Restriction of rights is a spectrum. For example, we know that driving cars carries some (very small) risk. If we banned driving, fewer people would die (from car related accidents). This must be balanced against individual rights and social outcomes. If we banned cars, how many people would lose their jobs? How many people would be unable to get to hospital? It's like that banning cars would cause more harm than lives it saves. This is an extreme scenario to illustrate not all bad things should be banned.
Smoking is more nuanced. For the most part (as long as public spaces and spaces with children are appropriately regulated), smokers hurt only themselves. In countries with public healthcare, this can increase care costs, but most studies now find that because smokers die much younger, their combined lifetime costs are actually lower. Old people are very expensive to care for. So the question becomes: to what degree do we want the state preventing people from hurting themselves? Where does that authority end? Alcohol? Sugar? Fatty foods? Less than eight hours of sleep? Not exercising? Too much TV and iPad? Social media? Not reading enough books? This is, IMHO, a slippery slope. For reasons of ideology and pragmatism, I do not support regulation for "victimless" activities, unless there are significant social costs/harm. This means I support legal tobacco, marijuana, MDMA, alcohol, and and many other drugs. I also support the right to partake in extreme sports, eating junk food and sugar, and not exercising.
The implications of this particular study are very difficult to morally and legally navigate. If smoking while young can make children age slightly faster, surely there is a moral imperative to prevent those who are 15 and younger from smoking? I believe that is the case in most of the West already. However we also know that parents who don't exercise and eat poorly also tend to pass along these habits to their children. Should we also ban parents from eating at McDonalds?