Study evaluates link between sedentary time and death among breast cancer survivors

Spending a lot of time watching television after breast cancer diagnosis is not linked to death in these breast cancer survivors. It appears that after accounting for self-reported physical activity levels after diagnosis, sedentary behavior was not an independent risk factor for death. These findings by Stephanie George, from the National Cancer Institute, and her colleagues, are published online in Springer's Journal of Cancer Survivorship.

On the one hand, research indicates that taking part in regular, moderate-to-vigorous intensity physical activity after a breast cancer diagnosis may reduce the risk of death. On the other hand, it has been suggested that sedentary time may have negative health consequences. George and team's study is one of the first to evaluate the link between sedentary time and death among cancer survivors, in order to help inform lifestyle recommendations for this expanding and aging population.

Two and a half years after diagnosis, 687 women diagnosed with breast cancer, who took part in the Health, Eating and Lifestyle (HEAL) Study, were asked about the amount of time they spent sitting watching television, and the type, duration and frequency of activities they performed in the past year.. They were then followed up for a further seven years, during which time the researchers recorded 89 deaths.

Overall, women who watched the most television were older, more overweight and less active than those who watched the least. More deaths were observed for those who watched the most vs. the least television. However, once self-reported physical activity levels were taken into account along with other important risk factors, the relationship authors observed between television watching and death was weakened and no longer significant.

Dr. George concludes: "It is possible that there is no true independent relationship between post-diagnosis television time and death. HEAL survivors who reported the most television time also reported the equivalent of 140 minutes per week of moderate-to-vigorous intensity physical activity - which is the amount recommended to all adults for general health. Perhaps with this amount of recreational activity, television time may not have an independent effect on survival."