Women who spend more of their leisure time sitting are at an increased risk of developing certain cancers, including breast and ovarian cancer, a new study has found.

In recent decades, time spent sitting has increased due to a number of factors, such as better modes of transportation and technological advancements.

While it is already known that being physically active can reduce the risk of certain cancers, little is known about the potential link between time spent sitting and specific cancers. US researchers decided to look into this further.

They looked at over 146,000 men and women who were originally cancer-free and were then monitored between 1992 and 2009. During this period, over 30,000 were diagnosed with cancer.

The study found that women who spent more of their leisure time sitting had a 10% increased risk of cancer. These results stood even when other factors were taken into account, such as body mass index (BMI) and activity levels.

Specifically, these women had an increased risk of developing breast cancer, ovarian cancer and multiple myeloma, a type of cancer that affects the body's plasma (blood) cells.

No link between sitting time and cancer was found in men.

"Longer leisure time spent sitting was associated with a higher risk of total cancer risk in women, and specifically with multiple myeloma, breast and ovarian cancers, but sitting time was not associated with cancer risk in men. Further research is warranted to better understand the differences in associations between men and women," the researchers concluded.

Details of these findings are published in the journal, Cancer Epidemiology, Biomarkers, and Prevention.