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

Weight-centric prevention of cancer

Background

The link between excess adiposity and carcinogenesis has been well established for multiple malignancies, and cancer is one of the main contributors to obesity-related mortality. The potential role of different weight-loss interventions on cancer risk modification has been assessed, however, its clinical implications remain to be determined. In this clinical review, we present the data assessing the effect of weight loss interventions on cancer risk.

Methods

In this clinical review, we conducted a comprehensive search of relevant literature using MEDLINE, Embase, Web of Science, and Google Scholar databases for relevant studies from inception to January 20, 2024. In this clinical review, we present systematic reviews and meta-analysis, randomized clinical trials, and prospective and retrospective observational studies that address the effect of different treatment modalities for obesity in cancer risk. In addition, we incorporate the opinions from experts in the field of obesity medicine and oncology regarding the potential of weight loss as a preventative intervention for cancer.

Results

Intentional weight loss achieved through different modalities has been associated with a reduced cancer incidence. To date, the effect of weight loss on the postmenopausal women population has been more widely studied, with multiple reports indicating a protective effect of weight loss on hormone-dependent malignancies. The effect of bariatric interventions as a protective intervention for cancer has been studied extensively, showing a significant reduction in cancer incidence and mortality, however, data for the effect of bariatric surgery on certain specific types of cancer is conflicting or limited.

Conclusion

Medical nutrition therapy, exercise, antiobesity medication, and bariatric interventions, might lead to a reduction in cancer risk through weight loss-dependent and independent factors. Further evidence is needed to better determine which population might benefit the most, and the amount of weight loss required to provide a clinically significant preventative effect.

Increased metabolic variability in Korean patients with new onset bipolar disorder: a nationwide cohort study

Introduction

The aim of this study was to determine associations between changes of metabolic parameters and the development of BD using nationally representative data.

Methods

We used health examination data provided by the South Korean National Health Insurance System (NHIS) (n = 8,326,953). The variability of each metabolic parameter including weight circumference, blood pressure, fasting blood glucose, high-density lipoprotein cholesterol, and triglyceride levels was caculated using variability independent of mean (VIM) indices. The presence of metabolic syndrome was associated with new onset BD. Each metabolic parameter with high variability was associated with a higher risk of new onset BD compared to those with low variability after adjusting for age, sex, smoking, alcohol drinking, regular exercise, income status, baseline diabetes, hypertension, and dyslipidemia.

Results

As the number of highly variable metabolic parameters increased, the risk for new onset depression also increased even after covariates adjustment. The associations between new onset BD and metabolic variability were greater in populations with age > 50 years. In addition, these associations remained significant after adjusting for the presence of depression prior to diagnoses of BD.

Discussion

Our results suggest possibility of metabolic variability as an independent environmental risk factor for BD even after adjusting for the presence of metabolic syndrome.

Higher metabolic variability increases the risk of depressive disorder in type 2 diabetes mellitus: a longitudinal nationwide cohort study

BACKGROUND AND OBJECTIVES

While variabilities in metabolic parameters (METv) have been linked to adverse health outcomes in type 2 DM, their association with depression is yet to be studied. This research aimed to investigate the association between METv and depressive disorder in patients with type 2 DM.

METHODS

The study involved a nationwide cohort of 1,119,631 type 2 DM patients who had undergone three or more serial health examinations between 2005 and 2012. At each visit, body mass index (BMI), fasting glucose (FG), systolic blood pressure (BP), and total cholesterol (TC) were measured and stratified into quartiles, with Q4 being the highest and Q1 the lowest. The risk of depressive disorder was evaluated using Cox proportional hazard regression models, which accounted for METs in the indexes, after adjusting for sex, income status, lifestyle habits, medical comorbidities, DM severity, and baseline levels of BMI, FG, BP, and TC.

RESULTS

During a mean follow-up period of 6.00 ± 2.42 years, 239,477 (21.4%) cases of type 2 DM patients developed depressive disorder. The risk of developing depressive disorder was gradually increased as the number of METv increased (HR 1.18; 95% CI 1.13, 1.23 for the group with the highest METv in all parameters compared to those with the lowest METv in all parameters). In the subgroup analysis, the risk of developing depressive disorder was 43% higher in men (HR 1.43; 95% CI 1.34, 1.51), and 31% higher in those younger than 65 years of age (HR 1.31; 95% CI 1.23, 1.39) in the group with the highest number of METv compared to the group with the lowest number of METv.

CONCLUSION

In type 2 DM, higher METv was an independent risk factor for depressive disorder. This risk is notably elevated in men and individuals under the age of 65 years.

Association of variability in metabolic parameters with the incidence of type 2 diabetes: evidence from a functional community cohort

BACKGROUND

To investigate the association of variability in metabolic parameters such as total cholesterol concentrations (TC), uric acid (UA), body mass index (BMI), visceral adiposity index (VAI) and systolic blood pressure (SBP) with incident type 2 diabetes (T2D) and whether variability in these metabolic parameters has additive effects on the risk of T2D.

METHODS

Based on the Beijing Functional Community Cohort, 4392 participants who underwent three health examinations (2015, 2016, and 2017) were followed up for incident T2D until the end of 2021. Variability in metabolic parameters from three health examinations were assessed using the coefficient of variation, standard deviation, variability independent of the mean, and average real variability. High variability was defined as the highest quartile of variability index. Participants were grouped according to the number of high-variability metabolic parameters. Cox proportional hazards models were performed to assess the hazard ratio (HR) and 95% confidence interval (CI) for incident T2D.

RESULTS

During a median follow-up of 3.91 years, 249 cases of incident T2D were identified. High variability in TC, BMI, VAI and SBP was significantly associated with higher risks of incident T2D. As for UA, significant multiplicative interaction was found between variability in UA and variability in other four metabolic parameters for incident T2D. The risk of T2D significantly increased with the increasing numbers of high-variability metabolic parameters. Compared with the group with low variability for 5 parameters, the HR (95% CI) for participants with 1-2, 3, 4-5 high-variability metabolic parameters were 1.488 (1.051, 2.107), 2.036 (1.286, 3.222) and 3.017 (1.549, 5.877), respectively. Similar results were obtained in various sensitivity analyses.

CONCLUSIONS

High variability of TC, BMI, VAI and SBP were independent predictors of incident T2D, respectively. There was a graded association between the number of high-variability metabolic parameters and incident T2D.

Association of body mass index and weight change with pneumonia mortality in a Japanese population: Japan Public Health Center-based Prospective Study

BACKGROUND

Accumulating evidence suggests that pneumonia mortality is lower for individuals with high body mass index (BMI) compared to normal BMI, but it remains unclear whether weight change during adulthood influences subsequent mortality due to pneumonia in Asian populations, who have a relatively lean body mass. This study aimed to examine the association of BMI and weight change over 5 years with the subsequent risk of pneumonia mortality in a Japanese population.

METHODS

The present analysis included 79,564 Japan Public Health Center (JPHC)-based Prospective Study participants who completed a questionnaire between 1995 and 1998 were followed for death through 2016. BMI was categorized into four groups: underweight (<18.5 kg/m²), normal weight (BMI: 18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), and obese (BMI: ≥30.0 kg/m²). Weight change was defined as the difference of body weight between questionnaire surveys with a 5-year interval. Cox proportional hazards regression was used to estimate hazard ratios of baseline BMI and weight change for pneumonia mortality.

RESULTS

During a median follow-up of 18.9 y, we identified 994 deaths from pneumonia. Compared with participants with normal weight, an elevated risk was observed among those who were underweight (hazard ratio = 2.29, 95% confidence interval [CI]: 1.83-2.87), whereas a decreased risk was found among those who were overweight (hazard ratio = 0.63, 95% CI: 0.53-0.75). Regarding weight change, the multivariable-adjusted hazard ratio (95% CI) of pneumonia mortality for a weight loss of 5 kg or more versus a weight change of less than 2.5 kg was 1.75 (1.46-2.10), whereas that for a weight gain of 5 kg or more was 1.59 (1.27-2.00).

CONCLUSION

Underweight and greater weight change was associated with an increase in the risk of pneumonia mortality in Japanese adults.

Weight fluctuation, mortality, and cardiovascular disease in adults in 18 years of follow-up: Tehran Lipid and Glucose Study

PURPOSE

Controversies exist in the effect of body weight loss and fluctuation on cardiovascular disease (CVD) and mortality. This study aims to assess the effect of weight variability on CVD and all-cause and cardiovascular mortality in the Tehran Lipid and Glucose Study (TLGS) cohort.

METHOD

Participants aged  ≥ 40 year at the baseline period with at least 3 BMI measurements were included in this study. After excluding individuals with cancer, CVD, end-stage renal disease, systemic use of glucocorticoids, pregnancy, and missing covariates at the baseline, a total of 3461 participants were enrolled and followed for 18 years. BMI variability was defined using root mean squared error (RMSE) and average successive variability (ASV). In the RMSE method, BMI variability was calculated using the best-fitting model for BMI trend of each subject. Multivariate Cox proportional hazard models were applied to assess BMI variability's effect on CVD and mortality.

RESULTS

Among the 3461 participants in this study, the group with the highest weight variability had an increased risk of death for all-cause (HR 1.65; 95% CI 1.21-2.25), non-cardiovascular (HR 1.77; 95% CI 1.24-2.53), and non-cancer (HR 1.77; 95% CI 1.25-2.50) mortality. However, BMI variability showed to be protective against CVD (HR 0.76; 95% CI 0.6-0.97). These findings were significant in males, non-smokers, participants with age  ≤ 60 year, BMI < 30, negative BMI slope, and both diabetic and non-diabetic subjects.

CONCLUSION

High BMI variability is associated with increased risk of all-cause, non-CVD, and non-cancer mortality, although protective for the CVD event. Appropriate strategies for body weight maintenance after weight loss could be adopted to avoid weight variability, particularly in non-obese subjects.

Underweight and Weight Change Increases End-Stage Renal Disease Risk in Patients with Diabetes: A Nationwide Population-Based Cohort Study

Weight variability has known as a risk factor for cardiovascular events and mortality. However, its effect on end-stage renal disease (ESRD) development remains controversial. We investigated the relationship between weight change and ESRD risk. Overall, 97,029 patients with DM aged >20 years were selected from the Korean National Health Screening Program 2009–2012. Weight change was defined as differences in body weight from the index year to 2 years later. Newly diagnosed ESRD was observed until 2017 end. Over a 5.1-year median follow-up period, ESRD was newly diagnosed in 7932 (4.81%) DM patients. BMI < 18.5 kg/m² and waist circumferences <85/80 and >100/95 cm were ESRD risk factors. ESRD risk increased with increasing weight change; ≥10% weight loss (hazard ratio [HR], 1.247) followed by ≥10% weight gain (1.247) was associated with a higher HR than ≤5% weight change after adjusting for several confounding factors. The association between weight change and ESRD risk in a subgroup analysis was significantly stronger in patients aged <65 years, without proteinuria, with BMI ≥ 25, with DM duration <5 years, and prescribed less than 3 classes of DM medication. Underweight patients showed higher ESRD risks than overweight patients. Weight loss >10% was associated with the fastest decline in renal function.

Increased metabolic variability is associated with newly diagnosed depression: A nationwide cohort study

BACKGROUND

The effect of dynamic changes in metabolic parameters over time on the development of depression has yet to be examined. In this study, we aimed to determine the association between the variability of metabolic parameters and the development of depression using nationally representative data.

METHODS

We used health examination data provided by the South Korean National Health Insurance System (NHIS) and included those who underwent the examination ≥ 3 times within five years of enrollment, without a previous history of depression (n = 9,058,424). The variability of each metabolic parameter including weight circumference, blood pressure, fasting blood glucose, high-density lipoprotein cholesterol, and triglyceride levels was estimated using variability independent of mean (VIM) indices. High variability was defined as the highest quartile (Q4) of variability.

RESULTS

Each metabolic parameter with high variability was associated with a higher risk of newly diagnosed depression compared to those with low variability, after adjusting for age, sex, smoking, alcohol drinking, regular exercise, income status, baseline diabetes, hypertension, and dyslipidemia. As the number of highly variable metabolic parameters increased, the risk for newly diagnosed depression increased even after adjusting for the aforementioned covariates (hazard ratio (HR) = 1.4, 95% confidence interval (CI): 1.3 - 1.4 in those with five highly variable parameters compared to those with no highly variable parameter).

LIMITATIONS

relatively short observation period; no systematic measure of depression severity.

CONCLUSIONS

Our results suggest that the variability of metabolic parameters is an independent risk factor for depression.

Age-Related Difference in Weight Change and All-Cause Mortality in Middle-Aged and Older Korean Populations: Korean Longitudinal Study of Aging

Background

Obesity is associated with increased mortality as a significant risk factor for chronic diseases, including cardiovascular diseases and cancer. Several people believe that weight gain is harmful, and weight loss helps maintain health. However, some studies have shown that weight loss, particularly among older adults, is more likely to increase the risk of mortality than weight gain.

Methods

We used data for the cohort of the Korean Longitudinal Study of Aging, which is a nationwide stratified multi-stage sample of adults aged 45 years. The all-cause mortality risk was assessed using the survival status and the number of months of survival calculated from 2006 (baseline year) to 2016. Cox proportional hazard regression were used to study the causal link between weight change and all-cause mortality risk.

Results

The results showed interactive associations between weight loss and mortality among middle-aged and older adults. The hazard ratio was 1.62 (95% confidence interval [CI], 1.10–2.40) for the participants aged 45–65 years with weight losses greater than 5 kg and 1.56 (95% CI, 1.29–1.89) for those older than 65 years with weight losses greater than 5 kg. The results for the group with weight gain above 5 kg were not significant. Middle-aged and older men showed an increase in all-cause mortality associated with weight loss of more than 5 kg, but only the older women showed significant results.

Conclusion

This large-scale cohort study in Korea showed a relationship between weight loss and all-cause mortality in middle-aged and older individuals.

Body weight variability and cancer incidence in men aged 40 years and older-Korean National Insurance Service Cohort

Repeated weight fluctuation has been proposed as a potential risk factor for increasing morbidity and mortality including cancer. We aimed to investigate the association between body weight variability (BWV) and all cancer and site-specific cancer incidence and the impact of smoking on these associations. A total of 1,759,848 cancer-free male subjects who had their weight measured at least 5 times from the National Health Insurance Service-Health Screening Cohort from 2002 to 2011 were included and followed up until 2015. BWV was defined as the average absolute difference between successive values (ASV). The risk of cancer and site-specific cancer from BWV was identified using Cox proportional hazards regression analysis using hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for potential confounders including weight, and stratified analysis was also conducted according to smoking status. During the 7,015,413 person-years of follow-up, 11,494 patients (0.65%) developed new-onset cancers. BWV was associated with a higher risk of all cancers after adjustment for confounders. The highest BWV quintile group compared to the lowest had greater risks of all cancers and site-specific cancers including lung, liver, and prostate cancer (HR 1.22, 95% CI 1.15–1.30; HR 1.22, 95% CI 1.07–1.39; HR 1.46, 95% CI 1.19–1.81; HR 1.36, 95% CI 1.15–1.62, in all cancers, lung, liver and prostate cancer, respectively). Due to small number of cancer occurrence, the risk of kidney cancer was increased, but statistically insignificant (HR 1.38, 95% CI 0.91–2.10). Similar results were observed in noncurrent smokers. However, in current smokers, the risks of all cancers and only prostate cancer were significantly increased in the highest BWV quintile group (HR 1.19, 95% CI 1.09–1.31; HR 1.51, 95% CI 1.08–2.11). The risk of kidney cancer also increased in this group, although the finding was not statistically significant (HR 1.77, 95% CI 0.87–3.63) This study suggested BWV is an independent risk factor for cancer in men, especially in lung, liver, and prostate cancer, but evidence was weaker in kidney cancer. This association remained significant only in prostate cancer in current smokers.

Natural Killer Cell Dysfunction in Obese Patients with Breast Cancer: A Review of a Triad and Its Implications

Natural killer cells (NK cells) are a crucial constituent of the innate immune system as they mediate immunity against viruses, bacteria, parasites, and most importantly, tumor cells. The exact mechanism of how the innate immune system and specifically NK cells interact with cancer cells is complex and is yet to be understood. Several factors that constitute the tumor microenvironment (TME) such as hypoxia and TGF-β are believed to play a role in the complex physiological reaction of NK cells to tumor cells. On the other hand, several risk factors are implicated in the development and progression of breast cancer, most importantly: obesity. Cytokines released from adipose tissue such as adipokines, leptin, and resistin, among others, are also believed to facilitate tumor progression. In this study, we aimed to build a triad of breast cancer, obesity, and NK cell dysfunction to elucidate a link between these pillars on a cellular level. Directing efforts towards solidifying the link between these factors will help in designing a targeted immunotherapy with a low side-effect profile that can revolutionize breast cancer treatment and improve survival in obese patients.

Body weight variability and the risk of cardiovascular outcomes in patients with nonalcoholic fatty liver disease

We investigated the association between body weight variability and the risks of cardiovascular disease and mortality in patients with nonalcoholic fatty liver disease (NAFLD) using large-scale, nationwide cohort data. We included 726,736 individuals with NAFLD who underwent a health examination between 2009 and 2010. NAFLD was defined as a fatty liver index ≥ 60, after excluding significant alcohol intake, viral hepatitis, and liver cirrhosis. Body weight variability was assessed using four indices, including variability independent of the mean (VIM). During a median 8.1-year follow-up, we documented 11,358, 14,714, and 22,164 cases of myocardial infarction (MI), stroke, and all-cause mortality, respectively. Body weight variability was associated with an increased risk of MI, stroke, and mortality after adjusting for confounding variables. The hazard ratios (HRs) (95% confidence intervals) for the highest quartile, compared with the lowest quartile, of VIM for body weight were 1.15 (1.10-1.20), 1.22 (1.18-1.26), and 1.56 (1.53-1.62) for MI, stroke, and all-cause mortality, respectively. Body weight variability was associated with increased risks of MI, stroke, and all-cause mortality in NAFLD patients. Appropriate interventions to maintain a stable weight could positively affect health outcomes in NAFLD patients.

Variabilities in Weight and Waist Circumference and Risk of Myocardial Infarction, Stroke, and Mortality: A Nationwide Cohort Study

BACKGROUND

Evidence regarding the association between variabilities in obesity measures and health outcomes is limited. We aimed to examine the association between variabilities in obesity measures and cardiovascular outcomes and all-cause mortality.

METHODS

We identified 4,244,460 individuals who underwent health examination conducted by the Korean National Health Insurance Service during 2012, with ≥3 anthropometric measurements between 2009 and 2012. Variabilities in body weight (BW) and waist circumference (WC) were assessed using four indices including variability independent of the mean (VIM). We performed multivariable Cox proportional hazards regression analyses.

RESULTS

During follow-up of 4.4 years, 16,095, 18,957, and 30,200 cases of myocardial infarction (MI), stroke, and all-cause mortality were recorded. Compared to individuals with the lowest quartiles, incrementally higher risks of study outcomes and those of stroke and all-cause mortality were observed among individuals in higher quartiles of VIM for BW and VIM for WC, respectively. The multivariable adjusted hazard ratios and 95% confidence intervals comparing the highest versus lowest quartile groups of VIM for BW were 1.17 (1.12 to 1.22) for MI, 1.20 (1.16 to 1.25) for stroke, and 1.66 (1.60 to 1.71) for all-cause mortality; 1.07 (1.03 to 1.12) for stroke and 1.29 (1.25 to 1.33) for all-cause mortality regarding VIM for WC. These associations were similar with respect to the other indices for variability.

CONCLUSION

This study revealed positive associations between variabilities in BW and WC and cardiovascular outcomes and allcause mortality. Our findings suggest that variabilities in obesity measures are associated with adverse health outcomes in the general population.

Childhood Obesity and Cancer Risk in Adulthood

PURPOSE OF REVIEW

The purpose of this review is to summarize our current understanding of the association between childhood obesity and cancer risk later in life.

RECENT FINDINGS

Adipose tissue secrets a variety of adipocytokines, and expression and/or secretion rate of most of them seems to be increased or dysregulated in obesity. In addition, obesity leads to increased secretion of proinflammatory cytokines such as interferon-γ (IFN-γ), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α), which promotes an infiltration of inflammatory immune cells into adipose tissue. This process may facilitate a state of "subclinical inflammation" (metaflammation) and may lead to the development of the metabolic syndrome (MetS), starting as early as during childhood. In addition, several oncogenes have been linked to inflammation and cancer development via different pathways, and several types of tumors need an inflammatory environment before a malignant change occurs. An inflammatory environment seems to promote the proliferation and survival of malignant cells as well as angiogenesis. Natural killer (NK) cells play an important role in this process, as they are able to kill transformed cells without prior sensitization and coordinate subsequent immune responses by producing distinct cytokines, thus providing antitumor immunity. First studies in children have suggested that NK cells from obese children are activated, metabolically stressed, and functionally deficient. This may lead to a suppression of antitumor immunity as early as during childhood, probably many years before the development of cancer. Epidemiological studies have shown a strong association between higher body mass index (BMI) during childhood and adolescence and increased risk for several malignancies in adulthood, including leukemia, Hodgkin's disease, colorectal cancer, and breast cancer. Underlying mechanisms are not completely understood, but several adipocytokines and inflammatory markers including NK cells seem to be "key players" in this process.

Obesity-Associated Alterations of Natural Killer Cells and Immunosurveillance of Cancer

Obesity is accompanied by a systemic chronic low-grade inflammation as well as dysfunctions of several innate and adaptive immune cells. Recent findings emphasize an impaired functionality and phenotype of natural killer (NK) cells under obese conditions. This review provides a detailed overview on research related to overweight and obesity with a particular focus on NK cells. We discuss obesity-associated alterations in subsets, distribution, phenotype, cytotoxicity, cytokine secretion, and signaling cascades of NK cells investigated in vitro as well as in animal and human studies. In addition, we provide recent insights into the effects of physical activity and obesity-associated nutritional factors as well as the reduction of body weight and fat mass on NK cell functions of obese individuals. Finally, we highlight the impact of impaired NK cell physiology on obesity-associated diseases, focusing on the elevated susceptibility for viral infections and increased risk for cancer development and impaired treatment response.

The association between weight fluctuation and all-cause mortality: A systematic review and meta-analysis

BACKGROUND

Many observational studies have reported an association between weight fluctuation and all-cause mortality. However, the conclusions obtained from these studies have been unclear.

OBJECTIVE

The current meta-analysis aimed to clarify the association between weight fluctuation and all-cause mortality.

DATA SOURCE

We electronically searched PubMed, Embase, and Web of Science for articles reporting an association between weight fluctuation and all-cause mortality that were published before April 30, 2018.

STUDY APPRAISAL AND SYNTHESIS METHODS

The methodological quality of each study was appraised using the modified Newcastle Ottawa Quality Assessment Scale. The hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were extracted from the included studies and pooled using random-effect models. Meta-regression approaches were also performed to explore sources of between-study heterogeneity.

RESULTS

A total of 15 studies were eligible for the current meta-analysis. The pooled overall HR for all-cause mortality in the group with the greatest weight fluctuations compared with the most stable weight category was 1.45 (95% CI: 1.29-1.63). Considerable between-study heterogeneity was observed, some of which was partially explained by the different follow-up durations used by the included studies. Moreover, publication bias that inflated the risk of all-cause mortality was detected using Egger's test (P = .001).

CONCLUSION

Weight fluctuation might be associated with an increased risk of all-cause mortality.

Elucidating Under-Studied Aspects of the Link Between Obesity and Multiple Myeloma: Weight Pattern, Body Shape Trajectory, and Body Fat Distribution

Background

Although obesity is an established modifiable risk factor for multiple myeloma (MM), several nuanced aspects of its relation to MM remain unelucidated, limiting public health and prevention messages.

Methods

We analyzed prospective data from the Nurses' Health Study and Health Professionals Follow-Up Study to examine MM risk associated with 20-year weight patterns in adulthood, body shape trajectory from ages 5 to 60 years, and body fat distribution. For each aforementioned risk factor, we report hazard ratios (HRs) and 95% confidence intervals (CIs) for incident MM from multivariable Cox proportional-hazards models.

Results

We documented 582 incident MM cases during 4 280 712 person-years of follow-up. Persons who exhibited extreme weight cycling, for example, those with net weight gain and one or more episodes of intentional loss of at least 20 pounds or whose cumulative intentional weight loss exceeded net weight loss with at least one episode of intentional loss of 20 pounds or more had an increased MM risk compared with individuals who maintained their weight (HR = 1.71, 95% CI = 1.05 to 2.80); the association was statistically nonsignificant after adjustment for body mass index. We identified four body shape trajectories: lean-stable, lean-increase, medium-stable, and medium-increase. MM risk was higher in the medium-increase group than in the lean-stable group (HR = 1.62, 95% CI = 1.22 to 2.14). Additionally, MM risk increased with increasing hip circumference (HR per 1-inch increase: 1.03, 95% CI = 1.01 to 1.06) but was not associated with other body fat distribution measures.

Conclusions

Maintaining a lean and stable weight throughout life may provide the strongest benefit in terms of MM prevention.

Impact of weight reduction on selected immune system response among Hepatitis C virus Saudi patients

Background

Recently, about 2.35% of the world populations are estimated to be chronically infected with hepatitis C virus (HCV). Previous cohort studies indicated that obesity increases risk of hepatic steatosis and fibrosis in non-diabetic patients with chronic hepatitis C infection due to diminished response to anti-viral therapy and as a result obesity is considered as an important factor in the progression of chronic HCV. However, there is a strong association between BMI and the human immune system among HCV patients.

Objective

This study aimed to examine effects of weight reduction program on selected immune parameters among HCV Saudi patients.

Material and methods

One-hundred obese Saudi patients with chronic HCV infection participated in this study, their age ranged from 50–58 years and their body mass index (BMI) ranged from 30–35 kg/m². All Subjects were included in two groups: The first group received weight reduction program in the form of treadmill aerobic exercises in addition to diet control whereas, the second group received no therapeutic intervention. Parameters of CD3, CD4 and CD8 were quantified; Leukocyte, differential counts and BMI were measured before and after 3 months, at the end of the study.

Results

The mean values of BMI, white blood cells, total neutrophil count, monocytes, CD3, CD4 and CD8 were significantly decreased in the training group as a result of weight loss program; however the results of the control group were not significant. Also, there were significant differences between both groups at the end of the study.

Conclusion

Weight loss modulates immune system parameters of patients with HCV.

Change in Weight and Body Mass Index Associated With All-Cause Mortality in Korea: A Nationwide Longitudinal Study

CONTEXT

Many studies have reported conflicting evidence on the association between weight change and mortality.

OBJECTIVE

We investigated the association between weight change and subsequent all-cause mortality, using a large-scale, population-based cohort from the National Health Insurance System health checkup data between 2005 and 2015.

METHODS

A total of 11,524,763 subjects older than age 20 years were included. Weight was measured every 2 years and weight change over 4 years was divided into eight categories, from weight loss ≥15% to weight gain ≥20%, for every 5% of weight change. The hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality were analyzed using multivariable Cox proportional hazard models compared with the stable weight group (weight change <5%) after adjusting for age, sex, smoking, drinking, exercise, diabetes mellitus, hypertension, dyslipidemia, cancer, and income.

RESULTS

Weight loss was associated with increased mortality rates compared with weight gain; the group with weight loss ≥15% had the highest HR for all-cause mortality (HR, 2.598; 95% CI, 2.537 to 2.659). The HR for all-cause mortality in the ≥20% weight gain group was 1.784 (95% CI, 1.695 to 1.877). Across all body mass index (BMI) categories, weight loss ≥15% was associated with increased mortality rates and the highest mortality rates were found in the BMI ≥30 kg/m2 group (HR, 3.469; 95% CI, 2.236 to 5.381).

CONCLUSIONS

Weight change over 4 years showed a reverse J-shaped all-cause mortality curve, independent of BMI status. Weight loss was associated with a greater risk of mortality than was weight gain.

Weight Fluctuation and Cancer Risk in Postmenopausal Women: The Women's Health Initiative

Background: Weight cycling, defined by an intentional weight loss and subsequent regain, commonly occurs in overweight and obese women and is associated with some negative health outcomes. We examined the role of various weight-change patterns during early to mid-adulthood and associated risk of highly prevalent, obesity-related cancers (breast, endometrial, and colorectal) in postmenopausal women.Methods: A total of 80,943 postmenopausal women (age, 63.4 ± 7.4 years) in the Women's Health Initiative Observational Study were categorized by self-reported weight change (weight stable; weight gain; lost weight; weight cycled [1-3, 4-6, 7-10, >10 times]) during early to mid-adulthood (18-50 years). Three site-specific associations were investigated using Cox proportional hazard models [age, race/ethnicity, income, education, smoking, alcohol, physical activity, hormone therapy, diet, and body mass index (BMI)].Results: A total of 7,464 (breast = 5,564; endometrial = 788; and colorectal = 1,290) incident cancer cases were identified between September 1994 and August 2014. Compared with weight stability, weight gain was significantly associated with risk of breast cancer [hazard ratio (HR), 1.11; 1.03-1.20] after adjustment for BMI. Similarly, weight cycling was significantly associated with risk of endometrial cancer (HR = 1.23; 1.01-1.49). Weight cycling "4 to 6 times" was most consistently associated with cancer risk, showing a 38% increased risk for endometrial cancer [95% confidence interval (CI), 1.08-1.76] compared with weight stable women.Conclusions: Weight gain and weight cycling were positively associated with risk of breast and endometrial cancer, respectively.Impact: These data suggest weight cycling and weight gain increase risk of prevalent cancers in postmenopausal women. Adopting ideal body-weight maintenance practices before and after weight loss should be encouraged to reduce risk of incident breast and endometrial cancers. Cancer Epidemiol Biomarkers Prev; 26(5); 779-86. ©2017 AACR.

Diet-Induced Obesity Is Associated with an Impaired NK Cell Function and an Increased Colon Cancer Incidence

Obesity is associated with an increased colon cancer incidence, but underlying mechanisms remained unclear. Previous studies showed altered Natural killer (NK) cell functions in obese individuals. Therefore, we studied the impact of an impaired NK cell functionality on the increased colon cancer risk in obesity. In vitro investigations demonstrated a decreased IFN-γ secretion and cytotoxicity of human NK cells against colon tumor cells after NK cell preincubation with the adipokine leptin. In addition, leptin incubation decreased the expression of activating NK cell receptors. In animal studies, colon cancer growth was induced by injection of azoxymethane (AOM) in normal weight and diet-induced obese rats. Body weight and visceral fat mass were increased in obese animals compared to normal weight rats. AOM-treated obese rats showed an increased quantity, size, and weight of colon tumors compared to the normal weight tumor group. Immunohistochemical analyses demonstrated a decreased number of NK cells in spleen and liver in obesity. Additionally, the expression levels of activating NK cell receptors were lower in spleen and liver of obese rats. The results show for the first time that the decreased number and impaired NK cell function may be one cause for the higher colon cancer risk in obesity.

Long-Term Body Weight Maintenance among StrongWomen-Healthy Hearts Program Participants

Background. The repeated loss and regain of body weight, referred to as weight cycling, may be associated with negative health complications. Given today's obesity epidemic and related interventions to address obesity, it is increasingly important to understand contexts and factors associated with weight loss maintenance. This study examined BMI among individuals who had previously participated in a 12-week, evidence-based, nationally disseminated nutrition and physical activity program designed for overweight and obese middle-aged and older women. Methods. Data were collected using follow-up surveys. Complete height and weight data were available for baseline, 12-week program completion (post-program) and follow-up (approximately 3 years later) for 154 women (response rate = 27.5%; BMI characteristics did not differ between responders and nonresponders). Results. Mean BMI decreased significantly from baseline to post-program (−0.5, P < 0.001) and post-program to follow-up (−0.7, P < 0.001). Seventy-five percent of survey respondents maintained or decreased BMI post-program to follow-up. Self-efficacy and social support for healthy eating behaviors (but not physical activity) were associated with BMI maintenance or additional weight loss. Conclusions. These findings support the durability of weight loss following participation in a relatively short-term intervention.

The Effectiveness of Screening for Obesity in Primary Care: Weighing the Evidence

In response to growing alarm about the increase in the prevalence of obesity in the United States, several organizations have recommended that physicians screen their adult patients for this condition and initiate treatment. Screening can be an effective intervention when the condition is grave and prevalent, when an accurate test exists, when effective treatment exists, when the screening program itself does not pose undue risks, and when early detection and treatment improve outcomes. This article critically reviews the evidence supporting these criteria in the case of obesity in adults. It extends previous reviews by assessing the potential impact that uncertainties in the evidence base may have on the effectiveness a screening program. It also examines the feasibility of such a program. We conclude that following the recommendation to screen all adults for obesity is unlikely to improve outcomes.

Alteration of Natural Killer cell phenotype and function in obese individuals

Obesity is associated with increased cancer rates and higher susceptibility to infections. The adipose tissue of obese individuals is inflammatory and may negatively impact on innate and adaptive immunity in a systemic way. Here, we explored the phenotype and function of peripheral Natural Killer (NK) cells of patients in correlation with their body mass index (BMI). We found that high BMI was associated with an increased activation status of peripheral NK cells, as measured by surface levels of CD69 and levels of granzyme-B. However, these activated NK cells had an impaired capacity to degranulate or to produce cytokines/chemokines when exposed to tumor cell lines deficient in MHC-I expression or coated with antibodies. This suggests that chronic stimulation of NK cells during obesity may lead to their incapacity to respond normally and eliminate target cells, which could contribute to the greater susceptibility of obese individuals to develop cancers or infectious diseases.

Weight cycling and cancer incidence in a large prospective US cohort

Weight cycling, which consists of repeated cycles of intentional weight loss and regain, is common among individuals who try to lose weight. Some evidence suggests that weight cycling may affect biological processes that could contribute to carcinogenesis, but whether it is associated with cancer risk is unclear. Using 62,792 men and 69,520 women enrolled in the Cancer Prevention Study II Nutrition Cohort in 1992, we examined the association between weight cycling and cancer incidence. Weight cycles were defined by using baseline questions that asked the number of times ≥10 pounds (4.54 kg) was purposely lost and later regained. Multivariable-adjusted hazard ratios and 95% confidence intervals for all cancer and 15 individual cancers were estimated by using Cox proportional hazards regression. During up to 17 years of follow-up, 15,333 men and 9,984 women developed cancer. Weight cycling was not associated with overall risk of cancer in men (hazard ratio = 0.96, 95% confidence interval: 0.83, 1.11 for ≥20 cycles vs. no weight cycles) or women (hazard ratio = 0.96, 95% confidence interval: 0.86, 1.08) in models that adjusted for body mass index and other covariates. Weight cycling was also not associated with any individual cancer investigated. These results suggest that weight cycling, independent of body weight, is unlikely to influence subsequent cancer risk.

Temperamental factors in severe weight cycling. A cross-sectional study

OBJECTIVE

Weight cycling is a prevalent phenomenon in obese individuals. There is evidence that temperamental factors are associated with obesity and subgroups among the obese have been identified based on reactive and regulative aspects of temperament.

METHODS

We aimed at investigating the association between reactive and regulative aspects of temperament and severe weight cycling in overweight and obese individuals of a representative German population sample (n = 923). Participants completed questionnaires assessing weight parameters including BMI and weight cycling, sensitivity to punishment and to reward (BIS/BAS scales), self-regulatory abilities (effortful control scale), depressive symptoms, and binge eating.

RESULTS

Severe weight cycling was more common in women, and was associated with higher reward sensitivity, higher current and maximum-ever BMI, higher weight suppression, more depressive symptoms, and a higher prevalence of binge eating. In contrast, sensitivity to punishment and effortful control were not associated with severe weight cycling. Also, the interaction between sensitivity to reward and effortful control did not predict weight cycling.

DISCUSSION

Higher reward sensitivity might not only render individuals vulnerable for weight regain but might also be associated with a higher frequency of weight loss attempts due to the putative rewarding properties of the initial success in weight loss at the early stages of a diet. Temperamental factors should be considered in the treatment of obesity.

Self-rated health status and subjective health complaints associated with health-promoting lifestyles among urban Chinese women: a cross-sectional study

Objective

This study aimed to investigate whether self-rated health status (SRH) and subjective health complaints (SHC) of urban Chinese women are associated with their health-promoting lifestyles (HPL).

Methods

We conducted a cross-sectional study on 8142 eligible Chinese participants between 2012 and 2013. Demographic and SHC data were collected. Each subject completed the SRH questionnaire and the Chinese version of the Health-Promoting Lifestyle Profile-II (HPLP-II). Correlation and binary regression analyses were performed to examine the associations of SRH and SHC with HPL.

Results

Both SRH and HPL of urban Chinese women were moderate. The most common complaints were fatigue (1972, 24.2%), eye discomfort (1571, 19.3%), and insomnia (1542, 18.9%). Teachers, highly educated subjects and elderly women had lower SRH scores, while college students and married women had better HPL. All items of HPLP-II were positively correlated with SRH (r = 0.127-0.533, P = 0.000) and negatively correlated with SHC to a significant extent (odds ratio [OR] = 1.40-11.37).

Conclusions

Aspects of HPL, particularly stress management and spiritual growth, are associated with higher SRH and lower SHC ratings among urban Chinese women. Physical activity and health responsibility are additionally related to reduced fatigue and nervousness. We believe that these findings will be instrumental in encouraging researchers and urban women to adopt better health-promoting lifestyles with different priorities in their daily lives.

Plasma polychlorinated biphenyl concentrations and immune function in postmenopausal women

BACKGROUND

Polychlorinated biphenyl (PCB) exposure has been associated with non-Hodgkin lymphoma in several studies, and the immune system is a potential mediator.

OBJECTIVES

We analyzed associations of plasma PCBs with immune function measures. We hypothesized that higher plasma PCB concentrations are associated with lower immune function cross-sectionally, and that increases in PCB concentrations over a one year period are associated with decreases in immune function.

METHODS

Plasma PCB concentrations and immune function [natural killer (NK) cell cytotoxicity and PHA-induced T-lymphocyte proliferation (PHA-TLP)] were measured at baseline and one year in 109 postmenopausal overweight women participating in an exercise intervention study in the Seattle, Washington (USA) area. Mixed models, with adjustment for body mass index and other potential confounders, were used to estimate associations of PCBs with immune function cross-sectionally and longitudinally.

RESULTS

Associations of PCBs with immune function measures differed across groups of PCBs (e.g., medium- and high-chlorinated and dioxin-like [mono-ortho-substituted]) and by the time frame for the comparison (cross-sectional vs. longitudinal). Higher concentrations of medium- and high-chlorinated PCBs were associated with higher PHA-TLP cross-sectionally but not longitudinally. The mean decrease in 0.5 µg/mL PHA-TLP/50.0 pmol/g-lipid increase in dioxin-like PCBs over one year was 51.6 (95% confidence interval 2.7, 100.5; P=0.039). There was no association between plasma PCBs and NK cytotoxicity.

CONCLUSIONS

These results do not provide strong evidence of impaired cellular immunity from PCB exposure. Larger longitudinal studies with greater variability in PCB exposures are needed to further examine temporal associations of PCBs with immune function.

History of weight cycling does not impede future weight loss or metabolic improvements in postmenopausal women

OBJECTIVE

Given that the repetitive loss and regain of body weight, termed weight cycling, is a prevalent phenomenon that has been associated with negative physiological and psychological outcomes, the purpose of this study was to investigate weight change and physiological outcomes in women with a lifetime history of weight cycling enrolled in a 12-month diet and/or exercise intervention.

METHODS

439 overweight, inactive, postmenopausal women were randomized to: i) dietary weight loss with a 10% weight loss goal (N=118); ii) moderate-to-vigorous intensity aerobic exercise for 45 min/day, 5 days/week (n=117); ii) both dietary weight loss and exercise (n=117); or iv) control (n=87). Women were categorized as non-, moderate- (≥3 losses of ≥4.5 kg), or severe-cyclers (≥3 losses of ≥9.1 kg). Trend tests and linear regression were used to compare adherence and changes in weight, body composition, blood pressure, insulin, C-peptide, glucose, insulin resistance (HOMA-IR), C-reactive protein, leptin, adiponectin, and interleukin-6 between cyclers and non-cyclers.

RESULTS

Moderate (n=103) and severe (n=77) cyclers were heavier and had less favorable metabolic profiles than non-cyclers at baseline. There were, however, no significant differences in adherence to the lifestyle interventions. Weight-cyclers (combined) had a greater improvement in HOMA-IR compared to non-cyclers participating in the exercise only intervention (P=.03), but no differences were apparent in the other groups.

CONCLUSION

A history of weight cycling does not impede successful participation in lifestyle interventions or alter the benefits of diet and/or exercise on body composition and metabolic outcomes.

Adiposity, body composition, and weight change in relation to organochlorine pollutant plasma concentrations

We investigated cross-sectional associations of body composition and weight change with polychlorinated biphenyls (PCB) and organochlorine pesticides/pesticide metabolites measured in blood collected at the baseline of the Physical Activity for Total Health study of postmenopausal, overweight women living in the Seattle, Washington metropolitan area. Indicators of greater adiposity were associated with lower plasma concentrations of most PCBs with six or more chlorine atoms. This pattern was observed for current weight, body mass index, fat mass percent, subcutaneous abdominal fat, intra-abdominal fat, waist circumference, hip circumference, waist-to-hip ratio, and maximum adult weight. Conversely, PCB 105, PCB 118, and p,p'-DDE were generally increased or showed no association with these variables. Weight gain since age 35 was associated with lower concentrations of almost every organochlorine we studied, and past weight loss episodes of at least 20 pounds (≥9.1 kg) were associated with higher concentrations. Our results have implications for epidemiologic studies of organochlorines in terms of covariates that may be important to consider in statistical analyses, particularly as such considerations may differ importantly by specific analyte. Our finding of increased organochlorine concentrations with past weight loss episodes may have public health significance; however, this association requires confirmation in longitudinal studies.

Immune cells and cardiovascular health in premenopausal women of rural India chronically exposed to biomass smoke during daily household cooking

Changes in cells of the immune system are important indicators of systemic response of the body to air pollution. The aim of this study was to investigate the immunological changes in rural women who have been cooking exclusively with biomass for the past 5 years or more and compare the findings with women cooking exclusively with liquefied petroleum gas (LPG). We conducted a cross-sectional analysis of the associations between indices of indoor air pollution (IAP) and a set of immune assays. Biomass users illustrated marked suppression in the total number of T-helper (CD4+) cells and B (CD19+) cells while appreciable rise was documented in the number of CD8+ T-cytotoxic cells and CD16+CD56+ natural killer (NK) cells. A consistent finding among biomass users was rise in regulatory T (Treg) cells. Among biomass users, peripheral lymphocyte subpopulations, Treg cells, and the number of typical monocytes (CD16-CD64+ cells), antigen presenting types (CD16+CD64- cells) and plasmacytoid cells (CD16-CD64- cells) were found to be significantly altered in those who daily cooked with dung in comparison to wood and crop residue users (p<0.05). Biomass users who cooked in kitchens adjacent to their living areas had significant changes in peripheral lymphocyte subpopulations, typical monocytes (CD16-CD64+) with high phagocytic activity and antigen presenting monocytes (CD16+CD64-) against women who cooked in separate kitchens (p<0.01). This study has shown that women who cooked exclusively with biomass fuel had alterations in immune defense compared with their neighbors who cooked with LPG.

Metabolic, hormonal and immunological associations with global DNA methylation among postmenopausal women

DNA methylation is an epigenetic modification essential for the regulation of gene expression that has been implicated in many diseases, including cancer. Few studies have investigated the wide range of potential predictors of global DNA methylation, including biomarkers. Here, we investigated associations between DNA methylation and dietary factors, sex-steroid hormones, metabolic, lipid, inflammation, immune and one-carbon biomarkers. Data and baseline biomarker measurements were obtained from 173 overweight/obese postmenopausal women. Global DNA methylation in lymphocyte DNA was measured using the pyrosequencing assay for LINE-1 repeats. We used correlations and linear regression analyses to investigate associations between continuous data and DNA methylation, while t-tests were used for categorical data. Secondary analyses stratified by serum folate levels and multivitamin use were also conducted. There was little variability in LINE-1 methylation (66.3-79.5%). Mean LINE-1 methylation was significantly higher among women with elevated glucose levels. Mean LINE-1 methylation was also higher among women with high CD4+/CD8+ ratio, and lower among women with elevated vitamin B6, but neither reached statistical significance. In analyses stratified by folate status, DNA methylation was negatively associated with sex hormone concentrations (estrone, estradiol, testosterone and sex hormone binding globulin) among women with low serum folate levels (n = 53). Conversely, among women with high serum folate levels (n = 53), DNA methylation was positively associated with several immune markers (CD4/CD8 ratio, NK1656/lymphocytes and IgA). Results from this screening suggest that global DNA methylation is generally stable, with differential associations for sex hormones and immune markers depending on one-carbon status.

The role of obesity in cancer survival and recurrence

Obesity and components of energy imbalance, that is, excessive energy intake and suboptimal levels of physical activity, are established risk factors for cancer incidence. Accumulating evidence suggests that these factors also may be important after the diagnosis of cancer and influence the course of disease, as well as overall health, well-being, and survival. Lifestyle and medical interventions that effectively modify these factors could potentially be harnessed as a means of cancer control. However, for such interventions to be maximally effective and sustainable, broad sweeping scientific discoveries ranging from molecular and cellular advances, to developments in delivering interventions on both individual and societal levels are needed. This review summarizes key discussion topics that were addressed in a recent Institute of Medicine Workshop entitled, "The Role of Obesity in Cancer Survival and Recurrence"; discussions included (i) mechanisms associated with obesity and energy balance that influence cancer progression; (ii) complexities of studying and interpreting energy balance in relation to cancer recurrence and survival; (iii) associations between obesity and cancer risk, recurrence, and mortality; (iv) interventions that promote weight loss, increased physical activity, and negative energy balance as a means of cancer control; and (v) future directions.

Weight cycling and mortality in a large prospective US study

Weight cycling has been associated with an increased risk of death in some studies, but few studies differentiated weight cycling initiated by intentional weight loss from that initiated by illness. The association of weight cycling with death was examined among 55,983 men and 66,655 women in the Cancer Prevention Study II Nutrition Cohort from 1992 to 2008. A weight cycle was defined as an intentional loss of 10 or more pounds (≥4.5 kg) followed by regain of that weight, and the lifetime number of weight cycles was reported on a questionnaire administered at enrollment in 1992. A total of 15,138 men and 10,087 women died during follow-up, which ended in 2008. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards regression models. When the models were adjusted for age only, weight cycling was positively associated with mortality (P for trend < 0.0001). However, after adjustment for body mass index and other risk factors, low numbers of weight cycles (1-4 cycles) were associated with slightly lower mortality rates (hazard ratio (HR) = 0.93, 95% confidence interval (CI): 0.89, 0.97 in men and HR = 0.93, 95% CI: 0.89, 0.98 in women), whereas high numbers of weight cycles (≥20 cycles) were not associated with mortality (HR = 1.03, 95% CI: 0.89, 1.19 in men and HR = 0.99, 95% CI: 0.88, 1.12 in women). These results do not support an increased risk of mortality associated with weight cycling.

Fine particulate matter (PM₂.₅) air pollution and immune status among women in the Seattle area

Changes in immune status have been suggested as a possible biologic mechanism by which particulate matter (PM) air pollution could lead to adverse health effects. The authors studied associations between ambient PM₂.₅ and immune status among 115 postmenopausal, overweight women in the greater Seattle, Washington, area. The authors evaluated 3-day, 30-day, and 60-day average PM₂.₅ values in relation to inflammation markers (C-reactive protein, serum amyloid A, interleukin-6) and functional assays of cellular immunity (natural killer cell cytotoxicity, T-lymphocyte proliferation) at 3 time points for each woman during 1 year. Three-day averaged PM₂.₅ was inversely associated with anti-CD3-stimulated lymphocyte proliferation. There were no notable associations between the inflammation markers and PM₂.₅. If additional studies confirm our findings, then future health effect assessments for PM₂.₅ should consider changes in cellular immunity as an endpoint that may lead to overt clinical disease.

FIT – Do Something Different

Two 3-month longitudinal studies examined weight loss following a 1-month behavioral intervention (FIT-DSD) focusing on increasing participants’ behavioral flexibility and breaking daily habits. The goal was to break the distal habits hypothesized as playing a role in unhealthy dietary and activity behaviors. The FIT-DSD intervention required participants to do something different each day and to engage in novel weekly activities to expand their behavioral repertoire. These activities were not food- or exercise-related. In Study 1, the FIT-DSD program was compared with a control condition where participants engaged in daily tasks not expected to influence behavioral flexibility. Study 2 used an active or quasicontrol group in which half the participants were also on food diets. Measures in both studies were taken pre-, post-, and post-postintervention. In Study 1, FIT-DSD participants showed greater weight loss that continued post-postintervention. In Study 2, all participants on the FIT-DSD program lost weight, weight loss continued post-postintervention, and participants who were also dieting lost no additional weight. A dose relationship was observed between increases in behavioral flexibility scores and weight loss, and this relationship was mediated by calorie intake. Corresponding reductions in BMI were also present. Increasing behavioral flexibility may be an effective approach for tackling obesity and also provides affective and potential life-skill benefits.

Frequent intentional weight loss is associated with higher ghrelin and lower glucose and androgen levels in postmenopausal women

Population-based studies suggest that repetitive cycling of weight loss and regain may be associated with future weight gain. Therefore, to better define the relationship between weight cycling, energy homeostasis, and future weight gain, we examined associations between frequent intentional weight loss and hormonal profiles in postmenopausal women. This cross-sectional study evaluated the relationship between a history of frequent weight loss and biomarkers, including serum glucose, insulin, leptin, and ghrelin, as well as sex steroid hormones. We hypothesized that frequent intentional weight loss would be associated with changes in normal appetite and body weight regulatory hormones, favoring increased appetite and weight gain. One hundred fifty-nine healthy, weight stable, sedentary, overweight, postmenopausal women who had been recruited for an exercise intervention participated in this study. History of intentional weight loss (frequency and magnitude) was assessed by questionnaire. Hormonal assays were performed by radioimmunoassay (insulin, leptin, ghrelin, estrogens, androgens, and dehydroepiandrosterone), chemiluminescence immunoassay (insulin-like growth factor-1), and immunometric assay (sex hormone binding globulin). Analysis of variance and regression analyses were used to investigate the relationship between weight loss history and metabolic hormones. A higher degree of weight cycling, characterized by the frequency of intentionally losing more than 10 lb, was associated with an appetite-stimulating hormonal profile, including higher concentrations of ghrelin (P trend = .04), lower glucose (P trend = .047), and to some extent, lower insulin (P trend = .08). Frequent weight loss was also associated with lower androgen concentrations, including androstenedione (P trend = .02), testosterone (P trend = .04), and free testosterone (P trend = .01). No independent associations between the concentrations of leptin or estrogens and weight cycling were observed. This study suggests that frequent intentional weight loss may affect hormones involved in energy regulation.

Effect of hydration status on high-intensity rowing performance and immune function

PURPOSE

This study determined the effect of dehydration and rehydration (DR) on performance, immune cell response, and tympanic temperature after high-intensity rowing exercise.

METHODS

Seven oarswomen completed two simulated 2000-m rowing race trials separated by 72 h in a random, cross-over design. One trial was completed in a euhydrated (E) condition and the other using a DR protocol.

RESULTS

The DR condition resulted in a 3.33+/-0.14% reduction in body mass (P<.05) over a 24-h period followed by a 2-h rehydration period immediately before the simulated rowing race. There was a greater change in tympanic temperature observed in the DR trial (P<.05). There were increases in the blood concentration of leukocytes, lymphocytes, lymphocyte subsets (CD3+, CD3+/4+, CD3+/8+, CD3-/16+, CD4+/25+; P<.05) and decreases in lymphocyte proliferation and neutrophil oxidative burst activity immediately following the simulated race (P<.05) in both trials. Blood leukocyte and neutrophil concentrations were greater after exercise in the DR trial (P<.05). Whereas most immune measures returned to resting values after 60 min of recovery in both trials, lymphocyte proliferation and the concentrations of CD3+/4+ and CD4+/25+ cells were significantly lower than before exercise. Blood leukocyte and neutrophil concentrations were significantly higher before and after exercise in the E trial.

CONCLUSION

The effects of dehydration/rehydration did not negatively influence simulated 2000-m rowing race performance in lightweight oarswomen but did produce a higher tympanic temperature and had a differential effect on blood leukocyte, neutrophil, and natural killer (CD3-/16+) cell concentrations after exercise compared with the euhydrated state.

Proximity to traffic, inflammation, and immune function among women in the Seattle, Washington, area

BACKGROUND

Traffic-related air pollution has been associated with adverse health outcomes, and the immune system may be a biologic mediator of health effects.

OBJECTIVES

We analyzed associations between living near major roads and immune status as measured by five immune assays. We hypothesized that living near a freeway, arterial, or truck route would be associated with increased inflammation and decreased immune function.

METHODS

We used a geographic information system (GIS) to determine residential proximity to major roads among 115 postmenopausal, overweight women in the greater Seattle, Washington (USA), area whose immunity was assessed at the baseline visit of an exercise intervention trial. We evaluated three inflammatory markers (C-reactive protein, serum amyloid A, and interleukin-6) and two functional assays of cellular immunity [natural killer (NK) cell cytotoxicity and T-lymphocyte proliferation].

RESULTS

Women living within 150 m of arterial roads had 21% lower NK cytotoxicity compared with women who lived farther from an arterial [mean cytotoxicity, 19.5%; 95% confidence interval (CI), 15.6-23.5%; vs. mean cytotoxicity, 24.8%; 95% CI, 22.0-27.5%], after adjustment for both individual-level and census tract-level demographic characteristics. This association was limited to women who reported exercising near traffic. Fewer women lived near freeways and truck routes. Markers of inflammation and lymphocyte proliferation did not consistently differ according to proximity to major roads.

CONCLUSIONS

If the observed association between residential proximity to traffic and decreased NK cytotoxicity is confirmed in other populations, our results may have implications for local land use policy.

Nutritional status and behavior in subjects with type 1 diabetes, before and after islet transplantation

BACKGROUND

To investigate whether changes of nutritional status and behavior are associated with islet transplantation (ITx) and to assess their possible mechanisms.

METHODS

In this observational study, 52 subjects with type 1 diabetes, 30 of whom received ITx, underwent nutritional assessments. The study consisted of questionnaires complemented by a dietary intake recording, anthropometric measurements, and body composition analysis. Laboratory tests were also reviewed as part of the follow up.

RESULTS

After ITx, significant reductions in body weight (3.7 kg; P<0.0001), body mass index (1.39 kg/m2; P<0.0001), waist circumference (3.96 cm; P=0.006), and fat weight (3.28 kg; P<0.01) were observed. The average consumption of carbohydrate and protein were also lower than pretransplant, together with some micronutrients (vitamins B12 and B6, zinc, and phosphorus). Insulin administration and changes in A1C were not associated with a significant change in anthropometric measurements. Subjects on exenatide after ITx showed significantly lower weight and body mass index than those not taking exenatide.

CONCLUSIONS

ITx is associated with modifications in nutritional behavior and status. Drugs and health conditions are likely to be at least in part responsible for these changes, but a voluntary modification of eating habits by the patients also plays a role. Strict monitoring of nutritional parameters, counseling by experts in nutrition, and multivitamin/mineral supplement after ITx could be of benefit to the patients.

[Body fat percentage and natural killer cell activity of breast and rectal cancer patients after diagnosis but before treatment]

PURPOSE

To examine the relationship between body fat percentage (BFP) and N-K cell activity (NKCA) in Korean breast and rectal cancer patients just after diagnosis.

METHODS

With 35 subjects enrolled between November 2002 and May 2003, Bioelectrical Impedance Analysis was used to estimate BFP. FACS Analysis was used to measure N-K cell activity. The relationships between BFP and NKCA were identified by using curve estimation, simple regression, and multiple regression.

RESULTS

The mean BFPs of the subjects and all the sub-groups were higher than acceptable BFPs. Both the mean NKCAs of male and female subjects were lower than that of healthy women. NKCA was explained by BFP with a 14.9% variance in the total subjects (p<.05). There were significant negative relationships between BFP and NKCA after controlling age, type of cancer, and stage of cancer while no significant relationship was found after controlling for gender. The relationships between BFP and NKCA in the sub-groups of female, breast cancer, and stage I, and II were significant. The relationships between male, rectal cancer, and the stage III, and VI sub-groups were not identified, but they revealed a mild to moderate steep in curve estimation.

CONCLUSION

Weight reduction could prevent the risk and advancement of breast and rectal cancer in Koreans.

Effect of exercise on in vitro immune function: a 12-month randomized, controlled trial among postmenopausal women

Cross-sectional studies suggest that moderate physical activity is associated with enhanced resting immune function; however, few randomized controlled trials have investigated this link. We investigated the effect of 12-mo aerobic exercise, relative to stretching control, on in vitro immune function in a randomized, controlled trial of 115 postmenopausal, overweight, or obese sedentary women, aged 50-75 yr. The exercise goal was > or =45 min/day, 5 days/wk. Control women participated in 1 day/wk stretching classes. Immune markers (natural killer cell cytotoxicity, T-lymphocyte proliferation, immune cell counts and phenotypes, and serum immunoglobulins) were assessed at baseline, 3 mo, and 12 mo under strict blood-draw criteria. General estimation equations evaluated intervention effects at 3 and 12 mo, controlling for baseline. Of the 115 women who began the trial, blood samples were available from 109 at 3 mo (95%) and 108 at 12 mo (94%). From baseline to 12 mo, the exercise group participated in 87% of the prescribed physical activity minutes per week and increased maximal O(2) uptake by 13.8%; controls experienced no change in fitness. The main outcomes, natural killer cell cytotoxicity and T-lymphocyte proliferation, did not differ between groups at 3 and 12 mo. Secondary outcome and subgroup (e.g., stratification by baseline categories of body mass index, immune status, C-reactive protein, and age) analyses did not show any clear patterns of association. This 12-mo randomized, controlled trial showed no effect of aerobic exercise on in vitro immune function, despite excellent retention, high adherence, and demonstrable efficacy of the exercise intervention.

Evaluation of a “Nondieting” Stress Reduction Program for Overweight Women: A Randomized Trial

Purpose.

Determine if a “nondieting” intervention focused on intensive training in eliciting the relaxation response enhances health outcomes compared with nondieting interventions without such training.

Design.

Randomized trial with follow-up at 10 weeks, 4 months, and 12 months.

Setting.

General community.

Subjects.

Total of 225 overweight and obese women with at least one other cardiovascular risk factor.

Interventions.

Three 10-week nondieting interventions: a group program (P1) focused on intensive training in techniques for eliciting the relaxation response (n = 60), a group program (P2) focused on healthy eating and physical activity (n = 61), and a self-guided, mail-delivered version of P2 (P3; n = 101).

Measures.

The Revised Symptom Checklist measured psychological distress, the Medical Symptoms Checklist measured the experience of medical symptoms, and the Health-Promoting Lifestyle Profile measured a range of lifestyle behaviors. Self-efficacy for low-fat eating, intuitive eating, and body mass index were also assessed.

Analysis.

An intention-to-treat analysis was used.

Results.

At 12 months, P1 produced statistically greater improvements in stress management behaviors and medical symptom discomfort and was the only program to significantly improve self-efficacy for low-fat eating. In P1, the effect sizes for reductions in depression (0.75) and interpersonal sensitivity (0.85) were large. At 12 months, mean weight was unchanged.

Conclusion.

Inclusion of intensive relaxation response training in a nondieting program for overweight women enhanced stress management and medical symptoms outcomes but not weight outcomes.

Weight gain prior to diagnosis and survival from breast cancer

BACKGROUND

To examine the effects of prediagnostic obesity and weight gain throughout the life course on survival after a breast cancer diagnosis, we conducted a follow-up study among a population-based sample of women diagnosed with first, primary invasive, and in situ breast cancer between 1996 and 1997 (n = 1,508).

METHODS

In-person interviews were conducted shortly after diagnosis to obtain information on height and weight at each decade of life from age 20 years until 1 year before diagnosis. Patients were followed to determine all-cause (n = 196) and breast cancer-specific (n = 127) mortality through December 31, 2002.

RESULTS

In multivariate Cox proportional hazards models, obese women had increased mortality due to breast cancer compared with ideal weight women among those who were premenopausal at diagnosis [hazard ratio (HR), 2.85; 95% confidence interval (95% CI), 1.30-6.23] and postmenopausal at diagnosis (HR, 1.91; 95% CI, 1.06-3.46). Among women diagnosed with premenopausal breast cancer, those who gained >16 kg between age 20 years and 1 year before diagnosis, compared with those whose weight remained stable (+/-3 kg), had more than a 2-fold elevation in all-cause (HR, 2.45; 95% CI, 0.96-6.27) and breast cancer-specific mortality (HR, 2.09; 95% CI, 0.80-5.48). Women diagnosed with postmenopausal breast cancer who gained more than 12.7 kg after age of 50 years up to the year before diagnosis had a 2- to 3-fold increased risk of death due to all-causes (HR, 2.69; 95% CI, 1.63-4.43) and breast cancer (HR, 2.95; 95% CI, 1.36-6.43).

CONCLUSIONS

These results indicate that high levels of prediagnostic weight and substantial weight gain throughout life can decrease survival in premenopausal and postmenopausal breast cancer patients.

Associations between healthy eating patterns and immune function or inflammation in overweight or obese postmenopausal women

BACKGROUND

The link between poor nutritional status and impaired immune function is well established; however, most studies have focused on individual nutrients instead of overall dietary patterns.

OBJECTIVE

Our objective was to investigate associations between 3 indexes of overall diet quality [the Diet Quality Index (DQI), the DQI including supplementary calcium (DQI-Ca), and the Healthy Eating Index (HEI)] and biomarkers of inflammation and immunity.

DESIGN

This cross-sectional study included 110 overweight or obese postmenopausal women. Dietary intake measured by food-frequency questionnaire was used to calculate diet quality scores. C-reactive protein (CRP) and serum amyloid A (SAA) were measured by latex-enhanced nephelometry. Flow cytometry was used to measure natural killer (NK) cell cytotoxicity and to enumerate and phenotype lymphocyte subsets. T lymphocyte proliferation was assessed by (3)H-thymidine incorporation as well as by the carboxyfluorescein-succinimidyl ester method of cell division tracking. Multivariable-adjusted linear regression analysis was used to investigate associations between diet quality scores and markers of inflammation and immune function.

RESULTS

Higher diet quality was associated with increased proportions of cytotoxic and decreased proportions of helper T lymphocytes. CRP and SAA concentrations were higher among women with a lower-quality diet; these associations became nonsignificant after adjustment for body mass index or percentage body fat. We observed limited evidence for an association between healthy eating patterns and greater lymphocyte proliferation and no evidence for an association with NK cell cytotoxicity.

CONCLUSION

Our results provide limited evidence that healthy eating patterns contribute to enhanced immune function and reduced inflammation in overweight and obese postmenopausal women.