1 Calcium and vitamin D intake. 2  A diet low in calcium and vitamin D makes you more prone to bone loss. 3  Medication use. 4  Some medicines increase the risk of osteoporosis. 5  Activity level. 6  Lack of exercise or long-term bed rest can cause weak bones. 7  Smoking.
Signs and Symptoms. 1  Nail splitting affects the fingernails and the toenails. The condition may appear as a single horizontal split between layers of the nail plate at the growing end or as multiple splits and loosening of the growing edge of the nail plate.
Psoriasis starts in the nails up to 10% of the time and causes splitting and pitting of the nail bed. Heart disease can turn the nail beds red. Obsessive-compulsive disorder can show up in the nails through persistent nail-biting or picking, Fox says.