In patients only with elevated BP, the CC genotype was the main risk factor for stroke; in hypertensive patients with other comorbid conditions, many nongenetic factors related to coronary heart disease or diabetes, such as smoking, physical activities, and dietary factors [31, 45, 46], might affect stroke development and conceal the association of ADRB1 (1165G > C) gene polymorphism with stroke. This evidence concerns the gene ADRB1 and diabetes mellitus.