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.

Obesity or obesities? Controversies on the association between body mass index and premature mortality.

Obesity is still defined on the basis of body mass index (BMI) and BMI in itself is generally accepted as a strong predictor of overall early mortality. However, an inverse association between BMI and mortality has been reported in patients with many disease states and in several clinical settings: hemodialysis, cardiovascular diseases, hypertension, stroke, diabetes, chronic obstructive pulmonary disease, surgery, etc. This unexpected phenomenon is usually called obesity-survival paradox (OP). The contiguous concepts of metabolically healthy obesity (MHO, a phenotype having BMI ≥ 30 but not having any metabolic syndrome component and having a homeostasis model assessment of insulin resistance, HOMA, <2.5) and metabolically obese normal weight (MONW, normal-weight individuals displaying obesity-related phenotypic characteristics) have received a great deal of attention in recent years. The interactions that link MHO, MONW and OP with body composition, fat distribution, aging and cardiorespiratory fitness are other crucial areas of research. The article is an introductory narrative overview of the origin and current use of the concepts of MHO, MONW and OP. These phenomena are very controversial and appear as a consequence of the frail current diagnostic definition of obesity based only on BMI. A new commonly established characterization and classification of obesities based on a number of variables is needed urgently.

Personality features of obese women in relation to binge eating and night eating.

Personality traits can affect eating behaviors, the development of obesity, and obesity treatment failure. We investigated the personality characteristics and their relation with disordered eating in 586 obese women consecutively seeking treatment at eight Italian medical centers (age, 47.7±9.8 years) and 185 age-matched, normal weight women without symptoms of eating disorders (Eating Attitude Test<20). The assessment included anthropometry, the Temperament and Character Inventory (TCI), the Binge Eating Scale (BES) and the Night Eating Questionnaire (NEQ). Logistic regression analyses were carried out in different models with BES score≥27 and NEQ≥30 as dependent variables and TCI scores as independent factors. Personality traits of obese individuals included significantly lower self-directedness and cooperativeness on TCI. BES and NEQ scores were higher in obese women, and values above the defined cut-offs were present in 77 and 18 cases (14 with high BES), respectively. After controlling for age and BMI, high BES values were associated with high novelty seeking and harm avoidance and low self-directedness, the last two scales being also associated with high NEQ. We conclude that personality traits differ between obese patients seeking treatment and controls, and the presence of disordered eating is associated with specific personality characteristics.

The quantity of meal fat influences the profile of postprandial hormones as well as hunger sensation in healthy elderly people.

BACKGROUND: In healthy elderly people, reduced appetite and the consequent decrease in food intake has been defined as the "anorexia of aging"; this condition may lead to malnutrition. The aim of this study was to investigate how different compositions of macronutrients affect satiety and hunger signals as well as subjective sensations after meals in healthy elderly subjects. METHODS: Experimental controlled study. Ambulatory healthy community-dwelling subjects evaluation in a single center on 12 elderly subjects, (75.2+/-2 years old) and 12 younger controls (28.2+/-2 years old). Using a visual analogical scale, hunger was evaluated under fasting conditions and at 30-minute intervals for up to 4 hours after two 800-kcal meals, where 20% and 40% of the calories were derived from fat. Serum samples were collected at -30, 60, 120, and 240 minutes to determine the concentrations of GLP-1, acylated and desacylated ghrelin, triglycerides, glucose, and insulin. RESULTS: Serum concentrations of GLP-1 were higher after the 40% fat meal than after the 20% fat meal (P < .01) in the elderly but not in the younger subjects. Acylated to desacylated ratio was lower after the 40% fat meal (P < .05) in the elderly. Only in the older group were triglycerides higher (P < .05), whereas hunger was significantly lower (P < .05) after the 40% fat meal. CONCLUSION: In healthy elderly people relatively large amounts of fat increase the satiety signal from GLP-1 and lower the acylated to desacylated ratio of ghrelin, consequently decreasing hunger. This condition may lead to a reduction in calorie intake.

Prevalence of overweight and obesity in Italy (2001-2008): is there a rising obesity epidemic?

PURPOSE: To provide national, population-based estimates of the prevalence of overweight and obesity in the Italian population. METHODS: Prevalence estimates of overweight and obesity were calculated in seven waves (2001-2008) of the cross-sectional Multipurpose Household Survey organized by the Italian National Institute of Statistics, which are representative of the general adult Italian population. Sampling weights were used to estimate prevalence figures as well as their standard errors. Mean-difference plot was used to evaluate changes in the distribution of body mass index across sex and age categories. RESULTS: Almost half of Italian men and about 1 of 3 Italian women are overweight or obese. Between 2001 and 2008 the age-standardized prevalence of overweight (obesity) increased 1.4% (1.9%) in men and 0.4% (0.5%) in women. Mean-difference plots showed an upward shift for body mass index distribution with an increasing skewness. CONCLUSIONS: The obesity epidemic is one of the major issues in United States and other developed countries. However, if for "epidemic" we mean that in Italy obesity is steadily increasing, then our data give little support to this interpretation. In fact, trends observed between 1983 and 2008 suggest that the rates of changes in the prevalence of overweight and/or obesity are not increasing.

Abdominal obesity and subclinical vascular damage in the elderly.

OBJECTIVE: The aim of the present study was to assess the relationships between metabolic syndrome, its components and arterial stiffness as well as evaluate the waist measurement that would accurately identify subclinical vascular damage. METHODS: Ninety-one participants (16 men) free of cardiovascular diseases with mean age 68.5 +/- 5.1 (range 60-80 years) and a BMI of 27.73 +/- 3.89 were included in the study. In each participant, we evaluated BMI, waist circumference, SBP and DBP, fasting glucose, cholesterol, low-density lipoprotein and high-density lipoprotein cholesterol, triglycerides and body composition by dual energy X-ray absorptiometry. Arterial stiffness was assessed by carotid-femoral and carotid-radial pulse wave velocity. We defined subclinical vascular damage as pulse wave velocity higher than 12 m/s. Metabolic syndrome was defined using both International Diabetes Federation (IDF) and National Cholesterol Education Program (NCEP) criteria. RESULTS: Significant associations were observed between age, triglycerides, waist circumference, trunk fat, SBP and DBP and carotid-femoral pulse wave velocity. Carotid-femoral pulse wave velocity but not carotid-radial pulse wave velocity was significantly higher in patients with metabolic syndrome than in those without metabolic syndrome, independently of its definition (IDF or NCEP). By using waist circumference cut-off suggested by IDF, it was possible to recognize a higher percentage of patients with subclinical vascular damage than by using those suggested by NCEP (88.5 vs. 50%, P = 0.01 and 0.35, respectively). CONCLUSION: These data show that in apparently healthy elderly, metabolic syndrome is strongly associated with subclinical vascular damage. Abdominal obesity and hypertriglyceridemia are also significant predictors of vascular damage. More conservative values of waist cut-off, as suggested by IDF, seem to be able to identify a larger group of patients with subclinical vascular damage, who should be better taken in consideration for treatment.

Adipose tissue infiltration in skeletal muscle of healthy elderly men: relationships with body composition, insulin resistance, and inflammation at the systemic and tissue level.

BACKGROUND: Association between inflammatory markers and intermuscular adipose tissue (IMAT) has been reported. We hypothesized that subclinical inflammation of adipose tissue surrounding and infiltrating muscle could be related to the metabolic and functional abnormalities of the "aging muscle." METHODS: In 20 healthy elderly men undergoing elective vertebral surgery, IMAT within erector spinae was evaluated by magnetic resonance imaging and body composition by dual-energy x-ray absorptiometry. Fasting glucose, insulin, high-sensitive C-reactive protein (hs-CRP), leptin, adiponectin, and interleukin 6 (IL-6) were measured, and insulin resistance was estimated by homeostasis model assessment (HOMA) index. In subcutaneous adipose tissue (SAT) biopsies near the erector spinae, quantification of gene expression was performed. RESULTS: IMAT showed a significant association with body mass index and total and regional body fat, even after adjustment for age. Insulin, HOMA, and leptin were significantly correlated with IMAT, whereas hs-CRP presented an association of borderline significance. IL-6 expression in SAT was significantly associated with IMAT; IL-6 messenger RNA (mRNA) was negatively associated with adiponectin and peroxisome proliferator-activated receptor gamma expression. In multivariate regression analysis, 68% of IMAT variance was explained by fat mass and age, independent of waist circumference, leptin, HOMA, and IL-6 mRNA. CONCLUSION: IMAT was primarily related to age and total body adiposity; subclinical inflammation in fat significantly contributes to IMAT.

In vitro aging of 3T3-L1 mouse adipocytes leads to altered metabolism and response to inflammation.

We used an in vitro model to evaluate the effects of cellular aging and inflammation on the gene expression and protein secretion profiles of adipocytes. 3T3-L1 mouse preadipocytes were cultured according to standard conditions and analyzed at different time points both at the basal state and after an acute stimulation with LPS. The mRNA levels of CCAAT/enhancer-binding protein (C/EBP)alpha, peroxisome proliferator-activated receptor (PPAR)gamma and S100A1 were maximal during adipocyte differentiation and then significantly decreased. The expression of the GLUT4 and IRS-1 genes peaked during differentiation and then decreased in aged cells. The mRNA levels and secretion of adiponectin, quickly rose as adipocytes matured and then declined. The mRNA levels of IL6, as well as its secretion, increased as preadipocytes matured and became old cells; a similar trend was also found for MCP-1. LPS decreased the mRNA levels of C/EBPalpha and PPARgamma at all time points, as well as those of GLUT4, IRS-1 and adiponectin. LPS significantly increased the mRNA levels of IL-6, as well as its secretion, with a similar trend also observed for MCP-1. These data suggest that aging adipocytes in vitro show a decline in pro-adipogenic signals, in genes involved in glucose metabolism and cytoskeleton maintenance and in adiponectin. These changes are paralleled by an increase in inflammatory cytokines; inflammation seems to mimic and amplify the effects of cellular aging on adipocytes.

The anorexia of aging.

Malnutrition in the elderly is one of the greatest threats to health, well-being and autonomy, it is therefore crucial to understand and to contrast the causal factors of inadequate energy intake. This review focuses on the mechanisms of the so-called 'anorexia of aging'. In recent years, it has been shown that elderly subjects have abnormal peripheral signal patterns and alterations in central hypothalamic control relays. Negative feedback from impaired gastric motility, exaggerated long-term adiposity signals (leptin, insulin) and postprandial anorexigenic signals (CCK, PYY) seem to prevail over the central feeding drive. If nutritional strategies of intervention are to be improved, these data need to be taken into account.

High baseline values of fat mass, independently of appendicular skeletal mass, predict 2-year onset of disability in elderly subjects at the high end of the functional spectrum.

BACKGROUND AND AIMS: To evaluate the relation between baseline body composition and 2- year onset of functional limitation in elderly subjects at the high end of the functional spectrum. METHODS: Anthropometric measurements, physical functioning as measured by a modified version of the Activities of Daily Living Scale, and baseline albumin, were evaluated in 145 men and women aged 66-78 years, free of functional limitations, selected from the general population of Verona. In each subject, total body fat mass (FM) and appendicular FFM (ASMM) were measured by dual-energy X-ray absorptiometry; the FM (FMI) and ASMM indexes (ASMMI) were also calculated by dividing each body composition variable by height squared. RESULTS: After 2 years of follow-up, 48.2% of women and 40% of men had developed mild levels of disability, with limitations in kneeling, bending and climbing stairs. In women, but not in men, a BMI higher than 25 Kg/m2 or values of FMI higher than the 50th percentile, were significantly associated with a 3 to 5 times increased risk of limitations in climbing stairs and lower body performance. In men, a trend was found between low values of ASMMI and an increased risk of limitations in kneeling and bending. After cross-tabulating categories based on the 50th percentile of ASMMI and FMI, high values of FMI, independently of ASMMI, were significantly related with higher incidence of limitation in climbing stairs in women. In women, the highest 2-year incidence of limitation in climbing stairs was found in the group of obese subjects. CONCLUSIONS: High body fat and high BMI values were associated with a greater probability of developing functional limitations 2 years later in a population of elderly subjects at the high end of the functional spectrum. Moreover, in women, high baseline values of fat mass, independently of appendicular fat-free mass, were more likely to predict the future onset of functional limitations.

Longitudinal body composition changes in old men and women: interrelationships with worsening disability.

BACKGROUND: Few studies have evaluated prospectively age-related body composition changes and their relationships with worsening disability in the elderly population. METHODS: Ninety-seven women and 62 men aged 71.4+/-2.2 and 71.6+/-2.2 years, respectively, at baseline underwent dual-energy x-ray absorptiometry determinations at baseline and at 2- and 5.5-year follow-up intervals to measure total body and leg fat (FM) and total, appendicular, and leg fat-free mass (FFM). Height, weight, body mass index (BMI), and waist circumference (as well as reported disabilities using a four-level scale) were evaluated at baseline and at 2- and 5.5-year follow-up. RESULTS: In both sexes, total FM did not change significantly, while total, appendicular, and leg FFM significantly decreased over the study follow-up. In men and women losing weight, BMI, total and leg FM, and total, appendicular, and leg FFM significantly decreased. In weight-stable men and women, appendicular and leg FFM significantly decreased and BMI, waist circumference, and total FM significantly increased. Men lost significantly more total, appendicular, and leg FFM than did women, irrespective of whether they maintained or lost weight. Over the follow-up period, 43.3% of women and 43.5% of men declined in one or more levels of reported disability. We evaluated the effect of age, baseline BMI, FM, FFM, number of diseases, baseline 6-minute walking test, categories of weight change, total, appendicular, or leg FFM changes, total FM and waist changes on the probability of a decline in one or more levels of reported disability score over the follow-up period, taking into account sex. Patients losing appendicular and leg FFM were 2.15 and 2.53 times, respectively, more likely to report increased disability than were patients without FFM loss. CONCLUSIONS: Reduction in appendicular or leg FFM was the main predictor of decline in one or more levels of reported disability in older men and women, and accounted for about a 2-fold increase in risk.

Interrelations between fat distribution, muscle lipid content, adipocytokines, and insulin resistance: effect of moderate weight loss in older women.

BACKGROUND: Interrelations between fat distribution, muscle lipid infiltration, adipocytokines, insulin resistance, and moderate weight loss have not been investigated in obese older subjects. OBJECTIVE: The objective was to evaluate relations between fat distribution, muscle lipid content, adipocytokines, and insulin resistance in older women and the effects of moderate weight loss. DESIGN: In 35 healthy women aged 58-83 y, body mass index, waist circumference, sagittal abdominal diameter (SAD), and body composition measured by dual-energy X-ray absorptiometry were evaluated. A midthigh single computed tomography scan was performed to determine subcutaneous adipose tissue (AT), intermuscular AT (IAT), muscular tissue, and muscle lipid infiltration, evaluated as low-density lean tissue. Metabolic variables, insulin resistance measured by homeostasis model assessment, adiponectin, leptin, and high-sensitivity C-reactive protein were measured in all subjects and after weight loss in a subgroup of 15 obese women. RESULTS: Waist circumference and SAD were positively correlated with leptin and insulin resistance and negatively correlated with adiponectin. Adiponectin was associated negatively with insulin resistance and positively with HDL cholesterol, whereas leptin was positively associated with insulin resistance and triacylglycerols. Midthigh subcutaneous AT was associated with insulin resistance and leptin, whereas IAT was associated with triacylglycerols. Stepwise regression with insulin resistance as the dependent variable and body mass index, SAD, triacylglycerols, HDL cholesterol, adiponectin, leptin, high-sensitivity C-reactive protein, and midthigh subcutaneous AT as independent variables showed that SAD entered the regression first (R(2) = 0.492) followed by adiponectin (R(2) = 0.63). After moderate weight loss, midthigh subcutaneous AT, IAT, low-density lean tissue, leptin, and insulin resistance decreased significantly; no significant changes in adiponectin were observed. CONCLUSIONS: Fat distribution indexes and adiponectin are independently associated with insulin resistance. Even in older women, moderate weight loss improves body fat distribution, muscle lipid infiltration, and insulin resistance. Moderate weight loss results in a significant decrease in leptin but no changes in adiponectin.

Unbalanced serum leptin and ghrelin dynamics prolong postprandial satiety and inhibit hunger in healthy elderly: another reason for the "anorexia of aging".

BACKGROUND: In healthy elderly, a reduction from the appetite and food intake of younger years has been defined as the "anorexia of aging," which may cause malnutrition. Leptin and ghrelin may alter the control of hunger and satiety and thus lead to anorexia. OBJECTIVE: The aim of this study was to investigate how aging affects serum leptin and ghrelin concentrations in response to a meal and the relation of those hormones to hunger and satiety sensations. DESIGN: We studied 8 community-dwelling elderly (x +/- SD age: 78 +/- 1 y) subjects and 8 younger (29.5 +/- 1 y) control subjects. Under fasting conditions and for 4 h after an 800-kcal mixed meal, satiety and hunger were evaluated at intervals, by using a visual analogic scale. Blood samples for leptin, ghrelin, and insulin measurements were collected at the following times: 30 min before and immediately and 30, 60, 120, and 240 min after the meal. RESULTS: Postprandial satiety lasted significantly longer in the elderly than in the control subjects, and hunger was suppressed in the elderly throughout the observation. Fasting leptin was higher in the elderly than in the young (x +/- SE: 4.3 +/- 1.9 and 1.3 +/- 0.4 ng/mL, respectively; P < 0.05), and postprandial fluctuation was not significant. Fasting insulin also was significantly higher in the elderly than in the young (6.8 +/- 1.3 and 3.5 +/- 0.6 mU/L, respectively; P < 0.05), and the postprandial insulin rise was greater in the elderly. Fasting and postprandial ghrelin values did not differ significantly between the 2 groups. Insulin was inversely correlated with hunger and directly correlated with satiety scores. CONCLUSIONS: In healthy elderly, anorexigenic signals prevail over orexigenic signals, and they contribute to prolonged satiety and inhibition of hunger. This condition may lead to a calorie deficit and finally to malnutrition in the elderly.