One would intuit that, contrary to the thrust of the article, the decline in active smoking induced by the ban - as evinced by the falloff in cigarette sales and consumption - would be a much more important factor in the reduction in acute MI admissions than a decline in passive smoking, since active smoking is much more of a risk factor than passive. Then again, other risk factors aren't even mentioned, nor are possible changes in the demographics between the newer and older populations in the area.
My guess is that the study design was flawed to a large degree and that the conclusions as to the huge contribution of reduced second hand smoke inhalation to the observed MI admissions decline had more to do with political correctness than statistical correctness.
To my experience, when an abstract or an article mentions just one specific population segment (and that one pretty amorphous, ''under-60s'') prominently, the authors of the ''study'' were generally fishing for a pre-desired result. There are doubtless exceptions to this, in the big, wide world. However, I'll stick with the Damon Runyon viewpoint:
''The race is not always to the swift, nor the battle to the strong ... but that's the way to bet.''