Associations between dietary patterns, socio-demographic factors and anthropometric measurements in adult New Zealanders: an analysis of data from the 2008/09 New Zealand Adult Nutrition Survey.

PURPOSE: To investigate associations between dietary patterns, socio-demographic factors and anthropometric measurements in adult New Zealanders. METHODS: Dietary patterns were identified using factor analysis in adults 15 years plus (n = 4657) using 24-h diet recall data from the 2008/09 New Zealand Adult Nutrition Survey. Multivariate regression was used to investigate associations between dietary patterns and age, gender and ethnicity. After controlling for demographic factors, associations between dietary patterns and food insecurity, deprivation, education, and smoking were investigated. Associations between dietary patterns and body mass index and waist circumference were examined adjusting for demographic factors, smoking and energy intake. RESULTS: Two dietary patterns were identified. 'Healthy' was characterised by breakfast cereal, low fat milk, soy and rice milk, soup and stock, yoghurt, bananas, apples, other fruit and tea, and low intakes of pies and pastries, potato chips, white bread, takeaway foods, soft drinks, beer and wine. 'Traditional' was characterised by beef, starchy vegetables, green vegetables, carrots, tomatoes, savoury sauces, regular milk, cream, sugar, tea and coffee, and was low in takeaway foods. The 'healthy' pattern was positively associated with age, female gender, New Zealand European or other ethnicity, and a secondary school qualification, and inversely associated with smoking, food insecurity, area deprivation, BMI and waist circumference. The 'traditional' pattern was positively associated with age, male gender, smoking, food insecurity and inversely associated with a secondary school qualification. CONCLUSIONS: A 'Healthy' dietary pattern was associated with higher socio-economic status and reduced adiposity, while the 'traditional' pattern was associated with lower socio-economic status.

Weight management practices associated with PCOS and their relationships with diet and physical activity.

STUDY QUESTION: Do weight management practices differ in women with and without PCOS? SUMMARY ANSWER: Women in the general population with self-reported PCOS are more likely to be using healthy weight management practices and alternative non-lifestyle measures for weight management than women without PCOS. WHAT IS KNOWN ALREADY: Lifestyle management is the first-line treatment in PCOS. However, the specific weight management practices used by women with PCOS and their effect on diet and physical activity are unclear. STUDY DESIGN, SIZE, DURATION: The study was a population-based observational cross-sectional study involving women in the 1973-1978 cohort (n = 7767 total; n = 556 with PCOS, n = 7211 without PCOS). PARTICIPANTS/MATERIALS, SETTING, METHODS: Women with and without self-reported PCOS were included. Self-reported outcome measures included healthy lifestyle-related or alternative non-lifestyle-related (e.g. laxatives or smoking) weight management practices, dietary intake and physical activity. MAIN RESULTS AND THE ROLE OF CHANCE: Women with PCOS were more likely to be following both healthy [reducing meal or snack size (odds ratio (OR) 1.50, 95% CI 1.14, 1.96, P = 0.004) and reducing fat or sugar intake (OR 1.32, 95% CI 1.03, 1.69, P = 0.027) or following a low glycaemic index diet (OR 2.88, 95% CI 2.30, 3.59, P < 0.001)] and alternative [smoking (OR 1.60, 95% CI 1.02, 2.52, P = 0.043) or use of laxative, diet pills, fasting or diuretics (OR 1.45, 95% CI 1.07, 1.97, P = 0.017)] weight management practices than women without PCOS. In PCOS, the use of a range of healthy weight management practices was associated with increases in physical activity (P < 0.001), diet quality (P < 0.001), percentage protein intake (P < 0.001) and decreases in glycaemic index (P < 0.001), and percentages of fat (P = 0.001), saturated fat (P < 0.001) or fibre (P = 0.003). Use of alternative weight management practices was associated with decreases in diet quality. LIMITATIONS, REASONS FOR CAUTION: Limitations include the use of self-reported data for PCOS, height, weight, diet, physical activity and weight management behaviours. WIDER IMPLICATIONS OF THE FINDINGS: In PCOS, we should focus on improving healthy weight practices across both diet quality and quantity, and on assessing alternative weight practices and their potential adverse effect on dietary intake. STUDY FUNDING/COMPETING INTEREST(S): L.M. is supported by a South Australian Cardiovascular Research Development Program Fellowship (ID AC11S374); a program collaboratively funded by the National Heart Foundation, the South Australian Department of Health and the South Australian Health and Medical Research Institute. H.T. is supported by the NHMRC. S.A.M. is supported by an NHMRC Career Development Fellowship Level 2, ID1104636 and was previously supported by an ARC Future Fellowship (2011-2015, FT100100581). The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: Not applicable.

Clustering of diet, physical activity and sedentary behaviour among Australian children: cross-sectional and longitudinal associations with overweight and obesity.

BACKGROUND/OBJECTIVES: Evidence suggests diet, physical activity (PA) and sedentary behaviour cluster together in children, but research supporting an association with overweight/obesity is equivocal. Furthermore, the stability of clusters over time is unknown. The aim of this study was to examine the clustering of diet, PA and sedentary behaviour in Australian children and cross-sectional and longitudinal associations with overweight/obesity. Stability of obesity-related clusters over 3 years was also examined. SUBJECTS/METHODS: Data were drawn from the baseline (T1: 2002/2003) and follow-up waves (T2: 2005/2006) of the Health Eating and Play Study. Parents of Australian children aged 5-6 (n=87) and 10-12 years (n=123) completed questionnaires. Children wore accelerometers and height and weight were measured. Obesity-related clusters were determined using K-medians cluster analysis. Multivariate regression models assessed cross-sectional and longitudinal associations between cluster membership, and body mass index (BMI) Z-score and weight status. Kappa statistics assessed cluster stability over time. RESULTS: Three clusters, labelled 'most healthy', 'energy-dense (ED) consumers who watch TV' and 'high sedentary behaviour/low moderate-to-vigorous PA' were identified at baseline and at follow-up. No cross-sectional associations were found between cluster membership, and BMI Z-score or weight status at baseline. Longitudinally, children in the 'ED consumers who watch TV' cluster had a higher odds of being overweight/obese at follow-up (odds ratio=2.8; 95% confidence interval: 1.1, 6.9; P<0.05). Tracking of cluster membership was fair to moderate in younger (K=0.24; P=0.0001) and older children (K=0.46; P<0.0001). CONCLUSIONS: This study identified an unhealthy cluster of TV viewing with ED food/drink consumption, which predicted overweight/obesity in a small longitudinal sample of Australian children. Cluster stability was fair to moderate over 3 years and is a novel finding. Prospective research in larger samples is needed to examine how obesity-related clusters track over time and influence the development of overweight and obesity.

Clustering of children's obesity-related behaviours: associations with sociodemographic indicators.

BACKGROUND/OBJECTIVES: Research suggests obesity-related behaviours cluster together in children and adolescents, but how these cluster patterns differ by sociodemographic indicators remains unclear. Furthermore, few studies examining clustering of behaviours have included younger children or an objective measure of physical activity (PA) and sedentary behaviour. Therefore, the aim of this study was to examine clustering patterns of diet, PA and sedentary behaviour in 5- to 6- and 10- to 12-year-old children, and their cross-sectional associations with sociodemographic indicators. SUBJECTS/METHODS: In this cross-sectional study, data from the baseline wave (2002/2003) of the Health Eating and Play study (HEAPS) were used. Questionnaires were completed by parents of Australian children aged 5-6 (n=362) and 10-12 years (n=610). Children wore accelerometers for up to 7 days. K-medians cluster analysis identified groups of children with similar diet, PA and sedentary behaviours. Chi-square tests assessed cluster differences by gender, maternal education and marital status. RESULTS: For each age group, three reliable and meaningful clusters were identified and labelled 'most healthy', 'energy-dense (ED) consumers who watch TV' and 'high sedentary behaviour/low moderate-to-vigorous PA (MVPA)'. Clusters varied by sociodemographic indicators. For example, a higher proportion of older girls comprised the 'high sedentary behaviour/low MVPA' cluster (χ(2)=22.4, P<0.001). Among both age groups, the 'ED consumers who watch TV' cluster comprised more children with lower educated mothers (younger children: χ(2)=34.9, P<0.001; older children: χ(2)=27.3, P<0.001). CONCLUSIONS: Identification of cluster patterns of obesity-related risk factors in children, and across sociodemographic groups may assist the targeting of public health initiatives, to those most in need.

The contribution of diet, physical activity and sedentary behaviour to body mass index in women with and without polycystic ovary syndrome.

STUDY QUESTION: What is the contribution of diet, physical activity and sedentary behaviour to body mass index (BMI) in women with and without polycystic ovary syndrome (PCOS)? SUMMARY ANSWER: PCOS status, higher energy intake and glycaemic index and lower physical activity were independently associated with BMI. WHAT IS KNOWN ALREADY: Obesity worsens the clinical features of PCOS and women with PCOS have an elevated prevalence of overweight and obesity. It is not known whether there is a contribution of lifestyle factors such as dietary intake, physical activity or sedentary behaviour to the elevated prevalence of obesity in PCOS. STUDY DESIGN, SIZE, DURATION: This study is a population-based observational study with data currently collected at 13 year follow-up. The study commenced in 1996. For this analysis, data are analysed at one time point corresponding to the Survey 5 of the cohort in 2009. At this time 8200 participants remained (58% retention of baseline participants) of which 7466 replied to the questionnaire; 409 self-reported a diagnosis of PCOS and 7057 no diagnosis of PCOS. PARTICIPANTS/MATERIALS, SETTING, METHODS: Australian women born in 1973-1978 from the Australian Longitudinal Study on Women's Health. MAIN RESULTS AND THE ROLE OF CHANCE: Mean BMI was higher in women with PCOS compared with non-PCOS (29.3 ± 7.5 versus 25.6 ± 5.8 kg/m(2), P < 0.001). Women with PCOS reported a better dietary intake (elevated diet quality and micronutrient intake and lower saturated fat and glycaemic index intake) but increased energy intake, increased sitting time and no differences in total physical activity compared with non-PCOS. PCOS status, higher energy intake and glycaemic index and lower physical activity, as well as age, smoking, alcohol intake, occupation, education and country of birth, were independently associated with BMI. LIMITATIONS, REASONS FOR CAUTION: The weaknesses of this study include the self-reported diagnosis of PCOS, and the women not reporting PCOS not having their control status clinically verified which is likely to underrepresent the PCOS population. We are also unable to determine if lifestyle behaviours contributed to the PCOS diagnosis or were altered in response to diagnosis. WIDER IMPLICATIONS OF THE FINDINGS: The strengths of this study include the community-based nature of the sample which minimizes selection bias to include women with a variety of clinical presentations. These results are therefore generalizable to a broader population than the majority of research in PCOS examining this research question which are performed in clinic-based populations. This study is in agreement with the literature that PCOS is independently associated with elevated BMI. We provide new insights that diet quality is subtly improved but that sedentary behaviour is elevated in PCOS and that PCOS status, higher energy intake and glycaemic index and lower physical activity are independently associated with BMI. STUDY FUNDING/COMPETING INTEREST(S): L.J.M. was supported by a South Australian Cardiovascular Research Development Program (SACVRDP) Fellowship (AC11S374); a program collaboratively funded by the National Heart Foundation of Australia, the South Australian Department of Health and the South Australian Health and Medical Research Institute, S.A.M. was funded by an Australian Research Council Future Fellowship (FT100100581), S.Z. was funded by a Heart Foundation Career Development Fellowship (ID CR10S5330) and H.J.T. was funded by an NHMRC fellowship (ID 545888). None of the authors has any conflict of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

Socioeconomic variation in diet and activity-related behaviours of Australian children and adolescents aged 2-16 years.

BACKGROUND: Evidence for age-related variation in the relationship between obesity-related behaviours and socioeconomic position may assist in the targeting of dietary and physical activity interventions among children. OBJECTIVE: To investigate the relationship between different indicators of socioeconomic position and obesity-related behaviours across childhood and adolescence. METHODS: Data were from 4487 children aged 2 to 16 years participating in the cross-sectional 2007 Australian National Children's Nutrition and Physical Activity Survey. Socioeconomic position was defined by the highest education of the primary or secondary carer and parental income. Activity was assessed using recall methods with physical activity also assessed using pedometers. Intake of energy-dense drinks and snack foods, fruits and vegetables was assessed using 2 × 24-h dietary recalls. RESULTS: A socioeconomic gradient was evident for each dietary measure (although in age-specific analyses, not for energy-dense snacks in older children), as well as television viewing, but not physical activity. Whether each behaviour was most strongly related to parental income or education of the primary or secondary carer was age and sex dependent. The socioeconomic gradient was strongest for television viewing time and consumption of fruit and energy-dense drinks. CONCLUSIONS: A strong socioeconomic gradient in eating behaviours and television viewing time was observed. Relationships for particular behaviours differed by age, sex and how socioeconomic position was defined. Socioeconomic indicators define different population groups and represent different components of socioeconomic position. These findings may provide insights into who should be targeted in preventive health efforts at different life stages.

Major dietary patterns of young and middle aged women: results from a prospective Australian cohort study.

OBJECTIVE: The aim of this study was to assess the major dietary patterns of two age cohorts of women, to determine to the extent to which the dietary patterns differ between the cohorts and to assess whether they vary according to sociodemographic and behavioural characteristics and patterns of nutrient intake. METHOD: Dietary intake was assessed using an 80-item food frequency questionnaire for women aged 50-55 years (n=10 150; 'middle age') in 2001 and aged 25-30 years (n=7371; 'young') in 2003, from the Australian Longitudinal Study on Women's Health. Factor analysis using principal component extraction was used to identify dietary patterns, and a pattern score was calculated from the consumption of the food items identified with each dietary pattern. Associations between the dietary pattern scores and sociodemographic and behavioural characteristics and nutrient intakes were investigated using regression analysis. RESULTS: Six dietary patterns were identified and were labelled: cooked vegetables; fruit; Mediterranean-style; processed meat, meat and takeaway; reduced fat dairy; and high-fat and sugar foods. Regression analysis revealed that healthier dietary patterns were significantly associated with other favourable health-related behaviours, higher socioeconomic status and living in urban areas (P-values <0.05). CONCLUSIONS: In spite of differences in the level of consumption of individual food items, the similarity in dietary patterns across two generations of women suggests that policies and interventions to improve diet should focus on social and economic factors and general health-related behaviour rather than different age groups.

Validation of a FFQ to estimate the intake of PUFA using plasma phospholipid fatty acids and weighed foods records.

Due to the growing knowledge about the role of specific fatty acids in health and disease, dietary intake measurements of individual fatty acids or classes of fatty acids are becoming increasingly important. The objective of this study was to evaluate the ability of the Nambour FFQ to estimate intakes of specific fatty acids, particularly PUFA. The study population was a sub-sample of adult participants in a randomised controlled trial of beta-carotene and sunscreen in the prevention of skin cancer (n 43). Dietary intake was assessed by a self-administered FFQ and a weighed food record (WFR). Non-fasting blood samples were collected and analysed for plasma phospholipid fatty acids. Median intakes on the FFQ were generally higher than the WFR except for the n-3 PUFA groups, where the FFQ estimated higher intakes. Correlations between the FFQ and WFR were moderate (r 0 x 32-0 x 59) except for trans fatty acids (r 0 x 03). Correlations between each of the dietary assessment methods and the plasma phospholipids were poor for all fatty acids other than the PUFA. Using the methods of triads approach, the FFQ validity coefficients for total n-3 fatty acids, total long chain n-3 fatty acids, EPA, arachidonic acid, docosapentaenoic acid and DHA were 0 x 50, 0 x 63, 0 x 45 and 0 x 62 and 0 x 62, respectively. For most fatty acids, the FFQ adequately estimates group mean fatty acid intakes and can adequately rank individuals; however, the ability of this FFQ to estimate trans fatty acids was poor.

Validation of a food-frequency questionnaire assessment of carotenoid and vitamin E intake using weighed food records and plasma biomarkers: the method of triads model.

BACKGROUND: Reliability or validity studies are important for the evaluation of measurement error in dietary assessment methods. An approach to validation known as the method of triads uses triangulation techniques to calculate the validity coefficient of a food-frequency questionnaire (FFQ). OBJECTIVE: To assess the validity of an FFQ estimates of carotenoid and vitamin E intake against serum biomarker measurements and weighed food records (WFRs), by applying the method of triads. DESIGN: The study population was a sub-sample of adult participants in a randomised controlled trial of beta-carotene and sunscreen in the prevention of skin cancer. Dietary intake was assessed by a self-administered FFQ and a WFR. Nonfasting blood samples were collected and plasma analysed for five carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, lycopene) and vitamin E. Correlation coefficients were calculated between each of the dietary methods and the validity coefficient was calculated using the method of triads. The 95% confidence intervals for the validity coefficients were estimated using bootstrap sampling. RESULTS: The validity coefficients of the FFQ were highest for alpha-carotene (0.85) and lycopene (0.62), followed by beta-carotene (0.55) and total carotenoids (0.55), while the lowest validity coefficient was for lutein (0.19). The method of triads could not be used for beta-cryptoxanthin and vitamin E, as one of the three underlying correlations was negative. CONCLUSIONS: Results were similar to other studies of validity using biomarkers and the method of triads. For many dietary factors, the upper limit of the validity coefficients was less than 0.5 and therefore only strong relationships between dietary exposure and disease will be detected.

Development of a food composition database for the estimation of dietary intakes of glucosinolates, the biologically active constituents of cruciferous vegetables.

Evidence indicates that cruciferous vegetables are protective against a range of cancers with glucosinolates and their breakdown products considered the biologically active constituents. To date, epidemiological studies have not investigated the intakes of these constituents due to a lack of food composition databases. The aim of the present study was to develop a database for the glucosinolate content of cruciferous vegetables that can be used to quantify dietary exposure for use in epidemiological studies of diet-disease relationships. Published food composition data sources for the glucosinolate content of cruciferous vegetables were identified and assessed for data quality using established criteria. Adequate data for the total glucosinolate content were available from eighteen published studies providing 140 estimates for forty-two items. The highest glucosinolate values were for cress (389 mg/100 g) while the lowest values were for Pe-tsai chinese cabbage (20 mg/100 g). There is considerable variation in the values reported for the same vegetable by different studies, with a median difference between the minimum and maximum values of 5.8-fold. Limited analysis of cooked cruciferous vegetables has been conducted; however, the available data show that average losses during cooking are approximately 36 %. This is the first attempt to collate the available literature on the glucosinolate content of cruciferous vegetables. These data will allow quantification of intakes of the glucosinolates, which can be used in epidemiological studies to investigate the role of cruciferous vegetables in cancer aetiology and prevention.

Energy expenditure and the body cell mass in cystic fibrosis.

Poor nutritional status in patients with cystic fibrosis (CF) is associated with severe lung disease, and possible causative factors include inadequate intake, malabsorption, and increased energy requirements. Body cell mass (which can be quantified by measurement of total body potassium) provides an ideal standard for measurements of energy expenditure. The aim of this study was to compare resting energy expenditure (REE) in patients with CF with both predicted values and age-matched healthy children and to determine whether REE was related to either nutritional status or pulmonary function. REE was measured by indirect calorimetry and body cell mass by scanning with total body potassium in 30 patients with CF (12 male, mean age = 13.07 +/- 0.55 y) and 18 healthy children (six male, mean age = 12.56 +/- 1.25 y). Nutritional status was expressed as a percentage of predicted total body potassium. Lung function was measured in the CF group by spirometry and expressed as the percentage of predicted forced expiratory volume in 1 s. Mean REE was significantly increased in the patients with CF compared with healthy children (119.3 +/- 3.1% predicted versus 103.6 +/- 5% predicted, P < 0.001) and, using multiple regression techniques, REE for total body potassium was significantly increased in patients with CF (P = 0.0001). There was no relation between REE and nutritional status or pulmonary disease status in the CF group. In conclusion, REE is increased in children and adolescents with CF but is not directly related to nutritional status or pulmonary disease.

Nutritional status of children with cystic fibrosis measured by total body potassium as a marker of body cell mass: lack of sensitivity of anthropometric measures.

OBJECTIVE: To investigate measures aimed at defining the nutritional status of cystic fibrosis (CF) populations, this study compared standard anthropometric measurements and total body potassium (TBK) as indicators of malnutrition. METHODS: Height, weight, and TBK measurements of 226 children with CF from Royal Children's Hospital, Brisbane, Australia, were analyzed. Z scores for height for age, weight for age, and weight for height were analyzed by means of the National Centre for Health Statistics reference. TBK was measured by means of whole body counting and compared with predicted TBK for age. Two criteria were evaluated with respect to malnutrition: (1) a z score < -2.0 and (2) a TBK for age <80% of predicted. RESULTS: Males and females with CF had lower mean height-for-age and weight-for-age z scores than the National Centre for Health Statistics reference (P <.01), but mean weight-for-height z score was not significantly different. There were no significant gender differences. According to anthropometry, only 7.5% of this population were underweight and 7.6% were stunted. However, with TBK as an indicator of nutritional status, 29.9% of males and 22.0% of females were malnourished. CONCLUSION: There are large differences in the percentage of patients with CF identified as malnourished depending on whether anthropometry or body composition data are used as the nutritional indicator. At an individual level, weight-based indicators are not sensitive indicators of suboptimal nutritional status in CF, significantly underestimating the extent of malnutrition. Current recommendations in which anthropometry is used as the indicator of malnutrition in CF should be revised.

Growth failure in cystic fibrosis.

OBJECTIVE: The aim of this study was to describe and compare the nutritional status of children aged 0-18 years attending the cystic fibrosis (CF) clinic at the Royal Children's Hospital, Brisbane, Australia, as outpatients in 1986 and 1996. METHODOLOGY: The heights, weights and pulmonary function of children attending the CF clinic as outpatients in 1986 (n = 97) and 1996 (n = 227) were retrospectively analysed using a computerized database maintained by the CF clinic. The heights and weights were analysed in terms of z scores for height for age (HAZ), weight for age (WAZ) and weight for height (WHZ). Pulmonary function data is not available for all children. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and forced mid expiratory flows (FEF) were expressed as a percentage of predicted and are presented here. RESULTS: The 1986 sample consisted of 41 males (age range 0.18-14.59 years, mean age 6.52 (4.33)) and 56 females (age range 0.15-14.97 years, mean age 7.75 (3.70)). The 1996 sample consisted of 111 males (age range 0.09-17.97 years, mean age 8.80 (5.49)) and 114 females (age range 0.12-17.98 years, mean age 8.49 (5.26)). In 1986, males were shorter than females (P = 0.0096) and females had a lower mean FVC than males (P = 0.0438). In 1996, males were shorter, lighter and more wasted than females (P = 0.0357, P = 0.0034 and P = 0.0273, respectively) and females had a lower mean FEV1 and mean FVC than males (P = 0.0176 and P = 0.0079, respectively). Males in 1996 were lighter and more wasted than males in 1986 (P = 0.0023 and P = 0.0139, respectively) and had a lower mean FEV1, mean FVC and mean FEF (P < 0.0001, P = 0.0012 and P = 0.0069, respectively). Females in 1996 were shorter and lighter than females in 1986 (P = 0.0273 and P = 0.0405, respectively) and had a lower mean FEV1, mean FVC and mean FEF (P < 0.0001, P < 0.0001 and P < 0.0001, respectively). When subjects were classified according to FEV1 (FEV1 > or = 75% or FEV1 < 75%), there were no significant differences in z scores between the 1986 group and 1996 group. Similarly, when the 1986 group were matched for gender and FEV1 with the 1996 group, there were no significant differences in z scores for males or females. CONCLUSIONS: It is suggested that the apparent worsening of nutritional status among the 1996 group of CF patients is in fact due to an effect of increased survival of patients with more severe clinical symptoms. The findings from this study highlight the continuing, and in fact, worsening problem of growth failure in children with CF.