Obesity

The Risk of Cancer In Obese Postmenopausal Women

To date at least 68 percent of adult Americans are overweight or obese and that number seems to be on the rise.  Obesity is known to be associated with all types of health issues including cancer.  Obesity increases the risk for esophagus, pancreas, colon, breast, kidney, thyroid, uterine and gallbladder cancers just to name a few.  In fact, obesity is known to be associated with 33 types of cancer in men and women.  Not only does obesity put women at risk but also the mix of obesity and being postmenopausal raises the risk even higher.  One study, using results from the NCI Surveillance, Epidemiology, and End Results (SEER) data, found that in 2007 in the United States approximately 50,500 new cases of cancer (7 percent) in women were due to obesity.

According to one study at the University of Minnesota, Masonic Cancer Center, the risk of dying from colon cancer is higher among women with abnormal body weight after menopause, including women who were obese, those with abdominal obesity and those that were underweight. Results of their findings are published in the September 2010 issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

  • Data from 1,096 women diagnosed with colon cancer were part of the study and were observed over a 20-year period.
  • Obese women with a body mass index (BMI) of at least 30 had a 45 percent higher mortality rate.
  • Underweight women with a BMI less than 18.5 had an 89 percent higher death rate when compared to women with a normal BMI.
  • The risk of colon cancer related death was found to be 30 to 40 percent higher in women with a high waist-to-hip ratio.
  • The link between obesity and a higher risk of death from colon cancer is yet to be discovered.  It can be that obese women are not diagnosed as early, that treatment may differ or that they may have more underlying health problems to begin with.
  • The research suggests colon cancer mortality in this population of women has a direct effect on women with abdominal obesity.  They believe that higher hormone levels in these women, directly leads to acquiring a more aggressive form of colon cancer.
  • At this point it is difficult to say whether reaching a healthy weight once a woman is diagnosed with colon cancer will decrease her mortality risk.
    • Because postmenopausal women are already at risk of increased abdominal fat, due to hormonal changes, this type of research should lead doctors and patients, especially those that are overweight or obese, to be more diligent about screening for early detection.

 

Many studies have found a direct correlation between being overweight or obese and an increase in the risk of postmenopausal breast cancer, especially in those not taking hormone therapy after menopause.  The increased risk of breast cancer is believed to be caused by the increase in estrogen in obese women.  After menopause the fat cells in the body become the primary source of estrogen and since obese women have more fat cells they naturally have higher estrogen levels, which promotes the growth of cancer cells in the breasts.  The same hormonal mechanism of estrogen is also associated with the risk for ovarian cancer.  In obese women who did not undertake hormonal therapy after menopause, the risk of developing ovarian cancer was found to be nearly 80 percent.

The relationship between obesity, the postmenopausal stage and cancer may be affected by the stage of life where women tend to gain weight and many times abdominal weight, due to hormonal changes.  The best advice is to maintain a normal healthy body weight throughout life.  For women who find themselves postmenopausal, this may be a more difficult task but surely not impossible.  A healthy diet and regular exercise is a good start.  In addition, regular screenings such as mammograms and colonscopies are also a smart idea.

References

Obesity and Cancer Risk: http://www.cancer.gov/cancertopics/factsheet/Risk/obesity

Obesity in post menopausal women with a family history of breast cancer: prevalence and risk awareness: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2628939/

Breast Cancer: http://www.cancer.org/Cancer/BreastCancer/DetailedGuide/breast-cancer-risk-factors

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