The study of 1.3 million women found that smoking tripled the chances of dying over nine years compared with non-smokers. Most of the increased death rate resulted from smoking-related diseases such as lung cancer, chronic lung disease, heart disease or stroke.
Smokers who kicked the habit around age 30 avoided 97% of their excess risk of premature death, according to the Million Women Study.
Ms Soubry said: "Stoptober has been a great success - it has exceeded our expectations. But half of all smokers will die because of their habit. We know that most smokers want to give up, which is why we must keep encouraging them to make that step.
"I congratulate everyone who gave up for Stoptober - it's a fantastic achievement. They are five times more likely to give up for good after 28 days and I hope they will.
"For those who didn't manage to stop for Stoptober, I would urge them to keep at it. People can start their own 28 day quit challenge at any time."