A study displayed that nicotine aggravated atherosclerosis in ApoE−/− mice fed with a high-fat diet (HFD), indicated by the more sizeable plaques and more lipids measured by oil red O. In normal diet mice, nicotine also promotes atherosclerotic plaques size and lipid aggregation; even so, the effect of nicotine was not more effective in HFD-fed mice. The gene discussed is APOE; the disease is atherosclerosis.