Obesity, body fat distribution and eye diseases.

BACKGROUND: The prevalence of obesity, a chronic disease, is increasing, and obesity is now considered a global epidemic. Eye diseases are also increasing worldwide and have serious repercussions on quality of life as well as increasingly high costs for the community. The relationships between obesity and ocular pathologies are not yet well clarified and are not pathologically homogeneous: they seem to be somehow linked to excess body fat, especially to the distribution of adipose tissue and its ectopic deposits. PURPOSE: Our objective was to examine the associations between obesity and anthropometric indices, including body mass index (BMI), waist circumference (WC), and the waist/hip ratio (WHR), and the risk of most widespread eye diseases, with particular attention given to the most significant metabolic mechanisms. METHODS: This article provides a narrative overview of the effect of obesity and anthropometric measurements of body fat on prevalent eye diseases. We used the MEDLINE/PubMed, CINAHL, EMBASE, and Cochrane Library databases from 1984 to 2024. In addition, we hand-searched references from the retrieved articles and explored a number of related websites. A total of 153 publications were considered. RESULTS: There is significant evidence that obesity is associated with several eye diseases. Waist circumference (WC) and the waist/hip ratio (WHR) have been observed to have stronger positive associations with eye diseases than BMI. CONCLUSIONS: Obesity must be considered a significant risk factor for eye diseases; hence, a multidisciplinary and multidimensional approach to treating obesity, which also affects ocular health, is important. In the prevention and treatment of eye diseases related to obesity, lifestyle factors, especially diet and physical activity, as well as weight changes, both weight loss and weight gain, should not be overlooked. LEVEL OF EVIDENCE: Level V narrative review.

Obesity paradox and aging.

BACKGROUND: In association with the rapid lengthening of life expectancy and the ever-rising prevalence of obesity, many studies explored in the elderly the phenomenon usually defined as the obesity paradox. OBJECTIVE AND METHODS: This article is a narrative overview of seventy-two papers (1999-2019) that investigated the obesity paradox during the aging process. Twenty-nine documents are examined more in detail. RESULTS: The majority of studies suggesting the existence of an obesity paradox have evaluated just BMI as an index of obesity. Some aspects are often not assessed or are underestimated, in particular body composition and visceral adiposity, sarcopenic obesity, and cardio fitness. Many studies support that central fat and relative loss of fat-free mass may become relatively more important than BMI in determining the health risk associated with obesity in older ages. CONCLUSION: Inaccurate assessments may lead to a systematic underestimation of the impact of obesity on morbidity and premature mortality and, consequently, to clinical behaviors that are not respectful of the health of elderly patients. Knowledge of the changes in body composition and fat distribution will help to better understand the relationship between obesity, morbidity, and mortality in the elderly. LEVEL OF EVIDENCE: Level V, narrative overview.

Obesity paradox and heart failure.

BACKGROUND: There is scientific consensus that obesity increases the risk of cardiovascular diseases (CVD), including heart failure (HF). However, in CVD, many studies observed greater survival in overweight or class 1 obesity individuals. This counterintuitive observation was termed "obesity paradox" (OP). OBJECTIVE AND METHODS: This article is a narrative overview of the relationship between OP and CVD, particularly HF. The sources used were MEDLINE/PubMed, CINAHL, EMBASE, and Cochrane Library, from 2001 to 31 May 2020, exception for a 1983 work of historical importance. Studies reporting association and prognostic impact of obesity in HF and the impact of body composition on cardiac structure and myocardial function in obesity were also included in this review. In addition, we examined references from the retrieved articles and explored several related websites. Ultimately, we chose 79 relevant documents. Fifty-three were specifically focused on OP and HF. RESULTS: In this review, we made a summary of the evidence coming from a series of studies investigating OP. Many of these studies do not take into consideration or underestimate some of the more important morpho-functional variables of patients suffering from HF: among these, body composition and visceral adiposity, sarcopenic obesity, muscle fitness (MF), and cardiorespiratory fitness (CRF). A high body mass index (BMI) represents a risk factor for HF, but it also seems to exert a protective effect under certain circumstances. Fat distribution, lean mass, and cardio fitness could play an essential role in determining the observed differences in the HF population. CONCLUSION: BMI does not distinguish between the metabolically healthy and metabolically unhealthy obesity. The obesity impact on morbidity and premature mortality can be underestimated and, therefore, may lead to incorrect clinical courses. LEVEL OF EVIDENCE: Level V, Narrative review.

Assessing antimicrobial resistance gene load in vegan, vegetarian and omnivore human gut microbiota.

Massive antimicrobial use in animal farming is considered as the greatest contributor to the presence of antimicrobial-resistant bacteria (ARB) in food of animal origin. Nevertheless, sewage from treated animals may impact on vegetables grown on fertilised fields, but it is largely unknown whether and to what extent ARB are transferred to vegetables and the human gut. It could be hypothesised that food of animal and vegetal origin have a different role in ARB transfer to the human gut and that different diets could be characterised by different antimicrobial resistance gene (ARG) loads. This study included three groups comprising vegans (n = 26), vegetarians (n = 32) and omnivores (n = 43). Metadata regarding food consumption and anthropometric parameters were collected. Gut microbial communities were investigated by 16S rDNA analysis. Four ARGs (sul2, tetA, blaTEM and strB) were quantified by qPCR. The results showed a lower total load of investigated ARGs in vegan diet (pairwise comparison adjusted results: omnivorous-vegan, P = 0.0119; omnivorous-vegetarian, P = 0.7416; and vegan-vegetarian, P = 0.0119). No significant differences in abundance of each gene separately were found between the three groups. Neither the amount of animal protein nor the occurrence of ARGs was significant in explaining differences in the gut microbial community of individuals, and a large proportion of the differences between community composition (PERMANOVA, 46.87%) was not explained by the analysed variables. The results support the role of omnivorous and vegetarian diets in accumulating ARGs, suggesting a possible role for animal-derived food consumption.