Which of the following is not a predisposing factor for cardiovascular diseases?

Chemical agents are not considered a predisposing factor for cardiovascular diseases in the same way that obesity, genetic factors, and high blood pressure are. Predisposing factors typically refer to conditions or traits that increase an individual's risk of developing a disease over time, often due to lifestyle choices or inherited characteristics.

Obesity is a well-known risk factor, as excess body weight can lead to various metabolic disorders that strain the cardiovascular system. Genetic factors can influence an individual's likelihood of developing heart diseases, as hereditary traits often play a significant role in conditions such as hyperlipidemia or hypertension. High blood pressure, or hypertension, is directly linked to increased cardiovascular risk, as it can lead to damage of the arteries and heart over time.

Chemical agents, while potentially harmful in specific contexts (such as exposure to pollutants or toxins), do not directly function as a longstanding predisposing factor in the way the other options do. They might contribute to cardiovascular issues under specific exposures or conditions, but they don't serve as a broad, inherent risk factor like those listed above.