Risk factors of breast cancer in Finland.

The risk of breast cancer in Finland is low (40.1/100,000) compared with the other Nordic countries. A case-control study was carried out on 122 cases of breast cancer and 534 controls between the ages of 41 and 60. It was found that age at first marriage and birth of the first child as well as the number of abortions and parity adjusted for age at first birth were associated with the breast cancer risk, whereas lactation was not. The results did not confirm the hypothesis (de Waard) that overweight and/or the size of the woman influence the risk of breast cancer.