Unfortunately, I know only too well the pressure to find and publish something and the immense effort and money it would take to gather new material tailored to a new research objective. I am well aware of the temptation to oversell findings based on actually poor data and that almost everyone else it doing it as well.

Nonetheless, I urge you to be extra careful when using data that was never collected for a specific purpose in another context. It is easy to mislead others but also yourself, so ideally seek to corroborate such findings by other means, too. Harley at al. is for example one paper that we use(d) to dismantle in the statistics class as a group exercise for its blatant errors and yet the authors made worldwide headlines with it. Also in this study, urine samples initially collected for assaying Bisphenol A were later used in a completely different study design, without proper controls and calibration, eventually giving rise to those questionable results.

Of course, raising new questions based on previous results is fine and looking at existing data to give you hints whether it is worth working in this direction is too, but always mind: There is already enough crappy science published out there, please don't add more ;-)