As noted elsewhere in the forum, my father and at least two brothers and at least 2 neices also crack, but to a lesser degree than me. None of them share any of my listed symptoms. In chronological order:
Premature birth (6 weeks, considered extreme in 1962)
Pneumonia (stopped after age 6 or so)
Bronchitis (stopped after age 6 or so). Got ear tubes in at 6, out at 10.
Hyperactivity. Took amphetemines from ages 8 to 14. Shorter than
my brothers as a result.
Allergies to dust, fur, feathers, shrimp, peanuts, soy. I
don't avoid any of these. I have chronic sinus drip to my stomach.
Skin fungal infections (ages 16 to 24).
Prostate infections (ages 18 to 24). Stopped when I gave up beer.
Kidney stones (ages 40 and 43). Flared up when trying high-protein
diet to lose weight.
Lots of intestinal gas, but this is probably due to enjoying lots of fruit
and vegetables (along with everything else).
Overweight (gaining about 1.5 lbs per year since age 22)
I'm actually pretty happy. I rarely take medication for anything, just ibuprofen for pain after excercise. The cracking doesn't bother me, but I don't like the idea of paralysis or stroke due to neck cracking, so I try to keep up with the research every so often to see if anyone has any bright ideas. Of course, others are bothered so that is (slight) incentive to stop if a cure could be found for the stiffness and lack of mobility.