Overweight, obesity, and cancer risk

Impact of obesity on the surgical outcome following repeat hepatic resection in Japanese patients with recurrent hepatocellular carcinoma

AIM: To evaluate the impact of obesity on the posto-perative outcome after hepatic resection in patients with hepatocellular carcinoma (HCC).

METHODS: Data from 328 consecutive patients with primary HCC and 60 patients with recurrent HCC were studied. We compared the surgical outcomes between the non-obese group (body mass index: BMI < 25 kg/m²) and the obese group (BMI ≥ 25 kg/m²).

RESULTS: Following curative hepatectomy in patients with primary HCC, the incidence of postoperative complications and the long-term prognosis in the non-obese group (n = 240) were comparable to those in the obese group (n = 88). Among patients with recurrent HCC, the incidence of postoperative complications after repeat hepatectomy was not significantly different between the non-obese group (n = 44) and the obese group (n = 16). However, patients in the obese group showed a significantly poorer long-term prognosis than those in the non-obese group (P < 0.05, five-year survival rate; 51.9% and 92.0%, respectively).

CONCLUSION: Obesity alone may not have an adverse effect on the surgical outcomes of patients with primary HCC. However, greater caution seems to be required when planning a repeat hepatectomy for obese patients with recurrent HCC.

Obesity and risk of colorectal cancer: a meta-analysis of 31 studies with 70,000 events

BACKGROUND

Colorectal cancer is the second most common cause of death and illness in developed countries. Previous reviews have suggested that obesity may be associated with 30% to 60% greater risk of colorectal cancer, but little consideration was given to the possible effect of publication bias on the reported association.

METHODS

Relevant studies were identified through EMBASE and MEDLINE. Studies were included if they had published quantitative estimates of the association between general obesity [defined here as body mass index (BMI) > or = 30 kg/m(2)] and central obesity (measured using waist circumference) and colorectal cancer. Random-effects meta-analyses were done, involving 70,000 cases of incident colorectal cancer from 31 studies, of which 23 were cohort studies and 8 were case-control studies.

RESULTS

After pooling and correcting for publication bias, the estimated relative risk of colorectal cancer was 1.19 [95% confidence interval (95% CI), 1.11-1.29], comparing obese (BMI > or = 30 kg/m(2)) with normal weight (BMI <25 kg/m(2)) people; and 1.45 (95% CI, 1.31-1.61), comparing those with the highest, to the lowest, level of central obesity. After correcting for publication bias, the risk of colorectal cancer was 1.41 (95% CI, 1.30-1.54) in men compared with 1.08 (95% CI, 0.98-1.18) for women (P(heterogeneity) <0.001). There was evidence of a dose-response relationship between BMI and colorectal cancer: for a 2 kg/m(2) increase in BMI, the risk of colorectal cancer increased by 7% (4-10%). For a 2-cm increase in waist circumference, the risk increased by 4% (2-5%).

CONCLUSIONS

Obesity has a direct and independent relationship with colorectal cancer, although the strength of the association with general obesity is smaller than previously reported.

Carbohydrate consumption and esophageal cancer:an ecological assessment

OBJECTIVES

The incidence of esophageal adenocarcinoma is on the rise in the United States. In this ecological study using the Surveillance, Epidemiology, and End Results (SEER) program (1973-2001) and national food consumption data (1909-1997), we evaluated the correlation between secular trends of dietary macronutrient intakes and esophageal cancer rates.

METHODS

Linear regressions were performed to assess the correlation between age-adjusted incidence rates of esophageal cancers and nutrients.

RESULTS

The increase in esophageal adenocarcinoma was found to be strongly correlated with the rise in carbohydrate intake (P < 0.0001). The decline in squamous cell carcinoma rates was negatively correlated with carbohydrate intake in the univariate model (P < 0.0001), but this correlation disappeared when adjusted for other nutrients. Correlations of esophageal adenocarcinoma to percentage of calories from corn syrup, representing refined carbohydrates, were statistically significant in the univariate model (P < 0.0001), but decreased in significance in the multivariate model (P= 0.0118). We also found a significant correlation between obesity and esophageal adenocarcinoma (P < 0.0001) during the same time period.

CONCLUSION

Our ecological evaluation suggests that high carbohydrate intake and obesity can account for at least some of the rise in esophageal adenocarcinoma. Within-population studies are needed to clarify these trends.

Esophageal cancer and body mass index: results from a prospective study of 220,000 men in China and a meta-analysis of published studies

Several epidemiological studies have reported on the association between body mass index (BMI) and risk of esophageal cancer, but these were mostly in Western populations where many are overweight or obese. There is little direct evidence about the relationship in China where the mean BMI is relatively low and the disease rate is high. We examined the data from a population-based prospective study of 220,000 Chinese men aged 40-79 without a previous history of cancer (mean BMI 21.7 kg/m(2)), which included 1,082 esophageal cancer deaths during 10 years of follow-up. Adjusted hazard ratios for death from esophageal cancer by baseline BMI category were calculated using Cox proportional hazards models. Even among men with good self-assessed health and BMI >or= 18.5 kg/m(2), there was a strong inverse association between BMI and death from esophageal cancer, with each 5 kg/m(2) higher BMI associated with 25% (95%CI: 11-36%) lower esophageal cancer mortality. This inverse association persisted when analysis was restricted to men who had never smoked or when the first 5 years of follow-up were excluded. The strength of the relationship was consistent with the pooled estimate for squamous cell carcinoma of the esophagus in a meta-analysis of prospective studies (31% lower relative risk per 5 kg/m(2) higher BMI; 95% CI: 25-37%), but contrasted with that for adenocarcinoma which showed a positive association with BMI. Together, these data provide reliable evidence that in many populations low BMI is associated with an increased risk of squamous cell carcinoma of the esophagus.

Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies

BACKGROUND

Excess bodyweight, expressed as increased body-mass index (BMI), is associated with the risk of some common adult cancers. We did a systematic review and meta-analysis to assess the strength of associations between BMI and different sites of cancer and to investigate differences in these associations between sex and ethnic groups.

METHODS

We did electronic searches on Medline and Embase (1966 to November 2007), and searched reports to identify prospective studies of incident cases of 20 cancer types. We did random-effects meta-analyses and meta-regressions of study-specific incremental estimates to determine the risk of cancer associated with a 5 kg/m2 increase in BMI.

FINDINGS

We analysed 221 datasets (141 articles), including 282,137 incident cases. In men, a 5 kg/m2 increase in BMI was strongly associated with oesophageal adenocarcinoma (RR 1.52, p<0.0001) and with thyroid (1.33, p=0.02), colon (1.24, p<0.0001), and renal (1.24, p <0.0001) cancers. In women, we recorded strong associations between a 5 kg/m2 increase in BMI and endometrial (1.59, p<0.0001), gallbladder (1.59, p=0.04), oesophageal adenocarcinoma (1.51, p<0.0001), and renal (1.34, p<0.0001) cancers. We noted weaker positive associations (RR <1.20) between increased BMI and rectal cancer and malignant melanoma in men; postmenopausal breast, pancreatic, thyroid, and colon cancers in women; and leukaemia, multiple myeloma, and non-Hodgkin lymphoma in both sexes. Associations were stronger in men than in women for colon (p<0.0001) cancer. Associations were generally similar in studies from North America, Europe and Australia, and the Asia-Pacific region, but we recorded stronger associations in Asia-Pacific populations between increased BMI and premenopausal (p=0.009) and postmenopausal (p=0.06) breast cancers.

INTERPRETATION

Increased BMI is associated with increased risk of common and less common malignancies. For some cancer types, associations differ between sexes and populations of different ethnic origins. These epidemiological observations should inform the exploration of biological mechanisms that link obesity with cancer.

The role of insulin receptors and IGF-I receptors in cancer and other diseases

There is evidence, both in vitro and in vivo, that receptor tyrosine kinases play a key role in the formation and progression of human cancer. In particular, the insulin-like growth factor receptor (IGF-IR), a tyrosine kinase receptor for IGF-I and IGF-II, has been well documented in cell culture, animal studies, and humans to play a role in malignant transformation, progression, protection from apoptosis, and metastasis. In addition, the hormone insulin (which is very closely related to the IGFs) and its tyrosine kinase receptor (the IR, which is very closely related to the IGR-IR) have been documented both in vitro and in vivo to play a key role in cancer biology. Indeed, several epidemiological studies have shown that insulin resistance status, characterized by hyperinsulinaemia, is associated with an increased risk for a number of malignancies, including carcinomas of the breast, prostate, colon and kidney. Recent data have elucidated some molecular mechanisms by which IR is involved in cancer. IR is over-expressed in several human malignancies. Interestingly, one of the two IR isoform (IR-A) is especially over-expressed in cancer. IR-A is the IR foetal isoform and has the peculiar characteristic to bind not only insulin but also IGF-II. In addition, the IR contributes to formation of hybrid receptors with the IGF-IR (HR). By binding to hybrid receptors, insulin may stimulate specific IGF-IR signalling pathways. Over-expression of IR-A is, therefore, a major mechanism of IGF system over-activation in cancer. In this respect, IR-A isoform and hybrid receptors should be regarded as potential molecular targets, in addition to IGF-IR, for novel anti-cancer therapy. These findings may have important implications for both the prevention and treatment of common human malignancies. They underline the concept that hyperinsulinaemia, associated with insulin resistance and obesity, should be treated by changes in life style and/or pharmacological approaches to avoid an increased risk for cancer. Moreover, native insulin and insulin analogue administration should be carefully evaluated in terms of the possible increase in cancer risk.

Anthropometric factors and risk of melanoma in women: a pooled analysis

Anthropometric factors such as height, weight and body mass index are related to the occurrence of certain malignancies in women including cancers of the breast, ovary and endometrium. Several studies have investigated the relation between height and weight or body mass and the risk of cutaneous melanoma in women, but results have been inconsistent. We conducted a collaborative analysis of these factors using the original data from 8 case-control studies of melanoma in women (2,083 cases and 2,782 controls), with assessment of the potential confounding effects of socioeconomic, pigmentary and sun exposure-related factors. Women in the highest quartile of height had an increased risk of melanoma [pooled odds ratio (pOR) 1.3, 95% confidence interval (CI) 1.1-1.6]. We also found an elevated risk associated with weight gain in adult life of 2 kg or more (pOR 1.5, 95% CI 1.1-2.0). Stratifying by age at melanoma diagnosis (<50, >or=50 yr), we found this risk greater among women <50 yr of age. Associations were unaffected by adjustment for other known risk factors for melanoma. There was no evidence that the effects varied for different histologic subtypes of cutaneous melanoma. There was no association with body weight per se, body mass index, or body surface area, either recent or in young adulthood. In aggregate, data from these studies suggest that greater height and weight gain may be risk factors for cutaneous melanoma in women.

Associations among lipids, leptin, and leptin receptor gene Gin223Arg polymorphisms and breast cancer in China

We evaluated the relationship among the leptin receptor (LEPR) gene Gln223Arg polymorphism, body mass index (BMI), waist and hip circumference ratio (WHR), dietary structure, lifestyle, and other biomarkers with breast cancer and determined whether they could be effective for the prevention and treatment of breast cancer. The Gln223Arg polymorphisms in the LEPR gene were investigated in blood deoxyribonucleic acid (DNA) available for 240 breast cancer cases and 500 controls. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. Leptin, insulin were determined by enzyme-linked immunosorbent assays. We found that the serum levels of leptin, insulin, triglyceride (TG), free cholesterol (FCH), apolipoprotain (APO) A1, and BMI were significantly higher in breast cancer cases than the controls, while physical activity was clearly less in breast cancer cases (P < 0.02 approximately P < 0.001, respectively). Moreover, there were significant association between the Gln223Arg genotype and breast cancer risk; homozygotes for AA and heterozygotes for AG,AG + GG genotypes had been proved to increase the risk of breast cancer, and their corresponding odds ratio were 7.14 (95% confidence interval [CI] = 1.92-25.64), 1.33(95% CI = 1.03-2.70), and 2.04 (95% CI = 1.09-3.82). Interestingly, logistic regression analysis showed that LEPR gene Gln223Arg polymorphism and elevated leptin, insulin, TG, FCH, APOA1, WHR, and reduced APOB increased the risk of developing breast cancer, respectively. And, it also suggested that LEPR gene Gln223Arg polymorphisms, elevated leptin, insulin, TG, FCH, APOA1, WHR, and reduced APOB should play a major role in the development of breast cancer.

Overweight/obesity and cancer genesis: more than a biological link

The classical view according to which overweight/obesity is related to cancer considers adipose tissue as an active and metabolic "organ", acting through endocrine, autocrine and paracrine processes. Consequently, it has been hypothesized, that genesis and progression of cancer may be caused by different biological factors acting through diverse mechanisms including changes in the synthesis and bioavailability of sex hormones, insulin resistance, release of growth factors and/or proinflammatory cytokines and abnormal energetic disposal and expenditure. We have shown that overweight/obesity can be experimentally induced by benzo[a]pyrene, a universal well characterized chemical pollutant and that overweight/obesity may in fact be caused by several types of chemical pollutants. In this paper we propose that in addition to the above hypothetical biological mechanisms, adipose tissue acts as a reservoir for lipophilic, liposoluble environmental carcinogens, so that chemical pollution may in fact generate both overweight/obesity and cancer. More precisely, we propose that many carcinogens, be they mutagens or promotors can be stored in the adipose tissue, be released at convenient dose in the blood circulation and therefore target peripheral tissues to induce carcinogenesis. Such carcinogens mainly include organochlorine pesticides and PCBs. Their association with an increased risk of cancer seems to be demonstrated for breast and prostate carcinoma, as well as for lymphoma, not only in obese patients, but also in normal weight or even leaner patients suggesting that the adipose tissue may act as a reservoir for environmental carcinogens in obese as well as in non-obese patients.

Preventive oncology in the postmenopausal woman

Breast cancer and endometrial cancer are the most common gynecologic malignancies of the postmenopausal period. As preventive medicine becomes the focus of interest, preventive oncology with special regard to these diseases will undoubtedly become a substantial part of the practicing oncologist's field of duties. The aim of this review is to summarize recommendations dealing with the risk assessment and prevention of breast and endometrial cancer. Obesity, the level of exercise and dietary factors are associated with breast cancer. The selective estrogen receptor modulators tamoxifen and raloxifen have both been shown to decrease the risk to the same extent. Patients at particularly high risk are being detected through the use of the Gail model, a well-known statistical model of risk. Other factors, such as breast density, the serum level of endogenous estrogen and the presence of single nucleotide polymorphisms, have to be taken into consideration.

Availability and utility of body mass index for population-based cancer surveillance

OBJECTIVE

To evaluate the availability of body height and weight data in the hospital medical record of cancer patients and discuss the utility of the findings to population-based cancer research and the surveillance of overweight and obesity in the United States.

METHODS

Medical records were reviewed for up to three measures of height and weight for a random sample of 1,739 patients diagnosed (2001-2003) with one of the 12 types of cancer and reported to the population-based Greater Bay Area Cancer Registry of Northern California.

RESULTS

About 84% of cancer patients had at least one value of height, 91% had at least one value of weight, and 83% had both values recorded in the medical record such that body mass index (BMI) could be computed. About 60% of height and weight values were recorded within 2 months of cancer diagnosis, with most values (71%) recorded after cancer diagnosis. The availability of BMI varied somewhat by race/ethnicity, cancer site, initial treatment, and hospital characteristics.

CONCLUSIONS

BMI may be sufficiently available to be included routinely in the population-based cancer registries, and, if so, would be useful for studies of cancer diagnoses and outcomes and permit nationwide surveillance of BMI in a large population-representative cohort of cancer patients.

Is obesity an independent prognosis factor in woman breast cancer?

BACKGROUND

Breast cancer and obesity represent important public health issues in most western countries. A number of studies found a negative prognosis effect of obesity or excess of weight in woman breast cancer. However, to date, this issue remains controversial. The objectives of this study were to confirm the prognosis role of obesity on a large cohort of patients and to investigate a potential independent effect.

MATERIALS AND METHODS

We constituted a cohort of 14,709 patients who were recruited and treated at the Curie Institute (Paris) from 1981 to 1999. These patients were followed prospectively for a first unilateral invasive breast cancer without distant metastasis. Obesity was defined by a Body Mass Index (BMI) above 30 kg/m(2) according to the World Health Organization recommendations.

RESULTS

Obese patients (8%) presented more extended tumors at diagnosis time suggesting a delayed breast cancer diagnosis. However, obesity appeared as a negative prognosis factor for several events in respectively univariate and multivariate survival analysis: metastasis recurrence (HR = 1.32[1.19-1.48]; HR = 1.12[1.00-1.26]), disease free interval (1.20[1.08-1.32]; 1.10[0.99-1.22]), overall survival (1.43[1.28-1.60]; 1.12[0.99-1.25]) and second primary cancer outcome (1.57[1.19-2.07]; 1.43[1.09-1.89]). Even if obese patients presented more advanced tumors at diagnosis time, multivariate analysis showed that there was a relevant independent effect. Other BMI codings, distinguishing overweight patients or using BMI as a continuous variable, showed a consistent correlation between BMI's value and prognosis effect. Interaction analysis revealed a more important obesity effect in the presence of tumor estrogen receptors and among limited extent tumors.

CONCLUSIONS

This survey confirms the prognosis role of obesity on one of the largest cohort by investigating several prognosis events. While independent obesity effect linked to hormonal disorders appeared consistent as obesity's mechanism, we stress that obesity prognosis effect was also related to breast cancer presentation at diagnosis time.

A biopsychosocial approach to examining tobacco-related health disparities among racially classified social groups

AIMS

To articulate a broader, multi-causal model that incorporates psychosocial and environmental factors that can differ systematically across racially classified social groups (RCSGs) and impact biological pathways related to the development of tobacco-related diseases.

METHODS

This paper is built upon a review of the existing scientific literature on selected biopsychosocial factors (diet/nutrition, obesity, alcoholic intake, psychosocial stress, occupational/environmental exposures and exposure to other diseases and illnesses) and tobacco use in examining the biological contributions to differences in tobacco-related health outcomes among RCSGs.

FINDINGS

Recent work has focused on RCSG genetic variations as a possible explanation for differences in tobacco-related health disparities. It is argued in this paper that, given the genetic heterogeneity 'within' RCSGs, it is unlikely that across RCSG genetic variations are likely to be the major source of differences impacting biological pathways in tobacco-related health outcomes. The evidence shows that results, even at the level of within-population genetic variations, have been limited and often inconsistent. A conceptual framework is proposed to account for biological pathways related to the development of tobacco-related diseases.

CONCLUSIONS

Determinants of tobacco-related health disparities are not understood clearly. The contribution of biological factors may be important. Current efforts to determine biological differences in tobacco use and related diseases among RCSGs have focused primarily on genetic variations. However, this approach has limitations. An alternative biopsychosocial framework that examines the potential biological mechanisms through which life experiences and behavior might affect tobacco use and health outcomes in these population groups is needed, including those of life-style (e.g. diet/nutrition, obesity, physical exercise, alcohol consumption), psychosocial (e.g. stress and coping), occupational/environmental exposures and the presence of other diseases/illnesses.

The role of dietary factors in the epidemiology of non-Hodgkin's lymphoma

The incidence of non-Hodgkin's lymphoma (NHL) has risen dramatically over recent decades and, despite some known risk factors, such as compromised immunity, the etiology of NHL and the reasons for most of this increase are unknown. Dietary components may be a common and critical source of immunologic antigens and promoters, which needs to be incorporated more in the etiologic research of NHL. To date, epidemiologic evidence suggests that obesity and fat intake, in particular saturated or animal fat, may increase the risk of NHL; whereas whole-grains, vegetables and moderate consumption of alcohol may be inversely associated with NHL risk. Much of the current evidence is obtained from case-control studies, which are subject to dietary recall bias; therefore, this area of research requires further study within prospective cohorts with detailed dietary information and with a large number of cases to examine disease sub-type heterogeneity.

Components of the metabolic syndrome and colorectal cancer risk; a prospective study

OBJECTIVE

To examine the relation of well-known factors of the metabolic syndrome (MetS) as well as related circulating factors, with risk of colorectal cancer.

METHODS

We performed a case control study of 306 colorectal cancer cases and 595 matched controls nested in the Northern Sweden Health and Disease Cohort. Levels of C-peptide, glycated haemoglobin (HbA1c), leptin and adiponectin were measured in cryopreserved samples. Body mass index (BMI), systolic and diastolic blood pressure and fasting and post-load plasma glucose, had been measured in a subcohort. Conditional logistic regression was used to calculate odds ratios (OR) of disease, including risk assessments for the MetS factors: obesity (BMI>30 kg m(-2)), hypertension (blood pressure > or =140/90 mmHg or use of anti-hypertensive drugs) and hyperglycaemia (fasting glucose > or =6.1 mmol l(-1) or post-load glucose in capillary plasma > or =8.9 mmol l(-1)).

RESULTS

None of the studied variables were significantly associated with risk across quartiles. Presence of obesity, hypertension and hyperglycaemia significantly increased the risk of colorectal cancer; OR for three vs null factors was 2.57 (95% Confidence Interval [CI] 1.20-5.52; P (trend)=0.0021), as compared to a 30 to 70% increased risk for the factors in single. Similarly, top decile levels of C-peptide, HbA1c and leptin/adiponectin ratio were associated with an increased risk; ORs for top vs deciles 1-9 were 1.56 (95% CI 0.93-2.62; P=0.090), 1.83 (95% CI 1.00-3.36; P=0.051) and 1.50 (95% CI 0.83-2.71; P=0.18), respectively.

CONCLUSIONS

Our study support the view that components of the MetS increase risk of colorectal cancer, and further suggests that only very high levels of metabolic factors confer an increased risk.

The effect of body weight on altered expression of nuclear receptors and cyclooxygenase-2 in human colorectal cancers

Background

Epidemiological studies on risk factors for colorectal cancer (CRC) have mainly focused on diet, and being overweight is now recognized to contribute significantly to CRC risk. Overweight and obesity are defined as an excess of adipose tissue mass and are associated with disorders in lipid metabolism. Peroxisome proliferator-activated receptors (PPARs) and retinoid-activated receptors (RARs and RXRs) are important modulators of lipid metabolism and cellular homeostasis. Alterations in expression and activity of these ligand-activated transcription factors might be involved in obesity-associated diseases, which include CRC. Cyclooxygenase-2 (COX-2) also plays a critical role in lipid metabolism and alterations in COX-2 expression have already been associated with unfavourable clinical outcomes in epithelial tumors. The objective of this study is to examine the hypothesis questioning the relationship between alterations in the expression of nuclear receptors and COX-2 and the weight status among male subjects with CRC.

Method

The mRNA expression of the different nuclear receptor subtypes and of COX-2 was measured in 20 resected samples of CRC and paired non-tumor tissues. The association between expression patterns and weight status defined as a body mass index (BMI) was statistically analyzed.

Results

No changes were observed in PPARγ mRNA expression while the expression of PPARδ, retinoid-activated receptors and COX-2 were significantly increased in cancer tissues compared to normal colon mucosa (P ≤ 0.001). The weight status appeared to be an independent factor, although we detected an increased level of COX-2 expression in the normal mucosa from overweight patients (BMI ≥ 25) compared to subjects with healthy BMI (P = 0.002).

Conclusion

Our findings show that alterations in the pattern of nuclear receptor expression observed in CRC do not appear to be correlated with patient weight status. However, the analysis of COX-2 expression in normal colon mucosa from subjects with a high BMI suggests that COX-2 deregulation might be driven by excess weight during the colon carcinogenesis process.

Combination of physical activity, nutrition, or other metabolic factors and vaccine response

A number of lifestyle factors that reduce cancer risk in the primary prevention setting may be potential new targets for use in combination with cancer vaccines. This review discusses the modulation of energy balance (physical activity, calorie restriction, and obesity prevention), and the supplementation with natural and synthetic analogs of vitamins A and E, as potential interventions for use in combination with cancer vaccines. Additionally, the pharmacologic manipulation of nutrient metabolism in the tumor microenvironment (e.g., arachidonic acid, arginine, tryptophan, and glucose metabolism) is discussed. This review includes a brief overview of the role of each agent in primary cancer prevention; outlines the effects of these agents on immune function, specifically adaptive and/or anti-tumor immune mechanisms, when known; and discusses the potential use of these interventions in combination with therapeutic cancer vaccines. Modulation of energy balance through exercise and strategies targeting nutrient metabolism in the tumor microenvironment represent the most promising interventions to partner with therapeutic cancer vaccines. Additionally, the use of vitamin E succinate and the retinoid X receptor-directed rexinoids in combination with cancer vaccines offer promise. In summary, a number of energy balance- and nutrition-related interventions are viable candidates for further study in combination with cancer vaccines.

Association between glycosylated hemoglobin and cancer risk: a New Zealand linkage study

BACKGROUND

The purpose of this study was to examine the relationship between glycosylated hemoglobin (HbA(1c)) level and subsequent cancer risk.

MATERIAL AND METHODS

HbA(1c) measurements were made on blood samples of participants in a hepatitis B (HB) screening program (1999-2001). Cancer incidence was determined by linkage to cancer registrations and hospitalization records to the end of 2004. Participants previously diagnosed with diabetes or cancer were excluded. Hazard ratios (HR) and 95% confidence intervals (CIs) were estimated using Cox regression.

RESULTS

Among the 46 575 participants (70% Māori, 12% Pacific, 5% Asian and 12% Other), 634 cancer cases were observed. For all cancers combined, a significant increased risk was found in persons with moderately elevated HbA(1c) levels (6%-6.9%) (HR 1.40, 95% CI: 1.11-1.76), with a smaller increased risk in persons with highly elevated levels (> or =7%) (HR 1.09, 95% CI: 0.80-1.48) as compared with persons having low HbA(1c) levels (<6%). The HRs for respiratory cancers were 2.27 (95% CI: 1.34-3.86) for the moderate HbA(1c) category and 1.58 (95% CI: 0.77-3.26) for the upper HbA(1c) category. For endometrial cancers, the HRs were 4.05 (95% CI: 1.10-14.88) and 5.07 (95% CI: 1.20-21.31), respectively. For other cancer sites, no significantly increased risks were found.

CONCLUSIONS

These findings are consistent with other evidence that abnormal glucose metabolism may be associated with an increased risk of some cancers.

Risk factors for cholangiocarcinoma

Cholangiocarcinoma occurs with a varying frequency in different areas of the world. Some of the variations in incidence rates can be explained by the distribution of risk factors in different geographic regions and ethnic groups. Several accepted risk factors for cholangiocarcinoma include infestation with liver flukes, primary sclerosing cholangitis, hepatolithiasis, choledochal cysts, cirrhosis, and infusion of certain chemical agents. Approximately, 90% of patients diagnosed with cholangiocarcinoma do not have a recognized risk factor for the malignancy. The study by Ahrens et al. [16] finds that obesity and gallstones are risk factors for developing extrahepatic cholangiocarcinoma in men patients. Obesity was found to have a 'dose-effect' relationship with the strength of statistical association. No significant association was reported for tobacco or alcohol use, hepatitis, cirrhosis, diabetes, or inflammatory bowel disease. Although the author's definition of extrahepatic cholangiocarcinoma was unusual, the association of obesity with the risk of developing cholangiocarcinoma persisted for all anatomic subsites.

Extreme obesity reduces bone mineral density: complementary evidence from mice and women

OBJECTIVE

To evaluate the effects of body adiposity on bone mineral density in the presence and absence of ovarian hormones in female mice and postmenopausal women.

RESEARCH METHODS AND PROCEDURES

We assessed percentage body fat, serum leptin levels, and bone mineral density in ovariectomized and non-ovariectomized C57BL/6 female mice that had been fed various calorically dense diets to induce body weight profiles ranging from lean to very obese. Additionally, we assessed percentage body fat and whole body bone mineral density in 37 overweight and extremely obese postmenopausal women from the Women's Contraceptive and Reproductive Experiences study.

RESULTS

In mice, higher levels of body adiposity (>40% body fat) were associated with lower bone mineral density in ovariectomized C57BL/6 female mice. A similar trend was observed in a small sample of postmenopausal women.

DISCUSSION

The complementary studies in mice and women suggest that extreme obesity in postmenopausal women may be associated with reduced bone mineral density. Thus, extreme obesity (BMI > 40 kg/m2) may increase the risk for osteopenia and osteoporosis. Given the obesity epidemic in the U.S. and in many other countries, and, in particular, the rising number of extremely obese adult women, increased attention should be drawn to the significant and interrelated public health issues of obesity and osteoporosis.

Obesity in survivors of childhood acute lymphoblastic leukemia and lymphoma

PURPOSE

We evaluated the long-term effects of treatment on the body mass index (BMI) of children with acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma who received one of three CNS-directed therapies: intrathecal methotrexate with intravenous high-dose methotrexate (1 g/m2), intrathecal methotrexate with 18 Gy cranial radiation, or intrathecal methotrexate with 24 Gy cranial radiation.

PATIENTS AND METHODS

Between 1979 and 1984, 456 children with newly diagnosed ALL and lymphoma were enrolled onto a single protocol at St Jude Children's Research Hospital (Memphis, TN). The heights and weights of 422 of the children were measured at diagnosis, during treatment, at the end of therapy, and approximately every 6 to 12 months thereafter. Patients who had attained their adult height at the time of analysis (n = 248) were placed in weight categories based on their BMI, BMI percentile, or weight-for-length percentile depending on age.

RESULTS

The overall percentage of survivors who were overweight or obese approximated rates prevalent in the general population of the United States. Young age (< 6 years) and overweight/obesity at diagnosis were the best predictors of obesity at adult height. The rate of BMI increase did not differ significantly between children who received radiation and those who did not, nor between patients who received 18 or 24 Gy of cranial radiation.

CONCLUSION

BMI weight category at diagnosis, rather than type of CNS treatment received, predicted adult weight in long-term survivors of childhood hematologic malignancies.

Interaction of factors related to the metabolic syndrome and vitamin D on risk of prostate cancer

BACKGROUND

Factors related to the metabolic syndrome and low levels of vitamin D have been implicated as risk factors for prostate cancer. Insofar, no studies have assessed their joint effects on prostate cancer risk.

METHODS

We studied (a) the associations of vitamin D with the metabolic syndrome factors body mass index, systolic and diastolic blood pressure, and high-density lipoprotein cholesterol (HDL-C) and (b) the prostate cancer risk associated with these factors and especially their joint effects with vitamin D on risk of prostate cancer. We did a longitudinal nested case-control study on 132 prostate cancer cases and 456 matched controls from a cohort of 18,939 Finnish middle-aged men from the Helsinki Heart Study. The odds ratios (OR) of prostate cancer were assessed via conditional logistic regression analysis.

RESULTS

Apart from HDL-C, there was no linear association between the metabolic syndrome factors and vitamin D levels. In univariate analysis, men in the highest quartiles of body mass index (>28 kg/m(2)) and systolic blood pressure (>150 mmHg) showed a modest increase in risks of prostate cancer, with ORs of 1.37 (P = 0.16) and 1.53 (P = 0.05) when compared with the three lower quartiles, but low HDL-C entailed no prostate cancer risk. However, with all three factors present, the OR was 3.36 (P = 0.02), and jointly with low vitamin D (<or=40 nmol/L), the OR was 8.03 (P = 0.005) compared with those with no metabolic syndrome factors and intermediate levels of vitamin D. There was an interaction between vitamin D and the metabolic syndrome factors so that a clustering of these factors entailed high risk of prostate cancer but only if vitamin D level was low (<or=40 nmol/L). If it was at intermediate levels, the metabolic syndrome factors entailed no prostate cancer risk.

CONCLUSIONS

We conclude that the prostate cancer risk associated with factors related to the metabolic syndrome is strongly conditioned by levels of vitamin D.

Haplotype-Based Analysis of Common Variation in the Acetyl-CoA Carboxylase α Gene and Breast Cancer Risk: A Case-Control Study Nested within the European Prospective Investigation into Cancer and Nutrition

A key fatty acid synthesis enzyme, acetyl-CoA carboxylase alpha (ACC-alpha), has been shown to be highly expressed in human breast cancer and other tumor types and also to specifically interact with the protein coded by one of two major breast cancer susceptibility genes BRCA1. We used a comprehensive haplotype analysis to examine the contribution of the ACC-alpha common genetic variation (allele frequency >5%) to breast cancer in a case-control study (1,588 cases/2,600 controls) nested within the European Prospective Investigation into Cancer and Nutrition. We identified 21 haplotype-tagging polymorphisms efficiently capturing common variation within 325 kb of ACC-alpha and surrounding sequences using genotype data from the HapMap project and our resequencing data. We found an effect on overall risk of breast cancer in homozygous carriers of one common haplotype [odds ratio (OR), 1.74; 95% confidence interval (95% CI), 1.03-2.94]. When the data were subdivided by menopausal status, we found statistical evidence of heterogeneity for two other common haplotypes (P value for heterogeneity = 0.016 and 0.045). In premenopausal women, the carriers of these haplotypes, compared with noncarriers, had an altered risk of breast cancer (OR, 0.70; 95% CI, 0.53-0.92 and OR, 1.35; 95% CI, 1.04-1.76). These findings were not significant after adjustment for multiple testing and therefore should be considered as preliminary and evaluated in larger independent studies. However, they suggest a possible role of the ACC-alpha common sequence variants in susceptibility to breast cancer and encourage studies of other genes involved in fatty acid synthesis.

Body mass index: a marker for significant colorectal neoplasia in a screening population

BACKGROUND AND AIMS

Although some studies suggest a positive association between increasing body mass index (BMI) and risk for colorectal neoplasia, the impact on screening has not been examined. We performed a cross-sectional study to examine the association of BMI and colorectal neoplasia in a screening population.

METHODS

Data collected for 2493 patients presenting for screening colonoscopy included known risk factors for colorectal neoplasia, demographic information, and lifestyle factors. Our outcome was the endoscopic detection of significant colorectal neoplasia which included adenocarcinoma, high-grade dysplasia, villous tissue, adenomas 1 cm or greater and multiple (>2) adenomas of any size.

RESULTS

Overall, we observed an increased risk and prevalence for significant colorectal neoplasia in women as BMI increased (P value for trend <0.002). This relationship was the strongest for the women with a BMI > or =40 (odds ratios=4.26; 95% confidence intervals=2.00-9.11). There was no such relationship in our male population.

CONCLUSIONS

Increasing BMI, in our population, was associated with an increase risk for colorectal neoplasia in female patients. This study reinforces the importance of screening colonoscopy especially in obese women.

Adipocytes and preadipocytes promote the proliferation of colon cancer cells in vitro

Obesity, a risk factor for colon cancer, is associated with elevated serum levels of leptin, a protein produced by adipocytes. The aim of the present study was to clarify the effects of adipose tissue on colon cancer proliferation by using cultured cell lines. To achieve this, colon cancer cells (CACO-2, T84, and HT29) were cocultured with adipose tissue, isolated mature adipocytes, and isolated preadipocytes in a three-dimensional collagen gel culture system. The adipocytes and preadipocytes used were isolated from C57BL/6J and leptin-deficient ob/ob mice. Proliferation of the cancer cells was evaluated by nuclear bromodeoxyuridine uptake. The adipose tissue, mature adipocytes, and preadipocytes isolated from C57BL/6J mice significantly increased the proliferation of the colon cancer cells. This trophic effect of mature adipocytes on the cancer cell lines was observed only for cells from lean littermates and not for those from ob/ob mice. In contrast, the trophic effect of preadipocytes was not abolished in ob/ob mice, and this finding was supported by the result that leptin had a trophic effect on cancer cells. In conclusion, adipocytes were able to enhance the proliferation of colon cancer cells in vitro, partly via leptin, suggesting that adipose tissues, including mature adipocytes and preadipocytes, may promote the growth of colorectal cancer.

Obesity and the risk of Hodgkin lymphoma (United Kingdom)

OBJECTIVE

The aim of the study was to investigate the relationship between Hodgkin lymphoma (HL) and obesity.

METHODS

A population-based case-control study recruited incident cases of lymphoma in England during 1998-2003. Information on height and weight was collected from 216 cases with a histologically confirmed incident diagnosis of HL and their age- and sex-matched controls.

RESULTS

Obesity, defined as a body mass index of 30 kg m(-2) or above at 5 years prior to diagnosis, increased the risk of HL more than 2-fold compared to those in the normal range of 18.5-<25 kg m(-2) (odds ratio (OR) = 2.2, 95% confidence interval (CI): 1.1, 4.3). The association was more prominent among men (OR = 2.8, 95% CI: 1.2, 6.5) than women (OR = 1.1, 95% CI: 0.3, 3.8). Elevated risks tended to be among older (aged 36-50 and 51-69) rather than younger persons (aged < or =35 years), and for EBV-ve, rather than EBV+ve, HL.

CONCLUSIONS

This study suggests that obesity may increase the risk of HL, particularly among men. Further investigations are needed to confirm these findings.

Association of metabolic syndrome with proximal and synchronous colorectal neoplasm

BACKGROUND & AIMS

Metabolic syndrome and its associated morbidities have become a major public health problem in both developed and developing countries. Insulin resistance, the core mechanism of metabolic syndrome, has been associated with the development of colorectal neoplasm, but the interrelation between metabolic syndrome and colon cancer is rarely addressed. Our study aimed to determine whether metabolic syndrome is associated with the risk and clinical presentation of colorectal neoplasia.

METHODS

Consecutive 4277 ethnic Chinese who received complete total colonoscopy and thorough health checkups were enrolled. Both National Cholesterol Education Program's Adult Treatment Panel III and modified Asian criteria were used for defining metabolic syndrome. Logistic regression modeling was used to elucidate the association between colorectal neoplasia and metabolic syndrome. The impact of metabolic syndrome on distribution and number of colorectal neoplasia was also assessed.

RESULTS

Of all those enrolled, 27.1% of men and 18.9% of women met the criteria of metabolic syndrome, and 9.8% had colorectal neoplasia. Metabolic syndrome was associated with odds ratio (OR) of 1.35 (95% confidence interval [CI], 1.05-1.73) for colorectal neoplasia. OR was 0.96 (95% CI, 0.67-1.38) for distal lesions, 1.62 (95% CI, 1.14-2.30) for proximal lesions, 2.15 (95% CI, 1.40-3.31) for synchronous lesions, and 2.30 (95% CI, 1.42-3.72) for synchronous lesions located at both sides of colon.

CONCLUSIONS

Subjects with metabolic syndrome have a higher risk of colon neoplasia at the proximal colon and synchronous lesions at both sides of the colon. These findings will help future colon cancer screening and prevention in patients with metabolic syndrome.

Understanding global nutrition dynamics as a step towards controlling cancer incidence

As we look to understand future forces that will affect cancer risk, poor dietary patterns, overweight and obesity are significant concerns. In the past two decades these factors have shifted from issues that face higher-income countries to a global pandemic, and are rapidly becoming less a problem of affluence and more a problem of poverty. Rapid shifts in food systems, food pricing and marketing are the causes that underlie this trend. It is imperative to understand these factors and implement global interventions to slow this pandemic. The alternative is an acceleration of the incidence of the main nutrition-related cancers, primarily in developing countries.

Relation of body mass index to cancer risk in 362,552 Swedish men

BACKGROUND

Obesity has been linked with increased risk for cancers of the colon, kidney, breast, endometrium and gallbladder. For other cancer sites, the relationship with obesity is less well quantified, and the effect of weight change on cancer risk is unclear.

METHODS

We examined the health records of 362,552 Swedish men who underwent at least one physical examination from 1971 to 1992, and were followed until death or the end of 1999. Incident cancer cases were identified by linkage to the Swedish cancer registry. Poisson regression models were used to estimate relative risks of cancer for both body-mass index (BMI) at baseline exam and, in a subgroup of 107,815 men, change in BMI after six years of follow-up, adjusting for age and smoking status.

RESULTS

Compared to men of normal weight, obese men had a significantly increased risk of all cancers combined (RR = 1.1; 95% CI = 1.0-1.2). The risks were most pronounced for esophageal adenocarcinoma (RR = 2.7; 95% CI = 1.3-5.6), renal cell carcinoma (RR = 1.8; 95% CI = 1.4-2.4), malignant melanoma (RR = 1.4; 95% CI = 1.1-1.7), and cancers of the colon (RR = 1.7; 95% CI = 1.5-2.0), rectum (RR = 1.4; 95% CI = 1.1-1.7), and liver (RR = 3.6; 95% CI = 2.6-5.0). Risk of esophageal squamous cell carcinoma was elevated for underweight men whose BMI was less than 18.5 (RR = 3.1; 95% CI = 1.1-8.3). An excess risk for cancers of the pancreas and connective tissue was observed only among nonsmokers. Compared to men whose weight remained stable, men with more than a 15% increase in BMI after six years of follow-up had an elevated risk of pancreas and renal cell cancers.

CONCLUSIONS

Obesity and weight gain increase the risk for several forms of cancer in men, and underscore the need for further study into carcinogenic mechanisms and preventive interventions.

DPPIV inhibitors extend GLP-2 mediated tumour promoting effects on intestinal cancer cells

BACKGROUND

The glucagon-like peptides-1 and -2 (GLP-1 and -2) are co-secreted after food intake from intestinal L cells. Since both peptides are rapidly degraded by dipeptidyl peptidase-IV (DPPIV), research is focused on the development of DPPIV inhibitors or DPPIV resistant.

AIMS

In this study we investigated, whether the inhibition of DPPIV activity and the resulting increased half-life of DPPIV substrates may influence cancer development and progression.

METHODS

We examined proliferation and migratory activity of two human colon cancer cell lines (SW480, HT29) after stimulation with GLP-2 in combination with or without DPPIV inhibitors.

RESULTS

Migratory activity was increased by 25% from 20% matrix induced activity to a maximum of 45% (100 nM GLP-2). In cells expressing CD26, migration was prolonged by addition of DPPIV inhibitors in a concentration dependent manner. After treatment with GLP-2 doubling time decreased from 2.4 to 1.5 days - and addition of DPPIV inhibitors enhanced the effect of GLP-2.

CONCLUSIONS

The use of DPPIV inhibitors together with GLP-2 led to increased proliferation as well as elevated migratory activity. Therefore, the use of DPPIV inhibitors could increase the risk of promoting an already existing intestinal tumour and may support the potential of colon cancer cells to metastasize.

Body size, physical activity, and risk of Hodgkin's lymphoma in women

Few studies have examined the associations of body size and physical activity with the development of Hodgkin's lymphoma (HL) in women. In data from a population-based case-control study in women ages 19 to 79 years, we assessed the relation of self-report height, weight, body mass index (BMI), and strenuous physical activity to HL risk in 312 cases with diagnostic re-review and 325 random-digit dialed controls using logistic regression. Analyses were stratified by age group and tumor cell presence of EBV. After adjustment for social class measures, taller childhood and adult height were associated with higher HL risk. In women ages 19 to 44 years, HL risk was elevated for higher, but healthy, BMI values, whereas in women ages 45 to 79 years, associations with BMI were inverse. The odds of developing HL were lower with participation (versus nonparticipation) in strenuous physical activity in the past year [odds ratio (OR), 0.58; 95% confidence interval (95% CI), 0.39-0.87 in women 19-44 years; OR, 0.45; 95% CI, 0.19-1.06 in women 45-79 years] and throughout adult life, and with sports team membership (versus nonmembership) in high school and/or at ages 18 to 22 years. Results were similar in cases (n = 269) with and without tumor-cell EBV compared with controls, although the inverse association with physical activity was somewhat stronger for women with EBV-positive disease. These findings show that in women, body size and strenuous physical activity, both modifiable characteristics, are associated with HL risk in adult life possibly through immunologic, infectious, or genetic mechanisms.

Carbohydrate, glycemic index, and glycemic load and colorectal adenomas in the Prostate, Lung, Colorectal, and Ovarian Screening Study

BACKGROUND

It is possible that high-glycemic-load diets, through their hyperinsulinemic effects, can increase the risk of colorectal cancer.

OBJECTIVE

We analyzed data from a cancer screening study to determine whether persons with high-glycemic-load diets would be at an increased risk of distal adenomas.

DESIGN

We included subjects with no prior adenoma or cancer from the Prostate, Lung, Colorectal, and Ovarian screening trial and whose results from flexible sigmoidoscopy exams indicated either no lesions (n = 34 817) or >/=1 distal adenoma (n = 3696). We used a 137-item food-frequency questionnaire to assess usual dietary intake over the preceding 12 mo. Using logistic regression analysis, we calculated, separately for men and women, prevalence odds ratios (ORs) and 95% CIs of sigmoidoscopy-detected, distal adenomas for quintiles of energy-adjusted dietary carbohydrate, glycemic index, and glycemic load.

RESULTS

ORs decreased with increasing intakes of carbohydrate for both the men and the women in unadjusted models, but these associations were attenuated in multivariate-adjusted models. Among the men, the association remained significant after adjustment (OR: 0.71; 95% CI 0.60, 0.84; P for trend < 0.0001), but in the women it did not (OR: 0.89; 95% CI: 0.73, 1.10; P for trend = 0.30). The results for glycemic index showed no associations in either men or women. Results for glycemic load closely mirrored those for carbohydrate.

CONCLUSION

Despite expectations that increasing glycemic load and glycemic index would increase the risk of adenoma, we observed no association in women and even an inverse association in men.

Light during darkness and cancer: relationships in circadian photoreception and tumor biology

The relationship between circadian phototransduction and circadian-regulated processes is poorly understood. Melatonin, commonly a circadian phase marker, may play a direct role in a myriad of physiologic processes. The circadian rhythm for pineal melatonin secretion is regulated by the hypothalamic suprachiasmatic nucleus (SCN). Its neural source of light input is a unique subset of intrinsically photosensitive retinal ganglion cells expressing melanopsin, the primary circadian photopigment in rodents and primates. Action spectra of melatonin suppression by light have shown that light in the 446-477 nm range, distinct from the visual system's peak sensitivity, is optimal for stimulating the human circadian system. Breast cancer is the oncological disease entity whose relationship to circadian rhythm fluctuations has perhaps been most extensively studied. Empirical data has increasingly supported the hypothesis that higher risk of breast cancer in industrialized countries is partly due to increased exposure to light at night. Studies of tumor biology implicate melatonin as a potential mediator of this effect. Yet, causality between lifestyle factors and circadian tumor biology remains elusive and likely reflects significant variability with physiologic context. Continued rigorous empirical inquiry into the physiology and clinical implications of these habitual, integrated aspects of life is highly warranted at this time.

Causes of death in obesity: Relevant increase in cardiovascular but not in all-cancer mortality

BACKGROUND AND OBJECTIVE

To assess the relation between body mass index (BMI) and the risk of death from various causes in a prospective cohort study.

METHODS

In 6,192 obese patients (BMI > or =25 kg/m(2)) with mean BMI 36.6 kg/m(2) (SD 6.1) and mean age 40.4 years (SD 12.9) who had been referred to the obesity clinic of the Heinrich-Heine-University Düsseldorf, Germany, between 1961 and 1994, there were 1,058 deaths from all causes during a median follow-up time of 14.8 years. We calculated standardized mortality ratios (SMRs) with 95% confidence intervals (CIs) for death from predefined groups of diseases by using Germany as reference population.

RESULTS

In both sexes, risk of death from cardiovascular diseases (men: SMR = 2.2, CI 1.9-2.5; women: SMR = 1.6, CI 1.5-1.8), from diabetes (men: SMR = 5.4, CI 3.2-8.7; women: SMR = 3.5, CI 2.6-4.8), and in men from digestive diseases (SMR = 1.6, CI 1.01-2.3) was significantly increased. In contrast to other studies, an association between obesity and all-cancer mortality could not be found. Only in morbidly obese women (BMI > or =40 kg/m(2)), all-cancer mortality was significantly increased (SMR = 1.5, CI 1.1-1.9).

CONCLUSION

Obesity is associated with increased risk of death from cardiovascular diseases and diabetes in both sexes, and from diseases of the digestive system in men.

Relationship between body size and prostate cancer in a sibling based case-control study

PURPOSE

Body size has been hypothesized to affect the risk of prostate cancer (PCa). However, previous studies have provided conflicting results, in that some show positive associations, whereas others indicate inverse associations or null findings. To further understand this we examined the effects of weight, height, body mass index and lean body mass (LBM) on PCa risk and aggressiveness in a sibling based case-control study.

MATERIALS AND METHODS

A total of 439 cases were recruited at major medical institutions in Cleveland, Ohio and Detroit, Michigan, and 479 unaffected brothers were recruited as controls. Conditional logistic regression with robust variance estimation was used to evaluate the association between body size and PCa.

RESULTS

Higher LBM was inversely associated with PCa, especially in men with more aggressive disease or a later age at onset. Comparing those above and below the 25th percentile showed an OR of 0.49 (95% CI 0.28 to 0.84) and 0.28 (95% CI 0.14, 0.56), respectively. Similar inverse patterns were observed for weight. No noteworthy associations were observed between PCa and height or body mass index.

CONCLUSIONS

These observations suggest that PCa may be affected by LBM.

Susceptibility to Induced and Spontaneous Carcinogenesis Is Increased in Fatless A-ZIP/F-1 but not in Obese ob/ob Mice

Obesity is typically associated with increased tumor susceptibility, whereas caloric restriction, a regimen resulting in leanness, inhibits carcinogenesis. The link between adiposity and malignancies suggests that adipose tissue may influence carcinogenesis. An adipose tissue hormone, leptin, could be procarcinogenic because it stimulates proliferation in various tissues and tumor cell lines. Leptin may contribute to the correlation between adiposity and malignancies as its levels are usually increased in obese subjects and reduced by caloric restriction. We hypothesized that leptin deficiency, despite obesity, would inhibit carcinogenesis in leptin-null ob/ob mice and tested this hypothesis in two models: (a) two-stage skin carcinogenesis initiated by 7,12-dimethylbenz(a)anthracene and promoted by phorbol 12-myristate 13-acetate (PMA) and (b) p53 deficiency. Contrary to a typical association between obesity and enhanced carcinogenesis, obese ob/ob mice developed induced skin papillomas and spontaneous p53-deficient malignancies, mostly lymphomas, similarly to their lean littermates. Surprisingly, lipodystrophic (ZIP) mice that had very little both adipose tissue and leptin were highly susceptible to carcinogenesis. Hyperphagia, hyperinsulinemia, and hyperglycemia are unlikely to have contributed significantly to the enhancement of carcinogenesis in ZIP mice because similarly hyperphagic, hyperinsulinemic, and hyperglycemic ob/ob mice had normal susceptibility to carcinogenesis. Our data suggest that, in contrast to a well-known correlation between obesity and cancer, the direct effect of adipose tissue may rather be protective.

Accelerated tumor formation in a fatless mouse with type 2 diabetes and inflammation

Epidemiologic studies show a positive association between obesity and cancer risk. In addition to increased body adiposity and secretion of fat-derived hormones, obesity is also linked to insulin resistance, type 2 diabetes, and chronic inflammation. We used the fatless A-ZIP/F-1 transgenic mouse to dissociate the relative role of each of these underlying factors in the development of cancer. These mice are unique in that they do not have white fat but do develop type 2 diabetes. In two cancer models, the classic two-stage skin carcinogenesis protocol and the C3(1)/T-Ag transgenic mouse mammary tumor model, A-ZIP/F-1 mice displayed higher tumor incidence, tumor multiplicity, and decreased tumor latency than wild-type mice. We examined circulating levels of adipokines, growth factors, and cytokines. As expected, adipokines (i.e., leptin, adiponectin, and resistin) were undetectable or found at very low levels in the blood of fatless mice. However, insulin, insulin-like growth factor-I, growth hormone, vascular endothelial growth factor, and proinflammatory Th2 cytokines, such as interleukin (IL)-1beta, IL-4, and IL-6, were elevated in A-ZIP/F-1 mice. Additionally, we examined multiple phosphorylated proteins (i.e., protein kinase B/Akt and ErbB2/HER-2 kinase) associated with cancer development. Results show that many of these phosphorylated proteins were activated specifically in the A-ZIP/F-1 skin but not in the wild-type skin. These findings suggest that adipokines are not required for the promotion of tumor development and thus contradict the epidemiologic data linking obesity to carcinogenesis. We postulate that insulin resistance and inflammation are responsible for the positive correlation with cancer observed in A-ZIP/F-1 mice.

Moderately overweight and obese patients in general practice: a population based survey

Background

Obesity is a main threat to public health in the Western world and is associated with diseases such as diabetes mellitus and coronary heart diseases. Up to now a minority of research studied the relation between obesity and the use of primary health care. In the Netherlands the general practitioner (GP) is the main primary health care provider. The objective of this article is to evaluate GP consultation and prescription of drugs in moderate and severely overweight (obese) persons in the Netherlands.

Methods

Data were used from a representative survey of morbidity in Dutch general practice in 2001. Our study sample consisted of 8,944 adult respondents (18+ years) who participated in an extensive health interview. Interview data were linked to morbidity and prescription registration data from 95 general practices where respondents were listed. Body mass index (BMI) was calculated using self-reported height and weight. Analyses were controlled for clustering within practices as well as for socio-demographic and life style characteristics.

Results

Obesity (BMI ≥ 30 kg/m2) was observed in 8.9% of men and 12.4% of women; for moderate overweight (BMI 25-<30 kg/m2) these percentages were 42.2% and 30.4% respectively. Obese men and women were more likely to consult their GP than persons without overweight. This especially holds for diseases of the endocrine system, the cardiovascular system, the musculoskeletal system, the gastro-intestinal system, and skin problems. Related to this, obese men and women were more likely to receive drugs for the cardiovascular system, the musculoskeletal system, alimentary tract and metabolism (including, for example, antidiabetics), and dermatologicals, but also antibiotics and drugs for the respiratory system. For moderately overweight men and women (BMI 25-<30 kg/m2) smaller but significant differences were found for diseases of the endocrine system, the cardiovascular system, and the musculoskeletal system.

Conclusion

Obesity increases the workload of Dutch general practitioners and the use of prescribed medication. The current increase in the prevalence of obesity will further increase the use of health care and related costs. Since a large majority of Dutch persons visit their GP over the course of one year, GPs' potential role in effective prevention strategies cannot be denied.

Progestin and estrogen potency of combination oral contraceptives and endometrial cancer risk

OBJECTIVE

Using data from a case-control study of endometrial cancer, we investigated the relationship between the progestin and estrogen potency in combination oral contraceptives (OCs) and the risk of developing endometrial cancer.

METHODS

Subjects included 434 endometrial cancer cases and 2,557 controls identified from the Cancer and Steroid Hormone (CASH) study. OCs were classified into four categories according to the individual potencies of each hormonal constituent (high versus low estrogen or progestin potency). Logistic regression was used to evaluate associations between endometrial cancer risk and combination OC formulations.

RESULTS

With non-users as the referent group, use of OCs with either high potency progestin [odds ratio for endometrial cancer (OR)=0.21, 95% confidence interval (CI)=0.10 to 0.43] or with low potency progestin (OR=0.39, 95% CI=0.25 to 0.60) were both associated with a decreased risk of endometrial cancer. Overall high progestin potency OCs did not confer significantly more protection than low progestin potency OCs (OR=0.52, 95% CI=0.24 to 1.14). However, among women with a body mass index of 22.1 kg/m2 or higher, those who used high progestin potency oral contraceptives had a lower risk of endometrial cancer than those who used low progestin potency oral contraceptives (OR=0.31, 95% CI=0.11 to 0.92) while those with a BMI below 22.1 kg/m2 did not (OR=1.36, 95% CI=0.39 to 4.70).

CONCLUSION

The potency of the progestin in most OCs appears adequate to provide a protective effect against endometrial cancer. Higher progestin-potency OCs may be more protective than lower progestin potency OCs among women with a larger body habitus.

Anthropometric measures, endogenous sex steroids and breast cancer risk in postmenopausal women: a study within the EPIC cohort

In a large case-control study on breast cancer risk and serum hormone concentrations, nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, we examined to what extent the relationship of excess body weight with breast cancer risk may be explained by changes in sex steroids. Height, weight, waist and hip circumferences, and serum measurements of testosterone [T], androstenedione [Delta4], dehydroepiandrosterone sulphate [DHEAS], estradiol [E2], estrone [E1] and sex-hormone binding globulin [SHBG] were available for 613 breast cancer cases, and 1,139 matched controls, who were all menopausal at the time of blood donation. Free T [fT] and free E2 [fE2] were calculated using mass action equations. Breast cancer risk was related to body mass index (BMI) (RR = 1.11 [0.99-1.25], per 5 kg/m2 increase in BMI), and waist (RR = 1.12 [1.02-1.24], per 10 cm increase) and hip circumferences (RR = 1.14 [1.02-1.27], per 10 cm increase). The increase in breast cancer risk associated with adiposity was substantially reduced after adjustment for any estrogens, especially for fE2 (from 1.11 [0.99-1.25] to 0.99 [0.87-1.12], from 1.12 [1.02-1.24] to 1.02 [0.92-1.14] and from 1.14 [1.02-1.27] to 1.05 [0.93-1.18] for BMI, waist and hip circumferences, respectively). A modest attenuation in excess risk was observed after adjustment for fT, but the remaining androgens had little effect on the association of body adiposity with breast cancer. Our data indicate that the relationship of adiposity with breast cancer in postmenopausal women could be partially explained by the increases in endogenous estrogens, and by a decrease in levels of SHBG.

Association of esophageal adenocarcinoma with other subsequent primary cancers

PURPOSE

Esophageal adenocarcinoma shares risk factors such as obesity and smoking with other common cancers. The association of esophageal adenocarcinoma with other primary cancers has not been systematically evaluated. The authors used the Surveillance, Epidemiology and End-Results database of the National Cancer Institute to explore the association of esophageal adenocarcinoma with other primary cancers.

PATIENTS AND METHODS

All adult patients with esophageal cancers, both adenocarcinoma and squamous cell carcinoma diagnosed between 1973 and 2001, were identified from the Surveillance, Epidemiology, and End-Results database, and standardized incidence rates were calculated for all subsequent primary cancers in these patients. The analysis was reversed to estimate the standardized incidence rate for subsequent primary esophageal cancer after a first primary cancer.

RESULTS

In comparison with a standard population, patients with esophageal adenocarcinoma were at higher risk for the development of another subsequent cancer, specifically, cancers of the oral cavity and pharynx, lung and bronchus, and kidney and renal pelvis, and adenocarcinoma of the colon/rectum and pancreas. With squamous cell esophageal cancer, there was an association with tobacco-related cancers such as those of the oral cavity and pharynx, the lung and bronchus, and the breast. There was either no association or even a negative association of esophageal adenocarcinoma with other obesity-related cancers such as breast, uterine, and prostate cancers.

CONCLUSIONS

Patients with esophageal adenocarcinoma and squamous cell carcinoma are at increased risk for the development of specific second primary cancers that share smoking as a common risk factor. Esophageal adenocarcinoma does not have a strong association with obesity-related cancers with respect to the relative risk for the development of subsequent primary cancers.

Association between diabetes mellitus and adverse characteristics of breast cancer at presentation

Type 2 diabetes mellitus is associated with increased incidence and inferior outcome of various malignancies. The aim of this study was to explore the impact of type 2 diabetes on breast cancer characteristics at presentation. The study population included 79 diabetic and 158 age-matched non-diabetic patients. Parity, country of birth, co-morbidity other than diabetes, and mode of diagnosis were similar in both groups. Mean body mass index (BMI) was higher among diabetic patients. Tumour stage and size were higher among diabetic patients and the differences remained significant after adjustment for BMI. Moreover, after adjustment for BMI, breast cancer among diabetic patients was more often hormone receptor negative. Our results show that diabetes mellitus is associated with negative prognostic factors at breast cancer presentation.

Overweight and obesity in Italian adults 2004, and an overview of trends since 1983

OBJECTIVE

Overweight has been increasing in several developed countries over the last few decades. No update information on the issue is available for Italy.

DESIGN AND SETTING

We conducted a computer assisted personal in-house interview survey in March-April 2004, on a sample of 2932 Italian individuals (1407 men and 1525 women) aged 18 years or over, representative of the general adult Italian population. Information on weight and height was self-reported.

RESULTS

Overall, 3.4% of the Italian adult population were underweight (< 18.5 kg/m2, 0.9% of men and 5.8% of women), 31.3% were overweight (25.0-29.9 kg/m2, 38.4% of men, 24.7% of women), and 8.2% were obese (> or = 30.0 kg/m2, 7.4% of men and 8.9% of women). Overweight or obesity was reported by 14.2% of subjects aged 18-24 years (20.6% of men and 7.6% of women). The highest proportions of overweight and obese subjects were in the 45-64 year age group for men (51.4% overweight, 10.0% obese) and in the > or = 65 year age group for women (38.8% overweight, 13.8% obese). Age- and sex-standardised prevalence of overweight or obesity was 36.0% for more educated subjects, and 54.0% for less educated ones. It was 32.3% in northern, 44.3% in central and 47.0% in southern Italy. Overweight increased from 1983 to the early 1990s, and levelled off thereafter. Prevalence of obesity remained around 8-9% across the last 20 years.

CONCLUSIONS

Trends of overweight and obesity in Italy are more favourable than in several developed countries. Still, approximately 15 million of Italian adults are overweight and 4 million obese.

Interleukin-6 production induced by leptin treatment promotes cell proliferation in an Apc (Min/+) colon epithelial cell line

Increased visceral adipose tissue results in elevated plasma leptin, which are associated with increased risk of a number of obesity-related cancers. However, research is contradictory regarding the role of elevated plasma leptin in colon cancer risk. Having established that leptin induced proliferation in a murine model of preneoplastic (Apc(Min/+); IMCE) colon epithelial cells but not normal (Apc(+/+); YAMC) cells, we hypothesized that the leptin-associated IMCE cell proliferation was a result of autocrine interleukin-6 (IL-6) production and ensuing IL-6 receptor (IL-6R) signaling. Here we show, for the first time, that leptin induces elevated IL-6 production in IMCE cells but not in YAMC cells. IL-6 treatment induced cell proliferation in IMCE cells, but not in YAMC cells, in a concentration-dependent manner from 0.1 to 100 ng/ml (P < 0.05). Interleukin-6-induced IMCE cell proliferation was blocked by the addition of a neutralizing anti-IL-6R antibody. In addition, leptin-induced IMCE cell proliferation was blocked by the addition of an anti-IL-6R neutralizing antibody. Further, we elucidate a novel mechanism by which leptin activates TACE/ADAM17-associated IL-6R shedding and trans-IL-6 signaling in IMCE by induction of IL-6 production. IL-6 treatment of IMCE cells was associated with STAT3, ERK, p38, MEK and JAK2 activation and associated STAT3 nuclear activation and translocation. These data implicate leptin-induced IL-6 production, signaling and subsequent STAT3 activation as early events promoting the survival/proliferation of colon epithelial preneoplastic cells. The elucidation of the leptin-initiated mechanism of preneoplastic cell proliferation establishes a biologically plausible link between the adipocyte-specific cytokine leptin and obesity-associated colon cancer.

Anthropometric measures in relation to basal cell carcinoma: a longitudinal study

BACKGROUND

The relationship between anthropometric indices and risk of basal cell carcinoma (BCC) is largely unknown. We aimed to examine the association between anthropometric measures and development of BCC and to demonstrate whether adherence to World Health Organisation guidelines for body mass index, waist circumference, and waist/hip ratio was associated with risk of BCC, independent of sun exposure.

METHODS

Study participants were participants in a community-based skin cancer prevention trial in Nambour, a town in southeast Queensland (latitude 26 degrees S). In 1992, height, weight, and waist and hip circumferences were measured for all 1621 participants and weight was remeasured at the end of the trial in 1996. Prevalence proportion ratios were calculated using a log-binomial model to estimate the risk of BCC prior to or prevalent in 1992, while Poisson regression with robust error variances was used to estimate the relative risk of BCC during the follow-up period.

RESULTS

At baseline, 94 participants had a current BCC, and 202 had a history of BCC. During the 5-year follow-up period, 179 participants developed one or more new BCCs. We found no significant association between any of the anthropometric measures or indices and risk of BCC after controlling for potential confounding factors including sun exposure. There was a suggestion that short-term weight gain may increase the risk of developing BCC for women only.

CONCLUSION

Adherence to World Health Organisation guidelines for body mass index, waist circumference and waist/hip ratio is not significantly associated with occurrence of basal cell carcinomas of the skin.