Smoking and the risk of breast cancer: an epidemiological analysis - Essay Example

have challenged this conclusion and suggested a connection between smoking and an increased risk of breast cancer, but more investigation is needed to resolve this issue. Passive smoking has been linked with an increased risk of lung cancer and heart disease. Understanding the potential association of active and passive smoking with breast cancer risk is important, because women have some control over their exposure to tobacco smoke, unlike many other breast cancer risk factors. In this paper we would be comparing two epidemiological studies in relation to measures of risk, association, risk, confounding and bias.

Breast cancer is a malignant tumor which starts within the breast tissue. If breast cancer spreads it usually first appears in the lymph nodes in the armpit. Beyond this it tends to go to the bones, liver and lungs and becomes known as metastatic breast cancer. Damaged genes cause breast cancer. In about 5% of women those genes are inherited. In 95% of women the cause of the damage is unknown. All of the known risk factors are weak predictors (quite unlike the relationship between smoking and lung cancer) and are the subject of on-going research.

Most studies have found no link between active cigarette smoking and breast cancer (Hamajima et al, 2002). Though both active smoking and second hand smoke have been suggested to increase the risk of breast cancer in a number of studies that restrict the comparison group to women who report no exposure to second hand smoke, this issue remains controversial. However, not smoking cigarettes and minimizing exposure to second hand smoke is beneficial for health reasons. Although passive exposure to tobacco smoke has been linked to a number of health problems, it is unresolved whether it alters breast cancer risk.

Most, but not all, studies that compared women who were passively exposed to tobacco smoke to women with no exposure to tobacco smoke reported an association of passive smoking with an increased risk of