Percentage of Cancer Due to Excess Body Weight Varies by State

More than one in 20 cases of incident cancer in every state in the United States is attributable to excess body weight, a study published in JAMA Oncology revealed. Among adults aged 30 or older, about 5% of all cancer cases in men and about 10% of cases in women were attributable to excess body weight.

“Increases in obesity prevalence over the past 40 years strongly suggest that the burden of [excess body weight] will further increase in the decades to come,” according to researcher Farhad Islami, MD, PhD, of the American Cancer Society, and colleagues. “Health care clinicians and policymakers at the state and federal levels must support efforts to substantially reduce the prevalence of [excess body weight] and the associated health burden, as well as disparities through comprehensive and broad implementation of known interventions at individual and community levels.”

Islami and colleagues conducted a study using data from the Behavioral Risk Factor Surveillance System to calculate the number of cancers attributable to EBW among adults 30 or older from 2011 to 2015 on a state-by-state basis. The data included self-reported body mass index, and cancer incidence rates by state were drawn from the US Cancer Statistics database.

Each year during the study period about 37,670 (4.9%) of cancer cases in men and 74,690 (9.6%) of cases in women were attributable to excess body weight.

Among men, the highest population attributable fraction (PAF) ranged from 3.9% in Montana to 6.0% in Texas. Rates were higher among women ranging from a PAF of 7.1% in Hawaii to 11.4% in the District of Columbia. Overall, the higher rate in women reflects “the associations of excess body weight with increased risk for several female-specific cancers (corpus uteri, female breast, and ovary) and the relatively higher prevalence of obesity in women than men nationally," the researchers wrote.

Grouping the data, the researchers found the highest PAFs in several states in the South and Midwest, Alaska, and the District of Columbia.

Looking at specific cancer types, at least one in four cases of esophageal, liver and gallbladder, kidney and renal pelvis, and corpus uteri cancers were attributable to excess body weight. In fact, the PAF for corpus uteri cancer ranged from 36.5% to as great as 54.9% across states, and was greater than 50% in 19 different states.

Commenting on these results, Mingyang Song, MD, assistant professor of epidemiology and nutrition at Harvard T.H. Chan School of Public Health in Boston, said that although obesity has been established as the second leading cause of cancer incidence and death in the United States after smoking, its contribution to cancer burden at the state level remains unclear.

"Addressing this question is important to guide cancer prevention efforts in each state because of the variation in obesity rates and cancer profiles across states," Song said. "There are two major take-home messages: 1) obesity contributes to a substantial proportion of cancer cases across all states; 2) there is a modest difference in this contribution between states (1/17 to 1/12).

"Therefore, comprehensive, dedicated efforts to reduce the prevalence of overweight and obesity are needed across the states, while each state may tailor their efforts based on their own needs, socioeconomic environment, and resources," Song said.