How many years does smoking cost me, and does quitting still help?

Smoking is among the largest preventable causes of premature death worldwide. GBD 2021 projections, a major international disease-burden study, show that under unchanged policy the years of life lost due to smoking will remain massively high on a global scale through 2050. Those studies do not give an exact number of years lost per individual smoker, but they demonstrate unequivocally at the population level that the damage is enormous and does not disappear on its own.

The scenario analyses examined compare a situation in which smoking prevalence stays the same with situations in which it falls more quickly. When the number of smokers declines faster, the number of years of life lost decreases measurably and life expectancy at the population level rises. Importantly, this effect also occurs when people quit at a later age. Every moment of quitting has a demonstrably positive effect.

Quitting therefore definitely still helps, even if you have smoked for a long time or are no longer young. How large the personal gain is depends on your age at quitting, the duration and intensity of your smoking history, and other health factors. The direction, however, is consistent and clear: smoking less or quitting entirely always leads to less harm compared with continuing.

An important caveat: the available data come from scenario models at the population level, not from randomised experiments on individuals. A precise figure such as 'X years lost per smoker' cannot be provided on the basis of this specific source. The causal direction, that smoking causes early death, is assessed as probably causal, but the exact magnitude differs considerably from person to person.