Women who drank cola daily had lower hip bone density; men did not
Against women drinking less than one cola a month, one hip site ran 5.4% lower. The pattern held for diet cola too, and non-cola sodas showed nothing.
What the study found
Daily cola tracked with 3.7% lower hip bone density in women
Against women drinking less than one cola a month, one hip site ran 5.4% lower. The pattern held for diet cola and, more weakly, for decaffeinated, which points at phosphoric acid rather than sugar or caffeine. Men showed nothing, and neither did non-cola sodas.
The caveat · The acid is inferred, not measured
This is diet recall at a single point in time, so daily cola drinkers may differ from occasional ones in ways nobody recorded, including what they were drinking instead. The difference showed at the hip and not the spine. Daily cola drinkers were not taking in more phosphorus overall, which makes phosphoric acid the authors' inference rather than something they measured.
What we don't know
This is diet recall at a single point in time, so daily cola drinkers may differ from occasional ones in ways nobody recorded, including what they were drinking instead. The difference showed at the hip and not the spine. Daily cola drinkers were not taking in more phosphorus overall, which makes phosphoric acid the authors' inference rather than something they measured.