NEW YORK (Reuters Health) – Adults who are regularly active, whether through exercise or work, are less likely to develop a range of cancers, a new study suggests.

The study, which followed nearly 80,000 Japanese adults for up to a decade, found that regularly active men and women had lower risks of developing any type of cancer. When the researchers looked at specific types of cancer, they found that exercise was linked to lower risks of colon, liver, pancreatic and stomach cancers.

They also found that the protective effect was strongest among normal-weight men and women – supporting the theory that physical activity helps lower cancer risk at least partly through better weight control.

Dr. Manami Inoue and colleagues at Japan's National Cancer Center, in Tokyo, report the findings in the American Journal of Epidemiology.

The researchers followed cancer incidence rates among 79,771 men and women who were between the ages of 45 and 74 at the outset. Between 1995 and 1999, study participants were surveyed about their physical activity levels, diet and other lifestyle habits; the researchers then followed them through 2004, documenting more than 4,300 new cancer diagnoses.

Overall, according to the researchers, the risk of developing any cancer dipped slightly as participants' activity levels climbed. On average, the most-active men were 13 percent less likely than the least active men to develop cancer; the most-active women had a 16 percent lower cancer risk than their sedentary counterparts.

The link held true when the researchers accounted for a range of other factors, including participants' age, weight, smoking habits, daily calorie intake.

Physical activity was defined not only as leisure-time exercise, but also the amount of time participants typically spent walking, doing physical labour and housework.