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.
Nail splitting may also be caused by nail cosmetics (hardeners, polish, polish removers/solvents), nail procedures, and occupational exposure to various chemicals (alkalis, acids, cement, solvents, thioglycolates, salt, sugar solutions). Injury (trauma) may also play a role in the development of brittle nails.