If you dig deep enough into any topic, you will find all sorts of associations. For example, when doing medical research on a given topic, you will find that many different disciplines (cardiology, nephrology, neurology, oncology, neonatology, etc.) may be studying the same or similar phenomenon. The interesting thing is that the disciplines rarely communicate with each other, and when you point that out to people, they are either amazed that scientists in one area of medicine have already figured out the biological pathways that may also apply to another area of medicine, or sometimes it is disregarded because the patient population isn't the same. As a respiratory therapist in the neonatal unit, part of my research over the years has been on the topic of oxygen radical production and its contributions to neonatal mortality and morbidities. Well, come to find out, the oncologists figured out all these pathways that apply to many of the common diseases that we see in all ages and all organ systems. When I pointed this out to my physician colleagues, they were rather taken back by the fact that I could come up with literally thousands of articles on a related topic, but very few were referenced in the neonatal literature, pointing out the fact that the disciplines rarely speak to each other, much to the detriment of the patient and the working knowledge of the physician.
Another example would be the topic of "fluidics", the movement of fluids and gases through conduits. Well, you can look at it from a mechanical engineering perspective, but also from the perspective of studying gas flow through the bronchial tree in the lungs, to blood flow through the heart and vascular system.
Since many autistics do have "special interests" or may get their brain focused upon something, and we can't seem to let it go, to the point of interrupting sleep. Some of those special interests or topics require a fair amount of research, it is not uncommon to find other topics associated with that special interest that may stimulate further research into other areas, leading to yet another "special interest". This is usually my routine, that is, taking a "deep dive" into a topic, only to find myself taking another "deep dive" into something that was connected to it.
I find most people tend to simply ask a question and want a short answer. Then there are others, like me, that find myself on this intellectual journey of discovery.