Changes in risk factors for cardiovascular disease with body fat loss in obese women

Semi-intensive and Intensive Interdisciplinary Treatments Have Similar Effects on Metabolic Syndrome and Selected Inflammatory Markers in Adolescents with Obesity

Background

The purpose of the present study was to compare the impact of semi-intensive and intensive interdisciplinary weight-loss therapies on the treatment of metabolic syndrome (MS) and selected inflammatory markers in adolescents with obesity.

Methods

The study included 166 adolescents enrolled in two groups for 22 weeks: the intensive group (in-person aerobic and resistance exercise three times a week, and psychological and nutritional counselling once a week), or the semi-intensive group (six in-person exercise orientation meetings and six in-person psychological support sessions with an online nutritional and exercise program). Anthropometric parameters, blood pressure, fasting glucose, insulin, lipid profile, triglycerides (TG), leptin and adiponectin were assessed before and after the interventions.

Results

Body weight and waist circumference decreased in both groups (P<0.001) and large effect sizes (η²= 0.586 and η²=0.465, respectively) were noted. Significant time and group interactions were found (P=0.001) with medium effect sizes (η²=0.095 and η²=0.105, respectively). The prevalence of MS decreased from 27.9% to 13.1% (P=0.012) and 29.4% to 5.9% (P=0.004) in the semi-intensive and intensive groups, respectively. All MS risk factors decreased significantly over time (P<0.001) and a significant time*group interaction was observed (P<0.05), except for fasting TG (P=0.832) and glucose (P=0.128, η²=0.021).

Conclusion

The results suggested that both approaches promoted significant clinical improvement in the condition of adolescents with MS and reduced associated risk factors. Studies that consider the cost effectiveness of both treatments are still needed to determine whether semi-intensive care, with its lower financial costs, may be a suitable option to treat obesity and MS in adolescents with obesity.

What change in body mass index is associated with improvement in percentage body fat in childhood obesity? A meta-regression

OBJECTIVE

Using meta-regression this paper sets out the minimum change in body mass index-SD score (BMI-SDS) required to improve adiposity as percentage body fat for children and adolescents with obesity.

DESIGN

Meta-regression.

SETTING

Studies were identified as part of a large-scale systematic review of the following electronic databases: AMED, Embase, MEDLINE via OVID, Web of Science and CENTRAL via Cochrane library.

PARTICIPANTS

Individuals aged 4-19 years with a diagnosis of obesity according to defined BMI thresholds.

INTERVENTIONS

Studies of lifestyle treatment interventions that included dietary, physical activity and/or behavioural components with the objective of reducing obesity were included. Interventions of <2 weeks duration and those that involved surgical and/or pharmacological components (eg, bariatric surgery, drug therapy) were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

To be included in the review, studies had to report baseline and post-intervention BMI-SDS or change measurements (primary outcome measures) plus one or more of the following markers of metabolic health (secondary outcome measures): adiposity measures other than BMI; blood pressure; glucose; inflammation; insulin sensitivity/resistance; lipid profile; liver function. This paper focuses on adiposity measures only. Further papers in this series will report on other outcome measures.

RESULTS

This paper explores the potential impact of BMI-SDS reduction in terms of change in percentage body fat. Thirty-nine studies reporting change in mean percentage body fat were analysed. Meta-regression demonstrated that reduction of at least 0.6 in mean BMI-SDS ensured a mean reduction of percentage body fat mass, in the sense that the associated 95% prediction interval for change in mean percentage body fat was wholly negative.

CONCLUSIONS

Interventions demonstrating reductions of 0.6 BMI-SDS might be termed successful in reducing adiposity, a key purpose of weight management interventions.

TRIAL REGISTRATION NUMBER

CRD42016025317.

What change in body mass index is needed to improve metabolic health status in childhood obesity: protocol for a systematic review

BACKGROUND

Childhood obesity is one of the most serious, global, public health challenges and has adverse health consequences in both the short-and long-term. The purpose of this study is to establish the change in body mass index (BMI) needed to achieve improvements in metabolic health status in obese children and adolescents attending lifestyle treatment interventions.

METHODS

The following electronic databases will be searched from their inception: AMED, Embase, MEDLINE via OVID, Web of Science and CENTRAL via Cochrane library. Randomised controlled trials (RCTs) or cohort studies of lifestyle interventions (i.e. dietary, physical activity and/or behavioural therapy) for treating obesity in children and adolescents (4-18 years) will be included. Interventions that last less than 2 weeks and trials that include overweight participants or those with a secondary or syndromic cause of obesity will not be included. No language restrictions will be applied. Titles and abstracts will be assessed for eligibility by two reviewers, and data from full-text articles will be extracted using a standardised data extraction template. Reference lists of all included articles will be hand-searched for additional publications. A narrative synthesis of the findings will be presented, and meta-analysis will be conducted if considered appropriate.

DISCUSSION

This will be the first systematic review of studies to establish the change in BMI required to improve metabolic health status in obese children and adolescents.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016025317.

Improvements in glucose metabolism and insulin sensitivity with a low-carbohydrate diet in obese patients with type 2 diabetes

OBJECTIVE

The optimal diet for weight loss in type 2 diabetes remains controversial. This study examined a low-carbohydrate, high-fat diet with detailed physiological assessments of insulin sensitivity, glycemic control, and risk factors for cardiovascular disease.

METHODS

Fourteen obese patients (body mass index [BMI] 40.6 ± 4.9 kg/m(2)) with type 2 diabetes were recruited for an "Atkins"-type low-carbohydrate diet. Measurements were made at 0, 12, and 24 weeks of weight, insulin sensitivity, HbA1c, lipids, and blood pressure.

RESULTS

Twelve completers lost a mean of 9.7 ± 1.8 kg over 24 weeks attributable to a major reduction in carbohydrates and resultant reduction in total energy intake. Glycemic control significantly improved (HbA1c -1.1 ± 0.25%) with reductions in hypoglycemic medication. Fasting glucose, homeostasis model assessment (HOMA), and area under the curve (AUC) glucose (intravenous glucose tolerance test [IVGTT]) were significantly reduced by week 12 ( p < 0.05). There were nonsignificant improvements in insulin sensitivity (SI) at week 12 ( p = 0.19) and week 24 ( p = 0.31). Systolic blood pressure was reduced (mean -10.0 mmHg between weeks 0 and 24, p = 0.13). Mean high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol all increased. The ratio of total: HDL cholesterol and triglycerides was reduced.

CONCLUSION

A low-carbohydrate diet was well tolerated and achieved weight loss over 24 weeks in subjects with diabetes. Glycemic control improved with a reduction in requirements for hypoglycemic agents.

Effects of prescribing 1,000 versus 1,500 kilocalories per day in the behavioral treatment of obesity: a randomized trial

OBJECTIVE

Controversy exists regarding the optimal energy prescription to promote successful long-term behavioral management of obesity. Prescribing intake of 1,000 (vs. 1,500) kcal/day may produce larger initial weight reduction, but long-term advantage remains unclear. The effects of prescribing 1,000 versus 1,500 kcal/day on 6- and 12-month weight changes within behavioral treatment of obesity were examined.

DESIGN AND METHODS

Participants were 125 obese women (mean ± SD; BMI = 37.84 ± 3.94 kg/m(2) ) randomly assigned goals of 1,000 or 1,500 kcal/day.

RESULTS

From months 0 to 6, participants prescribed 1,000 kcal/day lost more weight than those prescribed 1,500 kcal/day (mean ± SE = -10.03 ± 0.92g vs. -6.23 ± 0.94 kg, P = 0.045); however, from months 7 through 12, only the 1,000 kcal/day condition experienced a significant weight regain (1.51 ± 0.77 kg, P = 0.025). Baseline caloric consumption moderated the effect of treatment on regain; participants with baseline intakes ≧2,000 kcal/day who were assigned 1,000 kcal/day were significantly more susceptible to weight regain than those assigned 1,500 kcal/day (P = 0.049). At month 12, a significantly greater percentage of 1,000 kcal/day participants achieved weight reductions of 5% or more than those prescribed 1,500 kcal/day.

CONCLUSION

Encouraging obese individuals in behavioral treatment to adhere to a 1,000 kcal/day intake may increase their likelihood of achieving clinically meaningful weight losses.

Intentional weight loss in overweight and obese individuals and cognitive function: a systematic review and meta-analysis

High adiposity in middle age is associated with higher dementia risk. The association between weight loss and cognitive function in older adults is still controversial. A meta-analysis was undertaken to estimate the effectiveness of intentional weight loss on cognitive function in overweight and obese adults. A structured strategy was used to search randomized and non-randomized studies reporting the effect of intentional and significant weight loss on cognitive function in overweight and obese subjects. Information on study design, age, nutritional status, weight-loss strategy, weight lost and cognitive testing was extracted. A random-effect meta-analysis was conducted to obtain summary effect estimates for memory and attention-executive domains. Twelve studies met inclusion criteria. Seven were randomized trials and the remaining five included a control group. A low-order significant effect was found for an improvement in cognitive performance with weight loss in memory (effect size 0.13, 95% CI 0.00-0.26, P=0.04) and attention/executive functioning (effect size 0.14, 95% CI 0.01-0.27, P<0.001). Studies were heterogeneous in study design, sample selection, weight-loss intervention and assessment of cognitive function. Weight loss appears to be associated with low-order improvements in executive/attention functioning and memory in obese but not in overweight individuals.

The association between rate of initial weight loss and long-term success in obesity treatment: does slow and steady win the race?

BACKGROUND

Controversy exists regarding the optimal rate of weight loss for long-term weight management success.

PURPOSE

This study examined whether gradual initial weight loss was associated with greater long-term weight reduction than rapid initial loss.

METHODS

Groups were drawn from participants in the TOURS trial, which included a sample of middle-aged (mean = 59.3 years) obese women (mean BMI = 36.8) who received a 6-month lifestyle intervention followed by a 1-year extended care program. Participants were encouraged to reduce caloric intake to achieve weight losses of 0.45 kg/week. Groups were categorized as "FAST" (> or =0.68 kg/week, n = 69), "MODERATE" (> or =0.23 and <0.68 kg/week, n = 104), and "SLOW" (<0.23 kg/week, n = 89) based on rate of weight loss during first month of treatment.

RESULTS

The FAST, MODERATE, and SLOW groups differed significantly in mean weight changes at 6 months (-13.5, -8.9, and -5.1 kg, respectively, ps < 0.001), and the FAST and SLOW groups differed significantly at 18 months (-10.9, -7.1, and -3.7 kg, respectively, ps < 0.001). No significant group differences were found in weight regain between 6 and 18 months (2.6, 1.8, and 1.3 kg, respectively, ps < 0.9). The FAST and MODERATE groups were 5.1 and 2.7 times more likely to achieve 10% weight losses at 18 months than the SLOW group.

CONCLUSION

Collectively, findings indicate both short- and long-term advantages to fast initial weight loss. Fast weight losers obtained greater weight reduction and long-term maintenance, and were not more susceptible to weight regain than gradual weight losers.

Effect of regional fat loss assessed by DXA on insulin resistance and dyslipidaemia in obese women

OBJECTIVE

To investigate the impact of reduction in total fat mass (FM) and regional FMs on indices of insulin resistance and dyslipidaemia in obese women (BMI > 30 kg/m(2)) after a 1-year weight loss (WL) program; and, secondly, to investigate the potential predictive effect of baseline insulin resistance on reduction in total and regional FMs.

MATERIAL AND METHODS

In 35 women with > 4 kg weight loss, body composition by DXA (dual X-ray absorptiometry), fasting insulin, C-Peptide, insulin resistance (HOMA-IR), insulin sensitivity (QUICKI), metabolic clearance rate (MCRestOGTT) and serum lipids were assessed.

RESULTS

Mean WL was 9.6%; trunk and leg FM were reduced proportionally (14.9-14.7%). Improvement in HOMA-IR was 34.7%, insulin 30.7%, QUICKI 8.6% and MCRest OGTT 74%. The reduction in total, trunk and leg FM were similarly correlated with improvement in indices of insulin resistance (p < 0.001-0.05) and also with initial HOMA-IR (p = 0.000-0.02). In linear regressions improvement in HOMA-IR was similarly related with these FMs (p = 0.008), and initial HOMA predicted loss of trunk FM (p = 0.01). In multivariate analysis improvement in HOMA-IR was explained by loss of total FM (R(2) = 0.20, p = 0.004); improvement of QUICKI by loss of leg FM (R(2) = 0.33, p < 0.001).

CONCLUSION

Loss of leg FM and trunk FM had similar importance for the improvement in insulin resistance. Baseline HOMA-IR predicted the potential for reduction in trunk FM.

An increase in high-density lipoprotein cholesterol after weight loss intervention is associated with long-term maintenance of reduced visceral abdominal fat

OBJECTIVES

It is generally agreed that excess abdominal fat, in particular visceral abdominal fat (VAF), is related to an increased risk for obesity-related complications. We examined the association between metabolic risk factors and maintaining VAF after weight loss intervention.

METHODS

A total of 54 postmenopausal, obese women who achieved a VAF loss of at least 10% from their baseline values during a 14-week intervention were enrolled as subjects. Body weight, VAF assessed by CT scans, and metabolic risk factors (that is, blood pressure, lipids and glucose) were measured at baseline (week 0), post-intervention (week 15), and at a 2-year follow-up (week 105). The subjects were divided into two groups according to their changes in VAF between weeks 15 and 105 (follow-up period): (1) VAF gainers (VAF changes > 0 cm², n=28) or (2) VAF maintainers (VAF changes ≤ 0 cm², n=26).

RESULTS

The mean change in VAF of all subjects during the 14-week intervention was -34±16 cm² (-29.7±12.3%) (P<0.01). Along with this change, improvements (P<0.05) were observed in all metabolic risk factors except for high-density lipoprotein cholesterol (HDLC). During the follow-up period, there were interactions between the two VAF groups in HDLC, triglycerides (TG) and total cholesterol (TC)/HDLC ratio (all P<0.01). In particular, the HDLC of VAF maintainers improved, and the value at week 105 exceeded baseline level (P<0.01). However, systolic and diastolic blood pressure, TC and low-density lipoprotein cholesterol in the VAF maintainers increased (all P<0.05) back to their mean baseline level despite a further decrease in their VAF during the follow-up period (P<0.01).

CONCLUSIONS

This study shows that long-term maintenance of VAF after weight loss intervention is associated with improvements in HDLC and TG among obese, postmenopausal women.

Influence of n-3 polyunsaturated fatty acids on soluble cellular adhesion molecules as biomarkers of cardiovascular risk in young healthy subjects

BACKGROUND AND AIM

Serum levels of soluble cellular adhesion molecules (CAMs) and blood lipid parameters have been used as markers of inflammatory processes associated with cardiovascular disease (CVD) events. The present study evaluated the effects of the intake of n-3 polyunsaturated fatty acids (PUFAs) in fish and fish oil within energy-restricted diets, on soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular adhesion molecule-1 (sVCAM-1).

METHODS AND RESULTS

Two hundred and seventy-five healthy European subjects aged between 20 and 40 years, were randomized to one of four hypocaloric dietary groups: control (sunflower oil capsules, no seafood), lean fish (3 x 150 g portions of cod/week), fatty fish (3 x 150 g portions of salmon/week), fish oil ((docosahexaenoic acid (DHA)+eicosapentaenoic acid (EPA) capsules, no seafood)). Diets rich in lean fish significantly decreased ICAM-1 levels, around 5% from baseline to endpoint (p<0.05), and had no effect on VCAM-1 levels. No significant differences were observed in sICAM-1 levels after the intervention with fatty fish or fish oils. On the other hand, these two seafood based diets were responsible for a significant increase of VCAM-1 levels [fatty fish; 16.1% and fish oil; 21.9%] respectively (p<0.05).

CONCLUSIONS

CAMs as inflammatory biomarkers in young and healthy subjects are not conclusive for the evaluation of CVD risk. Hypocaloric fish diets had a different effect on CAMs, being lean fish responsible for the highest decrease in ICAM-1. On the other hand, VCAM-1 results allow speculation that a low dose of n-3 PUFA may be anti-inflammatory contrarily to a high dose which can have a pro-inflammatory effect. CAMs mechanism is complex and affected by multiple factors such as lifestyle, gender, and n-3 dose and source.

Circulating markers of inflammation and their link to indices of adiposity

BACKGROUND

Adipose tissue produces a number of inflammatory mediators. Circulating concentrations of these inflammatory markers are increasingly used as markers of local or systemic inflammation. This study compares results for 3 inflammatory adipokines measured using 2 techniques, (multiplex and ELISA), and determines the relationships with C-reactive protein (CRP), obesity, and the impact of moderate weight loss.

SUBJECTS AND METHODS

Fasting blood samples were collected at baseline and after a 24-week weight loss intervention. Interleukin 6 (IL-6), tumour necrosis factor alpha(TNF-alpha), and monocyte chemoattractant protein 1 (MCP-1) were measured using a standard ELISA technique or a new multiplex technique. A total of 54 women with complete data were included in this analysis.

RESULTS

Multiplex showed poor correlation with ELISA results, and were not significantly correlated with CRP. Using ELISA data, IL-6 and CRP were significantly correlated with body mass index (BMI) (r = 0.42 and r = 0.55), but MCP-1 and TNF-alpha were not (r = - 0.07 and r = 0.06). Changes in MCP-1, TNF-alpha, and IL-6 were not significantly different between control and weight loss groups. CRP was significantly reduced in weight loss vs. control group (p < 0.05), and change in CRP correlated with change in BMI (r = 0.31).

CONCLUSION

Circulating IL-6 and CRP, but not MCP-1 and TNF-alpha, are significantly associated with indices of adiposity in obese women. This study suggests that circulating IL-6 and CRP, but not MCP-1 and TNF-alpha, are useful markers of obesity-related inflammation.

The importance of free fatty acids in the development of Type 2 diabetes

The recent increase in the prevalence of obesity has been associated with a coincident rise in the prevalence of Type 2 diabetes, whereas weight loss has been shown to decrease the risk of Type 2 diabetes. The pathophysiological mechanisms that have been proposed to explain this link are fundamentally concerned with insulin resistance and the decline in pancreatic B-cell function that accompanies an increase in visceral obesity. They involve the rise in the plasma concentrations of free fatty acids (FFAs) that are associated with an increase in fat mass. Elevated levels of FFAs can lead to insulin resistance, and evidence is growing that B-cell function is impaired through lipotoxicity. Factors such as tumour necrosis factor-alpha (TNF-alpha) and adiponectin, released from adipose tissue, can also modulate insulin resistance. Many interventions that are helpful in treating or preventing Type 2 diabetes, such as weight loss and certain pharmacological interventions, reduce circulating FFA concentrations to a greater or lesser extent. Recent study results suggest that peroxisome proliferator-activated receptor (PPAR)gamma agonists have an effect on the development of Type 2 diabetes. However, in light of concerns over the apparent increase in congestive heart failure with PPARgamma agonists, their place in the prevention of Type 2 diabetes remains to be determined.

Validity of the leg-to-leg bioimpedance to estimate changes in body fat during weight loss and regain in overweight women: a comparison with multi-compartment models

OBJECTIVES

To investigate changes in body composition and the validity of the leg-to-leg bioimpedance (LTL) method to measure body fat during active weight loss (WL) and weight regain (WR).

DESIGN

Longitudinal, 12-week weight loss intervention (3.3-3.8 MJ/day) and subsequent follow-up at 1 year.

SUBJECTS

Fifty-eight adult women aged between 24 and 65 years (mean age: 46.8+/-8.9 years) and with a body mass index (BMI) > or =25 kg/m(2) (mean BMI: 31.6+/-2.5 kg/m(2), range=26.0-48.2 kg/m(2)) participated in the study.

MEASUREMENTS

Fat mass (FM) was measured at baseline, 12 weeks, 24 weeks and 52 weeks using three- and four-compartment (4-C) models, air displacement plethysmography (ADP), deuterium dilution - total body water (TBW), dual-energy X-ray absorptiometry (DXA), skinfold thickness (SFT), tetrapolar bioelectrical impedance analysis (T-BIA) and LTL.

RESULTS

At the end of the weight loss programme, subjects lost 9.9+/-3.5 kg weight (P<0.001) and 7.6+/-0.5 kg fat (P<0.001) but after 1 year they had regained 4.9+/-3.7 kg of weight and 3.7+/-2.9 kg of fat. The 4-C model showed that FM and TBW accounted for 76.2 and 23.6% of the loss in body mass and 81.8 and 17.7% of the tissue accrued during weight regain, respectively. The estimate of body fat change by LTL relative to multi-compartment models (WL(bias+/-2s.d.)=0.51+/-3.26 kg; WR(bias+/-2s.d.)=-0.25+/-2.30 kg) was similar to ADP, DXA and TBW in both phases but it was better than T-BIA (WL(bias+/-2s.d.)=0.17+/-7.90 kg; WR(bias+/-2s.d.)=-0.29+/-7.59 kg) and skinfold thickness (WL(bias+/-2s.d.)=2.68+/-6.68 kg; WR(bias+/-2s.d.)=-0.84+/-3.80 kg).

CONCLUSIONS

Weight loss and regain were associated with minimal changes in lean tissue as measured using multi-compartment models. The LTL system is a useful method to measure body composition changes during clinical weight management programmes.

Additive benefits of long-chain n-3 polyunsaturated fatty acids and weight-loss in the management of cardiovascular disease risk in overweight hyperinsulinaemic women

BACKGROUND

Obesity, inflammation, insulin resistance and cardiovascular disease (CVD) risk are inter-related. Both weight-loss and long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) are independently known to reduce metabolic risk, but the combined effects are unclear.

OBJECTIVE

This study examines whether addition of LC n-3 PUFA to a low fat/high carbohydrate weight-loss programme results in greater improvements in inflammation, insulin sensitivity and CVD risk, than weight-loss alone.

DESIGN

One hundred and sixteen overweight insulin-resistant women entered a 24-week randomised intervention study. Thirty-nine women were randomised to a weight-loss programme, with LC n-3 PUFA (WLFO), 38 to a weight-loss programme with placebo oil (WLPO), and 39 to receive placebo oil, with no weight-loss programme (control).

RESULTS

Ninety-three women completed the study (35 WLFO, 32 WLPO and 26 control), with significant weight-loss in WLFO (10.8+/-1.0%) and WLPO (12.4+/-1.0%) compared to the control group (P<0.0001). The WLFO, but not WLPO or control group, showed significant increases in adipose tissue LC n-3 PUFA (0.34+/-0.20 vs 0.17+/-0.10 and 0.16+/-0.10 %DHA, P<0.0001). Weight-loss showed significant improvements in insulin sensitivity (P<0.001), lipid profile (triglycerides P<0.05) and inflammation (sialic acid P<0.05). Time*group effects showed significant decreases in triglycerides (P<0.05) and increases in adiponectin (P<0.01) with LC n-3 PUFA, in the WLFO vs WLPO groups.

CONCLUSIONS

Weight-loss improved risk factors associated with CVD, with some additional benefits of LC n-3 PUFA on triglycerides and adiponectin. Given the current low dietary intake of LC n-3 PUFA, greater attention should be given to increase these fatty acids in the treatment of obesity.

Energy balance adiposity and breast cancer - energy restriction strategies for breast cancer prevention

Excess adiposity over the pre- and postmenopausal years is linked to risk of postmenopausal breast cancer. Weight loss could potentially reduce risk amongst those with excess weight via beneficial effects on the hormonal (decreased circulating levels of oestradiol, testosterone, insulin) and secretory profiles of adipocytes (decreased production of leptin, tumour necrosis factor-alpha, interleukin 6 and increased production of adiponectin). Only modest reductions in adipose tissue are achieved and sustained with current weight loss programmes, which makes strategies to mitigate the adverse metabolic effect of adiposity a priority for cancer prevention. The adverse hormonal and secretory effects of adipose tissue are influenced substantially by acute changes in energy balance prior to changes in adiposity. Human and animal studies have shown dietary energy restriction to bring about favourable changes in circulating levels of insulin, leptin, sex hormone binding globulin, insulin-like growth factor-1, oestradiol, testosterone, reactive oxygen species, and the production and secretion of locally acting adipokines and inflammatory cytokines, that is, increased adiponectin and decreased interleukin-6. Achieving and sustaining energy restriction remains a difficult challenge. Intermittent energy restriction is a potential strategy for promoting periods of energy restriction on a long-term basis. Animal and human data suggest that intermittent energy restriction may have cancer preventative effects beyond that of chronic energy restriction and weight loss. Intermittent energy restriction may be a potential strategy for the primary prevention of breast cancer.

Effect of weight loss on inflammatory and endothelial markers and FMD using two low-fat diets

OBJECTIVE

Cardiovascular disease is strongly associated with obesity and there is evidence that weight loss has positive effects on cardiovascular disease risk. The aims of this study were to compare meal replacements (MR) with a conventional low-fat diet as weight loss strategies and to examine the effect of weight loss on flow-mediated dilatation (FMD) and other markers of endothelial function in overweight Australians with raised triglycerides (TG) (> 2 mmol/l).

RESEARCH METHODS

Subjects matched for age, gender, fasting plasma TG and body mass index were randomized to two low- fat high- carbohydrate weight loss strategies (both < 6000 kJ), one using MR and the other a structured eating plan, control (C). Subjects followed both diets for 3 months. In total, 55 subjects completed the study. FMD, pulse wave velocity and blood pressure (BP) were measured at baseline and at 3 months, as were fasting blood samples for lipids, glucose, insulin, C reactive protein (CRP) and endothelium-derived factors.

RESULTS

Mean weight loss was 6.3 +/- 3.7 kg (6.0 +/- 4.2 vs 6.63 +/- 3.35 kg, MR vs C) with no difference between diet groups. TG, insulin, CRP, plasminogen activator inhibitor 1 (PAI-1) and soluble intracellular adhesion molecule-1 (sICAM1) fell after weight loss, but FMD did not change. Systolic BP fell by 8 mmHg and pulse wave velocity improved.

DISCUSSION

In subjects with elevated TG, weight loss resulted in significant improvements in cardiovascular risk markers, particularly endothelium-derived factors (PAI-1 and sICAM1). However, FMD did not improve with weight loss.

Obesity and hypertension: two epidemics or one?

The association between obesity and hypertension is well documented, although the exact nature of this relation remains unclear. Sympathetic nervous and renin-angiotensin-aldosterone system activation appear to play an important role in the sodium and water retention, rightward shift in the pressure-natriuresis, and blood pressure elevation observed in obese individuals. Visceral obesity and the ectopic deposition of adipose tissue may be important in the activation of these systems and in the target organ damage that ensues. Weight loss is critical in the effective management of obesity hypertension and the accompanying target organ damage, although recidivism rates are high. However, prevention of weight gain should be the major priority for combating hypertension and its consequences in the future. The present review will provide an overview of our understanding of the etiology, pathophysiology, and treatment of obesity hypertension. Our focus is on the state of knowledge in humans. The potential role of abdominal obesity is considered throughout our review. We refer to relevant animal literature for supportive evidence and where little or no data in humans are available.