Balancing training and outcomes in total knee replacement: A ten-year review.

INTRODUCTION: 10-year study examining differences in total knee arthroplasty (TKA) functional outcomes and survivorship in patients operated on by consultant and trainee orthopaedic surgeons. METHOD: Data was prospectively collected from all elective TKAs performed at our three linked institutions. Patient demographics, surgeon grade, and length of hospital stay were recorded. Outcomes pre-operatively and at 1, 3, 5, 7 and 10 years included mortality, need for revision surgery and function as documented by the patients' Knee Society Score. RESULTS: 686 patients were included in the study. 450 (65.5%) patients were operated by consultant surgeons and 236 (34.4%) by trainees. On multivariate analysis no significant differences were observed between groups in length of hospital stay (p = 0.695), implant survival (p = 0.422), and function (p = 0.507) at 10 years. On Cox regression analysis no significant difference was observed in mortality (p = 0.209) at 10 years. 4 patients over this time period were lost to formal follow up. CONCLUSION: No significant difference was observed in the TKA outcomes between consultants and trainees 10 years post-operatively.

The Iodine Status of Queensland Preschool Children After the Introduction of Mandatory Iodine Fortification in Bread: An Exploratory Study Using a Convenience Sample.

Introduction Appropriate dietary iodine is essential for thyroid hormone synthesis, especially in young children. Following an iodine fortification in bread initiative, approximately 6 % of Australian preschool children were expected to have an excessive iodine status. The aim of this study was to document the current iodine status of preschool children using urinary iodine concentration (UIC) as a biomarker of iodine intake. Methods A convenience sample of fifty-one preschool children, aged 2-3 years, were recruited from south east Queensland. UIC was ascertained from spot morning and afternoon urine samples collected on two consecutive days and food frequency questionnaires were completed for each participant. Dietary iodine intake was extrapolated from UIC assuming 90 % of dietary iodine is excreted in urine and a urine volume of 0.5 L/day. Results A median UIC of 223.3 µg/L was found. The calculated median dietary iodine intake was 124.8 µg/day (SD 47.0) with 9.8 % of samples above the upper level of 200 µg for dietary iodine for children within this age group. No foods were associated with UIC. Discussion Limited by sample size and recruitment strategies, no association was found between usual food intake and UIC. Extrapolated dietary iodine intake indicated that children within this cohort consumed adequate amounts of dietary iodine, although the number of children consuming above the upper limit of 300 µg/day was almost double of expected. The development of a UIC criteria to assess appropriate parameters for varying degrees of iodine status is required for the monitoring of iodine nutrition in this vulnerable age group.

Advantages of collecting multiple urinary iodine concentrations when assessing iodine status of a population.

AIM: To evaluate the effect of collecting multiple (four) urine samples on the extensive variance often observed within a cohort when determining iodine status via urinary iodine concentration (UIC). METHODS: Fifty-one children aged two to three years and thirty children aged 8-10 years participated in the study in South East Queensland, Australia. Each child's four urine samples were analysed using ammonium persulphate digestion before a Sandell-Kolthoff reaction method. Analysis of variance techniques were used to assess the effect of using multiple urine samples. RESULTS: The median UICs were 223.3 and 141 µg/L for two- to three-year-olds and eight- to 10-year-olds, respectively. The coefficient of variance (CV) of UIC for children aged two to three years was reduced by 35.6%, 36.5% and 39.7% when two, three and four samples were included in the adjustment, respectively. Similarly, the CV of UIC for children aged 8-10 years was reduced by 24.7%, 30.7% and 34.7%, respectively. CONCLUSION: Although the practicality and cost of collecting multiple UICs need to be considered, collecting multiple UIC samples from each participant provides a more accurate reflection of a cohort iodine status.

Can a Web-based food record accurately assess energy intake in overweight and obese women? A pilot study.

BACKGROUND: Innovative dietary intake measurement tools, such as web-based food records, are becoming increasingly available for self-monitoring. However, the accuracy of this method has not been well studied. This pilot study aimed to evaluate the accuracy of energy intake (EI) estimated by a web-based food record, by comparison with total energy expenditure (TEE) measured by doubly-labelled water (DLW) in overweight and obese women. METHODS: Total energy expenditure (TEE) was assessed in weight stable (±1 kg) women (n = 9), with a mean (SD) age of 34.5 (11.3) years and body mass index of 29.2 (1.4) kg m(-2) over 10 days using the DLW technique. All food and beverages were self-reported for 9-days using a web-based food record and mean daily EI calculated. Food record accuracy was assessed by calculating the absolute (EI - TEE) and percentage (EI/TEE × 100) differences between EI and TEE. Women were identified as under-reporters of EI based on the 95% confidence limits of the expected EI : TEE of 1. RESULTS: The mean (SD) self-reported EI was 8351 (1225) kJ day(-1) [1996 (293) kcal day(-1) ] and TEE was 10 648 (1774) kJ day(-1) [2545 (424) kcal day(-1) ]. The mean (SD) absolute difference in self-reported EI and TEE was -2301 (1535) kJ day(-1) [-550 (367) kcal day(-1) ], representing a mean reporting accuracy of 79.6% (14.1%), with four participants under-reporting EI. CONCLUSIONS: This pilot study highlights the opportunity for the use of the Internet as a novel medium for recording and assessing dietary intake. Although further research is needed in more diverse population groups, the accuracy of web-based food records for assessing EI appears to be consistent with other published dietary intake methods.

Defining anthropometric cut-off levels related to metabolic risk in a group of Sri Lankan children.

BACKGROUND: Body mass index (BMI) is widely used as a measure of adiposity. However, currently used cut-off values are not sensitive in diagnosing obesity in South Asian populations. AIM: To define BMI and waist circumference (WC), cut-off values representing percentage fat mass (%FM) associated with adverse health outcomes. SUBJECTS AND METHODS: A cross-sectional descriptive study of 285 5-14 year old Sri Lankan children (56% boys) was carried out. Fat mass (FM) was assessed using the isotope (D(2)O) dilution technique based on 2C body composition model. BMI and WC cut-off values were defined based on %FM associated with adverse health outcomes. RESULTS: Sri Lankan children had a low fat free mass index (FFMI) and a high fat mass index (FMI). Individuals with the same BMI had %FM distributed over a wide range. Lean body tissue grew very little with advancing age and weight gain was mainly due to increases in body fat. BMI corresponding to 25% in males and 35% in females at 18 years was 19.2 kg/m(2) and 19.7 kg/m(2), respectively. WC cut-off values for males and females were 68.4 cm and 70.4 cm, respectively. CONCLUSION: This chart analysis clearly confirms that Sri Lankan children have a high %FM from a young age. With age, more changes occur in FM than in fat free mass (FFM). Although the newly defined BMI and WC cut-off values appear to be quite low, they are comparable to some recent data obtained in similar populations.

Benefit of early commencement of growth hormone therapy in children with Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is a chromosomal disorder and growth failure is a common presentation. Growth hormone (GH) treatment is beneficial in PWS although the optimal age for starting GH is unknown. We investigated whether GH response in PWS was associated with the age of GH commencement by comparing 16 children who commenced GH before 3 years of age (early group) with 40 children who commenced GH after 3 years of age (late group) from the Ozgrow database. Height SDS, body mass index (BMI) SDS, bone age (BA)-chronological age (CA) ratio, change in height (delta Ht) SDS and change in BMI during 4 years of GH treatment were compared between the groups. The early group had better height SDS and delta Ht SDS. BA delay was more pronounced in the early group but BA did not mature beyond CA with GH therapy in either group. Although the initial GH dose for the early group was lower than that of the late group, the former had better height outcome. The starting GH dose seen in the database is lower than the dose used by international centres.

Validity of currently used cutoff values of body mass index as a measure of obesity in Sri Lankan children.

OBJECTIVE: The aim of the study was to determine the reliability of body mass index based (BMI) cutoff values in diagnosing obesity among Sri Lankan children. METHODS: Height, weight, waist circumference (WC) and hip circumference (HC) in 282 children were measured. Total body water was determined by deuterium dilution and fat mass (FM) derived using age and gender specific constants. A percentage FM of 30% for girls and 25% for boys were considered as cutoff levels for obesity. RESULTS: Two hundred and eighty two children (M/F: 158/124) were studied and 99 (80%) girls and 72 (45.5%) boys were obese based on % body fat. Eight (6.4%) girls and nine (5.7%) boys were obese based on International Obesity Task Force (IOTF) cutoff values. Percentage FM and WC centile charts were able to diagnose a significant proportion of children as true obese children. The FM and BMI were closely associated in both girls (r = 0.82, p < 0.001) and boys (r = 0.87, p < 0.001). Percentage FM and BMI had a very low but significant association; girls (r = 0.32, p < 0.001) and boys (r = 0.68, p < 0.001). FM had a significant association with WC and HC. BMI based cutoff values had a specificity of 100% but a very low sensitivity, varying between 8% and 23.6%. CONCLUSIONS: BMI is a poor indicator of the percentage fat and the commonly used cutoff values were not sensitive to detect cases of childhood obesity in Sri Lankan children.

An examination of children's eating behaviours as mediators of the relationship between parents' feeding practices and early childhood body mass index z-scores.

OBJECTIVE: Parent's use of restrictive feeding practices is associated with child weight. Similarly, the literature shows that children's eating behaviours are also associated with child weight. Given this interrelationship between children's eating behaviours, restrictive feeding practices and child weight, examination of possible mediator relationships is warranted. This study aimed to examine the relationships between overt restriction and covert restriction with child body mass index z-scores (BMIz) and determine if children's eating behaviours (satiety responsiveness and food responsiveness) act as mediators. METHOD: Parents of Australian children (n = 977) 2.0-5.0 years of age (49.4% male) provided data in an online survey on child eating behaviours, parent's restrictive feeding practices and child anthropometrics (modified z-scores were created to screen for biologically implausible values). Correlation analysis was used to determine variables to include in mediation models. Hayes' PROCESS macros in spss was used to examine mediation, controlling for covariates of child BMIz. RESULTS: Overt restriction was the only parent feeding practice related to child BMIz (B = 0.132, P = 0.04). Mediation analysis showed that the indirect effect of overt restriction on child BMIz (controlling for child age, gender, parent BMI and income) became non-significant when controlling for food responsiveness, thus suggesting full mediation, explaining 5.75% of the relation. CONCLUSION: Overt restriction and covert restriction have distinctly different relationships with children's eating behaviours. Food responsiveness appears an important intermediary in the relationship between overt restriction and child BMIz.

Breastfeeding: a key modulator of gut microbiota characteristics in late infancy.

The objective of this study was to investigate the impact of the most commonly cited factors that may have influenced infants' gut microbiota profiles at one year of age: mode of delivery, breastfeeding duration and antibiotic exposure. Barcoded V3/V4 amplicons of bacterial 16S-rRNA gene were prepared from the stool samples of 52 healthy 1-year-old Australian children and sequenced using the Illumina MiSeq platform. Following the quality checks, the data were processed using the Quantitative Insights Into Microbial Ecology pipeline and analysed using the Calypso package for microbiome data analysis. The stool microbiota profiles of children still breastfed were significantly different from that of children weaned earlier (P<0.05), independent of the age of solid food introduction. Among children still breastfed, Veillonella spp. abundance was higher. Children no longer breastfed possessed a more 'mature' microbiota, with notable increases of Firmicutes. The microbiota profiles of the children could not be differentiated by delivery mode or antibiotic exposure. Further analysis based on children's feeding patterns found children who were breastfed alongside solid food had significantly different microbiota profiles compared to that of children who were receiving both breastmilk and formula milk alongside solid food. This study provided evidence that breastfeeding continues to influence gut microbial community even at late infancy when these children are also consuming table foods. At this age, any impacts from mode of delivery or antibiotic exposure did not appear to be discernible imprints on the microbial community profiles of these healthy children.

Assessment of body composition in Sri Lankan children: validation of a bioelectrical impedance prediction equation.

OBJECTIVE: To develop bioelectrical impedance analysis (BIA) equations to predict total body water (TBW) and fat-free mass (FFM) of Sri Lankan children. SUBJECTS/METHODS: Data were collected from 5- to 15-year-old healthy children. They were randomly assigned to validation (M/F: 105/83) and cross-validation (M/F: 53/41) groups. Height, weight and BIA were measured. TBW was assessed using isotope dilution method (D(2)O). Multiple regression analysis was used to develop preliminary equations and cross-validated on an independent group. Final prediction equation was constructed combining the two groups and validated by PRESS (prediction of sum of squares) statistics. Impedance index (height(2)/impedance; cm(2)/Omega), weight and sex code (male=1; female=0) were used as variables. RESULTS: Independent variables of the final prediction equation for TBW were able to predict 86.3% of variance with root means-squared error (RMSE) of 2.1 l. PRESS statistics was 2.1 l with press residuals of 1.2 l. Independent variables were able to predict 86.9% of variance of FFM with RMSE of 2.7 kg. PRESS statistics was 2.8 kg with press residuals of 1.4 kg. Bland Altman technique showed that the majority of the residuals were within mean bias+/-1.96 s.d. CONCLUSIONS: Results of this study provide BIA equation for the prediction of TBW and FFM in Sri Lankan children. To the best of our knowledge there are no published BIA prediction equations validated on South Asian populations. Results of this study need to be affirmed by more studies on other closely related populations by using multi-component body composition assessment.

Assessment of body composition in Sri Lankan children: validation of a skin fold thickness equation.

BACKGROUND: Morbidity associated with obesity is related to the fat mass (FM) of the body. The direct estimation of FM is difficult. Skin fold thickness (SFT) is a simple and cheap alternative for accurate assessment of FM, and population specific equations are necessary for accurate assessment of FM using SFT. OBJECTIVE: To develop a SFT prediction equation to estimate FM of Sri Lankan children. DESIGN, SETTING AND METHOD: Across-sectional descriptive study was done at the University Paediatric Unit of Lady Ridgeway Hospital, Colombo. Data were collected from 5 to 15 year old healthy children. Triceps, biceps, supra-iliac and subscapular SFT were measured using Harpendens skin fold caliper. Total body water was assessed using an isotope dilution method (D2O), and fat free mass calculated. FM was assessed based on 2 compartment body composition model. Multiple regression analysis was used to develop prediction equation and validated using PRESS (prediction of sum of squares) statistical technique. Independent variables were age, triceps SFT, subscapular SFT and sex. RESULTS: Prediction equation for FM [(0.68 x age) + (0.246 x triceps SFT) + (0.383 x subscapular SFT) - (1.61 x sex code) -3.45] was able to predict 76.4% of variance with a root mean squared error (RMSE) of 3.4 kg. PRESS statistics was 3.4 kg with press residuals of 1.56 kg. Bland-Altman technique showed that the majority of the residuals were within mean bias +/-1.96 SD. CONCLUSION: Results of this study provide an SFT equation for the prediction of FM in Sri Lankan children.

Resting energy expenditure in children with inflammatory bowel disease.

OBJECTIVES: There is controversy in the literature regarding the effect of inflammatory bowel disease (IBD) on resting energy expenditure (REE). In many cases this may have resulted from inappropriate adjustment of REE measurements to account for differences in body composition. This article considers how to appropriately adjust measurements of REE for differences in body composition between individuals with IBD. PATIENTS AND METHODS: Body composition, assessed via total body potassium to yield a measure of body cell mass (BCM), and REE measurements were performed in 41 children with Crohn disease and ulcerative colitis in the Royal Children's Hospital, Brisbane, Australia. Log-log regression was used to determine the power function to which BCM should be raised to appropriately adjust REE to account for differences in body composition between children. RESULTS: The appropriate value to "adjust" BCM was found to be 0.49, with a standard error of 0.10. CONCLUSIONS: Clearly, there is a need to adjust for differences in body composition, or at the very least body weight, in metabolic studies in children with IBD. We suggest that raising BCM to the power of 0.5 is both a numerically convenient and a statistically valid way of achieving this aim. Under circumstances in which the measurement of BCM is not available, raising body weight to the power of 0.5 remains appropriate. The important issue of whether REE is changed in cases of IBD can then be appropriately addressed.

Body change strategies in children: relationship to age and gender.

The "Body Image and Body Change Inventory Questionnaire" was administered to 958 students, aged 8.00-13.99 years, to determine the types of strategies used by children to accomplish changes in body size/shape. Each individual strategy score was compared for each gender and with respect to age. The girls' score for food restrictive practices was significantly higher than for other body change strategies. For the boys, the score for the use of food and exercise strategies to increase muscle size was significantly higher than all other practices except exercise strategies to increase body size. Both boys and girls reported the lowest scores for food and exercise strategies to increase body weight. The variance explained by age was small and not considered biologically significant. While the findings do not demonstrate a relationship between desire to change body size/shape and age, weight concerns should not be overlooked, as both genders seem concerned with keeping their body weight low. The different practices used by each gender demonstrate that different body image ideals hold for boys and girls.

Antenatal breastfeeding intention, confidence and comfort in obese and non-obese primiparous Australian women: associations with breastfeeding duration.

BACKGROUND/OBJECTIVES: Maternal adiposity is known to affect breastfeeding initiation and duration via both antenatal and postnatal factors. This study investigates associations between maternal pregravid body mass index (BMI), breastfeeding duration and antenatal breastfeeding confidence, intention and social comfort among primiparous Australian women. SUBJECTS/METHODS: Women in their first pregnancy (n=462) were recruited by convenience sampling in Queensland, Australia. Participants responded to an antenatal and six postnatal questionnaires during their infants' first year between June 2010 and March 2012. Maternal pregravid BMI was examined against breastfeeding duration, participants' antenatal infant feeding intentions and measures of breastfeeding confidence and social comfort. RESULTS: Breastfeeding initiation in this cohort was 97%, but 46% of mothers had ceased breastfeeding at 52 weeks postpartum. Breastfeeding duration differed significantly (χ(2) (2)=7.21, P=0.007) between normal, overweight and obese women. No differences were found in antenatal intention for feeding type nor intended breastfeeding duration by one-way ANOVA (F(2,178)=1.77, P=0.17). More than half of the pregnant respondents anticipated social discomfort breastfeeding in public, with obese women significantly more likely to anticipate discomfort breastfeeding in the presence of close female friends, (χ(2) (1)=5.53, P=0.019). CONCLUSIONS: This study confirmed the risk of premature cessation of breastfeeding for obese mothers. Interventions during pregnancy that address body image issues in relation to breastfeeding may facilitate breastfeeding success for obese mothers and their infants and accrue short- and long-term health benefits for both.

Why do women stop breast-feeding? Results from a contemporary prospective study in a cohort of Australian women.

BACKGROUND/OBJECTIVES: Australian guidelines recommend infants be breast-fed for at least their first year of life; however, for a variety of reasons many mothers cease breast-feeding before this age. The objective of this study was to determine the reasons why women stop breast-feeding their infant completely, in relation to the age of the infant. SUBJECTS/METHODS: Primiparous Australian women aged between 18 and 40 years underwent a self-administered questionnaire-based birth cohort study on infant-feeding attitudes, behaviours and feeding patterns. Data were extracted from the demographic questionnaire and from questionnaires administered at 2, 4, 6 and 12 months of infant age between October 2010 and September 2011. RESULTS: Breast-feeding initiation in this cohort was 97%; however, by 52 weeks of infant age 46% of mothers had completely ceased breast-feeding. In those mothers who had ceased breast-feeding before 26 weeks the most common reason was 'I did not have enough milk'. In those mothers who had completely stopped breast-feeding between 26 and 52 weeks the most common reason reported as being very important in the decision to cease breast-feeding was 'My baby lost interest'. CONCLUSIONS: Maternal concerns regarding breast trauma, milk supply and infant satiety were central mediators of breast-feeding duration among these Queensland women. Further research into the antecedents of sucking pathologies and reasons for nipple trauma is indicated. Health professionals can assist women to recognise cues of hunger and satiety in their infants and understand the dynamics and natural history of breast-feeding to prolong breast-feeding relationships.

Dairy and plant based food intakes are associated with altered faecal microbiota in 2 to 3 year old Australian children.

The first 1000 days (conception to 24 months) is when gut microbiota composition and eating patterns are established, and a critical period influencing lifelong health. The aim of this study is to examine the associations between food intakes and microbiota composition at the end of this period. Diet was quantified for 37 well-nourished Australian children aged between 2 to 3 years by using a food frequency questionnaire and 24 hr recalls. Both dairy and plant-based (fruit, vegetables, soy, pulses and nuts) food intakes were associated with distinct microbiota profiles. Dairy intake was positively associated with the Firmicutes:Bacteroidetes ratio, and in particular Erysipelatoclostridium spp., but negatively associated with species richness and diversity. Vegetable intake was positively associated with the relative abundance of the Lachnospira genus, while soy, pulse and nut intake was positively associated with the relative abundance of bacteria related to Bacteroides xylanisolvens. Fruit intake, especially apples and pears, were negatively associated with the relative abundance of bacteria related to Ruminococcus gnavus. In this cohort of young children dairy and plant based food intakes were found to be associated with altered microbiota composition. Further exploration is needed to elucidate the effect of these dietary and microbial differences on host phenotype.

Early life nutrition and the opportunity to influence long-term health: an Australasian perspective.

There are now significant data to support the hypothesis that early life nutrition in the fetus, infant and young child can have profound effects on long-term health. This review considers some of this evidence with specific reference to the current burden of disease in Australia and New Zealand. As the findings of further research become available, recommendations on optimizing early life nutrition should be formulated and made widely available as part of the preventative health policy agenda in both Australia and New Zealand.

Nutritional status and energy expenditure in children pre-bone-marrow-transplant.

The aims of this study were to establish the nutritional status of children pre-BMT and to determine whether predictive methods of assessing nutritional status and resting energy expenditure (REE) are accurate in this population. We analysed the body cell mass (BCM) (n=26) and REE (n=24) in children undergoing BMT. BCM was adjusted for height (BCM/HT(p)) and expressed as a Z score to represent nutritional status. To determine whether body mass index (BMI) was indicative of nutritional status in children undergoing BMT, BMI Z scores were compared to the reference method of BCM/HT(p) Z scores. Schofield predictive equations of basal metabolic rate (BMR) were compared to measured REE to evaluate the accuracy of the predictive equations. The mean BCM/HT(p) Z score for the subject population was -1.09+/-1.28. There was no significant relationship between BCM/HT(p) Z score and BMI Z score (r=0.34; P>0.05); however there was minimal difference between measured REE and predicted BMR (bias=-11+/-149 kcal/day). The results of this study demonstrate that children undergoing BMT may have suboptimal nutritional status and that BMI is not an accurate indication of nutritional status in this population. However, Schofield equations were found to be suitable for representing REE in children pre-BMT.

Clinical accuracy of the MedGem indirect calorimeter for measuring resting energy expenditure in cancer patients.

OBJECTIVE: To compare, in patients with cancer and in healthy subjects, measured resting energy expenditure (REE) from traditional indirect calorimetry to a new portable device (MedGem) and predicted REE. DESIGN: Cross-sectional clinical validation study. SETTING: Private radiation oncology centre, Brisbane, Australia. SUBJECTS: Cancer patients (n = 18) and healthy subjects (n = 17) aged 37-86 y, with body mass indices ranging from 18 to 42 kg/m(2). INTERVENTIONS: Oxygen consumption (VO(2)) and REE were measured by VMax229 (VM) and MedGem (MG) indirect calorimeters in random order after a 12-h fast and 30-min rest. REE was also calculated from the MG without adjustment for nitrogen excretion (MGN) and estimated from Harris-Benedict prediction equations. Data were analysed using the Bland and Altman approach, based on a clinically acceptable difference between methods of 5%. RESULTS: The mean bias (MGN-VM) was 10% and limits of agreement were -42 to 21% for cancer patients; mean bias -5% with limits of -45 to 35% for healthy subjects. Less than half of the cancer patients (n = 7, 46.7%) and only a third (n = 5, 33.3%) of healthy subjects had measured REE by MGN within clinically acceptable limits of VM. Predicted REE showed a mean bias (HB-VM) of -5% for cancer patients and 4% for healthy subjects, with limits of agreement of -30 to 20% and -27 to 34%, respectively. CONCLUSIONS: Limits of agreement for the MG and Harris Benedict equations compared to traditional indirect calorimetry were similar but wide, indicating poor clinical accuracy for determining the REE of individual cancer patients and healthy subjects.

How much physical activity is enough to prevent unhealthy weight gain? Outcome of the IASO 1st Stock Conference and consensus statement.

A consensus meeting was held in Bangkok, 21-23 May 2002, where experts and young scientists in the field of physical activity, energy expenditure and body-weight regulation discussed the different aspects of physical activity in relation to the emerging problem of obesity worldwide. The following consensus statement was accepted unanimously. 'The current physical activity guideline for adults of 30 minutes of moderate intensity activity daily, preferably all days of the week, is of importance for limiting health risks for a number of chronic diseases including coronary heart disease and diabetes. However for preventing weight gain or regain this guideline is likely to be insufficient for many individuals in the current environment. There is compelling evidence that prevention of weight regain in formerly obese individuals requires 60-90 minutes of moderate intensity activity or lesser amounts of vigorous intensity activity. Although definitive data are lacking, it seems likely that moderate intensity activity of approximately 45 to 60 minutes per day, or 1.7 PAL (Physical Activity Level) is required to prevent the transition to overweight or obesity. For children, even more activity time is recommended. A good approach for many individuals to obtain the recommended level of physical activity is to reduce sedentary behaviour by incorporating more incidental and leisure-time activity into the daily routine. Political action is imperative to effect physical and social environmental changes to enable and encourage physical activity. Settings in which these environmental changes can be implemented include the urban and transportation infrastructure, schools, and workplaces.'