Both food habit change in the past and obesity status may influence the association between dietary factors and postmenopausal breast cancer

OBJECTIVE: Valid dietary data are essential when trying to identify whether or not one or more dietary exposures are responsible for disease. We examined diet composition in women who reported dietary change in the past compared with non-changers, and how the associations between dietary factors and postmenopausal breast cancer are influenced by dietary change, obesity status and misreporting of energy. DESIGN: A population-based prospective cohort study. Data were obtained by a diet history method, anthropometrical measurements and an extensive lifestyle questionnaire including items on past food habit change. SETTING: The Malm? Diet and Cancer (MDC) study, conducted in Malm?, Sweden. SUBJECTS: A subsample of 12,781 women from the MDC cohort recruited from 1991 to 1996. A total of 428 postmenopausal women were diagnosed with incident breast cancer, during 9.2 years of follow-up. RESULTS: Past food habit changers reported healthier food habits and lower energy intake compared with non-changers, a finding that raises issues regarding possible reporting biases. When excluding diet changers, the trend of increased breast cancer risk across omega-6 fatty acid quintiles was stronger, and a tendency of decreased risk emerged for 'fruit, berries and vegetables'. When excluding individuals with non-adequate reports of energy intake, risk estimates were similar to that of the whole sample. In women with body mass index < 27 kg m- 2, significant trends of increased breast cancer risk were seen for total fat and omega-6 fatty acids, and of decreased risk for 'fruit, berries and vegetables'. CONCLUSIONS: This study indicates that both obesity and self-reported past food habit change may be important confounders of diet-breast cancer relationships. The study demonstrates that sensitivity analysis, through stratification, may facilitate interpretation of risk relationships and study results.     

Prevalence of obesity, food choices and socio-economic status: a cross-sectional study in the north-west of Iran

AIM: To document the epidemiological features and influencing factors of obesity in the north-west of Iran, to provide baseline information for setting up a regional population-based centre to control and prevent obesity-related disorders in the area. METHODS: In this cross-sectional study, a total of 300 subjects were selected/studied in Tabriz, one of the major cities in Iran. Data on basic characteristics, anthropometric measurements, dietary assessment and physical activity were collected. Obesity was defined as body mass index > or =30 kg m(-2) for both women and men. RESULTS: Total prevalence of obesity in the area was 22.4% (95% confidence interval (CI): 18.0-27.6). The prevalence of obesity was 24% (95% CI: 18.5-31.4) for women and 18% (95% CI: 12.5-25.6) for men. For both women and men obesity prevalence showed a positive association with age (P<0.001), while there was a negative correlation of obesity with education and income (P<0.001). Fruit consumption decreased the risk of obesity in both women and men (odds ratio (OR)=0.60, 95% CI: 0.49-0.71 vs. OR=0.62, 95% CI: 0.51-0.74, respectively). The same significant pattern was observed for the consumption of green vegetables (OR=0.71, 95% CI: 0.57-0.63 vs. OR=0.86, 95% CI: 0.77-0.98 for women and men, respectively), legumes (OR=0.70, 95% CI: 0.59-0.84 vs. OR=0.78, 95% CI: 0.66-0.91 for women and men, respectively) and dairy products (OR=0.73, 95% CI: 0.61-0.91 vs. OR=0.77, 95% CI: 0.63-0.93 for women and men, respectively). CONCLUSIONS: Our study showed that educational attainment, higher income and consumption of certain food groups (i.e. vegetables, fruits, legumes and dairy products) may decrease the risk of obesity. Our findings also indicate the crucial necessity of establishing a population-based centre for obesity in the area. The essential information is now achieved to propose to local health authorities to act accordingly. However, more population-based investigations on dietary choices are needed to develop effective preventive strategies to control overweight and obesity disorders in different regions.     

Dietary intake of heterocyclic amines in relation to socio-economic, lifestyle and other dietary factors: estimates in a Swedish population

OBJECTIVES: To estimate the dietary intakes of heterocyclic amines (HCAs), to examine the intakes in relation to socio-economics, lifestyle and other dietary factors and to compare the classification of subjects by intake of HCA versus intake of meat and fish. DESIGN: Cross-sectional analysis within the Malm? Diet and Cancer (MDC) cohort. Data were obtained from a modified diet history, a structured questionnaire on socio-economics and lifestyle, anthropometric measurements and chemical analysis of HCAs. HCA intake was cross-classified against meat and fish intake. The likelihood of being a high consumer of HCAs was estimated by logistic regression analysis. Dietary intakes were examined across quintiles of HCA intake using analysis of variance. SETTING: Baseline examinations conducted in 1991-1994 in Malm?, Sweden. SUBJECTS: A sub-sample of 8599 women and 6575 men of the MDC cohort. RESULTS: The mean daily HCA intake was 583 ng for women and 821 ng for men. Subjects were ranked differently with respect to HCA intake compared with intake of fried and baked meat and fish (kappa = 0.13). High HCA intake was significantly associated with lower age, overweight, sedentary lifestyle and smoking. Intakes of dietary fibre, fruits and fermented milk products were negatively associated with HCA intake, while intakes of selenium, vegetables, potatoes, alcohol (among men) and non-milk-based margarines (among women) were positively associated with HCA intake. CONCLUSIONS: The estimated daily HCA intake of 690 ng is similar to values obtained elsewhere. The present study suggests that lifestyle factors (e.g. smoking, physical activity, fruit and vegetable intakes, and types of milk products and margarines) may confound associations between HCA intake and disease. The poor correlation between HCA intake and intakes of fried meat and fish facilitates an isolation of the health effects of HCAs.     

Dietary and socio-economic factors associated with overweight and obesity in a southern French population

OBJECTIVE: To investigate the socio-economic and dietary factors associated with overweight and obesity, respectively, in southern France. DESIGN: Cross-sectional analysis of socio-economic, lifestyle and nutritional characteristics of a representative population sample. A questionnaire elicited information on anthropometric measurements, socio-economic factors, physical activity, tobacco use, and alcohol and food intakes. Non-parametric tests, multiple linear regression models and correspondence factorial analysis (CFA) were used to estimate the association of the various factors with overweight and obesity. SETTING: French Southwest and Mediterranean areas. SUBJECTS: In total, 1169 subjects (578 women and 552 men), aged 30-77 years, were recruited at random. RESULTS: Overweight and obesity were associated with age and education in both genders, reproductive factors in women and tobacco use in men. A few dietary factors were identified (high energy intake and low intake of carbohydrates), but all these variables explained little of the variation (18.5% in women and 14.6% in men). The CFA further investigated the association of lifestyle and nutritional factors, giving more weight to nutritional behaviour for overweight men and women. Factors for obesity differed from those for overweight by being different in men and women, possibly related to psychological behaviour, and there were fewer of them, suggesting an insufficient coverage by the usual questionnaires. CONCLUSIONS: Overweight and obesity appear as two different entities. Energy imbalance induced by various lifestyle factors plays a major role in the development of overweight, whereas obesity represents a more complex entity where psychological and genetic factors that are difficult to assess may be more important. General nutritional guidelines appear more adapted to the prevention of overweight than to that of obesity, and individual counselling to the prevention of obesity.     

Obesity and related risk factors among low socio-economic status minority students in Chicago

OBJECTIVES: To assess overweight and related risk factors among urban low socio-economic status (SES) African-American adolescents in an attempt to study the underlying causes of ethnicity and gender disparities in overweight. METHODS: Cross-sectional data collected on anthropometric measures, diet, physical activity and family characteristics from 498 students in grades 5-7 in four Chicago public schools were analysed to study the risk factors for overweight using stepwise regression analysis. RESULTS: Only 37.2% of the students lived with two parents. Nearly 90% had a television (TV) in their bedroom, and had cable TV and a video game system at home. Overall. 21.8% (17.7% boys versus 25.1% girls) were overweight (body mass index (BMI) >/= 95th percentile); and 39.8% had a BMI >/= 85th percentile. Compared with national recommendations, they had inadequate physical activity and less than desirable eating patterns. Only 66.1% reported having at least 20 min vigorous exercise or 30 min of light exercise in >/= 5 days over the past 7 days; 62.1% spent >3 h days- 1 watching TV/playing video games/computer, while 33.1% spent >/= 5 h days- 1. Their vegetable and fruit consumption was low, and they consumed too many fried foods and soft drinks: 55.1% consumed fried food twice or more daily and 19.5% four times or more daily; 70.3% consumed soft drinks twice or more daily and 22.0% four times or more daily on average. Gender, physical activity and pocket money were significant predictors of overweight (P < 0.05). CONCLUSIONS: Several factors in the students' behaviours, school and family environments may increase overweight risk among this population. There is a great need for health promotion programmes with a focus on healthy weight and lifestyle, and targeting urban low-SES minority communities.     

Yeast survival during thermal and osmotic shocks is related to membrane phase change

The aim of this work was to study the survival of yeast cells exposed to a combination of thermal and osmotic treatments, as occurs during drying processes, and assess associated changes in fluidity of the plasma membrane, which have been studied previously in this laboratory. Cells that were maintained at a nonlethal dehydration temperature (5 or 30 degrees C) were rapidly dehydrated up to 120 MPa, and then thermal stress was suddenly applied between 5 and 30 degrees C. Cell viability was measured after a return to initial conditions (i.e., 1.38 MPa and 25 degrees C). Results showed that the viability of yeast cells exposed to identical combined thermal and osmotic treatments was dependent on the chronology of the stress application. Finally, the temperature at which the dehydration was conducted, up to 120 MPa, appeared to be the main factor involved in cell survival and could be related to fluidity variations of the plasma membrane.     

Socio-economic pathways to diet: modelling the association between socio-economic position and food purchasing behaviour

OBJECTIVES: To examine the association between education level and food purchasing behaviour and the contribution of dietary knowledge to this relationship; and the association between household income and purchasing behaviour and the contribution made by subjective perceptions about the cost of healthy food.DESIGN AND SETTING: The study was conducted in Brisbane City (Australia) in 2000. The sample was selected using a stratified two-stage cluster design. Data were collected by face-to-face interview from residents of private dwellings (n=1003), and the response rate was 66.4%. Dietary knowledge was measured using a 20-item index that assessed general knowledge about food, nutrition, health and their interrelationships. Food-cost concern was measured using a three-item scale derived from principal components analysis (alpha=0.647). Food purchasing was measured using a 16-item index that reflected a household's purchase of grocery items that were consistent (or otherwise) with dietary guideline recommendations. Associations among the variables were analysed using linear regression with adjustment for age and sex.RESULTS: Significant associations were found between education, household income and food purchasing behaviour. Food shoppers with low levels of education, and those residing in low-income households, were least likely to purchase foods that were comparatively high in fibre and low in fat, salt and sugar. Socio-economic differences in dietary knowledge represented part of the pathway through which educational attainment exerts an influence on diet; and food purchasing differences by household income were related to diet in part via food-cost concern.CONCLUSIONS: Our findings suggest that socio-economic differences in food purchasing behaviour may contribute to the relationship between socio-economic position and food and nutrient intakes, and, by extension, to socio-economic health inequalities for diet-related disease. Further, socio-economic differences in dietary knowledge and concerns about the cost of healthy food play an important role in these relationships and hence should form the focus of future health promotion efforts directed at reducing health inequalities and encouraging the general population to improve their diets.     

Diet and overweight and obesity in populations of African origin: Cameroon, Jamaica and the UK

OBJECTIVES: To determine the relationship of diet to overweight and obesity among populations of African origin. DESIGN AND SETTING: Cross-sectional data were obtained from adults aged 25-74 years in rural Cameroon (n = 686), urban Cameroon (n = 975), Jamaica (n = 924) and Afro-Caribbeans in the UK (n = 257). Dietary data were collected using food-frequency questionnaires specifically designed for each site. Body mass index (BMI) was used as a measure of overweight. RESULTS: The expected gradient in the distribution of overweight across sites was seen in females (rural Cameroon, 9.5%; urban Cameroon, 47.1%; Jamaica, 63.8%; UK, 71.6%); however, among males overweight was less prevalent in Jamaica (22.0%) than urban Cameroon (36.3%). In developing countries increased risks of overweight (BMI > or = 25 kg m(-2) were influenced by higher energy (urban Cameroonian men) and protein (Jamaican women) intakes. No dietary variables were associated with obesity (BMI > or = 30 kg m(-2) in Cameroon or Jamaica. In the UK, energy intakes were inversely related with overweight whereas increased risks of being overweight were associated with higher protein (men) and fat (women) intakes. Similarly, whereas higher protein and fat intakes in UK men and women were associated with obesity, carbohydrate intakes were associated with decreased risks of obesity in men. CONCLUSIONS: Diet and overweight were associated in the UK but few dietary variables were related to overweight in Jamaica and the Cameroon. These findings suggest that associations between diet and overweight/obesity are not generalisable among populations.     

Vitamin k contents of meat, dairy, and fast food in the u.s. Diet

The purpose of this study was to determine the contents of three forms of vitamin K [phylloquinone, dihydrophylloquinone, and menaquinone-4 (MK-4)] in representative samples (including different samples within the same food category) of meat (n = 128), dairy and eggs (n = 24), and fast foods (n = 169) common to the U.S. diet. The findings of our analysis indicate that no single food item in these categories is a rich dietary source of any one form of vitamin K. However, these foods are often consumed in large quantities; hence, they may be of importance in overall contribution to total vitamin K intake. The presence of MK-4 in meat, eggs, and dairy foods could be important as physiologic functions unique to MK-4 are identified.     

Mini Nutritional Assessment of rural elderly people in Bangladesh: the impact of demographic, socio-economic and health factors

OBJECTIVE: In stating the Millennium Development Goals, the United Nations aims to halve malnutrition around the world by 2015. Nutritional status of the elderly population in low-income countries is seldom focused upon. The present study aimed to evaluate the magnitude of malnutrition among an elderly population in rural Bangladesh. DESIGN AND SETTING: Data collection for a multidimensional cross-sectional study of community-based elderly people aged 60 years and over was conducted in a rural area in Bangladesh. SUBJECTS: Of 850 randomly selected elderly individuals, 625 participated in home interviews. Complete nutritional information was available for 457 individuals (mean age 69+/-8 years, 55% female). Nutritional status was assessed using an adapted form of the Mini Nutritional Assessment (MNA) including body mass index (BMI). Age, sex, education, household expenditure on food and self-reported health problems were investigated as potential predictors of nutritional status. RESULTS: BMI<18.5 kg m(-2), indicating chronic energy deficiency, was found in 50% of the population. MNA revealed a prevalence of 26% for protein-energy malnutrition and 62% for risk of malnutrition. Health problems rather than age had a negative impact on nutritional status. Level of education and food expenditure were directly associated with nutritional status. CONCLUSION: In order to reduce world hunger by half in the coming decade, it is important to recognise that a substantial proportion of the elderly population, particularly in low-income countries, is undernourished.