Carbohydrate intake, glycemic load, glycemic index, and risk of ovarian cancer

BACKGROUND

Our objective was to determine the relationship between dietary glycemic load (GL), glycemic index (GI), carbohydrate intake, and ovarian cancer risk in a population-based case-control study.

PATIENTS AND METHODS

A self-administered questionnaire was used to collect data on demographic and lifestyle factors, and a food frequency questionnaire was used to collect dietary information from 1366 women with ovarian cancer and 1414 population controls.

RESULTS

GL was positively associated with ovarian cancer. The adjusted odds ratio (OR) for the highest versus the lowest quartile of intake was 1.24 [95% confidence interval (CI) 1.00-1.55, P for trend = 0.03]. Fiber intake was inversely associated with risk. The OR comparing women in the highest fiber-intake group with those in the lowest was 0.78 (95% CI 0.62-0.98, P for trend = 0.11). We found no association between GI, carbohydrate intake, and ovarian cancer. In analyses stratified by body mass index, the risk estimates for GL, carbohydrate, and sugar were higher among overweight/obese women; however, the interaction term was only significant for sugar (P for interaction = 0.004).

CONCLUSIONS

Our results suggest that diets with a high GL may increase the risk of ovarian cancer, particularly among overweight/obese women, and a high intake of fiber may provide modest protection.

Diet, serum insulin-like growth factor-I and IGF-binding protein-3 in European women

OBJECTIVE

The aim of this study was to examine the relationship of diet with serum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 in women.

DESIGN

Cross-sectional study.

SETTING AND SUBJECTS

The population are 2109 women who were control subjects in a case-control study of breast cancer nested in the European Prospective Investigation into Cancer and Nutrition. Control subjects were randomly chosen among risk sets consisting of female cohort members alive and free of cancer (except non-melanoma skin cancer) at the time of diagnosis of the index case. Matching criteria were age at enrolment, follow-up time, time of the day of blood collection and study centre. Diet was measured through validated questionnaires. Serum hormone concentrations were measured by enzyme-linked immunosorbent assays. The relationship between serum IGF-I, IGFBP-3, and intake of nutrients and foods was explored by linear regression in models adjusted for energy intake, age, body mass index, smoking, physical activity, centre and laboratory batch.

RESULTS

Serum IGF-I levels were positively related to protein intake (P(trend)<0.001), but not related to energy, fat or carbohydrate intake. Positive relationships were observed with the intake of milk (P(trend)=0.007), calcium (P(trend)<0.001), magnesium (P(trend)=0.003), phosphorus (P(trend)<0.001), potassium (P(trend)=0.002), vitamin B6 (P(trend)=0.03), vitamin B2 (P(trend)=0.001) and inverse relationships with vegetables (P(trend)=0.02) and beta-carotene (P(trend)=0.02). IGFBP-3 was not related with most of the nutrients and foods in this study.

CONCLUSIONS

In this population, circulating IGF-I is modestly related with the intake of protein and minerals, and with milk and cheese, while IGFBP-3 does not appear to be related with diet.

IGF-I, IGFBP-3 and breast cancer risk in women: The European Prospective Investigation into Cancer and Nutrition (EPIC)

Blood concentrations of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) have recently been associated with breast cancer risk, notably in women who developed breast cancer at a young age. Prospective studies published so far, however, were relatively small and odds ratio (OR) estimates imprecise. We present the results of a large prospective case-control study nested within the European Prospective Investigation into Cancer and Nutrition on total IGF-I, IGFBP-3 and breast cancer risk including 1081 incident cases of invasive breast cancer and 2098 matched control subjects. Increasing IGF-I and IGFBP-3 concentrations were associated with a significant increase in breast cancer risk in women who developed breast cancer after 50 years of age (highest vs lowest quintile OR 1.38 (95% confidence interval (CI) 1.02-1.86), P = 0.01, and 1.44 (95% CI 1.04-1.98), P = 0.01, respectively), but no relationship was observed in younger women (OR = 1.03 (95% CI 0.60-1.77), P = 0.81 for IGF-I, and OR = 0.92 (95% CI 0.50-1.70), P = 0.69 for IGFBP-3). There was, however, significant heterogeneity in the relationship of breast cancer with serum IGF-I and IGFBP-3 levels depending on the time interval between blood donation and tumor diagnosis. A reduction in breast cancer risk with increasing IGF-I concentrations was observed in cases with a diagnosis of cancer less than 2 years after blood donation, (OR = 0.76 (95% CI 0.57-1.03)), while an increase in risk was observed for women with a later diagnosis (above or equal to two years after blood collection, OR = 1.51 (95% CI 1.19-1.91)). A similar pattern was observed for IGFBP-3. This study confirms previous findings for an association of serum IGF-I and IGFBP-3 concentrations with breast cancer risk, particularly for women with a later diagnosis of cancer, but it does not support the hypothesis of an involvement of IGF-I in younger women.

Body mass index, waist circumference and waist–hip ratio and serum levels of IGF-I and IGFBP-3 in European women

OBJECTIVE

To examine the relationship between body mass index (BMI) and waist-hip ratio (WHR) with serum levels of insulin-like growth factor-I (IGF-I), and its binding protein (IGFBP)-3.

DESIGN

Cross-sectional study on 2139 women participating in a case-control study on breast cancer and endogenous hormones. Data on lifestyle and reproductive factors were collected by means of questionnaires. Body height, weight, waist and hip circumferences were measured. Serum levels of IGF-I and insulin-like binding protein (IGFBP)-3 were measured by enzyme-linked immunosorbent assays. Adjusted mean levels of IGF-I and IGFBP-3 across quintiles of BMI, waist circumference, and WHR were calculated by linear regression. Results were adjusted for potential confounders associated with IGF-I and IGFBP-3.

RESULTS

Adjusted mean serum IGF-I values were lower in women with BMI<22.5 kg/m(2) or BMI>29.2 kg/m(2) compared to women with BMI within this range (P(heterogeneity)<0.0001, P(trend)=0.35). Insulin-like growth factor-I was not related to WHR after adjustment for BMI. IGF-binding protein-3 was linearly positively related to waist and WHR after mutual adjustment. The molar ratio IGF-I/IGFBP-3 had a non-linear relation with BMI and a linear inverse relationship with WHR (P (trend)=0.005).

CONCLUSIONS

Our data confirm the nonlinear relationship of circulating IGF-I to total adiposity in women. Serum IGFBP-3 was positively related to central adiposity. These suggest that bioavailable IGF-I levels could be lower in obese compared to non-obese women and inversely related to central adiposity.

Polymorphisms of genes coding for insulin-like growth factor 1 and its major binding proteins, circulating levels of IGF-I and IGFBP-3 and breast cancer risk: results from the EPIC study

Insulin-like growth factor I (IGF-I) stimulates cell proliferation and can enhance the development of tumours in different organs. Epidemiological studies have shown that an elevated level of circulating IGF-I is associated with increased risk of breast cancer, as well as of other cancers. Most of circulating IGF-I is bound to an acid-labile subunit and to one of six insulin-like growth factor binding proteins (IGFBPs), among which the most important are IGFBP-3 and IGFBP-1. Polymorphisms of the IGF1 gene and of genes encoding for the major IGF-I carriers may predict circulating levels of IGF-I and have an impact on cancer risk. We tested this hypothesis with a case–control study of 807 breast cancer patients and 1588 matched control subjects, nested within the European Prospective Investigation into Cancer and Nutrition. We genotyped 23 common single nucleotide polymorphisms in IGF1, IGFBP1, IGFBP3 and IGFALS, and measured serum levels of IGF-I and IGFBP-3 in samples of cases and controls. We found a weak but significant association of polymorphisms at the 5′ end of the IGF1 gene with breast cancer risk, particularly among women younger than 55 years, and a strong association of polymorphisms located in the 5′ end of IGFBP3 with circulating levels of IGFBP-3, which confirms previous findings. Common genetic variation in these candidate genes does not play a major role in altering breast cancer risk in Caucasians.

Increase in serum resistin during weight loss in overweight subjects is related to lipid metabolism

OBJECTIVE

Human resistin has been stated to influence preadipocyte cell numbers and to stimulate adipocyte triglyceride lipolysis in vivo and in vitro. However, its role in human obesity remains unclear.

DESIGN

Cross-sectional study for comparisons of lean and obese subjects, and subsequent longitudinal 4-month weight loss intervention study in obese subjects.

SUBJECTS

Healthy subjects, lean (n=20, BMI<25) and overweight (n=43, BMI>or=25).

MEASUREMENTS

Serum resistin, body weight, body fat, waist-to-hip ratio, as well as markers of insulin resistance and lipid metabolism at baseline and after 4 months of intervention.

RESULTS

Serum resistin was positively correlated to HOMA-IR (partial r=0.288; P=0.055), serum fructosamines (partial r=0.280; P=0.062), serum NEFA (partial r=0.276; P=0.066) and negatively to age (partial r=-0.349; P=0.019) and serum apolipoprotein A-1 (partial r=-0.363; P=0.014). During the intervention, serum resistin increased significantly (P<0.001). The increase was inversely related to changes in waist-to-hip ratio (P=0.025) and positively to serum apolipoprotein B (P=0.011). In males only, the increase in resistin during weight loss was predicted by total serum cholesterol at baseline (r=0.703, P=0.007). No relation was observed between changes in resistin and changes in HOMA-IR.

CONCLUSION

The present study indicates an association between serum resistin and markers of abdominal fat distribution as well as the regulation of lipid metabolism. However, human resistin is unlikely to play an independent role in the regulation of glucose metabolism.

Postmenopausal serum androgens, oestrogens and breast cancer risk: the European prospective investigation into cancer and nutrition

Considerable experimental and epidemiological evidence suggests that elevated endogenous sex steroids - notably androgens and oestrogens - promote breast tumour development. In spite of this evidence, postmenopausal androgen replacement therapy with dehydroepiandrosterone (DHEA) or testosterone has been advocated for the prevention of osteoporosis and improved sexual well-being. We have conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition. Levels of DHEA sulphate (DHEAS), (Delta4-androstenedione), testosterone, oestrone, oestradiol and sex-hormone binding globulin (SHBG) were measured in prediagnostic serum samples of 677 postmenopausal women who subsequently developed breast cancer and 1309 matched control subjects. Levels of free testosterone and free oestradiol were calculated from absolute concentrations of testosterone, oestradiol and SHBG. Logistic regression models were used to estimate relative risks of breast cancer by quintiles of hormone concentrations. For all sex steroids -the androgens as well as the oestrogens - elevated serum levels were positively associated with breast cancer risk, while SHBG levels were inversely related to risk. For the androgens, relative risk estimates (95% confidence intervals) between the top and bottom quintiles of the exposure distribution were: DHEAS 1.69 (1.23-2.33), androstenedione 1.94 (1.40-2.69), testosterone 1.85 (1.33-2.57) and free testosterone 2.50 (1.76-3.55). For the oestrogens, relative risk estimates were: oestrone 2.07 (1.42-3.02), oestradiol 2.28 (1.61-3.23) and free oestradiol (odds ratios 2.13 (1.52-2.98)). Adjustments for body mass index or other potential confounding factors did not substantially alter any of these relative risk estimates. Our results have shown that, among postmenopausal women, not only elevated serum oestrogens but also serum androgens are associated with increased breast cancer risk. Since DHEAS and androstenedione are largely of adrenal origin in postmenopausal women, our results indicated that elevated adrenal androgen synthesis is a risk factor for breast cancer. The results from this study caution against the use of DHEA(S), or other androgens, for postmenopausal androgen replacement therapy.

Long-term weight change and breast cancer risk: the European prospective investigation into cancer and nutrition (EPIC)

We examined prospectively the association between weight change during adulthood and breast cancer risk, using data on 1358 incident cases that developed during 5.8 years of follow-up among 40 429 premenopausal and 57 923 postmenopausal women from six European countries, taking part in the European prospective investigation into cancer and nutrition study. Multivariate Cox regression models were used to calculate hazard ratios according to weight change (kg), defined as the weight difference between age at enrolment and age 20 adjusted for other risk factors. Changes in weight were not associated with premenopausal breast cancer risk. In postmenopausal women, weight gain was positively associated with breast cancer risk only among noncurrent hormone replacement therapy (HRT) users (P-trend ⩽0.0002). Compared to women with a stable weight (±2 kg), the relative risk for women who gained 15–20 kg was 1.50 (95% confidence interval (CI) 1.06–2.13). The pooled RR per weight gain increment of 5 kg was 1.08 (95% CI 1.04–1.12). Weight gain was not associated with breast cancer risk in current HRT users, although, overall, these women experienced a much higher risk of breast cancer compared with nonusers. Our findings suggest that large adult weight gain was a significant predictor of breast cancer in postmenopausal women not taking exogenous hormones.

Birth weight is associated with postmenopausal breast cancer risk in Swedish women

There is some evidence that birth weight is associated with breast cancer. Whether this association differs between premenopausal and postmenopausal ages is still unclear. The results from this study suggest that higher birth weight is a risk factor for postmenopausal breast cancer (OR 1.06, CI 1.00–1.12, per 100 g), independent of selected early-life and adult factors.

Die Rolle des Gemeinsamen Krebsregisters bei der Identifizierung von Krebsfällen in der EPIC-Potsdam-Studie - Ergebnisse des ersten Datenabgleichs

AIM

The follow-up of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study has been identifying cancer diagnoses by an active follow-up through participant's self-report which is then confirmed by pathology registries or medical doctors. To utilise another source of information, a record linkage was performed with the Common Cancer Registry (CCR) of the states of Berlin, Brandenburg, Mecklenburg-Western Pomerania, Saxony-Anhalt and of the free states Saxony and Thuringia in November 2001, using the EPIC-Potsdam database of compliant study participants at that point in time (n = 27 087). This methodological study compares data of identified cancer cases in the EPIC-Potsdam study with those generated through the record linkage.

METHODS

The GKR identified 1468 study participants of the EPIC-Potsdam study. Cases (n = 108) with non-melanoma skin cancer were excluded. A separate analysis was done for prevalent (date of cancer diagnosis before baseline examination) and incident cancers (date of diagnosis after baseline examination). We examined how many subjects with at least one cancer were known to EPIC-Potsdam and the CCR, how many had been known only to the CCR and how many only to the EPIC-Potsdam study. Of incident cancer cases each diagnosis was counted. It was analyzed whether the diagnoses as they had been collected by EPIC-Potsdam were identified by the record linkage. Focus was on the diagnoses that had been unknown in EPIC-Potsdam before. The concordance of information from both sources was also considered.

RESULTS

According to the record linkage, 1298 subjects with at least one prevalent cancer were identified in the EPIC-Potsdam cohort, 593 (46 %) of whom were identified in both data sources, 241 (19 %) were newly identified, and 464 (36 %) participants self-reported at least one prevalent tumour which was not identified through the record linkage. Seven tumours were diagnosed before 1961 (the CCR's computerised data are only available since 1961). Fifty-seven percent (n = 187) of all tumours which could not be identified in the cancer registry dated from 1990 - 1995. After completion of the record linkage a total of 582 medically verified incident cancer cases were identified. These comprised 397 medically verified cases that were identified in the EPIC-cohort study prior to the record linkage, 18 self-reported cases where the medical verification was pending, and 167 newly identified cases. Eighty-five of the latter cases have not been identified by other sources in the two following years after record linkage indicating that 15 % of the medically verified cases have been found solely through the linkage.

CONCLUSION

The EPIC-Potsdam study had a significant benefit of the record linkage due to both the additional identification and verification of prevalent and incident cancer cases, as well as a timely advanced identification of incident diagnoses. The record linkage with the cancer registry improved the quality of the endpoint data of the EPIC-Potsdam study.

Overweight, obesity and fat distribution in 50- to 64-year-old participants in the European Prospective Investigation into Cancer and Nutrition (EPIC)

OBJECTIVE

To describe anthropometric characteristics of participants of the European Prospective Investigation into Cancer and Nutrition (EPIC).

DESIGN

A cross-sectional analysis of baseline data of a European prospective cohort study.

SUBJECTS

This analysis includes study populations from 25 centres in nine European countries. The British populations comprised both a population-based and a 'health-conscious' group. The analysis was restricted to 83 178 men and 163 851 women aged 50-64 years, this group being represented in all centres.

METHODS

Anthropometric examinations were undertaken by trained observers using standardised methods and included measurements of weight, height, and waist and hip circumferences. In the 'health-conscious' group (UK), anthropometric measures were predicted from self-reports.

RESULTS

Except in the 'health-conscious' group (UK) and in the French centres, mean body mass index (BMI) exceeded 25.0 kg m-2. The prevalence of obesity (BMI> or =30 kg m(-2)) varied from 8% to 40% in men, and from 5% to 53% in women, with high prevalences (>25%) in the centres from Spain, Greece, Ragusa and Naples (Italy) and the lowest prevalences (<10%) in the French centres and the 'health-conscious' group (UK). The prevalence of a large waist circumference or a high waist-to-hip ratio was high in centres from Spain, Greece, Ragusa and Naples (Italy) and among women from centres in Germany and Bilthoven (The Netherlands).

CONCLUSIONS

Anthropometric measures varied considerably within the EPIC population. These data provide a strong base for further investigation of anthropometric measures in relation to the risk of chronic diseases, especially cancer.

Serum concentrations of beta-carotene and alpha-tocopherol are associated with diet, smoking, and general and central adiposity

BACKGROUND

Previous studies of associations between diet, obesity, and blood concentrations of alpha-tocopherol and beta-carotene have been equivocal. Furthermore, most studies used only body mass index (BMI) as an obesity measure.

OBJECTIVES

Our objectives were to examine the associations between energy and nutrient intakes, alcohol consumption, tobacco use, and serum cholesterol and serum concentrations of alpha-tocopherol and beta-carotene, and to examine the associations between different measures of general and central adiposity and serum concentrations of alpha-tocopherol and beta-carotene.

DESIGN

This was a cross-sectional, population-based study of 253 men and 276 women aged 46-67 y. Nutrient data were collected by a modified diet history method. Measures of obesity included BMI, percentage of body fat (impedance analysis), waist-to-hip ratio, and waist circumference. The associations between serum nutrient concentrations and the other factors were examined by multiple linear regression.

RESULTS

Twenty-one percent of men and 34% of women used antioxidant supplements. The mean BMI was 26.1 in men and 25.4 in women. Serum beta-carotene concentration was positively associated with serum cholesterol concentration, fiber intake, and beta-carotene intake, and negatively associated with smoking and all measures of obesity. In men, serum beta-carotene concentration was not significantly associated with central adiposity after adjustment for body fat. Serum alpha-tocopherol concentration was positively correlated with serum cholesterol, obesity, and vitamin E intake. In women, serum alpha-tocopherol concentration was also positively associated with intakes of ascorbic acid and selenium. Serum alpha-tocopherol concentration was associated with central adiposity after adjustment for body fat.

CONCLUSION

Serum beta-carotene and alpha-tocopherol concentrations have different associations with diet, smoking, general adiposity, and central adiposity.

Differences in body fat and central adiposity between Swedes and European immigrants: the Malmö Diet and Cancer Study

OBJECTIVE

Comparative data on ecological differences in body fatness and fat distribution within Europe are sparse. Migration studies may provide information on the impact of environmental factors on body size in different populations. The objective was to investigate differences in adiposity between European immigrants and native Swedes, specifically to examine gender differences and the effect of time since immigration, and to compare two selected immigrant groups with their native countrymen.

RESEARCH METHODS AND PROCEDURES

A cross-sectional analysis of 27,808 adults aged 45 to 73 years participating in the Malmö Diet and Cancer prospective cohort study in Sweden was performed. Percentage body fat (impedance analysis) and waist-hip ratio (WHR) were compared between Swedish-born and foreign-born participants.

RESULTS

Obesity was 40% more prevalent in non-Swedish Europeans compared with Swedes. Controlling for age, height, smoking, physical activity, and occupation, it was found that women born in the former Yugoslavia, southern Europe, Hungary, and Finland had a significantly higher percentage of body fat, and those from Hungary, Poland, and Germany had more centralized adiposity compared with Swedish women. Men born in the former Yugoslavia, Hungary, and Denmark had a significantly higher mean percentage of body fat compared with Swedish-born men, whereas Yugoslavian, Finnish, and German men differed significantly in mean WHR. Length of residence in Sweden was inversely associated with central adiposity in immigrants. A comparison between German and Danish immigrants, their respective native populations, and Swedes indicated an intermediate positioning of German immigrants with regard to body mass index and WHR.

DISCUSSION

Differences in general and central adiposity by country of origin appear to remain after migration. Central adiposity seems to be more influenced than fatness per se by time of residency in Sweden.

Sociodemographic factors associated with long-term weight gain, current body fatness and central adiposity in Swedish women

OBJECTIVES

To examine sociodemographic factors associated with long-term adult weight gain and current general and central adiposity in women.

DESIGN

Cross-sectional analysis based on data from the Malmö Diet and Cancer prospective cohort Study (MDCS), Sweden.

SUBJECTS

5464 women aged 45-73 y, who participated in the MDCS between 1994 and 1996.

MEASUREMENTS

Weight change was defined as the difference between measured weight and recalled weight at age 20. Body composition was estimated from bioelectrical impedance analysis. Waist circumference and waist-hip ratio (WHR) were indicators of central obesity. Sociodemographic factors studied included reproductive, lifestyle and socioeconomic characteristics obtained from a questionnaire.

RESULTS

At current age 13% of all women were obese (BMI>/=30), and nearly one-third had a body fat content of >33%. Since age 20, the majority of women (77%) had gained more than 10% of their initial weight. On average, the mean weight change was 12.6+/-10.0 kg during adult life. Age-adjusted group mean comparisons identified a number of significant sociodemographic variables predicting past weight gain and current obesity. In multivariate analysis, significant independent correlates of weight gain were: age, initial small body size, high parity, early menarche, non-use of hormone therapy, low self-rated health, non-smoking, no consumption of alcohol, sedentary leisure activity, past change in diet, retirement, low education, low socioeconomic status, and low socioeconomic status of origin. Many of the same variables were independently associated with current waist circumference, WHR, and percentage body fat.

CONCLUSIONS

Large weight gain during adult life and a high rate of overweight were observed in this group of Swedish women. Many sociodemographic characteristics were associated with long-term weight gain and recent obesity indices. Initial BMI, smoking, age, physical activity and early socioeconomic status accounted for most of the explained variance in weight change. The findings indicate the importance of identifying environmental determinants of both weight gain and attained fatness, as well as fat distribution.