The obesity paradox for mid- and long-term mortality in older cancer patients: a prospective multicenter cohort study

International audience; ABSTRACT Background 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. In the context of cancer, the association between overweight/obesity and mortality is complicated by concomitant weight loss (WL). Sex differences in the relation between BMI (in kg/m2) and survival have also been observed. Objectives We studied whether a high BMI was associated with better survival, and whether the association differed by sex, in older patients with cancer. Methods We studied patients aged ≥70 y from the ELCAPA (Elderly Cancer Patients) prospective open cohort (2007–2016; 10 geriatric oncology clinics, Greater Paris urban area). The endpoints were 12- and 60-mo mortality. We created a variable combining BMI at cancer diagnosis and WL in the previous 6 mo, and considered 4 BMI categories—underweight (BMI