Educational level affects risk of cancer and chances of survival

Highly educated Swedish men and women have better chances of surviving various types of cancer than those with a low level of education. At the same time, the highly educated women are more often diagnosed with noninvasive breast cancer. One reason might be that greater numbers of highly educated women take advantage of Sweden’s universal, free program of mammography, suggests researchers at the medical university Karolinska Institutet.

"It’s also possible that there are differences in compliance with treatment instructions, in how cancer is detected and evaluated, and in the support patients receive from those around them", says Jan Sundquist, Professor at Karolinska Institutet and head of the Center for Family and Community Medicine (CeFAM) in Stockholm.

In the largest study on the association between educational level, cancer incidence, and cancer survival to date, a research team at CeFAM found that highly educated people had better chances of surviving cancer. A second study also showed that highly educated women run a greater risk of developing breast cancer — especially noninvasive breast cancer — than women with less education.

In the first study, researchers used the Swedish Family-Cancer Database to follow the records of more than three million men and women. They found that people with a high level of education had an average 40 percent higher chance of surviving 20 different types of cancer than people with a low level of education. Examples include colon, breast, urinary bladder, and lung cancer, as well as melanoma. According to the researchers, some explanations might be differences in how patients follow treatment instructions, how cancer is detected and evaluated, and in patients’ social networks. Another reason might be that lifestyle habits vary by educational level.

"Our research shows that educational level is an important factor that should be taken into account, not the least in debates about health policy", says Professor Jan Sundquist, one of the participating researchers. "But to understand mechanisms behind the finding, this kind of research should be supplemented with information about things like the size of the tumour at the time of diagnosis, and more facts about who goes to universal screening and how aware people are about the early signs of cancer."

The research team also studied the connection between educational level and risk of breast cancer. They followed the records of more than a million and a half Swedish women between 1990 and 2004. After accounting for factors like age, number of pregnancies, and cancer in other family members, the fact remained that women with a university education ran a 44 percent higher risk of noninvasive breast cancer than women with nine years or less of education. The highly educated women also had a higher risk of invasive breast cancer.

"It’s naturally not education itself that causes breast cancer. It’s most likely that highly educated women attend mammography in greater numbers. Such screening is the most reliable way to find the earliest stages of breast cancer", says researcher Shehnaz Hussain, main author of the second study. "We were surprised to find such large differences in a country where there is universal, minimal-cost health care and free, universal breast cancer screening."


Publications:

"Influence of education level on breast cancer risk and survival in Sweden between 1990 and 2004", S K Hussain, A Altieri, J Sundquist and K Hemminki, International Journal of Cancer, Online 20 August 2007, DOI: 10.1002/ijc.23007

"Influence of education level on cancer survival in Sweden", S K Hussain, P Lenner, J Sundquist and K Hemminki. Annals of Oncology, Online August 2007, DOI:10.1093/annonc/mdm413