Does quitting smoking reduce infection after surgery?

01

An infection is not every problem after an operation

A surgical site infection occurs where the operation took place. It can involve skin, deeper tissue, an organ or implanted material—not just a visible skin cut. Delayed healing or a wound separating is not automatically an infection. A lung infection is also a different endpoint from an infection at the surgical site; a study's broader category of pulmonary complications cannot be assumed to contain only infections.

Entirely fictional reading example: a report says fewer patients had any postoperative complication. That total might combine lung problems, wound problems and other events. Before calling it evidence of fewer infections, look for whether infections were counted separately. An improved combined total cannot establish that every component improved by the same amount.

[1][2][3]

02

Two reviews ask different questions

A 2012 review examined both observational smoking-status comparisons and randomised cessation-support trials. Its analysis of four intervention trials found fewer surgical site infections with the support programmes. Other healing complications did not show a clear reduction. The trials involved selected elective operations and support packages that could include counselling and medication; they did not isolate the effect of one particular support component. They were also small, limiting precise estimates for each complication.

A 2025 review, searching through August 2024, grouped studies by preoperative cessation duration. Of its 55 studies, most were observational and only one was a randomised trial. It found favourable associations for some pulmonary outcomes, but its surgical site infection comparison between people who had stopped for at least four weeks and current smokers did not show a statistically clear difference. That is not proof of equal infection risk or evidence that quitting is pointless.

The reviews do not test the same intervention, population or classification. The newer review relied largely on reported smoking status; operations and complication definitions varied, and postoperative smoking was often not reported. A duration-group comparison cannot be read as if patients had all been randomly assigned to quit for that duration. Nor can a lung-complication result be substituted for a surgical infection result.

[2][3]

03

Use the evidence to open a care-team conversation

A useful question is: “When you describe the benefit of quitting for this operation, do you mean surgical site infection, lung complications or a combined outcome—and how does quitting support fit my existing plan?” Tell the surgical team accurately about changes in smoking. They decide preparation, timing and follow-up; an article or a study's time category cannot clear, postpone or cancel an operation.

For separate quitting support in England, NHS local stop-smoking services are available; confirm access. Questions about an existing operation or possible postoperative infection belong with the treating team, using its contact instructions, not with a quitline or a risk calculation here. This page does not assess a wound, choose antibiotics, give wound-care steps or collect health information.

[1][2][3][4]

04

What to keep in mind

• Positive infection evidence exists, but its intervention and endpoint matter.
• A non-significant comparison does not prove no benefit or equal risk.
• The surgical team—not a population time category—sets the care plan.