Frequent intentional weight loss is associated with lower natural killer cell cytotoxicity in postmenopausal women: possible long-term immune effects.

OBJECTIVE: weight-loss attempts are likely to become more frequent as the prevalence of obesity rises. Repeated cycles of loss and gain are a common consequence of failed weight-loss attempts. The question of whether this pattern has negative health effects is unresolved. The objective of this research was to investigate associations between weight-loss history and current measures of immune function. DESIGN: The study design was a cross-sectional study. SUBJECTS: One hundred fourteen healthy, overweight, sedentary, postmenopausal women were recruited for an exercise intervention study and were currently weight stable. METHODS: History of intentional weight loss was assessed by questionnaire. Flow cytometry was used to measure natural killer cell (NK) cytotoxicity at four effector-to-target (E:T) ratios and for enumerating and phenotyping lymphocytes. Multiple linear regression analysis was used to investigate associations between weight loss within the past 20 years and current immune function. RESULTS: Women who reported ever intentionally losing >or=10 pounds had lower measured NK cytotoxicity than those who did not (24.7%+/-12.1% vs 31.1%+/-14.7%, respectively, at E:T 25:1; P=.01). Increasing frequency of previous intentional weight loss was associated with lower NK cytotoxicity (P=.003, trend). As an independent predictor, longer duration of recent weight stability was associated with higher NK cytotoxicity (21.6%+/-11.9%, 24.4%+/-11.0%, and 31.9%+/-14.4% for <or=2, >2 to <or=5, and >5 years of weight stability, respectively; P=.0002, trend). The frequency of weight loss episodes was also associated with differences in the number and proportion of NK cells. CONCLUSIONS: This study provides evidence that frequent intentional weight loss may have long-term effects on immune function.

A review of psychosocial pre-treatment predictors of weight control.

Prompted by the large heterogeneity of individual results in obesity treatment, many studies have attempted to predict weight outcomes from information collected from participants before they start the programme. Identifying significant predictors of weight loss outcomes is central to improving treatments for obesity, as it could help professionals focus efforts on those most likely to benefit, suggest supplementary or alternative treatments for those less likely to succeed, and help in matching individuals to different treatments. To date, however, research efforts have resulted in weak predictive models with limited practical usefulness. The two primary goals of this article are to review the best individual-level psychosocial pre-treatment predictors of short- and long-term (1 year or more) weight loss and to identify research needs and propose directions for further work in this area. Results from original studies published since 1995 show that few previous weight loss attempts and an autonomous, self-motivated cognitive style are the best prospective predictors of successful weight management. In the more obese samples, higher initial body mass index (BMI) may also be correlated with larger absolute weight losses. Several variables, including binge eating, eating disinhibition and restraint, and depression/mood clearly do not predict treatment outcomes, when assessed before treatment. Importantly, for a considerable number of psychosocial constructs (e.g. eating self-efficacy, body image, self-esteem, outcome expectancies, weight-specific quality of life and several variables related to exercise), evidence is suggestive but inconsistent or too scant for an informed conclusion to be drawn. Results are discussed in the context of past and present conceptual and methodological limitations, and several future research directions are described.

Modest weight loss and physical activity in overweight patients with chronic liver disease results in sustained improvements in alanine aminotransferase, fasting insulin, and quality of life.

BACKGROUND AND AIM: obesity is a risk factor for progression of fibrosis in chronic liver diseases such as non-alcoholic fatty liver disease and hepatitis C. The aim of this study was to investigate the longer term effect of weight loss on liver biochemistry, serum insulin levels, and quality of life in overweight patients with liver disease and the effect of subsequent weight maintenance or regain. PATIENTS: Thirty one patients completed a 15 month diet and exercise intervention. RESULTS: On completion of the intervention, 21 patients (68%) had achieved and maintained weight loss with a mean reduction of 9.4 (4.0)% body weight. Improvements in serum alanine aminotransferase (ALT) levels were correlated with the amount of weight loss (r = 0.35, p = 0.04). In patients who maintained weight loss, mean ALT levels at 15 months remained significantly lower than values at enrollment (p = 0.004), while in regainers (n = 10), mean ALT levels at 15 months were no different to values at enrollment (p = 0.79). Improvements in fasting serum insulin levels were also correlated with weight loss (r = 0.46, p = 0.04), and subsequent weight maintenance sustained this improvement. Quality of life was significantly improved after weight loss. Weight maintainers sustained recommended levels of physical activity and had higher fasting insulin levels (p = 0.03) at enrollment than weight regainers. CONCLUSION: In summary, these findings demonstrate that maintenance of weight loss and exercise in overweight patients with liver disease results in a sustained improvement in liver enzymes, serum insulin levels, and quality of life. Treatment of overweight patients should form an important component of the management of those with chronic liver disease.

G protein polymorphisms do not predict weight loss and improvement of hypertension in severely obese patients.

Both the gene encoding the alpha subunit of G stimulatory proteins (GNAS1) and the beta3 subunit gene (GNB3) of G proteins are associated with obesity and/or hypertension. Moreover, the TT/TC825 polymorphism of GNB3 predicts greater weight loss than the CC825 polymorphism in obese patients (mean body mass index, 35 kg/m2) undergoing a structured nonpharmacologic weight loss program. Gastric banding enforces a low-calorie diet by diminishing the need for volitional adherence. It is unknown whether these polymorphisms predict the variable weight loss in patients after bariatric surgery. Three hundred and four severely obese patients (mean +/- SEM age, 42 +/- 1 years; 245 women and 59 men; mean +/- SEM body mass index, 43.9 +/- 0.3 kg/m2) followed prospectively for at least 3 years after surgery were genotyped for the GNB3 C825T, G814A, and GNAS1 T393 polymorphisms. All analyses were performed blinded to the phenotypic characteristics of the study group. Frequencies of polymorphisms were comparable to those previously published. No polymorphism studied predicted 3-year weight loss or was associated with high blood pressure in severely obese patients after gastric banding. Multivariate analysis of potentially confounding factors such as reoperation rate or use of Sibutramine ( Meridia ) or Orlistat ( Xenical ) revealed similar results (P > 0.1). Regardless of the mechanism(s) involved for these discordant findings, GNB3 C825T, G814A, and GNAS1 T393C polymorphisms do not seem to be reliable predictors of long-term weight loss.

Effect of calcium and dairy foods in high protein, energy-restricted diets on weight loss and metabolic parameters in overweight adults.

OBJECTIVE:: To compare the effects two high-protein (HP) diets that differ in dietary calcium and protein source on weight loss, body composition, glucose and lipid metabolism, markers of liver function, fibrinolysis and endothelial function and blood pressure. DESIGN:: Randomized, parallel study (12 wk of energy restriction, 4 wk of energy balance) of high dairy protein/high-calcium (DP, 2400 mg Ca/d) and high mixed protein/moderate calcium (MP, 500 mg Ca/d) diets (5.5 MJ/d, 34% protein, 41% carbohydrate, 24% fat). SUBJECTS:: In all, 50 healthy, overweight (age 25-64 y; body mass index 25-35 kg/m(2);) males (n=20) and females (n=30). RESULTS:: Loss of total weight (-9.7+/-3.8 kg), fat mass (-8.3+/-0.4 kg) and lean mass (-1.6+/-0.3 kg) were independent of dietary group. Improvements in fasting insulin, lipids, systolic/diastolic blood pressure, and markers of liver function, fibrinolysis and endothelial function were independent of dietary intervention. CONCLUSIONS:: Increased dietary calcium/dairy foods in an energy-restricted, HP diet does not affect weight loss or body composition. Weight reduction following increased protein diets is associated with beneficial metabolic outcomes that are not affected by protein source.International Journal of obesity advance online publication, 15 February 2005; doi:10.1038/sj.ijo.0802895.

We treated 44 individuals, 31 women and 13 men, for 12 months; each one had a body mass index > or = 28 kg/m2. Mean age was 53 years (range 20-75 years). Each individual visited a nurse regularly for diet recommendations, and each was provided a prescription for Orlistat ( Xenical ) from his or her own doctor. The target weight loss of 2.5 kg prior to treatment with Orlistat ( Xenical ) was obtained by 28 patients. After 3 months the average weight loss was 3.3 kg, and after 6 months, when 10 women and 6 men remained, the average weight loss was 6.1 kg and 6.5 kg respectively. The average weight decrease between 6 and 12 months was 0.3 kg and 2.7 kg for 7 women and 4 men respectively. Total cost for medical staff's working hours was approximately 700 Swedish crowns per kg weight loss. This cost seems rather high in comparison with the unsatisfactory results obtained for the group as a whole.

Periodontal disease and weight loss in older adults.

OBJECTIVES: To determine the association between periodontal disease and weight loss in an elderly cohort. DESIGN: A longitudinal design was used with participants from the Health, Aging and Body Composition (Health ABC) cohort study to determine the association between periodontal disease status and weight loss of at least 5% of baseline body weight over a period of 2 years. SETTING: Participants were examined in research clinics in Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: A randomly selected subset of 1,053 individuals from the Health ABC examination, aged 65 and older, ambulatory and community-dwelling at baseline. MEASUREMENTS: Periodontal disease was measured as mean pocket depth and attachment loss, extent (percentage) of pockets with at least 6 mm probing depth, extent of bleeding on probing, and tissue inflammation. RESULTS: In logistic regression models adjusting for variables that may explain weight loss, extent of periodontal pockets with at least 6 mm probing depth showed a significant association with weight loss (odds ratio=1.53, 95% confidence interval=1.32-1.77). CONCLUSION: Periodontal disease may be causally related to weight loss in the elderly and thus may increase risk of morbidity and mortality.

Neuroprotective effect of low-dose lidocaine in a rat model of transient focal cerebral ischemia.

BACKGROUND: A low concentration of lidocaine (10 microM) has been shown to reduce anoxic damage in vitro. The current study examined the effect of low-dose lidocaine on infarct size in rats when administered before transient focal cerebral isehemia. METHODS: Male Wistar rats (weight, 280-340 g) were anesthetized with isoflurane, intubated, and mechanically ventilated. After surgical preparation, animals were assigned to lidocaine 2-day (n = 10), vehicle 2-day (n 12), lidocaine 7-day (n = 13), and vehicle 7-day (n = 14) groups. A 1.5-mg/kg bolus dose of ildocaine was injected intravenously 30 mm before isehemia in the lidocaine 2-day and 7-day groups. Thereafter, an infusion was initiated at a rate of 2 mg x kg(-1) x h(-1) until 60 min of reperfusion after isehemia. Rats were subjected to 90 min of focal cerebral isehemia using the intraluminal suture method. Infarct size was determined by image analysis of 2,3,5-triphenyltetrazolium chloride-stained sections at 48 h or hematoxylin and eosin-stained sections 7 days after reperfusion. Neurologic outcome and body weight loss were also evaluated. RESULTS: The infarct size was significantly smaller in the lidocaine 2-day group (185.0+/-43.7 mm3) than in the vehicle 2-day group (261.3+/-45.8 mm3, P < 0.01). The reduction in the size of the infarct in the lidocaine 7-day group (130.4+/-62.9 mm3) was also significant compared with the vehicle 7-day group (216.6+/-73.6 mm3, P < 0.01). After 7 days of reperfusion, the rats in the lidocaine group demonstrated better neurologic outcomes and less weight loss. CONCLUSIONS: The current study demonstrated that a clinical anriarrhythmic dose of lidocaine, when given before and during transient focal cerebral isehemia, significantly reduced infaret size, improved neurologic outcome, and inhibited postisehemic weight loss.