Trends in cancer-associated mortality may be changing as a consequence of the obesity epidemic, according to the results of a cross-sectional study published in JAMA Network Open.
Researchers from the University of North Carolina at Chapel Hill analyzed mortality data from the Centers for Disease Control and Prevention (CDC) from 1999 to 2018. Causes of death related to obesity and cancer among decedents were associated with trends over time. A total of 50,163,483 decedents were included, of whom 50.1% were women, 79.9% were non-Hispanic White, and 11.7% were non-Hispanic Black.
In 1999, 53.6% of all deaths were cancer related; in 2018, cancer-related deaths accounted for only 44.4%. From 1999 to 2011, the annual age-adjusted mortality rate (AAMR) decreased by -1.62 (95% CI, -1.57 to -1.52) and in 2011 to 2018, the rate accelerated to -1.77 (95% CI, -1.67 to -1.86).
Mortality resulting from heart disease decreased at an annual AAMR of -3.80 (95% CI, -3.66 to -3.93) from 1999 to 2011. From 2011 to 2018, the decline in heart disease-related mortality slowed to -0.72 (95% CI, -0.45 to -0.99), exhibiting the opposite trend as that reported for cancer-related deaths.
Cancers not associated with obesity accounted for a larger proportion of deaths in 1999 (66.8%) compared with 2018 (62.6%), expediting the decline from an annual AAMR of -1.62 (95% CI, -1.57 to -1.67) from 1999 to 2011 to -2.29 (95% CI, -2.19 to -2.39) in 2011 to 2018 (P <.001).
Obesity-associated cancer mortality had the opposite trend (annual AAMR, 1999-2011; -1.19; 95% CI, -1.13 to -1.26 vs 2011-2018: -0.83; 95% CI, -0.70 to -0.96; P <.001).
The decline in nonobesity-associated cancers between the 2 decades was most prevalent among female decedents (annual AAMR, -1.25 vs -2.10; P <.001) and the non-Hispanic White population (annual AAMR, -1.38 vs -2.07; P <.001), as were the obesity-related cancer deaths (annual AAMR, women: -1.45 vs -0.91 and non-Hispanic White decedents: -1.16 vs -0.68; both P <.001).
These trends may have been biased by the development of new treatment or diagnosis methods and not by an actual change in obesity rates. The study data indicated that mortality due to heart disease and some obesity-related cancers has continued to decline during the past 2 decades; however, the pace of this decline has been noted to be slowing recently.
Avery CL, Howard AG, Nichols HB. Comparison of 20-year obesity-associated cancer mortality trends with heart disease mortality trends in the US. JAMA Netw Open. 2021;4(5):e218356. doi:10.1001/jamanetworkopen.2021.8356