Moreover, in observational studies, there are many similar risks and genetic factors that provide relevant evidence to prove an association between HF and AD, for example, obesity, age, Apo E4, etc. Therefore, in future MR studies, valid results may be obtained if we conduct further MR analysis on large-scale summary-level GWAS datasets of risk factors (age and obesity) or genetic factors derived from Apo E4. The gene discussed is APOE; the disease is obesity due to melanocortin 4 receptor deficiency.