OBESE women who spend extended hours sitting each day may face an increased risk of developing breast cancer, according to a recent nationwide study. The research highlights a clear association between daily sitting time and breast cancer prevalence, particularly among those with sedentary lifestyles. The study, based on data from the National Health and Nutrition Examination Survey (NHANES) spanning 1999 to 2020, focused on 9,706 obese women aged around 50 years.
The study’s findings revealed a concerning dose-response relationship between sitting time and breast cancer risk. Compared to women who sat less than 4 hours daily, those sitting 4 to 6 hours, 6 to 8 hours, and more than 8 hours daily had significantly higher odds of developing breast cancer. Specifically, the odds ratios for breast cancer were 1.61, 1.86, and 2.21, respectively, showing a steep increase with prolonged sitting time. However, this association was mitigated in women who engaged in regular physical activity, emphasizing the protective role of exercise against the harmful effects of sedentary behavior.
The research also found that certain subgroups of obese women were particularly vulnerable to the detrimental effects of prolonged sitting. These included women aged 60 and older, non-Hispanic White women, those with higher levels of education, postmenopausal women, and individuals with higher obesity levels. Inactive women in these categories exhibited the highest risk, reinforcing the importance of physical activity in reducing health risks associated with sedentary lifestyles.
These findings underscore the critical need for healthcare professionals to promote active living, particularly among obese women, to reduce the risk of breast cancer and other chronic conditions linked to prolonged sitting. Further prospective studies are needed to confirm the long-term implications of sedentary behavior and physical activity on cancer development.
Reference:
Wang L et al. Association between daily sitting time and breast cancer among obese women: a nationwide population-based study. BMC Women’s Health. 2025;25:118.
