Studies link obesity and cancer


Sharon Carter does everything she can to lose weight. After years of overindulging, she says she eats three healthy meals per day, her snacks are healthy and few and far in between.

Carter regularly walks and sometimes jogs for exercise and she also encourages her 15-year-old daughter, Nichelle to eat only in moderation and to join in her daily regimen.

“Exercise, watching my diet, watching my daughter’s diet is important because we do have some [obese] individuals in my family,” said Carter, 48. “We also know that too much weight gain often leads to other problems.”

Those problems aren’t just a figment of Carter’s imagination. Two new studies presented on November 3, 2014, at the American Institute for Cancer Research’s annual meeting revealed that obesity increases the risk of certain types of breast cancer in postmenopausal black and Latino women.

One of the studies included research on 3,285 Latino women and it indicated that being overweight or obese increased the risk for estrogen receptor-negative and progesterone receptor-positive breast tumors among postmenopausal women.

“We’ve known this for a long time for white women, but now we are seeing this also in Latino women,” said the study’s author Dr. Esther John, a senior research scientist at the Cancer Prevention Institute of California.

A separate study, which included research on more than 15,000 black women, indicated that being overweight or obese increased postmenopausal women’s risk of estrogen receptor-positive breast cancer by 31 percent.

The researchers found the risk to be nearly double among black women who at one time could be classified as lean young adults, but later gained weight during adulthood.

“We know that breast cancer has several subtypes and there is growing evidence that these subtypes have different risk factors,” said Elisa Bandera, M.D., of the Rutgers Cancer Institute of New Jersey, who authored the second study. “The distribution of these subtypes and risk factors are different for African-Americans and Latinos compared to white women.”

However, Bandera says one study isn’t enough.

“We need to know more about what African-American women can do to prevent and survive breast cancers of all types, which are often aggressive and deadly,” she said.

The studies are not unlike those conducted two years ago by the nonprofit think tank, Rand Corporation, in Alexandria, Virginia, where officials said disparities in cancer between black and white residents locally are wider than those nationwide.

Rand officials found that African-Americans are more likely to be diagnosed with and die from cancer than their white peers.

While the overall cancer mortality rate proved about 21 percent higher among blacks than among whites nationally, Baltimore and Washington, D.C. has a much greater disparity than the overall mortality rate among local black residents 90 percent higher than whites.

“We know from available data that, once diagnosed with cancer, black patients in the district are more likely to begin treatment at a later stage compared to white patients,” said Rebecca Anhang Price, an associate policy researcher at Rand, who also conducted the group’s study. “But richer data on the trajectory of care among cancer patients are lacking.”

The new studies conducted this month by officials at the American Institute for Cancer Research could be considered significant because most breast cancer research has been conducted among white women, yet African-American and Latino females have a higher incidence of the more aggressive types of breast cancer that are more challenging to treat, such as estrogen receptor-negative tumors, according to the study’s authors.

“We know that black and Latino women are also more likely to die of breast cancer than white women,” said John, who noted that the few previous studies investigating obesity’s link to breast cancer among Latino women have been small with inconsistent findings.

She said this larger study fills in a lot of missing information about obesity and breast cancer in postmenopausal Latino women.

“Breast cancer appears to have different risk factors in younger versus older women but by far, breast cancer is more common among postmenopausal women,” John said.

“This has huge implications for not just Latinos but all women. We cannot change genetics or family history, but we can do something about obesity. You can eat less, choose healthier foods and do more physical activity. It may not be that easy but it’s possible. And it’s important for not just lowering breast cancer risk but for many other diseases.”