The research published in the medical journal Circulation cites five behaviors associated with significantly longer life: not smoking, keeping a healthy Body Mass Index (BMI), avoiding excess alcohol consumption, moderate-to-vigorous exercise, and keeping a healthy diet. Sticking to all five of those healthy habits was associated with 12.2 years of longer life for men and 14 years of longer life expectancy for women, according to the researchers. (Ok, this is a good time to note the caveat that this was an observational study and not a randomized clinical trial, and that correlation isn’t the same as causation.) Out of all these behaviors, however, avoiding smoking and tobacco products has been proven time and time again to be the most effective way to live longer—or at the very least avoid dying at an unnecessarily premature age.

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Let’s let the Centers for Disease Control (CDC) explain exactly why. “Smoking causes cancer, heart disease, stroke, lung diseases, diabetes, and chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis,” writes the agency.

On a larger scale, that amounts to an estimated 16 million Americans living with a disease caused by smoking in some way or another. And it checks all of the big-name killing boxes: heart disease (the number one killer of Americans), cancer (the number two killer of Americans), and COPD (the number three killer of Americans).

That’s a likely reason why the criteria in the latest study included avoiding smoking altogether. While the other associations surrounding diet and exercise have also shown strong associations with longer life expectancy and more healthy lives, avoiding smoking remains the single most powerful way to prevent an early death and extend life, according to multiple large-scale analyses.