A National Review of Neonatal Jaundice Identification.

Background Physiological neonatal hyperbilirubinemia is a normal transitional phenomenon, however bilirubin encephalopathy can develop due to exposure to very high bilirubin levels. A systematic approach to early detection of high levels can prevent this outcome. Methods We designed a questionnaire to assess local jaundice management practices in Irish maternity units. Results All 19 units responded to our clinical questionnaire. Early discharge (<48 hours) occurs in 12 units (63%). Six units universally screen all babies with a transcutaneous bilirubinometer (TCB) (32%) while 12 units only do so if clinically jaundiced (83%). 12 units follow up <5% of their babies for jaundice monitoring after discharge (67%), which is lower than expected for optimal jaundice management. Conclusion Our survey responses show a high degree of variability in jaundice identification and follow up practices around the country. As maternity units trend towards earlier discharge of mothers due to resource constraints, we need to develop national systems to stratify risk before discharge and monitor jaundice in the out-patient setting. Introduction

Mediating role of body-related shame and guilt in the relationship between weight perceptions and lifestyle behaviours.

INTRODUCTION: A substantial proportion of individuals with overweight or obesity perceive themselves as 'too heavy' relative to 'about right'. Perceiving one's weight as 'too heavy' is associated with lower levels of physical activity and higher levels of sedentary behaviour. However, the mechanisms underpinning the associations between weight perception and lifestyle behaviours have not been identified. Based on theoretical tenets and empirical evidence, the self-conscious emotions of shame and guilt may mediate these associations. METHODS: Participants were young adults (n = 618, Mage = 24.0 ± .6 years) who provided data on weight, weight perception, body-related shame and guilt, physical activity and screen time. RESULTS: Mediation analyses using the PROCESS macro indicated that shame and guilt significantly mediated the relationships between weight perception and physical activity and shame significantly mediated the relationship between weight perception and screen time. CONCLUSIONS: These findings provide preliminary evidence that self-conscious emotions may be mechanisms by which weight perception influences physical activity and sedentary behaviour in young adults. However, longitudinal investigations of this mechanism are needed.

Nicotine dependence and sleep quality in young adults.

INTRODUCTION: More cigarette smokers report poor sleep quality than non-smokers, but the association between nicotine dependence (ND) and sleep quality has not been well-characterized. The objective of this study was to describe the associations among frequency and intensity of cigarette smoking, ND symptoms, and sleep quality in young adults. METHODS: Data on past-year smoking frequency, number of cigarettes smoked in the past month, five ND indicators (i.e., withdrawal, craving, self-medication symptoms, mFTQ, ICD-10 criteria for tobacco dependence), and sleep quality (measured with the Pittsburgh Sleep Quality Index (PSQI)) were collected in 2011-12 in self-report questionnaires completed by 405 young adult smokers (mean age 24 (0.6) years; 45% male; 45% daily smokers) participating in a longitudinal investigation of the natural course of ND. Associations between indicators of cigarette smoking, ND symptoms, and sleep quality were examined in multivariable logistic regression analyses controlling for age, sex, mother's education, and alcohol use. RESULTS: Thirty-six percent of participants reported poor sleep quality (PSQI>5). Higher cigarette consumption (OR(95% CI), 1.03(1.001-1.05)) but not frequency of past-year smoking, more frequent withdrawal symptoms (1.05(1.004-1.10)), more frequent cravings (1.05(1.004-1.10)), higher mFTQ scores (1.14(1.02-1.27)), and endorsing more ICD-10 criteria for tobacco dependence (1.19(1.04-1.36)) were also associated with poor sleep quality. CONCLUSION: Cigarette smoking and ND symptoms are associated with poor sleep quality in young adult smokers. Advice from practitioners to cut back on number of cigarettes smoked per day and treatment of ND symptoms may improve sleep quality in young adult smokers.

Night-eating symptoms and 2-year weight change in parents enrolled in the QUALITY cohort.

BACKGROUND/OBJECTIVE: The timing of food intake may be implicated in weight gain. This study tested the hypothesis that symptoms commonly associated with night-eating syndrome are related to measures of weight gain in adults. SUBJECTS/METHODS: Parents participating in QUALITY (Québec Adipose and Lifestyle InvesTigation in Youth) completed the night eating questionnaire (NEQ) at baseline (2005-2008) and at follow-up (2008-2010). Height and weight were measured and self-report questionnaire data were available for 388 parents (59% female, mean (s.d.) age: 41.8±5.7, mean (s.d.) body mass index (BMI): 29.6±5.7). Linear regression models were used to test the associations between baseline night-eating symptoms (NEQ scores, night-eating behaviours) and percent change in each of BMI and waist circumference (WC). RESULTS: A high NEQ score predicted a small increase in percent change in BMI in nonobese parents but a decrease among those who were severely obese. Nocturnal ingestions of food predicted an increase in percent change in BMI; however, the effect size was small. Morning anorexia predicted an increase in percent change in WC. CONCLUSION: Certain night-eating symptoms may predict measures of weight gain in adults but the effects seem small and the findings need to be confirmed in more symptomatic samples.

Chronicling changes to the chronic disease prevention landscape in Canada's public health system 2004-2010.

The collective impact of major shifts in public health infrastructure and numerous new chronic disease prevention (CDP) capacity-building initiatives that have taken place in Canada over the last decade is unknown. The objective of this study was to determine if CDP capacity (i.e., skills and resources) and involvement in CDP programming improved in public health organizations in Canada from 2004 to 2010. Data for this repeated cross-sectional study were drawn from two waves of a national census of organizations mandated to carry out primary prevention of chronic disease and/or promotion of healthy eating, physical activity and tobacco control. Medians for continuous variables and frequencies for categorical variables were compared across time. Neither resources nor level of priority for CDP increased over time. There was little difference in the proportion of organizations with high levels of skills and involvement in core CDP practices (i.e., needs assessment, identification of relevant practices, planning, evaluation). Skills and involvement in CDP risk factor programming showed some gains, some steady states and some losses. Specifically, skill and involvement in tobacco control programming declined markedly while the proportion of organizations involved in healthy eating and physical activity programming increased. Skills to address and involvement in programming related to social determinants of health remained low over time as did involvement in programming addressing multiple risk factors concurrently. The lack of marked improvement in CDP capacity between 2004 and 2010 against a backdrop of initiatives favourable to strengthening the preventive health system in Canada suggests that efforts may have fallen short.

Adiposity and glucose intolerance exacerbate components of metabolic syndrome in children consuming sugar-sweetened beverages: QUALITY cohort study.

BACKGROUND: Sugar-sweetened beverage (SSB) consumption is linked to weight gain and metabolic syndrome (MetS) components in children, but whether these associations are modified by excess weight and glucose tolerance status in children is not known. OBJECTIVE: The objective of this study was to examine the cross-sectional associations between SSB intake and MetS components among children above and below the 85th body mass index (BMI) percentile and those with and without impaired glucose tolerance (IGT). METHODS: Data were from the QUébec Adiposity and Lifestyle InvesTigation in Youth study (2005-2008). Caucasian children aged 8-10 years (n = 632) were recruited from 1040 primary schools in Québec, Canada. SSB consumption was assessed by three 24-h dietary recalls, body fat mass by dual-energy absorptiometry, physical activity by 7-d accelerometer. Multivariate linear regressions were used, with age, sex, fat mass index and physical activity as covariates, including waist circumference (WC), systolic blood pressure (SBP), concentrations of triglyceride and high-density lipoprotein cholesterol and homeostasis model assessment of insulin resistance (HOMA-IR) as outcome variables. RESULTS: Among overweight children, a 100-mL higher SSB consumption was associated with a 0.1-unit higher HOMA-IR (P = 0.009) and a 1.1-mm Hg higher SBP (P = 0.001). In children with IGT, a 100-mL higher SSB consumption was associated with a 1.4-mm Hg higher SBP and a 4.0-cm higher WC (P < 0.001). These associations were not observed among children <85th BMI percentile. CONCLUSIONS: Our results suggest that the association between higher SSB consumption and MetS components is more evident in overweight/obese and glucose-intolerant children.

Physical activity vs. sedentary time: independent associations with adiposity in children.

OBJECTIVE: To investigate the independent associations between objectively measured levels of movement intensity (i.e., time spent sedentary and at light, moderate and vigorous intensities) and indicators of adiposity in a cohort of Canadian children. METHODS: A cross-sectional study was conducted in 550 Caucasian children aged 8-10 years with at least one obese biological parent. Physical activity and sedentary time (accelerometer over 7 d) and indicators of adiposity (% body fat measured by dual-energy X-ray absorptiometry and waist-to-height ratio) were objectively measured. We examined the associations between levels of movement intensity and adiposity in multi-level linear regression models adjusted for age, sex, sleep duration, energy intake, sexual maturation, parental socioeconomic status and parental body mass index. RESULTS: Objectively measured sedentary time was not associated with adiposity indicators in this cohort (unadjusted and adjusted models). However, moderate-to-vigorous physical activity (MVPA) was inversely associated with % body fat (adj. ß = -0.047; P = 0.02) and waist-to-height ratio (adj. ß = -0.071; P < 0.001), independent of sedentary time and other covariates. Additionally, we observed that children who did not accumulate ≥60 min d(-1) of MVPA were more likely to be overweight or obese compared to those who met the recommendation (odds ratio [OR] 2.22, 95% confidence interval [CI] 1.45-3.38). In contrast, there was no difference in the likelihood of being categorized as overweight or obese between those who met the recommendation of ≤2 h d(-1) of screen time and those who did not meet this recommendation (OR 1.27, 95% CI 0.75-2.01). CONCLUSION: The present study suggests that MVPA is independently associated with adiposity indices in this sample of children while sedentary time is not. Future studies should examine the best approach to increase MVPA in children and youth.

Physical activity fluctuations and body fat during adolescence.

OBJECTIVE: The objective of the study was to test the hypothesis that greater fluctuations in physical activity lead to greater increases in body fat during adolescence. METHODS: Seven hundred fifty-six adolescents in Montreal, Canada, aged 12-13 years at baseline, completed a 7-d physical activity recall questionnaire every 3 months over 5 years. Body mass index (BMI), waist circumference, and triceps and subscapular skinfold thickness were measured at baseline and at the end of follow-up. Subject-specific linear regressions, expressing physical activity as a function of time, were fitted and physical activity fluctuation scores were obtained by averaging the absolute values of regression residuals. The association between body fat after 5 years and the physical activity fluctuation score was assessed in linear regressions adjusting for baseline body fat, average number of physical activity sessions per week, diet and sociodemographic variables. RESULTS: Among boys, there were statistically significant positive associations between physical activity fluctuation and BMI (ß, 95% confidence interval: 0.12, 0.02-0.21) and triceps skinfold (0.40, 0.17-0.63). The associations with waist circumference or subscapular skinfold were not statistically significant (0.22, -0.04-0.49; 0.13, -0.05-0.32, respectively). In girls, there were statistically significant negative associations between physical activity fluctuation and BMI (-0.12, -0.20 to -0.03), waist circumference (-0.54, -0.91 to -0.17), subscapular skinfold (-0.41, -0.56 to -0.26) and triceps skinfold (-0.22, -0.38 to -0.05). CONCLUSION: Physical activity fluctuations appear to affect body fat during adolescence. Sex-specific interventions may be needed given that greater physical activity fluctuations seem unfavourable for boys and beneficial for girls.

The effect of smoking cessation counselling in pregnant women: a meta-analysis of randomised controlled trials.

BACKGROUND: Pregnant smokers are often prescribed counselling as part of multicomponent cessation interventions. However, the isolated effect of counselling in this population remains unclear, and individual randomised controlled trials (RCTs) are inconclusive. OBJECTIVE: To conduct a meta-analysis of RCTs examining counselling in pregnant smokers. SEARCH STRATEGY: We searched the CDC Tobacco Information and Prevention, Cochrane Library, EMBASE, Medline and PsycINFO databases for RCTs evaluating smoking cessation counselling. SELECTION CRITERIA: We included RCTs conducted in pregnant women in which the effect of counselling could be isolated and those that reported biochemically validated abstinence at 6 or 12 months after the target quit date. DATA COLLECTION AND ANALYSIS: Overall estimates were derived using random effects meta-analysis models. MAIN RESULTS: Our search identified eight RCTs (n = 3290 women), all of which examined abstinence at 6 months. The proportion of women that remained abstinent at the end of follow up was modest, ranging from 4 to 24% among those randomised to counselling and from 2 to 21% among control women. The absolute difference in abstinence reached a maximum of only 4%. Summary estimates are inconclusive because of wide confidence intervals, albeit with little evidence to suggest that counselling is efficacious at promoting abstinence (odds ratio 1.08, 95% confidence interval 0.84-1.40). There was no evidence to suggest that efficacy differed by counselling type. CONCLUSIONS: Available data from RCTs examining the isolated effect of smoking cessation counselling in pregnant women are limited but sufficient to rule out large treatment effects. Future RCTs should examine pharmacological therapies in this population.

Higher vitamin D intake is needed to achieve serum 25(OH)D levels greater than 50 nmol/l in Québec youth at high risk of obesity.

BACKGROUND/OBJECTIVES: Vitamin D levels are often observed to be low in Canadian youth, despite the mandatory fortification of fluid milk. We identified modifiable correlates of plasma vitamin D concentrations to inform public health efforts to remediate low-vitamin D status. SUBJECTS/METHODS: We recruited 159 children aged 8-11 years, who were at at high risk of obesity, non-systematically during different seasons. Vitamin D status was assessed by measuring plasma 25-hydroxyvitamin D (25(OH)D) using a radioimmunoassay. Dietary intake, including vitamin supplements, was measured using three dietitian-administered 24 h diet recalls. Fat mass was measured by dual energy X-ray absorptiometry. Accelerometers were worn for 7 days to estimate physical activity. Independent correlates of plasma 25(OH)D concentrations were identified using multiple regression in an analysis controlling for season of measurement. RESULTS: Approximately, 7% of youth had hypovitaminosis D (25(OH)D ≤37.5 nmol/l) during winter and spring when vitamin D levels are at their nadir. Only 55% of participants had vitamin D levels, which the Institute of Medicine considers optimal (25(OH)D >50 nmol/l). The mean dietary vitamin D intake, 6.6 mcg, was well below current recommendations set at 15 mcg. A serving increase in milk consumption and a s.d. increase in physical activity were associated with only a 2.9 and 2.1 nmol/l increase in plasma 25(OH)D, respectively. There was no association between 25(OH)D and adiposity. CONCLUSIONS: Our results indicate the challenges of obtaining adequate vitamin D intake from the current food supply to support a level of 25(OD)D >50 nmol/l.

Adverse effects of a social contract smoking prevention program among children in Québec, Canada.

OBJECTIVE: To evaluate the impact of a smoke-free class competition in elementary schools in Québec, Canada before widespread dissemination of the program across the province. METHODS: In a quasiexperimental study design, 843 students in 27 schools exposed to "Mission TNT.06" were compared to 1213 students in 57 matched comparison schools. Baseline data were collected in grade 6 prior to implementation of the program. Follow-up data were collected in grade 7 after students had transitioned to secondary school. RESULTS: The program improved knowledge about the harmful effects of second-hand smoke, but had no impact on knowledge about the harmful effects of smoking, attitudes about the acceptability of cigarettes, beliefs about the tobacco industry, or self-efficacy to resist peer pressure to smoke. After exposure to the program, intervention students were more likely to misreport their smoking status and to report unfavourable attitudes about classmates who smoke. CONCLUSION: Mission TNT.06 may encourage young smokers to misreport their smoking status and to marginalise classmates who smoke. These findings prompted recommendations to conduct more in-depth evaluation of the smoke-free class competition before widespread dissemination of the program across the province.

Distinguishing risk factors for the onset of cravings, withdrawal symptoms and tolerance in novice adolescent smokers.

AIM: While many studies report determinants of adolescent cigarette smoking, few identify risk factors for nicotine dependence (ND). This study distinguished between risk factors for three hallmarks of ND including cravings, withdrawal symptoms and tolerance. METHODS: A total of 319 novice smokers were followed every 3 months from first puff on a cigarette until the end of secondary school. Outcomes included time to first report of cravings, withdrawal symptoms and tolerance. RESULTS: Female sex, inhalation, smoking a whole cigarette, weekly smoking, daily smoking and alcohol use each independently increased the incidence of the onset of cravings. Inhalation, weekly smoking, daily smoking and alcohol use predicted the onset of withdrawal symptoms. Withdrawal symptoms, smoking a whole cigarette, monthly smoking, daily smoking and friends and siblings smoking increased the incidence of the onset of tolerance. None of parental education, impulsivity, novelty seeking, self-esteem, depression, stress, parental smoking, physical activity, or participation in sports teams was associated with the outcomes. CONCLUSION: The hallmarks of early ND are related to intensity and frequency of cigarette use. Avoidance of daily smoking may be particularly important in preventing the onset of ND symptoms and sustained smoking.

A structural equation model relating adiposity, psychosocial indicators of body image and depressive symptoms among adolescents.

OBJECTIVE: Psychosocial factors, including pressure to be thin and body dissatisfaction, have been hypothesized to mediate the relationship between obesity and depression, especially during adolescence when vulnerability to social pressures around body shape and image is heightened. The objective was to test a model of the relationships among adiposity, psychosocial factors and depression in adolescents. METHOD: In a population-based sample of 1127 boys and 1167 girls aged 13 and 16 years, a model of the relationships between adiposity, pressure to be thin, body dissatisfaction and depressive symptoms was tested using structural equation modeling. RESULTS: Among girls, adiposity accounted for 62% of the total effect of depressive symptoms through its association with pressure to be thin and body dissatisfaction. Pressure to be thin was also uniquely related to depressive symptoms. Among boys, only body dissatisfaction was associated with depressive symptoms. CONCLUSION: Results support a relationship between adiposity, body satisfaction, pressure to be thin and depressive symptoms. Depressive symptoms should be assessed in obese adolescents, and interventions to prevent and treat obesity should incorporate elements targeting body dissatisfaction.

Body image and C-reactive protein in adolescents.

BACKGROUND: The association between inflammation and obesity is well documented; however, there is little evidence linking physiological markers of inflammation and psychosocial factors such as body image. This study examined the relation between body image and C-reactive protein (CRP). METHODS: Data were available for 1503 adolescents aged 13 and 16 years in a province-wide survey of a representative sample of youth in Quebec, Canada. Participants completed questionnaires assessing body image indicators of social pressures to lose weight and personal body shape discrepancies, provided a fasting blood sample for CRP, and had height and weight measured. RESULTS: In separate multivariable logistic regression models for girls and boys, body shape discrepancy was positively associated with CRP (boys: OR=2.6, 95% CI=1.4-4.8; girls: OR=2.2, 95% CI=1.2-4.3) independent of body mass index, puberty status and socio-demographic variables. CONCLUSIONS: Adverse biological markers of cardiometabolic risk and negative body image are associated in adolescence. These findings suggest that, in addition to the well-known psychological problems, negative body image perceptions may also threaten adolescent's physical health.

Do you see what I see? Weight status misperception and exposure to obesity among children and adolescents.

OBJECTIVE: Obesity prevention in childhood is important. However, changing children's lifestyle behaviors to reduce overweight is a substantial challenge. Accurately perceiving oneself as overweight/obese has been linked to greater motivation to change lifestyle behaviors. Children and adolescents may be less likely to perceive themselves as overweight/obese if they are exposed to overweight/obese people in their immediate environments. This study examined whether youth who are exposed to overweight parents and schoolmates were more likely to misperceive their own weight status. DESIGN: The Quebec Child and Adolescent Health and Social Survey was a provincially representative, school-based survey of children and adolescents conducted between January and May 1999. SUBJECTS: 3665 children and adolescents (age 9, n=1267; age 13, n=1186; age 16, n=1212) from 178 schools. Mean body mass index (BMI) was 17.5, 20.6 and 22.2 kg/m(2), respectively. MEASUREMENTS: The misperception score was calculated as the standardized difference between self-perception of weight status (Stunkard Body Rating Scale) and actual BMI (from measured height and weight). Exposure to obesity was based on parent and schoolmate BMI. RESULTS: Overweight and obese youth were significantly more likely to misperceive their weight compared with non-overweight youth (P<0.001). Multilevel modeling indicated that greater parent and schoolmate BMI were significantly associated with greater misperception (underestimation) of weight status among children and adolescents. CONCLUSION: Children and adolescents who live in environments in which people they see on a daily basis, such as parents and schoolmates, are overweight/obese may develop inaccurate perceptions of what constitutes appropriate weight status. Targeting misperception may facilitate the adoption of healthy lifestyle behaviors and improve the effectiveness of obesity prevention interventions.

Reporting of ethnicity in research on chronic disease: update.

This paper examines the inclusion of ethnicity and race as variables in current, leading edge research on chronic disease and its risk factors. Of 100 randomly selected original research articles published in high-impact journals in 2005, 85% did not report either a definition of ethnicity or its conceptualisation in terms of theoretical reasoning, and 98% did not report an actual measurement item. Ethnicity and race remain non-standardised and largely underdescribed variables in research on chronic disease. This represents an important loss of opportunity to articulate and test hypotheses about the mechanisms underlying ethnic group differences in chronic disease.

Risk factors for tobacco dependence in adolescent smokers.

OBJECTIVE: To study the incidence of conversion to tobacco dependence (TD) and the prevalence of the TD state in relation to several potential determinants in a sample of adolescent smokers. METHODS: Questionnaires were administered every 3-4 months to document TD symptoms, amount of cigarette consumption, and depression symptoms in a prospective cohort of 1293 grade 7 students in a convenience sample of 10 schools. RESULTS: Over 54 months of follow-up, 113 of 344 novice smokers converted to TD. The referent series for the analysis of incidence comprised 823 person-surveys. The prevalence series included 1673 person-surveys, contributed by 429 smokers. Conversion to TD and TD status were associated with the intensity of recent (that is, past 3-month) cigarette consumption (adjusted incidence rate ratio (aIRR) 1.63 (95% confidence interval (CI) 1.36 to 1.97) and adjusted prevalence odds ratio (aPOR) 1.35 (95% CI 1.23 to 2.48) per 100 cigarettes per month), slowest CYP2A6 activity (aIRR 4.19 (95% CI 1.38 to 12.76) and aPOR 2.30 (95% CI 1.29 to 4.09)), depression score (aIRR 1.61 (95% CI 1.17 to 2.21) and aPOR 1.47 (95% CI 1.22, 1.75) per 1-unit change). Additional determinants included, for conversion to TD, time since onset of cigarette use (aIRR 0.76 (95% CI 0.58 to 1.00) per year) and, for the TD state, positive TD status six months ago (aPOR 3.53 (95% CI 2.41 to 5.19)). CONCLUSIONS: TD risk in adolescents is associated with intensity of recent cigarette consumption, while the role of more distant cigarette consumption appears small; subjects with slow nicotine metabolism and those with more depression symptoms are at increased risk of becoming tobacco dependent. The risk of being tobacco dependent is considerably higher in subjects who had previously developed the TD state.

Genetically decreased CYP2A6 and the risk of tobacco dependence: a prospective study of novice smokers.

OBJECTIVE: Case control studies in adults suggest that defective alleles in the gene that codes for the hepatic cytochrome P450 2A6 (CYP2A6) protect against nicotine dependence (ND) and higher levels of cigarette consumption. These two hypotheses were tested in young adolescents. DESIGN: Self reports of tobacco use and ND symptoms were collected every 3-4 months in a prospective study of 1293 grade 7 students from a convenience sample of 10 schools. SUBJECTS: 281 smokers with genetic data were analysed; those who were not already tobacco dependent and who had inhaled (n = 228) were followed 29.9 months on average, until they became dependent or were censored. MAIN OUTCOME MEASURES: The association between metabolic activity, represented by CYP2A6 genotype, and conversion to dependence was analysed using Cox's proportional hazards model. RESULTS: During follow up 67 subjects (29.4%) became dependent. Relative to CYP2A6*1/*1, having 1-2 copies of the inactive CYP2A6*2 or *4 variant was a strong risk factor for developing dependence (hazard ratio 2.8, 95% confidence 1.3 to 6.3). Subjects with 1-2 partially inactive CYP2A6*9 or *12 variants were not at increased risk. Mean past-week cigarette consumption at the end of follow up (controlling for age, sex, and number of months since first inhalation) among dependent subjects was 29.1 among normal inactivators, compared to 17.2, and 12.7 among slower (1-2 copies of *9 or *12), and slowest (1-2 copies of *2 or *4) inactivators, respectively (p = 0.09). CONCLUSION: Adolescents with 1-2 copies of CYP2A6*2 or *4 are at substantially increased risk of becoming dependent but smoke less once dependent. Genetic risk for ND may need to be considered in the conceptualisation of tobacco control programmes for adolescents.

Insulin resistance syndrome in a representative sample of children and adolescents from Quebec, Canada.

OBJECTIVES: To estimate the prevalence of insulin resistance syndrome (IRS) in a representative sample of youth. To test for the independent contribution of insulin resistance (IR) and adiposity to clustering of metabolic risk factors. To identify the underlying components of IRS. To examine the relationship between adiposity and fasting plasma levels of free fatty acids (FFA). METHODS: In 1999, we conducted a school-based survey of a representative sample of youth aged 9, 13 and 16 y in Quebec, Canada. Age-specific questionnaire data, standardized clinical measurements and a fasting blood sample were available for 2244 subjects. Fasting insulin and HOMA were used as surrogate measures of IR. RESULTS: In all age-sex groups, adiposity indices, blood pressure (BP), plasma glucose and triglycerides (TG) increased significantly with increasing insulin quartiles while HDL cholesterol (HDL-C) decreased. The overall prevalence of IRS defined as hyperinsulinaemia combined with two or more risk factors including overweight, high systolic BP, impaired fasting glucose, high TG and low HDL-C, was 11.5% (95% CI: 10.2-12.9). There were no significant differences in the prevalence of IRS across ages or between sexes. The independent contribution of adiposity to clustering of risk factors was stronger than that of fasting insulin (or HOMA-IR). Factor analysis revealed three factors (BMI/insulin/lipids, BMI/insulin/glucose and diastolic/systolic BP) consistent across ages suggesting that more than one pathophysiologic process underlies IRS. Although elevation of FFA might be in the causal pathway linking obesity to IR, we did not detect any consistent association between measures of fatness and fasting plasma FFA. CONCLUSION: IRS is highly prevalent in youth, even among children as young as age 9 y. Factor analysis identifies three physiologic domains within IRS with a unifying role for markers of IR and adiposity.