From the Journals

Possible obesity effect detected in cancer death rates



The obesity epidemic in the United States may be slowing improvements in cancer mortality, according to a new analysis of over 50 million cancer and heart disease deaths.

Mortality trends compared: Heart disease and cancer

“By integrating 20 years of cancer mortality data, we demonstrated that trends in obesity-associated cancer mortality showed signs of recent deceleration, consistent with recent findings for heart disease mortality,” Christy L. Avery, PhD, and associates wrote in JAMA Network Open.

Improvements in mortality related to heart disease slowed after 2011, a phenomenon that has been associated with rising obesity rates. The age-adjusted mortality rate (AAMR) declined at an average of 3.8 deaths per 100,000 persons from 1999 to 2011 but only 0.7 deaths per 100,000 from 2011 to 2018, based on data from the Centers for Disease Control and Prevention’s Wide-Ranging Online Data for Epidemiologic Research (WONDER).

To understand trends in cancer mortality and their possible connection with obesity, data for 1999-2018 from the WONDER database were divided into obesity-associated and non–obesity-associated categories and compared with heart disease mortality, they explained. The database included more than 50 million deaths that matched inclusion criteria.

The analysis showed there was difference between obesity-associated and non–obesity-associated cancers that was obscured when all cancer deaths were considered together. The average annual change in AAMR for obesity-associated cancers slowed from –1.19 deaths per 100,000 in 1999-2011 to –0.83 in 2011-2018, Dr. Avery and associates reported.

For non–obesity-associated cancers, the annual change in AAMR increased from –1.62 per 100,000 for 1999-2011 to –2.29 for 2011-2018, following the trend for all cancers: –1.48 per 100,000 during 1999-2011 and –1.77 in 2011-2018, they said.

“The largest mortality decreases were observed for melanoma of the skin and lung cancer, two cancers not associated with obesity. For obesity-associated cancers, stable or increasing mortality rates have been observed for liver and pancreatic cancer among both men and women as well as for uterine cancer among women,” the investigators wrote.

Demographically, however, the slowing improvement in mortality for obesity-associated cancers did not follow the trend for heart disease. The deceleration for cancer was more pronounced for women and for non-Hispanic Whites and not seen at all in non-Hispanic Asian/Pacific Islander individuals. “For heart disease, evidence of a deceleration was consistent across sex, race, and ethnicity,” they said.

There are “longstanding disparities in obesity” among various populations in the United States, and the recent trend of obesity occurring earlier in life may be having an effect. “Whether the findings of decelerating mortality rates potentially signal a changing profile of cancer and heart disease mortality as the consequences of the obesity epidemic are realized remains to be seen,” they concluded.

The investigators reported receiving grants from the National Institutes of Health during the conduct of the study, but no other disclosures were reported.

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