Numbness in the hands may be caused by diabetes, and similar symptoms may be caused by long-term cervical spondylosis or hyperlipidemia. 1. Long-term diabetes or poor blood sugar control can lead to serious damage to the blood supply in the peripheral circulation of the body, which can also lead to damage to the neurons in the peripheral areas, resulting in local sensory abnormalities that cause numbness. 2. This will affect the normal cranial blood supply and lead to mild ischemia and hypoxia of the brain tissue, which will also cause blood supply to the peripheral parts of the extremities, leading to numbness of the hands. In patients with hyperlipidemia, the increased viscosity of the blood affects the pumping function of the heart, and thrombosis may form in the microvessels of the peripheral parts of the extremities, resulting in local sensory nerve abnormalities.