Link between nationality and cervical cancer

Sep 3 2008

Gynaecological screening tests for cervical cancer have been available to all women in Sweden for almost four decades. Despite this, many immigrant women have a higher risk of developing the disease than Swedish-born women, according to a new study from Karolinska Institutet.

This is particularly the case for women from other Nordic countries and Central America, the differences being linked to, amongst other things, variation in the incidence of the Human Pappiloma Virus (HPV) around the world. HPV is a significant risk factor for cervical cancer.

"But there are other risk factors too, such as smoking, sexual habits and not taking screening tests, which make it interesting to compare cervical cancer rates between different groups of immigrant women in Sweden and native Swedes," says Professor Pär Sparén, who has led the study at the Department of Medical epidemiology and Biostatistics.

The study included more than 750,000 resident immigrant women from different countries, all of whom are registered on Karolinska Institutet's national database of women's health. During the period under study (1968 to 2004) there were 1,991 cases of cervical cancer in this group. Compared with Swedish-born women in general, this represents a slightly higher risk of developing the disease (10 per cent). Also, the incidence proportion of cervical cancer amongst women who had immigrated to Sweden was lower than amongst women in their respective countries.

However, the study also shows wide variation between the immigrant groups. Women from east Africa generally were five times less likely to develop cervical cancer than Swedish-born women, while women from southern Asia were half as likely. Conversely, the risk was much higher for women from Norway and Denmark (70 per cent and 80 per cent, respectively) and Central America (150 per cent).

Professor Sparén's team also observed that the risk of cervical cancer increased with the age of entry into Sweden, but declined during their period of residency in their new homeland. Professor Sparén believes that his findings are important for the more effective prevention of cervical cancer through, for example, targeted screening programmes.

"We need to introduce targeted screening for the prevention of cervical cancer amongst high-risk groups, particularly women over 50 during their first ten years in Sweden," he says.

The study, which was funded with a grant from the Swedish Council for Working Life and Social Research (FAS) and the National Health Care Sciences Postgraduate School at Karolinska Institutet, was a joint project with Tehran University of Medical Sciences in Iran and Mälardalen University.