Dietary Cadmium May Be Linked with Breast Cancer Risk

Dietary cadmium, a toxic metal widely dispersed in the environment and found in many farm fertilizers, may lead to an increased risk of breast cancer, according to a study published in Cancer Research, a journal of the American Association for Cancer Research.

Cadmium occurs at low concentrations naturally, but scientists are concerned because contamination of farmland mainly due to atmospheric deposition and use of fertilizers leads to higher uptake in plants.

“Because of a high accumulation in agricultural crops, the main sources of dietary cadmium are bread and other cereals, potatoes, root crops and vegetables,” said Agneta Åkesson, Ph.D., associate professor at Karolinska Institutet in Sweden. “In general, these foods are also considered healthy.”

For the current study, Åkesson and colleagues observed 55,987 women for more than 12 years. They estimated the dietary cadmium exposure using a food frequency questionnaire. During the follow-up period, researchers observed 2,112 incidences of breast cancer including 1,626 estrogen receptor-positive and 290 estrogen receptor-negative cases.

Cadmium consumption was divided into three groups with the highest levels of exposure compared with the lowest. Overall, a higher exposure to cadmium via diet was linked with a 21 percent increase in breast cancer. Among lean and normal weight women, the increased risk was 27 percent.

Both estrogen receptor-positive and negative tumors had the same risk increase at roughly 23 percent. Åkesson said that women who consumed higher amounts of whole grain and vegetables had a lower risk of breast cancer compared to women exposed to dietary cadmium through other foods.

Factors that are associated with an increased risk of breast cancer include:

Being female. Women are much more likely than men are to develop breast cancer.

Increasing age. Your risk of breast cancer increases as you age. Women older than 55 have a greater risk than do younger women.

A personal history of breast cancer. If you've had breast cancer in one breast, you have an increased risk of developing cancer in the other breast.

A family history of breast cancer. If you have a mother, sister or daughter with breast cancer, you have a greater chance of being diagnosed with breast cancer. Still, the majority of people diagnosed with breast cancer have no family history of the disease.

Inherited genes that increase cancer risk. Certain gene mutations that increase the risk of breast cancer can be passed from parents to children. The most common gene mutations are referred to as BRCA1 and BRCA2. These genes can greatly increase your risk of breast cancer and other cancers, but they don't make cancer inevitable.