Obesity, metabolic profile, and inhibition failure: Young women under scrutiny
Introduction
The global obesity epidemic is a cardinal public health problem affecting the patient as a whole (physically, socially, and mentally). The height and weight of the population have been increasing since the 18th century as education and living conditions gradually improved over time. Besides, the increased availability of high-energy density food, consumption of soft drinks, reduced energy expenditures, and marketing techniques designed to seduce and induce consumption have contributed to what some researchers call an “obesogenic” environment [1]. Although weight gain was considered to be beneficial decades ago, today we know that being overweight is dangerous. Severely obese people have been found to die sooner than normal-weight individuals, similarly to smokers and nonsmokers, respectively [2]. Obesity is responsible for an estimated 1% to 3% of the total health expenditure in most countries (5% to 10% in the United States), and this cost is predicted to increase rapidly in next years as obesity-related diseases set in [2]. Obesity is classically associated with cardiovascular risk factors, such as diabetes mellitus type 2 (TD2M), hypertension, and dyslipidemia. However, with the increasing medical knowledge on obesity, other associated health problems have become more evident, such as cancer and long-term risk of dementia [3], [4]. Some studies have shown that an elevated body mass index (BMI) is an independent risk factor for cognitive decline, including Alzheimer's disease [5], [6]. Over the past years, there has been increasing evidence that cognitive function (particularly executive functions) may be compromised in the short term in people with an elevated BMI [6], [7], [8]; however, the research results are not conclusive. The divergent findings may be attributable to differences in the sample size, age at assessment, inclusion and exclusion criteria of participants, and methods used to assess cognitive status [9].
Most studies are based on the assumption that obesity generates cognitive changes. Accordingly, cognitive impairment may result from known modifiable vascular and lifestyle-related factors, particularly hypertension and lipid parameters, higher levels of reactive oxygen species in the brain, and hormonal changes associated with obesity [10], [11], [12]. In fact, insulin resistance has been associated with deficits in memory, executive function, processing speed, verbal fluency, and overall cognitive function [13], [14], [15]. Nonetheless, association does not indicate causality, and we can speculate that the relationship may be the opposite: people with lower cognitive performance are at increased risk of developing obesity.
Executive functions are higher order neurocognitive processes that enable individuals to initiate and arrest actions, inhibit and modify behaviors when necessary, and adapt to environmental changes. They are critical for overriding default actions and maintaining goal-directed behavior (for example sustaining the recommended weight or maintaining a calorie restrictive diet). Inhibition of automatic responses, impulsivity and strategic planning—involved in successful self-regulation—are some of these executive functions proposed as related with the vulnerability to obesity [16]).
Considering that young people have been less exposed to the above-mentioned cognitive risk factors, young women constitute a remarkable study and intervention group. First, because the conditions or events that occur or develop during the reproductive life may have consequences not only on their physical and mental health but also on their reproductive capacity, social functioning, quality of life, and offspring. Second, because this group may be more uniform in terms of age and hormonal status (steroids) that could influence cognitive performance. Focusing on this population and helping them to acquire healthy lifestyles will bring major health benefits later in life, particularly lower mortality and disability from cardiovascular diseases, cerebrovascular diseases, and cancer.
Therefore, we speculated whether there are differences in cognition between obese young women and healthy controls and whether metabolic status is associated with the results. Our hypothesis was that, compared with their peers of normal weight, obese but otherwise healthy young women would have worse performances in tests that evaluate executive functions and that the results would be associated with clinical and biochemical variables. To test our hypothesis, we carried out a cross-sectional study among young women (18–45 years old) who visit a public hospital in the city of Buenos Aires, Argentina. Our first objective was to evaluate the executive performance of obese young women and compare it with that of a healthy control group. We further examined differences in the clinical and biochemical variables and looked for correlations between these variables and cognitive functioning.
Section snippets
Patients
All participants were informed about the research procedures and gave their written informed consent to take part in the study. The procedures were approved by the Ethics Committee of Hospital Dr. A. Zubizarreta. The study was carried out at the Assistance and Research Center in Cognitive Neuroscience and Memory Disorders at Hospital Dr. A. Zubizarreta, Buenos Aires, Argentina. Enrolment into the study was done between June 2013 and December 2014. The total sample comprised 115 participants [32
Demographic, clinical, and biochemical characteristics
Table 1 shows the demographic and clinical characteristics of the participants. Our sample consisted of 115 women. Two patients in the OB group were diagnosed with T2DM (fasting glucose > 126 mg/dl twice); they were eliminated from the study and referred to a specialist. Thus, the analysis included 113 patients: 81 obese women and 32 HC. The groups did not differ significantly in either age or educational level.
Unsurprisingly, the women in the OB group had significantly larger WC, HipC, BMI, fat
Discussion
Accumulating evidence suggests that cognitive dysfunction, particularly executive dysfunction, is related to extreme weight conditions [8], [33]. Our objective was to evaluate the executive performance of obese young women and compare it with that of a healthy control group. We also studied differences in clinical and biochemical variables and looked for correlations between these and cognitive functioning.
In comparison with other investigations, our study has some particular features and
Conclusions
In summary, in our study, obesity in young women was associated with cognitive impairment. Additionally, glucose metabolism, lipid profile, FMP and WC may be associated with this finding. Our results provide further evidence that obesity management should be multidisciplinary and that the professionals in treatment groups should be involved in the complexity of this area. We argue that detecting and understanding cognitive dysfunction in this population is essential to setting an appropriate
Acknowledgments
The authors thank Claudio Senestrari for his assistance at Clinical Laboratory and the health professionals at Hospital Dr. A. Zubizarreta.
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