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.
1 Liver disease can damage nails. 2  Thyroid diseases such as hyperthyroidism or hypothyroidism may cause brittle nails or splitting of the nail bed from the nail plate (onycholysis).  Severe illness or surgery may cause horizontal depressions in the nails (Beau's lines).