Quitting smoking, the earlier the better

It costs nothing — in fact, it saves money. A pack-a-day habit costs roughly $3–$4, which you’ll no longer spend after quitting. The hard part is getting through the withdrawal period, which usually lasts a few weeks to several months.

One U.S. study that tracked participants without assigning them to groups found that current smokers have a life expectancy more than 10 years shorter than those who never smoked. Quitting before age 40 removes about 90% of this excess mortality risk. Quitting between ages 25–34 adds roughly 10 years to life expectancy; between 35–44, about 9 years; and between 45–54, about 6 years (as reported in the original source). Similar Chinese research from the 2010s shows that urban male smokers have a 1.65 times higher death risk than non-smokers (RR 1.65), while rural male smokers have a 1.22 times higher risk. After 10 years of sustained abstinence, this smoking-related risk nearly disappears.

Jha P 等 (2013). 21st-century hazards of smoking and benefits of cessation in the United States. NEJM. https://doi.org/10.1056/NEJMsa1211128；Chen Z 等 (2015). Contrasting male and female trends in tobacco-attributed mortality in China: evidence from successive nationwide prospective cohort studies. Lancet. https://doi.org/10.1016/S0140-6736(15)00340-2；Oberg M 等 (2011). Worldwide burden of disease from exposure to second-hand smoke: a retrospective analysis of data from 192 countries. Lancet. https://doi.org/10.1016/S0140-6736(10)61388-8（二手烟那两个数字）

Secondhand smoke is deadly too: in 2004, an estimated 603,000 people worldwide died from exposure to it, accounting for roughly 1% of all global deaths that year. Even if you don’t smoke yourself, you must avoid secondhand smoke, especially to protect children. Specific quitting strategies are outlined in the following sections: Section 3 (smoking cessation medications), Section 4 (setting a quit date), Section 5 (visiting a smoking cessation clinic), and Section 6 (e-cigarettes).