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

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 < 22.5), normal weight (BMI = 22.5-24.9), overweight (BMI = 25-29.9), and obesity (BMI ≥ 30)-and 3 WL categories-<5% (minimal), 5% to <10% (moderate), and ≥10% (severe). Univariate and multivariate Cox proportional hazards analyses were conducted in men and women.

RESULTS

A total of 2071 patients were included (mean age: 81 y; women: 48%; underweight: 30%; normal weight: 23%; overweight: 33%; obesity: 14%; predominant cancer sites: colorectal (18%) and breast (16%); patients with metastases: 49%). By multivariate analysis, obese women with WL < 5% had a lower 60-mo mortality risk than normal-weight women with WL < 5% (adjusted HR: 0.56; 95% CI: 0.37, 0.86; P = 0.012). Overweight/obese women with WL ≥ 5% did not have a lower mortality risk than normal-weight women with WL < 5%. Overweight and obese men did not have a lower mortality risk, irrespective of WL.

CONCLUSIONS

By taking account of prediagnosis WL, only older obese women with cancer with minimal WL had a lower mortality risk than their counterparts with normal weight.This trial was registered at clinicaltrials.gov as NCT02884375.

Obesity paradox in older cancer patients for middle and long-term mortality: A prospective multicenter cohort study of 2,071 patients

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Background: Overweight and obesity are associated with numerous adverse health outcomes. However, among older adults, substantial literature suggests an improved survival among overweight and obese patients. This phenomenon, referred to as the “obesity paradox” remains controversial. In the context of cancer, the association between overweight/obesity and mortality is complex due to the concomitant weight loss and cachexia. We aim to assess the impact of high Body Mass Index (BMI) on mortality in a large population of older cancer patients. Methods: We studied patients aged ≥70 from the ELCAPA prospective open-cohort (2007-2016; 10 geriatric oncology clinics, Great Paris urban area). Endpoints were 12- and 48-months mortality. A variable combining BMI at cancer diagnosis and weight loss (in the 6 months preceding the diagnosis) was created. BMI categories considered: underweight, (BMI < 22.4kg/m²), normal weight (BMI 22.5-24.9), overweight (BMI 25-29.9), and obese (BMI ≥30); weight loss (WL) categories: < 5%, 5- < 10%, ≥10%. Univariate and multivariate Cox proportional-hazards analysis were conducted in males and females. Results: A total of 2071 patients were included (mean age, 81; female, 48%; metastases, 49%; main localizations: digestive (37%), urinary (26%), breast (16%); underweight (30%), normal weight (23%), overweight (33%), obese (14%)). After adjustment for age, smoking, inpatient status, cancer site, metastasis, performance status and comorbidities, overweight women with < 5% WL were at lower risk of 12- and 48-months mortality compared to normal weight women with < 5% WL (aHR = 0.56; p = 0.043 and 0.65; p = 0.031, respectively). Obese women with < 5% WL had a lower mortality risk only at 48-months (aHR = 0.63; p = 0.036). The obesity paradox was stronger in overweight metastatic women. Overweight or obese women with 5- < 10% or ≥10% WL had no reduced risk of mortality compared to normal weight women. Overweight and obese men had no reduced risk of mortality irrespective of weight loss. Conclusions: By taking into account initial weight loss, we did not found evidence for obesity paradox in older patients with cancer except in the subgroup of women with minimal weight loss. Clinical trial information: NCT02884375.

Maternal deprivation induces deficits in temporal memory and cognitive flexibility and exaggerates synaptic plasticity in the rat medial prefrontal cortex

Early life adverse events can lead to structural and functional impairments in the prefrontal cortex (PFC). Here, we investigated whether maternal deprivation (MD) alters PFC-dependent executive functions, neurons and astrocytes number and synaptic plasticity in adult male Long-Evans rats. The deprivation protocol consisted of a daily separation of newborn Long-Evans pups from their mothers and littermates 3h/day postnatal day 1-14. Cognitive performances were assessed in adulthood using the temporal order memory task (TMT) and the attentional set-shifting task (ASST) that principally implicates the PFC and the Morris water maze task (WMT) that does not essentially rely on the PFC. The neurons and astrocytes of the prelimbic (PrL) area of the medial PFC (mPFC) were immunolabelled respectively with anti-NeuN and anti-GFAP antibodies and quantified by stereology. The field potentials evoked by electrical stimulation of ventral hippocampus (ventral HPC) were recorded in vivo in the PrL area. In adulthood, MD produced cognitive deficits in two PFC-dependent tasks, the TMT and ASST, but not in the WMT. In parallel, MD induced in the prelimbic area of the medial PFC an upregulation of long-term potentiation (LTP), without any change in the number of neurons and astrocytes. We provide evidence that MD leads in adults to an alteration of the cognitive abilities dependent on the PFC, and to an exaggerated synaptic plasticity in this region. We suggest that this latter phenomenon may contribute to the impairments in the cognitive tasks.

Maternal deprivation induces depressive-like behaviours only in female rats

Maternal deprivation (MD) has been developed to study the effects of early adverse experiences on behaviour and neurobiology. It has been proposed to represent a potential animal model of major depression. The purpose of our study was to examine the responses induced by MD in male and female adult Long-Evans rats in tasks designed to explore depressive-like behaviours (forced swimming test (FST), repeated open space swim test (OSST), sucrose solution consumption) and in the novel object recognition and object location tasks. A consistent sexual dimorphism was observed in the responses of male and female rats that underwent MD. In male rats, MD led to increased transitions between behaviours in the FST and increased consumption and preference for sucrose (1%) in comparison with non-deprived rats. In female rats, MD induced a decreased swimming activity on the second day of the OSST and reduced the cognitive performance in an object location task. In both sexes, MD did not alter the swimming activity in the FST and the performance in a novel object recognition task. These divergent responses in male and female rats can be related to the gender differences which exist in depression. However, due to the low amplitude of responses obtained in our study, the MD model in Long-Evans rats does not seem to mimic symptoms of major depression. In contrast, our present results suggest the use of the MD model, especially in females, as a model of the dysthymia, a mild chronic-depressive condition, which has been related to poorer maternal relationship.

Optimisation of a large WWTP thanks to mathematical modelling

Better controlling and optimising the plant's processes has become a priority for WWTP (Wastewater Treatment Plant) managers. The main objective of this project is to develop a simplified mathematical tool able to reproduce and anticipate the behaviour of the Tougas WWTP (Nantes, France). This tool is aimed to be used directly by the managers of the site. The mathematical WWTP model was created using the software WEST. This paper describes the studied site and the modelling results obtained during the stage of the model calibration and validation. The good simulation results have allowed to show that despite a first very simple description of the WWTP, the model was able to correctly predict the nitrogen composition (ammonia and nitrate) of the effluent and the daily sludge extraction. Then, a second more detailed configuration of the WWTP was implemented. It has allowed to independently study the behaviour of each of four biological trains. Once this first stage will be completely achieved, the remainder of the study will focus on the operational use of a simplified simulator with the purpose of optimising the Tougas WWTP operation.