I think they controlled for age, based on the language of the article, but didn't make that very clear. I would however reserve judgement until we actually see the published data.
If they controlled for age, and found that men of equal age with more grey hair than others have a higher risk, then it could be a good and reasonable screening tool.
That being said, I think that we have more sensitive screening tools available at an even earlier age that makes me feel like this isn't all that helpful. It's pretty obvious that certain things put you at higher risk for CAD, and by avoiding those risk factors you lower your risk.
If they controlled for age, and found that men of equal age with more grey hair than others have a higher risk, then it could be a good and reasonable screening tool.
That being said, I think that we have more sensitive screening tools available at an even earlier age that makes me feel like this isn't all that helpful. It's pretty obvious that certain things put you at higher risk for CAD, and by avoiding those risk factors you lower your risk.