Specifically, we conducted a systematic search of PubMed using the following keywords: “Alzheimer's disease”, “osteoporosis”, “brain”, “bone”, “osteocyte”, “estrogen”, “thyroid hormone”, “follicle-stimulating hormone”, “insulin”, “glucocorticoids ”, “melatonin”, “metal ions”, “sleep”, “diet ”, “exercise”, “smoking”, “inflammation”, “education level”, “air pollution”, “gut microflora”, “alcohol consumption”, “extracellular vesicles” This search focused on English-language studies up to November 2024, addressing genetic and environmental factors in AD and OP. The gene discussed is TG; the disease is Alzheimer disease.