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.     

Trends in overweight by socio-economic status in Vietnam: 1992 to 2002

OBJECTIVE: To explore socio-economic factors associated with rising rates of overweight among Vietnamese adults. DESIGN: The study was based on three national surveys of socio-economic factors and health conducted over a 10-year period. The studies were: the Vietnamese Living Standard Survey 1992-1993 (11 982 participants); the Vietnamese Living Standard Survey 1997-1998 (15 975 participants); and the Vietnamese National Health Survey 2001-2002 (94 656 participants). SUBJECTS: Male and female adults >18 years old were stratified by gender, age group, area of residence, occupation, education and relative food expenditures. Overweight was defined using body mass index (BMI) > or = 25 kg m(-2). RESULTS: Overweight rates in Vietnam more than doubled between 1992 and 2002 (from 2.0 to 5.7%). Significant increases were observed for men and women, in urban and rural areas, and for all age groups. In univariate analyses, both age and higher socio-economic status were associated with higher rates of overweight. Using the most recent survey, urban populations were more likely to be overweight than rural ones (odds ratio (OR) = 1.79), white-collar workers were more likely to be overweight than manual labourers (OR = 1.95) and persons in the top level of food expenditures were more likely to be overweight than persons in the bottom level (OR = 4.96) after adjustment for other factors. Education was inversely associated with overweight after adjusting for covariates. CONCLUSION: Economic growth and improved standard of living are associated with higher rates of overweight in nations in early stages of economic development. In Vietnam, higher rates of overweight were observed among the higher income and occupation groups.     

Past food habit change is related to obesity, lifestyle and socio-economic factors in the Malmo Diet and Cancer Cohort

OBJECTIVES: To examine if obesity status and socio-economic and lifestyle factors are associated with self-reported past food habit change, and also whether the level of obesity depends on the reason for change. DESIGN: Cross-sectional analysis within the Malmo Diet and Cancer (MDC) study using data from the baseline examination and the extensive socio-economic and lifestyle questionnaire including questions of past food habit change. The risk of having changed food habits in the past was examined using logistic regression. Mean differences in obesity status across categories of reasons for past food habit change were examined using analysis of variance. SETTING: Malm?, the third largest city in Sweden. SUBJECTS: A sub-sample (15 282 women and 9867 men) from the MDC cohort recruited from 1992 to 1996. RESULTS: Individuals with body mass index (BMI) >30 kg m(-2) had an increased risk of having reported past food habit change compared with individuals with BMI <25 kg m(-2) (odds ratio (OR) = 1.63, 95% confidence interval (CI) = 1.48-1.83 for women; OR = 1.53, 95% CI = 1.32-1.76 for men). The highest level of obesity was observed among individuals who had changed their diet due to reasons related to the metabolic syndrome. Changers were more likely to be highly educated and to live alone, be retired, ex-smokers and non-drinkers at baseline. CONCLUSIONS: Because past food habit change is related to obesity and other lifestyle and socio-economic factors, a complex confounding situation may exist that could seriously influence observed relationships between diet and disease. Studies need to collect information on past food habit change and take this information into account in the analysis and when interpreting study outcomes.     

Adjusted population attributable fractions and preventable potential of risk factors for childhood obesity

OBJECTIVE: A number of individual risk factors for childhood obesity have been identified, but only some of these are amenable to prevention. To assess the amount of cases in a general population attributable to these risk factors, adjusted population-attributable fractions were estimated. DESIGN: Cross-sectional study. SETTING: Obligatory school entry examination in 2001/2002 in six Bavarian communities (Germany). SUBJECTS: 5472 children at age 5-6 years. MEASURES: Anthropometric measures were ascertained by public health nurses, and measures concerning sociodemographics, lifestyle and child behaviour such as child's daily meal frequency were obtained with self-administered parental questionnaires. Obesity was defined according to sex- and age-specific body mass index cut-off points proposed by the International Obesity Task Force. Adjusted population-attributable fractions were calculated based on logistic regression. RESULTS: A combination of the risk factors low meal frequency, decreased physical activity, watching television >1 h day- 1, formula feeding and smoking in pregnancy accounted for 48.2% of obese children. This combination yielded a maximal achievable prevalence reduction of 1.5% for obesity (3.2% observed prevalence). CONCLUSIONS: A modification of five known risk factors for childhood overweight and obesity could reasonably lower obesity prevalences at school entry. These risk factors should be particularly considered in decision making on preventive measures.     

Prevalence of overweight and obesity among young people in Great Britain

OBJECTIVE: To determine the prevalence of overweight and obesity in British young people (4-18 years) in 1997. DESIGN: Cross-sectional analysis of the National Diet and Nutrition Survey of young people. SETTING: Great Britain. SUBJECTS: Nationally representative sample of 1836 young people (age 4-18 years). RESULTS: The prevalence of obesity based on body mass index (weight/height(2)) and the International Obesity Task Force cut-offs was 4.0%, with a further 15.4% identified as overweight. Asians were almost four times as likely to be obese as white subjects (13.6 vs. 3.5%, P<0.001). Among white subjects there was no significant difference in the prevalence of obesity between girls and boys, or with age. The risk of obesity was significantly higher in subjects from social classes IV and V than from social classes I-III (6.5 vs. 2.7%, P=0.003). Subjects living in Scotland and Wales were significantly more likely to be obese than those in England (7.6 and 6.5 vs. 2.9%, respectively, P<0.01). Multiple logistic regression showed that, among white subjects, those in social classes IV and V living in Wales and Scotland were three times more likely to be obese than the other children in the survey (odds ratio 3.3, 95% confidence interval 1.1-9.8). CONCLUSION: These data provide information on the national prevalence of overweight and obesity in Great Britain and baseline data from which to monitor future trends. This analysis provides important demographic information on those most at risk of obesity, which may be used to inform public health strategies to prevent obesity in young people.     

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.     

Water erosion in the southern French alps: climatic and human mechanisms

A large number of studies have focused on water erosion in the southern Alps because of its intensity and the high erodability affecting numerous outcrops in this region.The aim of this paper is to determine the relations between natural and human factors on the one hand, geomorphologic behaviour of hillslopes and fluvio-torrential dynamics at two time scales (geological and historical) on the other hand. This paper specially focuses on the recent weakening of torrential activity and its linkage with reforestation and rural desertion on the watersheds. Another objective is to compare these results with a rich mainly French scientific production on this theme.Experimental data on:

• –current erosion measurements and the analysis of its processes on the one hand,
• –and geomorphologic background of river beds and slopes,

are compared and analysed using archives and the present knowledge on historical climate.It has been shown that the overexploitation of watersheds leads to an increase in soil loss, in the number and intensity of floods in alpine valleys, as well as to an enhancement of sediment transport. However, climatic changes during the Holocene and during the past millennium have resulted in changes in morphological behaviour of the hillslopes upstream and of river beds downstream.Moreover, a strong sedimentary deficit can be observed over the last three or four decades in all the Alpine massifs. The consequences of this sediment deficit are firstly an entrenchment of river beds, which threatens bridges and embankments. This recent trend is probably due to the excessive extraction of material in gravel pits and the sedimentation in the numerous dams built between 1920 and 1980 in the entire alpine range. However, the entrenchment appeared recently on non-exploited rivers; therefore, the deficit is also due to the success of the natural and artificial reforestation and torrent correction since the end of 19th century.