Too Much Sitting May Raise a Woman's Cancer Risk
Effect was not seen in men, and held even after researchers factored out a lack of exercise
By Robert Preidt
TUESDAY, July 14, 2015 (HealthDay News) -- Lots of time spent sitting may increase a woman's odds for cancer, but it does not seem to have a similar effect on men, a new study suggests.
"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," concluded a team led by Dr. Alpa Patel, who directs the Cancer Prevention Study-3 at the American Cancer Society.
One doctor said the message from the study is clear.
"Encouraging individuals across all categories of weight to reduce sitting time would have an impact on their physical activity, with beneficial effects on cancer and other chronic diseases," said Dr. Paolo Bofetta, a professor of preventative medicine at the Icahn School of Medicine at Mount Sinai, in New York City.
Reported recently in the journal Cancer Epidemiology, Biomarkers & Prevention, the study tracked outcomes for more than 146,000 men and women who were cancer-free at the start of the study and then followed from 1992 to 2009. During that time, nearly 31,000 of the participants developed cancer.
More time spent sitting during leisure time was associated with a 10 percent overall higher risk of cancer in women, after the researchers adjusted for factors such as physical activity levels and weight. There was no such link found in men, however.
Among women, specific cancers associated with high levels of sitting during leisure time were the blood cancer multiple myeloma, invasive breast cancer, and ovarian cancer.
"Further research is warranted to better understand the differences in associations between men and women," Alpa Patel and colleagues wrote.
Previous research has shown that physical activity can reduce cancer risk, but few studies have examined the link between sitting time and cancer risk. Over the past few decades, sitting time in the United States has increased, the researchers said.
The study wasn't designed to prove cause-and-effect. However, given the large amount of time Americans spend sitting, even a slight link between sitting and increased cancer risk could have major public health implications, Patel's group said.