Cancer prevention: Flexible work environment, folate supplementation may be protective

A flexible work environment that enables staff to make time for physical activity appears to reduce cancer risk in middle-aged workers, according to researchers at the Harvard School of Public Health (HSPH) Center for Work, Health, and Well-being. Staying physically active and maintaining a healthy weight are two ways to reduce the risk of developing cancer.

The new study was one of two HSPH studies in a March 2014 American Journal of Preventive Medicine (AJPM) supplement on preventing cancer in midlife (roughly ages 45 to 64), a time when cancer often surfaces. The supplement was sponsored by the Centers for Disease Control and Prevention (CDC)’s Division of Cancer Prevention and Control.

Approximately 64% of adults spend about 34 hours per week on the job, making the workplace an important factor in health, wrote the authors.

Lead author Candace Nelson, Harvard-Liberty Mutual Post Doctoral Fellow in HSPH’s Department of Environmental Health, and colleagues studied data on nearly 1,600 patient-care workers at two Boston hospitals. “We found that workplace characteristics were more strongly related to physical activity than age,” Nelson said.

The researchers found that workers with more control over their work schedule and job tasks were more physically active. Workers who lacked enough sleep or who were harassed at work – for example, yelled at – were more likely to be obese. “These findings underscore the persistent impact of the work environment on health for workers of all ages,” said Nelson.

Glorian Sorensen, professor of social and behavioral sciences, principal investigator of the Center for Work, Health, and Well-being, and vice president for faculty development at Dana-Farber Cancer Institute, was senior author.

Colorectal cancer and folic acid

Colorectal cancer (CRC) is the third most commonly diagnosed cancer among men and women and the fourth-leading cause of cancer death worldwide. The U.S. is reportedly the only country experiencing a CRC decline. While increased screening is likely a factor in the decrease, the authors of an HSPH study in the AJPM supplement believe increased consumption of folate in the U.S. also may contribute to the lower rate.

In the U.S., a short-term increase in CRC rates occurred in the late 1990’s with the initiation of nationwide folic acid fortification, in which food manufacturers added folate to certain foods. This led to a hypothesis that folic acid might increase CRC incidence. This concern led some European countries to forego folic acid fortification, and some in the U.S. to reconsider fortification policy.

In the new paper, the authors argue that the initial hypothesis of increased risk of CRC following the fortification was simplistic and did not account for certain factors, such as a long period between improved folate status and potential protection from CRC.

“By examining the time trends in a more comprehensive manner, we concluded that folic acid fortification was unlikely to have increased incidence of CRC, and in fact, possibly may have reduced it,” said lead author NaNa Keum, a doctoral student in the Department of Nutrition and Department of Epidemiology. While more research is needed, Keum and senior author Edward Giovannucci, professor of nutrition and epidemiology, concluded that folic acid appears to be one of the most promising factors contributing to the declining U.S. colorectal cancer rate.

Read the studies: “Physical Activity and Body Mass Index: The Contribution of Age and Workplace Characteristics” and “Folic Acid Fortification and Colorectal Cancer Risk” in the AJPM supplement Opportunities for Cancer Prevention During Midlife

Learn more

CDC: Midlife cancer prevention tips