I’d be interested to know exactly what’s motivating your question, but here’s a stab at the reasoning that might be behind it:
Suppose that a society is (collectively) obligated to care for the disabled. Caring for the disabled imposes burdens on the rest of society. But it’s wrong for us to knowingly act so as make ourselves (more) burdensome to others. So it would be wrong for us to knowingly act so as to disable ourselves, and since it is permissible to permit others from wronging us, it is permissible to prevent people from disabling themselves.
Before we address the soundness of this reasoning, I’d note that very few disabled persons have chosen to be disabled. In the vast majority of cases, disability either doesn’t stem from a person’s choice at all (the disability is traced to genetic or environmental causes) or results from a choice that carried a risk of disability (working in a dangerous profession like logging, engaging in a dangerous form of leisure). Most societies address these with schemes of insurance, either government-provided or through the private market. The idea there is to spread the risk of inherently dangerous activities (such as driving a car) across a large population. That isn’t inconsistent with certain people bearing more of the risks (bad drivers, those who operate logging companies). And of course, there’s health insurance in order to distribute the risk of being alive!
So I suspect that if you have in mind individuals intentionally disabling themselves, that phenomenon is rare. But does the reasoning I outlined above support the conclusion that it’s morally permissible to try to prevent others from intentionally disabling themselves because that’s burdensome to others? On the one hand, maybe the best reasons we have for putting suicide barriers on bridges or requiring that consumer products be safe is that these policies preclude people from harming themselves in ways that result in disabilities for which others in society will ultimately bear the costs. On the other hand, we sometimes permit people to impose burdens on us through means other than disabling themselves. Pollution burdens others. So does procreation (societies end up caring for many children who are abandoned, etc.) This suggests that whether we have a right to prevent others from burdening us may not depend on how they cause that burden — whether by disabling themselves or through other activities or choices. In the end, my guess is that the best account of when someone else can permissibly burden us, versus when it is permissible for us to prevent them from burdening us, turns on how important the ‘burdening’ activity is.
A final note: Even if it is permissible in general to prevent people from disabling themselves, that moral permission has limits. I doubt that it would be morally permissible to (for example) install surveillance cameras in every dwelling in order to prevent people from disabling themselves through drug abuse, ‘failed’ suicide attempts, etc.