LONGY

 A

When it comes to predictors of lifespan, smoking is the single strongest behavioral risk factor, but if we look beyond that, the second-strongest predictor is typically body weight / obesity or physical activity, depending on the study.

Here’s a more detailed breakdown:

1. Smoking – strongest predictor; heavy impact on mortality.

2. Obesity / Overweight – especially abdominal obesity, strongly predicts cardiovascular disease, diabetes, and reduced lifespan.

3. Physical inactivity – lack of regular exercise is also a major independent predictor of early death.

4. Alcohol consumption – excessive drinking is linked to liver disease, cancer, and cardiovascular risks.

5. Social factors – low socioeconomic status, social isolation, and chronic stress can also strongly influence lifespan.

Some large epidemiological studies (e.g., the Harvard Alumni Health Study, EPIC cohort) rank obesity / metabolic health as the second most influential after smoking, because it directly impacts multiple chronic diseases.

If you want, I can make a ranked list of the top 10 lifespan predictors with relative effect sizes. That way you can see exactly how smoking compares to everything else. Do you want me to do that?