I just turned 80, and have had some digestive issues, such as nausea, bloating and diarrhea during the last few years, often in connection with my hobby of running ultramarathons, which suggested a late-life onset of
lactose intolerance. As an experiment, I started using the chewable lactase supplements (Lactaid, etc.) before meals, and that seems to have taken care of the problem, which seems like prima facie evidence of LI, although I haven't been tested or diagnosed.