Trends in Obesity Prevalence in Adults With a History of Cancer: Results From the US National Health Interview Survey, 1997 to 2014

Abstract

Purpose: Obesity after a diagnosis of specific cancers has been associated with worse prognosis. We examined the trend in obesity prevalence among cancer survivors in the United States in the past two decades and compared trends with those of adults without a history of cancer.

Patients and methods: This was a population-based nationally representative sample of 538,969 noninstitutionalized US adults 18 to 85 years old with and without a history of cancer who participated in annual cross-sectional National Health Interview Surveys from 1997 to 2014. Obesity was defined as body mass index ≥ 30 kg/m(2) for non-Asians and body mass index ≥ 27.5 kg/m(2) for Asians.

Results: Among 32,447 cancer survivors identified, the most common cancer diagnoses were breast (n = 6,948), prostate (n = 3,984), and colorectal (n = 2,546). From 1997 to 2014, the prevalence of obesity increased from 22.4% to 31.7% in cancer survivors and from 20.9% to 29.5% in adults without a history of cancer (P for trend < .001, both groups). Over this period, the estimated rate of annual increase in obesity prevalence was higher in women and men with a history of cancer compared with those without a history of cancer (all P for interaction < .001). The estimated rate of annual increase in obesity prevalence was 3.1% in female and 3.7% in male colorectal cancer survivors, 3.0% in breast cancer survivors, and 2.1% in prostate cancer survivors (all P < .001). In subgroup analyses, populations with the highest rates of increasing obesity burden were colorectal cancer survivors, breast cancer survivors, and non-Hispanic blacks.

Conclusion: From 1997 to 2014, obesity increased more rapidly among adult cancer survivors compared with the general population. Colorectal and breast cancer survivors and non-Hispanic blacks were identified as being at the highest risk for obesity.

Fig 1.

Changes in BMI categories from 1997 to 2014 in US adults with and without a history of a cancer diagnosis. Survey-weighted and age-standardized prevalence of five BMI categories were estimated for men and women with and without a history of cancer at each survey year. BMI was categorized according to National Heart, Lung, and Blood Institute guidelines as underweight (BMI < 18.5 kg/m²), normal weight (BMI, 18.5 to < 25 kg/m²), overweight (BMI, 25 to < 30 kg/m²), class I obesity (BMI, 30 to < 35 kg/m²), and class II/III obesity (BMI ≥ 35 kg/m²). For Asians, the WHO Asian cut points were applied for underweight (BMI < 23 kg/m²), overweight (BMI, 23 to < 27.5 kg/m²), and obesity (class I, BMI ≥ 27.5 kg/m² and class II/III, BMI ≥ 32.5 kg/m²). Data were plotted as smoothed lines using locally weighted scatterplot smoothing. BMI, body mass index.

Fig 2.

Trends in obesity prevalence in US adults from 1997 to 2014, by sex, cancer history and race/ethnicity. (A) Obesity trends by sex and cancer history. Obesity (defined as body mass index ≥ 30 kg/m²) prevalence was estimated for men and women with a history of any cancer, colorectal, breast, and prostate cancers, and those without a history of cancer. Separate Poisson regression models were fit for each group to estimate the annual increase rates in obesity prevalence during this period. Each line represents the trend of predicted obesity prevalence over the specific period. Tests of differential increased rates showed that the increased rates were significantly higher among female cancer survivors compared with women without a history of cancer, and significantly higher among survivors of all cancer and colorectal cancer in men (all P for interaction < .001). (B) Obesity trends by race/ethnicity. Subgroup analyses by sex and race/ethnicity were conducted for all cancer survivors. The difference in increased rates of obesity prevalence was greater in non-Hispanic blacks compared with non-Hispanic whites and Hispanics.

Fig A1.

The percentages of adults with one or more noncancer chronic condition(s) increased over time independent of body mass index and cancer history.