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Background: Obesity is linked to a higher incidence of Alzheimer's disease (AD). Studies show that plasma amyloid-β (Aβ) dyshomeostasis, particularly low 42/40 ratio indicates a heightened risk for developing AD. However, the relationship between body mass index (BMI) and circulating plasma Aβ has not been extensively studied. Objective: We hypothesized that people with a high BMI have altered plasma Aβ homeostasis compared with people with a lower BMI. We also tested whether reducing BMI by calorie-restriction could normalize plasma concentrations of Aβ. Methods: Plasma concentrations of Aβ40, Aβ42, and Aβ42/40 ratio were measured in 106 participants with BMIs classified as lean, overweight, or obese. From this cohort, twelve participants with overweight or obese BMIs entered a 12-week calorie-restriction weight loss program. We then tested whether decreasing BMI affected plasma Aβ concentrations. Results: Plasma Aβ42/40 ratio was 17.54% lower in participants with an obese BMI compared to lean participants (p < 0.0001), and 11.76% lower compared to participants with an overweight BMI (p < 0.0001). The weight loss regimen decreased BMI by an average of 4.02% (p = 0.0005) and was associated with a 6.5% decrease in plasma Aβ40 (p = 0.0425). However, weight loss showed negligible correlations with plasma Aβ40, Aβ42, and Aβ42/40 ratio. Conclusion: Obesity is associated with aberrant plasma Aβ homeostasis which may be associated with an increased risk for AD. Weight loss appears to lower Aβ40, but large-scale longitudinal studies in addition to molecular studies are required to elucidate the underlying mechanisms of how obesity and weight loss influence plasma Aβ homeostasis. [ABSTRACT FROM AUTHOR]

Improving dietary reporting among people living with obesity is challenging as many factors influence reporting accuracy. Reactive Reporting may occur in response to dietary recording, but little is known about how image-based methods influence this process. Using a 4-d image-based mobile food record (mFRTM), this study aimed to identify demographic and psychosocial correlates of measurement error and reactivity bias, among adults with BMI 25–40 kg/m2. Participants (n 155, aged 18–65 years) completed psychosocial questionnaires and kept a 4-d mFRTM. Energy expenditure (EE) was estimated using ≥ 4 d of hip-worn accelerometer data, and energy intake (EI) was measured using mFRTM. EI:EE ratios were calculated, and participants in the highest tertile were considered to have Plausible Intakes. Negative changes in EI according to regression slopes indicated Reactive Reporting. Mean EI was 72 % (sd = 21) of estimated EE. Among participants with Plausible Intakes, mean EI was 96 % (sd = 13) of estimated EE. Higher BMI (OR 0·81, 95 % CI 0·72, 0·92) and greater need for social approval (OR 0·31, 95 % CI 0·10, 0·96) were associated with lower likelihood of Plausible Intakes. Estimated EI decreased by 3 % per d of recording (interquartile range − 14 %,6 %) among all participants. The EI of Reactive Reporters (n 52) decreased by 17 %/d (interquartile range − 23 %,–13 %). A history of weight loss (> 10 kg) (OR 3·4, 95 % CI 1·5, 7·8) and higher percentage of daily energy from protein (OR 1·1, 95 % CI 1·0, 1·2) were associated with greater odds of Reactive Reporting. Identification of reactivity to measurement, as well as Plausible Intakes, is recommended in community-dwelling studies to highlight and address sources of bias. [ABSTRACT FROM AUTHOR]

Abstract Background Evidence suggests that exercise training improves CVD risk factors. However, it is unclear whether health benefits are limited to aerobic training or if other exercise modalities such as resistance training or a combination are as effective or more effective in the overweight and obese. The aim of this study is to investigate whether 12 weeks of moderate-intensity aerobic, resistance, or combined exercise training would induce and sustain improvements in cardiovascular risk profile, weight and fat loss in overweight and obese adults compared to no exercise. Methods Twelve-week randomized parallel design examining the effects of different exercise regimes on fasting measures of lipids, glucose and insulin and changes in body weight, fat mass and dietary intake. Participants were randomized to either: Group 1 (Control, n = 16); Group 2 (Aerobic, n = 15); Group 3 (Resistance, n = 16); Group 4 (Combination, n = 17). Data was analysed using General Linear Model to assess the effects of the groups after adjusting for baseline values. Within-group data was analyzed with the paired t-test and between-group effects using post hoc comparisons. Results Significant improvements in body weight (−1.6%, p = 0.044) for the Combination group compared to Control and Resistance groups and total body fat compared to Control (−4.4%, p = 0.003) and Resistance (−3%, p = 0.041). Significant improvements in body fat percentage (−2.6%, p = 0.008), abdominal fat percentage (−2.8%, p = 0.034) and cardio-respiratory fitness (13.3%, p = 0.006) were seen in the Combination group compared to Control. Levels of ApoB48 were 32% lower in the Resistance group compared to Control (p = 0.04). Conclusion A 12-week training program comprising of resistance or combination exercise, at moderate-intensity for 30 min, five days/week resulted in improvements in the cardiovascular risk profile in overweight and obese participants compared to no exercise. From our observations, combination exercise gave greater benefits for weight loss, fat loss and cardio-respiratory fitness than aerobic and resistance training modalities. Therefore, combination exercise training should be recommended for overweight and obese adults in National Physical Activity Guidelines. This clinical trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR), registration number: ACTRN12609000684224.

Cognitive decline and dementia due to Alzheimer's disease (AD) have been associated with genetic, lifestyle, and environmental factors. A number of potentially modifiable risk factors should be taken into account when preventive or ameliorative interventions targeting dementia and its preclinical stages are investigated. Bone mineral density (BMD) and body composition are two such potentially modifiable risk factors, and their association with cognitive decline was investigated in this study. 164 participants, aged 34-87 years old (62.78 ± 9.27), were recruited for this longitudinal study and underwent cognitive and clinical examinations at baseline and after 3 years. Blood samples were collected for apolipoprotein E (APOE) genotyping and dual energy x-ray absorptiometry (DXA) was conducted at the same day as cognitive assessment. Using hierarchical regression analysis, we found that BMD and lean body mass, as measured using DXA were significant predictors of episodic memory. Age, gender, APOE status, and premorbid IQ were controlled for. Specifically, the List A learning from California Verbal Learning Test was significantly associated with BMD and lean mass both at baseline and at follow up assessment. Our findings indicate that there is a significant association between BMD and lean body mass and episodic verbal learning. While the involvement of modifiable lifestyle factors in human cognitive function has been examined in different studies, there is a need for further research to understand the potential underlying mechanisms. [ABSTRACT FROM AUTHOR]

To assess the role of body adiposity index (BAI) in predicting cardiovascular disease (CVD) and coronary heart disease (CHD) mortality, in comparison with body mass index (BMI), waist circumference (WC), and the waist circumference to hip circumference ratio (WHR). This study was a prospective 15 year mortality follow-up of 4175 Australian males, free of heart disease, diabetes and stroke. The Framingham Risk Scores (FRS) for CHD and CVD death were calculated at baseline for all subjects. Multivariable logistic regression was used to assess the effects of the measures of obesity on CVD and CHD mortality, before adjustment and after adjustment for FRS. The predictive ability of BAI, though present in the unadjusted analyses, was generally not significant after adjustment for age and FRS for both CVD and CHD mortality. BMI behaved similarly to BAI in that its predictive ability was generally not significant after adjustments. Both WC and WHR were significant predictors of CVD and CHD mortality and remained significant after adjustment for covariates. BAI appeared to be of potential interest as a measure of % body fat and of obesity, but was ineffective in predicting CVD and CHD. [ABSTRACT FROM AUTHOR]

The role of physical activity in preventing CVD has been highlighted by Professor Jerry Morris in the 1950’s. We report outcome of a 15-year prospective study with the aim to identify whether physical activity showed cardiovascular benefit independent of common risk factors and of central obesity. Baseline data of 8662 subjects, with no previous history of heart disease, diabetes or stroke, were obtained from an age- and gender- stratified sample of adults in Australian capital cities and were linked with the National Death Index to determine the causes of death of 610 subjects who had died to 31 December 2004. The study consisted of 4175 males (age 42.3±13.1 years) and 4487 females (age 42.8±13.2 years). Fasting serum lipid levels, systolic and diastolic blood pressure and smoking habits at baseline were recorded. The Framingham Risk Scores of 15-year mortality due to CHD and CVD were calculated using established equations. Subjects were also asked if they engaged in vigorous exercise, less vigorous exercise or walk for recreation and exercise in the past 2 weeks. Subjects in the high recreational physical activity category were 0.16 (0.06–0.43; p<0.001) and 0.12 (0.03–0.48; p = 0.003) times as likely as subjects in the low category for CVD and CHD mortality respectively. After adjusting for both the Framingham Risk Score and central obesity (Waist circumference to Hip circumference Ratio), those in the high recreational physical activity group were 0.35 (0.13–0.98) times less likely compared to the low category for CVD mortality. Recreational physical activity independently predicted reduced cardiovascular mortality over fifteen years. A public health focus on increased physical activity and preventing obesity is required to reduce the risk of CVD and CHD. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The effects of 30min of exercise on postprandial lipaemia in the overweight and obese are unknown as previous studies have only investigated bouts of at least 60min in lean, healthy individuals. The aim of this study was to investigate whether a single 30-min bout of resistance, aerobic or combined exercise at moderate-intensity would decrease postprandial lipaemia, glucose and insulin levels as well as increase resting energy expenditure and increase fat oxidation following a high fat meal consumed 14h after the exercise bout, in overweight and obese individuals compared to no exercise. We also compared the effects of the different exercise modalities. Methods: This study was a randomized cross-over design which examined the postprandial effects of 30min of different types of exercise in the evening prior to a breakfast meal in overweight and obese men and women. Participants were randomized on four occasions, each one-week apart, to each condition; either no exercise, aerobic exercise, resistance exercise or a combination of aerobic exercise and resistance exercise. Results: An acute bout of combination training did not have any significant effect on postprandial measurements compared to no exercise. However, aerobic exercise significantly reduced postprandial triglyceride levels by 8% compared to no exercise (p =0.02) and resistance exercise decreased postprandial insulin levels by 30% compared to aerobic exercise (p =0.01). Conclusion: These results indicate that a single moderate-intensity 30min bout of aerobic or resistance exercise improves risk factors associated with cardiovascular disease in overweight and obese individuals. [ABSTRACT FROM AUTHOR]

Objectives: To assess the adequacy of self-reported weight and height as indicators for BMI in communitybased obesity control programs. Methods: Self-reported and measured weight and height and calculated BMI in 6979 adults were assessed using analysis of covariance. Results: Prevalence of obesity (BMI >25kg/m2) and overweight (25- 29.9kg/m2) was lower using selfreported values by 3.2% and 5.0%, respectively. Females underreported BMI more than males did; and older subjects, more than younger subjects. Conclusions: Self-reported weight and height measurements may be used for the evaluation of community-based obesity control programs with the application of correction factors. This will minimize costs associated with physical measurements. [ABSTRACT FROM AUTHOR]

Abstract: Background: Our objective is to develop a parsimonious model to predict coronary heart disease (CHD) and cardiovascular disease (CVD) deaths using individual components of the Framingham risk score plus measures of central obesity. Methods: 15 year mortality follow-up of 8662 representative Australian adults in the National Heart Foundation Risk Factor Prevalence Survey of 1989, excluding those with a baseline history of heart disease, stroke or diabetes. Measures included blood pressure, fasting lipids, smoking history, body mass index (BMI), waist circumference (WC) and waist to hip ratio (WHR). Multivariable logistic regression was used to assess the effects of the Framingham risk variables and central obesity variables on cardiovascular disease mortality. Results: Smoking status, high density lipoprotein cholesterol (HDL-C) and the total cholesterol (TC) to HDL-C ratio were significant univariate predictors of CHD deaths. These together with systolic blood pressure were significant predictors of CVD deaths. The obesity measures of WC and WHR were significant univariate predictors but BMI was not. In multivariable analyses, only smoking status and waist to hip ratio were identified as key independent risk factors for CHD and CVD deaths, although TC to HDL-C ratio contributed minimally to CHD deaths. Receiver operator characteristic (ROC) curves for the Framingham risk score in comparison to the WHR plus smoking model were virtually identical, with no added effect of the lipid ratio. Conclusion: The preferred model for predicting CHD and CVD deaths uses central obesity plus smoking with no added influence of measured lipids or blood pressure. A public health focus on identifying and modifying central obesity is at least as important as the measurement and treatment of lipids and hypertension. [Copyright &y& Elsevier]

Abstract: Background: Methods of estimating central obesity are important because of the increasing frequency of obesity related diseases worldwide. Here we evaluate the precision of measuring waist circumference and the waist to hip ratio with comparisons across ethnic groups. Methods: The third Australian Risk Factor Prevalence Study (1989) of 9279 adults recorded height, weight, and Body Mass Index together with duplicate measurements of the waist and hip circumferences, the waist to hip ratio, and blood pressure levels using clearly defined survey techniques. Measurement error and precision for these variables were calculated, and comparisons were made across ethnic groups. Results: Coefficients of variation for the waist circumference and the waist to hip ratio were less than 1% indicating good precision in comparison with quite large variability for systolic and diastolic pressure readings. Waist circumference showed increased variability in subjects with larger body build in comparison with waist to hip ratio. Equivalence tests across ethnic groups indicated that the waist to hip ratio was independent of ethnicity. Conclusion: Waist to hip ratio provides a superior measure of central obesity with low measurement error, high precision, and no bias over a wide range of ethnic groups. We believe that it is essential to standardize methods in the assessment of central obesity. Assessment criteria should be based on waist to hip ratio rather than waist circumference. [Copyright &y& Elsevier]

To evaluate the role of measurements of central obesity in the multivariable prediction of cardiovascular risk using the Framingham risk scores, we studied 4,175 representative men from Australian cities, free of heart disease, stroke, and diabetes in 1989, and followed the cohort for mortality to 2004. Baseline lipids, blood pressure, and current cigarette smoking were recorded. Obesity was assessed by body mass index, waist circumference (WC), and waist-to-hip ratio (WHR) by strictly standardized methods. The Framingham equations were strong predictors of coronary heart disease (CHD) and cardiovascular disease (CVD) deaths. Of the obesity measurements, WHR and WC predicted deaths using Cox proportional hazards regression but body mass index did not. In the multivariable analyses, WHR was an independent predictor of CHD deaths, and WHR and WC were independent predictors of CVD deaths. There was little or no attenuation of hazard ratios for WHR and WC after correction for the Framingham scores. The 2 measurements of central obesity were more strongly predictive of CHD and CVD deaths in subjects at the lower levels of Framingham risk. In contrast, cigarette smoking risk appeared to contribute more in the higher Framingham risk categories. In conclusion, central obesity significantly and independently contributes to cardiovascular outcomes and to residual risk after accounting for the Framingham equations. [Copyright &y& Elsevier]

Overweight and obesity is one of the risk factors for developing CVD. At present, very little is known about the acute effects of dietary fibre on lipids, glucose and insulin, resting energy expenditure and diet-induced thermogenesis in overweight and obese individuals. This study examined the postprandial metabolic effects of dietary fibre in overweight and obese men. Ten overweight and obese men consumed a mixed meal accompanied by either a high-fibre or low-fibre supplement on two separate visits, in a random order, 1 week apart. Two isoenergetic breakfast meals with similar composition were consumed by ten overweight/obese men. The meals contained either a low (3??g) or high (15??g) amount of fibre, low-fibre meal (LFM) and high-fibre meal (HFM) respectively. Analysis was carried out using paired t test and ANOVA. Serum TAG incremental area under the curve during 6??h of the postprandial period was significantly lower after the consumption of HFM compared with LFM. At the first hour of the postprandial period, plasma apo B48 concentration after consumption of HFM was significantly lower compared with LFM. The resting energy expenditure and diet-induced thermogenesis after both meals was similar during 6??h of the postprandial period. Collectively, these findings suggest that a single acute dose of dietary fibre in the form of psyllium supplement can decrease arterial exposure to TAG and modify chylomicron responses in the postprandial period. [ABSTRACT FROM PUBLISHER]