Perceptions of local neighbourhood environments and their relationship to childhood overweight and obesity

OBJECTIVES

To examine associations between parent and child perceptions of the local neighbourhood and overweight/obesity among children aged 5-6 and 10-12 y.

DESIGN

Cross-sectional survey.

SUBJECTS

In total, 291 families of 5-6-y-old and 919 families of 10-12-y-old children.

MEASURES

Parent's perceptions of local neighbourhood and perceived child access to eight local destinations within walking distance of home; 10-12-y-old children's perception of local neighbourhood; socio-demographic characteristics (survey). Children's height and weight (measured).

RESULTS

No perceptions of the local neighbourhood were associated with weight status among 5-6-y-old children. Among 10-12-y-old children, those whose parents agreed that there was heavy traffic in their local streets were more likely to be overweight or obese (OR=1.4, 95% CI=1.0-1.8), and those whose parents agreed that road safety was a concern were more likely to be obese (OR=3.9, 95% CI=1.0-15.2), compared to those whose parents disagreed with these statements.

CONCLUSIONS

This study suggests that parental perceptions of heavy traffic on local streets and concern about road safety may be indirect influences on overweight and obesity among 10-12-y-old children. Future work should also consider perceptions of the neighbourhood related to food choice.

Risk behaviours and benign prostatic hyperplasia

OBJECTIVE

To identify risk factors for benign prostatic hyperplasia (BPH).

SUBJECTS AND METHODS

Medical history data, including reported urological conditions and treatments, and risk factor data were collected from 34 694 participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, a randomized controlled trial designed to evaluate methods for the early detection of cancer.

RESULTS

Asian men had the lowest risks (odds ratio, 95% confidence interval) for nocturia (0.7, 0.5-0.9), physician-diagnosed BPH (0.3, 0.2-0.5) and transurethral prostatectomy (TURP, 0.2, 0.1-0.6), while risks for Whites and Blacks were similar for most measures of BPH. Greater alcohol intake was associated with decreased nocturia (P trend = 0.002), BPH (P trend < 0.001) and TURP (P trend < 0.001). Current tobacco use was associated with decreased nocturia (0.8, 0.7-0.9), BPH (0.7, 0.6-0.8) and TURP (0.6, 0.4-0.8) but dose-response patterns were weak.

CONCLUSION

Asian-Americans have the lowest risk of clinical BPH. Alcohol and possibly cigarettes are related to a lower risk for BPH.

Public perceptions of the causes and prevention of obesity among primary school children

OBJECTIVE

To investigate lay perceptions of the causes and prevention of obesity among primary school children.

DESIGN

A cross-sectional survey of randomly selected sample of adults in a shopping centre.

SUBJECTS

315 adults in Melbourne, Australia.

MEASUREMENTS

Subjects completed a self-completion questionnaire, in which they rated the importance of 25 possible causes of obesity and the importance of 13 preventive measures on four-point scales: not important; quite important; very important; extremely important. Demographic information about the respondents' age, sex, marital status, education level and parental status was also collected.

RESULTS

The most important reported causes of childhood obesity were related to overconsumption of unhealthy food, parental responsibility, modern technology and the mass media. The most popular prevention activities were associated with specific actions aimed at children. Principal components analysis of the causes data revealed eight factors, provisionally named: parental responsibility, modern technology and media, overconsumption of unhealthy food, children's lack of knowledge and motivation, physical activity environment, lack of healthy food, lack of physical activity and genes. Two prevention factors were also derived, named government action and children's health promotion. Parents saw modern technology and media, and government activities as more important causes, and government policy as a more important means of prevention than nonparents and men. Women's responses tended to be similar to those of parents. There were few educational differences, although nontertiary educated respondents reported that modern technology and media were more important causes of obesity than did the tertiary educated.

CONCLUSION

The findings suggest that the public appears to hold quite sophisticated views of the causes and prevention of children's obesity. They suggest that a number of prevention strategies would be widely supported by the public, especially by parents.

Validity and reliability of a physical activity recall instrument among overweight and non-overweight men and women

This study examined the validity and reliability of survey items measuring one-week recall of physical activity (PA) and examined differences by weight status. A sub-aim of the study was to objectively assess the intensity of activity that most closely matches self-report. A questionnaire was administered to adults twice, three days apart. It was again administered after subjects wore a MTI/CSA accelerometer for seven days (n = 118). Several metabolic equivalent (MET) thresholds were applied to the accelerometer data. Agreement between test and re-test estimates of sufficient physical activity for health benefits (150 min/week) was high (% agreement > 90%). Correlations (rho) between total reported PA (mins/day) and accelerometer data were 0.29 (p < 0.05) among men and 0.25 (p < 0.05) among women. Among men, self-reported duration of moderate PA (3-5.9 METS) and accelerometer data were significantly correlated (rho = 0.40, p < 0.01), with no differences by weight status. Among women, a significant relationship was found only for those who were not overweight (rho = 0.52, p < 0.001). A significant correlation between self-reported duration of vigorous PA (6+ METS) and accelerometer data was only found for overweight men (rho = 0.40, p < 0.05). When lower MET thresholds were applied to the accelerometer data, women's reported duration of moderate-intensity PA was most strongly correlated with moderate PA (accelerometer) defined as 2.0-5.9 METS (rho = 0.39, p < 0.01). The recall instrument provides a consistent measure of physical activity and validation coefficients were similar to those obtained for other physical activity recall questionnaires. However, the ability to measure PA by self-report may vary by weight status.

Income differences in food consumption in the 1995 Australian National Nutrition Survey

OBJECTIVE

To assess the relationships between an index of per capita income and the intake of a variety of individual foods as well as groups of food for men and women in different age groups.

DESIGN

Cross-sectional national survey of free-living men and women.

SUBJECTS

A sample of 5053 males and 5701 females aged 18 y and over who completed the Australian National Nutrition Survey 1995.

METHODS

Information about the frequency of consumption of 88 food items was obtained. On the basis of scores on the Food Frequency Questionnaire, regular and irregular consumers of single foods were identified. The relationships between regularity of consumption of individual foods and per capita income were analysed via contingency tables. Food variety scores were derived by assigning individual foods to conventional food group taxonomies, and then summing up the dichotomised intake scores for individual foods within each food group. Two-way ANOVA (income x age group) were performed on the food variety scores for males and females, respectively.

RESULTS

Per capita income was extensively related to the reported consumption of individual foods and to total and food group variety indices. Generally, both men and women in low income households had less varied diets than those in higher-income households. However, several traditional foods were consumed less often by young high-income respondents, especially young women.

CONCLUSIONS

Major income differentials in food variety occur in Australia but they are moderated by age and gender. Younger high-income women, in particular, appear to have rejected a number of traditional foods, possibly on the basis of health beliefs. The findings also suggest that data aggregation has marked effects on income and food consumption relationships.

Social factors and obesity: an investigation of the role of health behaviours

OBJECTIVES

This study evaluated a behavioural model of the relation between social factors and obesity, in which differences in body mass index (BMI) across sociodemographic groups were hypothesized to be attributable to social group differences in health behaviours affecting energy expenditure (physical activity, diet and alcohol consumption and weight control).

METHODS

A total of 8667 adults who participated in the 1995 Australian National Health and Nutrition Surveys provided data on a range of health factors including objectively measured height and weight, health behaviours, and social factors including family status, employment status, housing situation and migration status.

RESULTS

Social factors remained significant predictors of BMI after controlling for all health behaviours. Neither social factors alone, nor health behaviours alone, adequately explained the variance in BMI. Gender-specific interactions were found between social factors and individual health behaviours.

CONCLUSIONS

These results suggest that social factors moderate the relation between BMI and weight-related behaviours, and that the mechanisms underlying sociodemographic group differences in obesity may vary among men and women. Additional factors are likely to act in conjunction with current health behaviours to explain variation in obesity prevalence across sociodemographic groups.

Who does not gain weight? Prevalence and predictors of weight maintenance in young women

OBJECTIVE

To investigate the prevalence and predictors of weight maintenance over time in a large sample of young Australian women.

DESIGN

This population study examined baseline and 4 y follow-up data from the cohort of young women participating in the Australian Longitudinal Study on Women's Health.

SUBJECTS

A total of 8726 young women aged 18-23 y at baseline.

MEASURES

Height, weight and body mass index (BMI); physical activity; time spent sitting; selected eating behaviours (eg dieting, disordered eating, takeaway food consumption); cigarette smoking, alcohol consumption; parity; and sociodemographic characteristics.

RESULTS

Only 44% of the women reported their BMI at follow-up to be within 5% of their baseline BMI (maintainers); 41% had gained weight and 15% had lost weight. Weight maintainers were more likely to be in managerial or professional occupations; to have never married; to be currently studying; and not to be mothers. Controlling for sociodemographic factors, weight maintainers were more likely to be in a healthy weight range at baseline, and to report that they spent less time sitting, and consumed less takeaway food, than women who gained weight.

CONCLUSIONS

Fewer than half the young women in this community sample maintained their weight over this 4 y period in their early twenties. Findings of widespread weight gain, particularly among those already overweight, suggest that early adulthood, which is a time of significant life changes for many women, may be an important time for implementing strategies to promote maintenance of healthy weight. Strategies which encourage decreased sitting time and less takeaway food consumption may be effective for encouraging weight maintenance at this life stage.

Dietary patterns of Australian adults and their association with socioeconomic status: results from the 1995 National Nutrition Survey

OBJECTIVE

To describe dietary patterns among men and women in the Australian population, and to explore how these varied according to socioeconomic status (SES).

DESIGN

A cross-sectional self-report population survey, the 1995 Australian National Nutrition Survey (NNS), was used.

SETTING

Private dwelling sample, covering urban and rural areas across Australia.

SUBJECTS

Data provided by 6680 adults aged 18-64 who participated in the NNS were used in the analyses.

METHODS

Factor analyses were used to analyse data from a Food Frequency Questionnaire (FFQ) completed by participants. Associations between SES and dietary pattens were assessed using ANOVA.

RESULTS

Separate factor analyses of the FFQ data for men and women revealed 15 factors, accounting for approximately 50% of the variance in both men's and women's dietary patterns. Several gender and SES differences in food patterns were observed. Lower SES males more frequently consumed 'tropical fruits', 'protein foods', and 'offal and canned fish', while high SES males more often ate 'breakfast cereals' and 'wholemeal bread'. Lower SES females more often ate 'traditional vegetables', 'meat dishes' and 'pasta, rice and other mixed foods', while high SES females more frequently ate 'ethnic vegetables' and 'breakfast cereal/muesli'.

CONCLUSIONS

These findings contribute to a better understanding of the dietary patterns that underscore gender-specific SES differences in nutrient intakes. Analyses of the type employed in this study will facilitate the development of interventions aimed at modifying overall eating patterns, rather than specific components of the diet.

Which aspects of socioeconomic status are related to obesity among men and women?

OBJECTIVE

This study aimed to investigate the relationships between body weight and fat distribution, and four empirically derived domains of socioeconomic status: employment, housing, migration status and family unit.

DESIGN

A population-based study was used.

PARTICIPANTS

A total of 8667 randomly-selected adults (4167 men; 4500 women) who participated in the 1995 Australian National Health and Nutrition Surveys provided data on a range of health factors including objective height, weight and body fat distribution, and a range of sociodemographic indicators.

RESULTS

Results demonstrated associations for women, after controlling for age, between the employment domain, and body mass index and waist-to-hip ratio. Low status employed women were 1.4 times as likely to be overweight as high status employed women. There were less consistent relationships observed among these factors for men. Relationships between family unit and indicators of body weight and body fat distribution were observed for both men and women, with those who were married, particularly men (OR = 1.6, 95% CI 1.4-2.0), at higher risk of overweight. The migration and housing socioeconomic status domains were not consistently associated with body mass index or waist-to-hip ratio.

CONCLUSIONS

These findings indicate that different components of socioeconomic status may be important in predicting obesity, and thus should be examined separately. Future research would benefit from investigating the underlying mechanisms governing the relationships between socioeconomic status domains further, particularly those related to employment and family unit and obesity.

Regional mapping of low-affinity kainate receptors in mouse brain using [(3)H](2S,4R)-4-methylglutamate autoradiography

Recent data indicate that (2S,4R)-4-methylglutamate is a selective agonist for low affinity (GluR5 and GluR6) kainate receptor subunits. In the present study, we have employed [(3)H](2S,4R)-4-methylglutamate to examine low affinity kainate receptor distribution in mouse brain. [(3)H](2S,4R)-4-Methylglutamate labelled a single site in murine cerebrocortical membranes (K(d)=9.9+/-2.7 nM, B(max)=296.3+/-27.1 fmol mg protein(-1)). The binding of 8 nM [(3)H](2S,4R)-4-methylglutamate was displaced by several non-NMDA receptor ligands (K(i)+/-S.E.M.): domoate (1.1+/-0.2 nM)>kainate (7.1+/-1.1 nM) >> L-glutamate (187.6+/-31.9 nM) >> (S)-alpha-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) (>50 microM). [(3)H](2S,4R)-4-Methylglutamate autoradiography revealed a widespread regional distribution of low affinity kainate receptors. Highest binding densities occurred within deep layers of the cerebral cortex, olfactory bulb, basolateral amygdala and hippocampal CA3 subregion. Moderate labelling was also evident in the nucleus accumbens, dentate gyrus, caudate putamen, hypothalamus and cerebellar granule cell layer. These data show that [(3)H](2S,4R)-4-methylglutamate is a useful radioligand for selectively labelling low affinity kainate receptors.

Health-related quality of life and cost-effectiveness studies in the European randomised study of screening for prostate cancer and the US Prostate, Lung, Colon and Ovary trial

Decisions on policies for screening for prostate cancer require that information upon health-related quality of life (HRQL) and cost-effectiveness (CE) be available, as the lead time for some of the cases detected by screening will be very long and detriments in quality of life could have a major impact on the subjects remaining life-span. A framework within which both HRQL and cost-effectiveness of prostate cancer screening can be assessed is presented. Studies of both are ongoing in the European Randomised Study of screening for prostate cancer and the US Prostate, Lung, Colon and Ovary trial. Preliminary information confirms that it is important to study screened subjects and controls, and not to assume that inferences derived from study of prostate cancer outside screening trials can be extrapolated to the trials. However, it will require prolonged study to enable the overall effects on quality of life, and on cost-effectiveness to be determined. Such studies are ongoing for the two trials.

Beliefs about the causes of weight change in the Australian population

OBJECTIVE

To describe self-reported weight change and beliefs about the causes of weight change and to examine whether these vary by sex and weight status.

DESIGN

This cross-sectional population study examined data from the 1995 Australian National Health and Nutrition Surveys.

SUBJECTS

A total of 10 624 randomly-selected adults provided data.

MEASURES

Objectively measured height and weight, perceptions of current weight status, self-reported weight change over the past year, and reasons for weight change.

RESULTS

Thirty-five percent of participants reported a weight gain in the last 12 months, with females, and those already overweight more likely to report a recent increase in weight. Approximately one in five participants reported a recent weight loss. Those who had recently gained weight were more likely to perceive themselves as overweight regardless of actual weight status. Commonly reported reasons for weight gain included a change in physical activity level (52% males and 35% females) and a change in the amount of food/drink consumed (30% males, 27% females). Similar reasons were given for weight loss.

CONCLUSIONS

: Findings of widespread reported weight gain, particularly among those already overweight, suggest Australia's obesity epidemic may be worsening. Strategies are urgently required to better inform individuals about the factors impacting on their weight in order to prevent further weight gain.

Identification of a novel retrovirus expressed in rat Sertoli cells and granulosa cells

Differential display reverse transcriptase-polymerase chain reaction (DDRT-PCR) was used to identify a novel retrovirus, designated SC1, that is expressed at high levels in rat granulosa cells and prepubertal Sertoli cells. The initial DDRT-PCR screen was performed using RNA from cultured prepubertal rat Sertoli cell, liver, and brain samples. SC1 was detected in the prepubertal rat Sertoli cell samples but not in those from liver and brain. SC1 cDNA was 6 kilobases in length and contained regions encoding for the gag, pol, and env retroviral proteins. Northern blot analysis failed to detect expression of the SC1 gene in total RNA isolated from adult brain, heart, spleen, lung, liver, skeletal muscle, kidney, prostate, and epididymis. Similarly, Northern blot analysis of testes from rats at various ages of development showed that high-level expression of the SC1 gene was limited to prepubertal testis samples. In situ hybridization analysis localized the SC1 mRNA to the seminiferous tubules of prepubertal testes and at a much lower level in Sertoli cells of adult testes. Northern blot analysis of total RNA isolated from Sertoli cells from 20-, 27-, and 35-day-old rat Sertoli cells and type A spermatogonia, pachytene spermatocytes, and round spermatids showed expression of the SC1 gene to be restricted to 20- and 27-day-old Sertoli cells, with no expression detected in germ cells. Furthermore, Northern blot analysis also showed expression of the SC1 gene in rat ovaries, and the level of expression was affected during eCG/hCG-induced ovulation. Expression of SC1 mRNA was localized by in situ hybridization of eCG-treated ovaries to the granulosa cell layer in developing follicles. Southern blot analysis showed SC1 to be endogenous in the rat and absent in mouse and human cell genomes. Transient transfection assays using the SC1 promoter region showed high promoter activity in MSC-1 and cultured prepubertal rat Sertoli cells, and no activity in 3T3 or MCF-7 cell lines.

Is the link between nutrients and foods understood? The case of fibre and folate

OBJECTIVES

To assess and contrast awareness of the link between dietary fibre and folate and their major food sources (fruit, vegetables, bread and cereals).

DESIGN

Mailed questionnaire investigating changes made to dietary intake of fibre, folate, fruit, vegetables, bread and cereals in the previous six months.

SETTING

The survey was conducted between June and November 1998 in the Australian Capital Territory.

SUBJECTS

One thousand one hundred and twenty-six adults randomly selected from the electoral roll.

RESULTS

More women than men in both older (50+ years) and younger (18-49 years) age groups reported increasing their consumption of folate, fibre, fruit and vegetables in the prior six months. In contrast, more men than women reported increased consumption of bread, cereals, rice and pasta in the previous six months. For food categories and fibre, less than 4% of respondents were unsure about changes in these food habits. However, 26% of men and women were 'not sure' about changes to folate intake. Similar proportions of men and women (about 33%) reported consuming more fruit, vegetables or cereal-based foods over the prior six months, yet only 6% of these men and 14% of these women reported consuming more folate. In contrast, 44% of men and 51% of women who reported consuming more plant foods also reported consuming more dietary fibre.

CONCLUSIONS

The results suggested that subjects, particularly the younger age group, had a poor understanding of the relationship between folate intake and its major food sources. The understanding of the relationship between fibre intake and its food sources appeared substantial, but confusion about specific food sources was still evident. These outcomes question the effectiveness of nutrition education used to date, particularly for the current priority of increasing folate intake in younger women in the new, 'health claims' environment.

[(3)H](2S,4R)-4-Methylglutamate: a novel ligand for the characterization of glutamate transporters

[(3)H](2S,4R)-4-Methylglutamate ([(3)H]4MG), used previously as a ligand for low-affinity kainate receptors, was employed to establish a binding assay for glutamate transporters (GluTs), as 4MG has also been shown to have affinity for the glial GluTs, GLT1 and GLAST. In rat brain membrane homogenates in the presence of Na(+) ions at 4 degrees C, specific binding of [(3)H]4MG was rapid and saturable (t(1/2) approximately 15 min), representing > 90% of total binding. Dissociation of [(3)H]4MG occurred in a biphasic manner, however, saturation studies and Scatchard analysis indicated a single site of binding (n(H) = 0.85) and a K(d) of 6.2 +/- 0.8 microM with a B(max) of 111.8 +/- 23.8 pmol/mg protein. Specific binding of [(3)H]4MG was Na(+)-dependent and inhibited by K(+) and HCO(3-). Pharmacological inhibition with compounds acting at GluTs revealed that Glu, D- and L-aspartate, L-serine-O-sulfate and Ltrans-pyrrolidine-2,4-dicarboxylate fully displaced specific binding. Drugs having preferential affinity for GLT1, kainate, dihydrokainate and Lthreo-3-methylglutamate, all inhibited approximately 40% of specific binding. The inhibition pattern of L-serine-O-sulfate in the presence of a saturating concentration of dihydrokainate was suggestive of [(3)H]4MG also labelling GLAST. 6-Cyano-7-nitroquinoxaline, a kainate receptor antagonist, and a range of Glu receptor agonists and antagonists failed to significantly inhibit [(3)H]4MG binding. The pharmacological profile of binding of [(3)H]4MG resembled that found for [(3)H]D-aspartate, a ligand specific for GluTs, reinforcing the hypothesis that [(3)H]4MG was labelling GluTs in this assay. Together, these data illustrate the development of an efficient, economic binding assay that is suitable for the characterization of different subtypes of GLuTs.

Motorcycle taxi drivers and sexually transmitted infections in a Peruvian Amazon City

BACKGROUND

In Iquitos, Peru, motorcycle taxis are a common form of public transportation used both by residents and visitors.

GOAL

To evaluate the prevalence of factors associated with sexually transmitted disease risk and of Neisseria gonorrhoeae and Chlamydia trachomatis infections among motorcycle taxi drivers working in Iquitos, Peru.

STUDY DESIGN

A convenience sample of motorcycle taxi drivers was recruited through street outreach. Participants were confidentially interviewed and provided urine specimens for gonococcal and chlamydial infection testing.

RESULTS

A history of sexually transmitted disease (62%) or symptoms in the past year (35%) and of referral of clients to commercial sex workers (60%) was common. The prevalence of gonococcal or chlamydial infection was 3.5%.

CONCLUSIONS

Motorcycle taxi drivers are a major means of public transportation in Iquitos, Peru, have high personal risks for sexually transmitted disease, and interface often with at-risk persons.

Milk choices made by women: what influences them, and does it impact on calcium intake?

OBJECTIVE

: To identify influences on type of milk consumed and the impact of milk choice on calcium intakes in Australian women of pre- and postmenopausal age.

DESIGN AND SETTING

: Questionnaires covering calcium intake, health-related dietary issues and priorities self-completed in a group setting.

SUBJECTS

: A total of 300 women recruited from community groups and government departments.

RESULTS

: Mean milk and calcium intake were higher in older (> or = 50 years) compared to younger women. Milk provided over 50% of calcium intake for both groups. Participants rated the importance of eating foods low in fat, energy or cholesterol, high in calcium or dietary fibre or of 'limiting their intake of added sugar or sugary foods'. Younger and older women ranked eating foods low in fat as the most important food habit for their health, then ranked dietary fibre next in importance. Calcium ranked third for younger women, and fourth for older women. These rankings were reflected in the higher proportion of older women choosing fat-reduced milk in general, and skim milk in particular. This concern about eating foods low in fat was consistent with the choices made of skim, reduced fat/higher calcium or whole milk.

CONCLUSIONS

: Results from this study suggest that concerns about fat are prejudicing the type of milk and amount of calcium consumed. Public health strategies targeting calcium intake need to address age-related differences in quantity and type of milk consumed, including the food attribute conflicts influencing these.