Does obesity reduce risk of death in cancer patients?

Older obese women with cancer with minimal weight loss (WL) appear to have a lower risk of death compared to their counterparts with normal weight, results of a prospective multicentre cohort study have shown.

“Overweight and obesity are associated with adverse health outcomes. However, substantial literature suggests that they are associated with longer survival among older people. This ‘obesity paradox’ remains controversial,” the authors said.

A total of 2,071 patients (mean age, 81 years; 48 percent women) from the ELCAPA prospective open cohort (2007–2016; 10 geriatric oncology clinics, Greater Paris urban area) were included in this study.

The authors generated a variable combining body mass index (BMI) at cancer diagnosis and WL in the previous 6 months. They considered four BMI categories—underweight (BMI, <22.5 kg/m²), normal weight (BMI, 22.5–24.9 kg/m²), overweight (BMI, 25–29.9 kg/m²), and obesity (BMI, 30 ≥kg/m²)—and three WL categories: minimal (<5 percent), moderate (5 to <10 percent), and severe (≥10 percent).

Univariate and multivariate Cox proportional hazards analyses were performed in men and women. Twelve- and 60-month mortality were the primary endpoints.

Of the patients, 30 percent were underweight, 23 percent normal weight, 33 percent overweight, and 14 percent obese. The predominant cancer sites were colorectal (18 percent) and breast (16 percent). Forty-nine percent of patients had metastases.

Multivariate analysis revealed a lower 60-month mortality risk among obese women with WL <5 percent than normal-weight counterparts with WL <5 percent (adjusted hazard ratio, 0.56, 95 percent confidence interval, 0.37–0.86; p=0.012).

On the other hand, there was no reduction in mortality risk among overweight/obese women with WL ≥5 percent compared with normal-weight counterparts with WL <5 percent. Overweight and obese men also did not have a lower mortality risk, regardless of WL.