Field Notes

Obesity Increasing in Adults With Cancer History

A study at Columbia University’s Mailman School of Public Health showed that obesity was more prevalent in patients with a history of cancer than in the general population, and survivors of colorectal and breast cancers were particularly affected. The study is among the first to compare rates of obesity among US cancer survivors and adults without a history of cancer. Findings are published online in the Journal of Clinical Oncology.

Results were based on data from a nationally representative sample of 538,969 noninstitutionalized adults aged 18 to 85 with or without a history of cancer who participated in the annual National Health Interview Survey from 1997 to 2014. Obesity was defined as BMI of 30 kg/m2 or greater for non-Asians and 27.5 kg/m2 or greater for Asians.

Among 32,447 cancer survivors, the most common diagnoses were cancers of the breast, followed by prostate and colorectal cancers. Populations with the highest rates of increasing obesity were colorectal cancer survivors followed by breast cancer survivors. African American survivors of all three cancers particularly were affected.

“Our study identified characteristics of cancer survivors at the highest risk of obesity, which are important patient populations in which oncology care providers should focus their efforts,” says Heather Greenlee, ND, PhD, an assistant professor of epidemiology at the Mailman School and principal investigator.

From 1997 to 2014, prevalence of obesity increased from 22% to 32% in cancer survivors and from 21% to 30% of adults without a history of cancer. During this time, rates of obesity grew more rapidly in female cancer survivors compared with both male cancer survivors and compared with women with no history of cancer.

In female colorectal cancer survivors, those who are young and non-Hispanic black and had been diagnosed within two to nine years had the highest increasing rates of obesity. Similarly, among female breast cancer survivors, those who were young, diagnosed within the past year, and non-Hispanic white had the highest increasing obesity rate. Among male colorectal cancer survivors, the highest increases in obesity were among older men, non-Hispanic blacks, and those at or greater than 10 years from diagnosis. In contrast, prostate cancer survivors with the highest increases in obesity were younger, non-Hispanic whites, and two to nine years from diagnosis.

“While our findings can be partially explained by the growing population of patients with breast and colorectal cancer—the two cancers most closely linked to obesity—we identified additional populations of cancer survivors at risk of obesity not as well understood and which require further study,” Greenlee observes.

“These results suggest that obesity is a growing public health burden for cancer survivors that requires targeted interventions including weight management efforts to stave off the increasing obesity trends we’re seeing in cancer survivors,” Greenlee notes.

— Source: Columbia University Mailman School of Public Health


Vitamin D Levels May Drop When Women
Stop Using Birth Control

Women risk having their vitamin D levels fall when they stop using birth control pills or other contraceptives containing estrogen, according to a new study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.

A small portion of the body’s vitamin D supply—about 10%—comes from food, including fatty fish and milk fortified with the vitamin. Chemical changes to vitamin D are needed to produce the active form.

During pregnancy, women produce increased amounts of the active form of vitamin D to support formation of the fetal skeleton. As a result, pregnant women face an increased risk of developing vitamin D deficiency, according to the Endocrine Society’s Clinical Practice Guideline on vitamin D deficiency.

“Our study found that women who were using contraception containing estrogen tended to have higher vitamin D levels than other women,” says lead study author Quaker E. Harmon, MD, PhD, of the National Institutes of Health’s National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. “We could not find any behavioral differences such as increased time spent outdoors to explain the increase. Our findings suggest that contraceptives containing estrogen tend to boost vitamin D levels, and those levels are likely to fall when women cease using contraception.”

For the cross-sectional data analysis, researchers analyzed data from the Study of Environment, Lifestyle & Fibroids, a study of reproductive health in nearly 1,662 black women between the ages of 23 and 34. The women all lived in Detroit or the surrounding area. As part of the study, the participants answered questions about contraceptive use, as well as the amount of time they spent outdoors and any vitamin D supplements they took.

The participants provided blood samples, which were analyzed to measure levels of 25-hydroxy vitamin D, the primary circulating form of vitamin D.

After adjusting for seasonal exposure to sunlight, the researchers found the use of contraceptive pills, patch, or ring containing estrogen was associated with a 20% higher 25-hydroxy vitamin D level. While current birth control users tended to have higher levels of vitamin D in the blood, past contraceptive users had average levels of vitamin D.

“Our findings indicate women may run the risk of developing vitamin D deficiency just when they want to become pregnant,” Harmon says. “For women who are planning to stop using birth control, it’s worth taking steps to ensure that vitamin D levels are adequate while trying to conceive and during pregnancy.”

— Source: Endocrine Society