Which of the following is not known as a harmful effect of lead in the human body?

Lead exposure can result in various harmful health effects, particularly affecting the nervous system, cardiovascular system, and reproductive health. The detrimental impacts of lead on the body are well-regarded; however, it is less commonly associated with leading to a heart attack.

Sterility can occur because lead affects reproductive systems in both men and women, potentially leading to issues such as low sperm count and hormonal changes. Miscarriage is also linked to lead exposure—the toxic metal can interfere with fetal development, leading to higher risks of pregnancy loss. Liver damage can occur because lead accumulation can be toxic to the liver, impacting its functionalities.

In contrast, while lead exposure does elevate the risk of hypertension and may indirectly contribute to cardiovascular problems, it does not have a direct, commonly recognized causal link to a heart attack, making this choice stand out among the others regarding lead's known harmful effects.