Common factors that lead to osteoporosis include aging, lack of exercise, insufficient calcium and vitamin D in the diet, smoking, excessive alcohol consumption, and the effects of certain diseases and medications. As people age, their bones naturally become more fragile. Lack of exercise can cause bones to lose strength and density. Calcium and vitamin D are essential nutrients for maintaining bone health, and their deficiency can increase the risk of osteoporosis. Smoking and excessive drinking can also negatively affect bone health. Additionally, some chronic diseases like thyroid problems and long-term use of certain medications can lead to osteoporosis.