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.

Effects of weight loss on changes in insulin sensitivity and lipid concentrations in premenopausal African American and white women.

BACKGROUND: Few studies have tested the hypothesis that changes in disease risk factors are more closely associated with changes in visceral fat than with changes in other adipose tissue depots, particularly in subjects with different ethnic or racial backgrounds. OBJECTIVE: We describe changes in triacylglycerol, total cholesterol, HDL cholesterol, LDL cholesterol, insulin sensitivity (S(i)), visceral fat, and subcutaneous abdominal adipose tissue (SAAT) with weight loss in premenopausal, overweight [body mass index (in kg/m(2)): 27-30], African American (n = 19) and white (n = 18) women. DESIGN: Assessments were performed before and after diet-induced weight loss to a BMI < 25. Body composition and body fat distribution were assessed with dual-energy X-ray absorptiometry and computed tomography, respectively; S(i) was assessed with an intravenous-glucose-tolerance test and minimal modeling. RESULTS: White women lost significantly more visceral fat and less SAAT than did African American women despite similar weight losses (approximately 13 kg). Mixed-model analysis indicated significant effects of time (ie, weight loss) on S(i), triacylglycerol, HDL cholesterol, and LDL cholesterol and of race on triacylglycerol. Time x race interaction terms were not significant. After adjustment for either total body or visceral fat, time was not related to any outcome variable; however, race remained significantly related to triacylglycerol. CONCLUSIONS: With weight loss, moderately overweight African American and white women experienced significant improvements in S(i) and lipids. The beneficial effects of weight loss did not differ with race and could not be attributed to a specific body fat depot. Lower triacylglycerol concentrations among African American women are independent of both obesity status and body fat distribution.

Laparoscopic adjustable gastric banding versus laparoscopic gastric bypass for morbid obesity: a single-institution comparison study of early results.

Laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic adjustable gastric banding (LAGB) are common surgical procedures for morbid obesity, but few studies have compared LRYGB and LAGB. All patients who underwent LRYGB and LAGB by a single surgeon at Legacy Health System were identified from a prospectively maintained database. Preoperatively, most patients were allowed to choose between LRYGB and LAGB. Age, sex, body mass index (BMI), complications, mortality, and weight loss were examined. From October 2000 to November 2003, 219 patients underwent LRYGB and 154 patients underwent LAGB. Mean preoperative BMI was 49.5+/-6.6 and 50.9+/-9.4 kg/m2, respectively (P=0.10). Mean age was 42+/-9 and 47+/-11 years (P<0.001). The LAGB group had a higher proportion of male patients (21% versus 7%, P<0.001). Patients undergoing LRYGB had longer operative times (134 versus 76 minutes, P<0.001), more blood loss (43 versus 28 ml, P<0.01), and longer hospital stays (2.6 versus 1.3 days, P<0.001). Excess weight loss was 35% for LRYGB versus 19% for LAGB at 3-month follow-up (P<0.001), 49% versus 25% at 6 months (P<0.001), 64% versus 36% at 12 months (P<0.001), 70% versus 45% at 24 months (P<0.001), and 60% versus 57% at 36 months (P=0.85). Major complications occurred in 7% and 6% (P=0.58) and minor complications occurred in 18% and 20% (P=0.65) of patients, respectively. Reoperation occurred in 21 patients (10%) after LRYGB and 31 (20%) patients after LAGB (P<0.01). Of patients undergoing reoperation, eight (38%) LRYGB patients and one (3%) LAGB patient required open laparotomy. One death occurred in each group. Patients undergoing laparoscopic adjustable gastric banding have shorter operative times, less blood loss, and shorter hospital stays compared with laparoscopic gastric bypass patients. The incidence of major and minor complications is similar; however, morbidity after LRYGB is potentially greater and the reoperation rate is higher in the LAGB group. Early weight loss is greater with gastric bypass, but the difference appears to diminish over time.

Self-efficacy as a predictor of weight change in African-American women.

OBJECTIVE: Although self-efficacy has received increasing attention for its role in weight loss, there is less research examining this relationship in minority samples. The purpose of this study was to determine whether self-efficacy for weight loss was predictive of weight change in a sample of African-American women. RESEARCH METHODS AND PROCEDURES: Subjects were 106 overweight or obese, low-income African-American women participating in a weight management intervention that involved either personalized monthly sessions with their primary care physician or standard care. Weight and self-efficacy for weight loss were assessed at baseline and at the end of the 6-month treatment. RESULTS: For subjects in the personalized intervention, baseline self-efficacy was predictive of subsequent weight change, such that higher levels of self-efficacy before treatment were associated with less weight loss. In contrast, improvements in self-efficacy during treatment were associated with greater weight loss for the personalized intervention group. DISCUSSION: Results suggest high self-efficacy for weight loss before treatment may be detrimental to success, whereas treatments that improve participants' self-efficacy may result in greater weight loss. High pretreatment self-efficacy may be indicative of overconfidence or lack of experience with the difficulties associated with weight loss efforts. Whereas replication is needed, our results suggest that self-efficacy is an important variable to consider when implementing weight loss interventions.

The early identification of poor treatment outcome in a women's weight loss program.

Research examining factors associated with program attrition or failure to lose weight during active treatment has yielded mixed findings. The goal of the current investigation was to confirm and extend prior research on the predictors and correlates of attrition and failure to lose weight during treatment. This investigation examined whether baseline characteristics, early weight loss, attendance, weight-related quality of life, confidence and difficulties with eating and exercise, and diet-related thoughts and feelings during the final week of treatment were associated with percentage change in body weight. Forty-four, obese, sedentary, postmenopausal women were recruited to participate in a 24-session weight loss intervention. Poor treatment outcome (i.e., percentage change in body weight) was significantly associated with several baseline characteristics including higher body mass index (BMI), greater fat and lower carbohydrate consumption, poor body image, and greater expectations for program success. Poor treatment outcome was also significantly associated with poor program attendance, unsatisfactory early weight loss, unsatisfactory improvements in weight-related quality of life, and lower self-control and self-confidence. By the end of active treatment, women with poor treatment outcome evidenced significantly higher levels of guilt and feelings of failure. The need for early identification and intervention with participants at risk for treatment failure is discussed.

The effect of participation in a weight loss programme on short-term health resource utilization.

Obese people consume significantly greater amounts of health resources. This study set out to determine if health resource utilization by obese people decreases after losing weight in a comprehensive medically supervised weight management programme. Four hundred and fifty-six patients enrolled in a single-centred, multifaceted weight loss programme in a universal health care system were studied. Patient information was anonymously linked with administrative databases to measure health resource utilization for 1 year before and after the programme. Mean body mass index (BMI) decreased by more than 15%. The mean annual physician visits (pre = 9.6, post = 9.4) did not change significantly after the programme. However, patients saw a significantly fewer number of different physicians per year following the programme (pre = 4.5, post = 3.9; P < 0.001). Mean annual number of emergency visits (pre = 0.2; post = 0.2) and hospital admissions (pre = 0.05; post = 0.08) did not change. Neither baseline BMI, nor its change during the programme, influenced changes in health resource utilization. Our study suggests that weight loss in a supervised weight management programme does not necessarily decrease short-term health resource utilization. Further study is required to determine if patients who maintain their weight loss experience a decrease in health utilization.

Association between a polymorphism of the 5-HT2C receptor and weight loss in teenage girls.

Receptors of the 5-HT2C subtype are assumed to be involved in the influence of serotonin on food intake. A polymorphism in the coding region of the gene for this receptor, resulting in a cysteine to serine substitution, has been reported. Fifty-seven somatically healthy teenage girls displaying weight loss and 91 normal-weight girls of the same age, all recruited by means of a population-based screening study, were compared with respect to this polymorphism. Subjects in the weight loss group displayed a higher frequency of the serine allele than those in the comparison group (23.7% vs. 7.7%, p =.0001). Seventy-two percent of the weight loss girls fulfilled the diagnostic criteria of anorexia nervosa, whereas 28% did not; when these two groups were separately analyzed, both differed significantly from controls with respect to serine allele frequency. The results support the notion that the studied gene may be involved in the regulation of food intake in young women.

Interest in healthy diet and physical activity interventions peripartum among female partners of active duty military.

Overweight and obesity among soldiers and their dependents have increased over the last decade, mirroring rates in the general population. In general, few programs that result in sustained weight loss have been evaluated, although effective interventions could have clear health and cost benefits for the military. For women, the postpartum period represents a "teachable moment" to promote healthy diet and exercise behaviors related to weight loss, but the attitudes and preferences for weight-loss interventions in this population are unknown. With a view to developing a weight-loss intervention tailored to this population, we surveyed 161 peripartum women at a military base to assess their interests and preferences. Eighty-six percent were dependents. Despite their youth, more than one-third reported entering pregnancy overweight or obese. Interest was high for interventions that promote physical activity and facilitate social interaction. Based on these results, a postpartum exercise intervention is being designed for female partners of active duty soldiers.