cigarettes per day, and measurements of height, weight and blood pressure, and a blood sample where serum was analysed for total serum cholesterol and triglycerides.

The key findings of the study are

• The all-cause mortality rate was 30% higher among quitters less than 1 year ago compared with never smokers (adjusted HR=1.30, 95% CI 1.18–1.43 in men and HR=1.31, 95% CI 1.16 to 1.50 in women).

• Quitters who had smoked longer than 20 years had 23% higher mortality in men (HR=1.23, 95% CI 1.14 to 1.34) and 32% higher mortality in women (HR=1.32, 95% CI 1.18 to 1.49).

• Past smoking of more than 20 cigarettes/day was associated with HR=1.14 (1.05–1.23) in men and HR=1.16 (1.01–1.32) in women.

• The HR for lung cancer was 6.77 (95% CI 4.86 to 9.45) for quitting men who had smoked for more than 20 years compared with never smokers. The corresponding figure for women was 5.75 (95% CI 4.08 to 8.09).

Researchers concluded that “The mortality among quitters was close to that of never smokers, except for a higher mortality for lung cancer, which on the other hand was much lower than the lung cancer mortality in current smokers.”

Reference: Tverdal A, Selmer R, Thelle DS; Smoking history and all-cause, ischaemic heart disease and lung cancer mortality: follow-up study of 358 551 men and women aged 40–43 years Tobacco Control Published Online First: 14 November 2023. doi: 10.1136/tc-2023-057977