Can a 31 year old loose his teeth what would cause it?

Many: trauma, poor hygiene, drugs, meth mouth

Yes: Sometimes you can have healthy teeth, but unhealthy gums, in which case you can lose your teeth even if you have healthy teeth!. Cavities and cracked teeth can also cause you to lose teeth and can occur at any age. If you are on medication that causes dry mouth, then you may be more prone to dental disease because of a lack of saliva. Saliva is important in keeping the teeth healthy.

Many possibilities: Periodontal disease comes to mind first. Severe decay resulting in unrestorable teeth is another possibility. How diligent was this 31 year old in maintaining his health and in visiting his dentist for professional cleanings and restorations?