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Background. Asthma and obesity are two common health problems in the pediatric population. Obesity is associated with several comorbidities which are of great consequence. Excess adipose tissue has been linked to asthma in a number of studies. However, little is known about childhood body mass index (BMI) trajectories and the development of asthma phenotypes. Objective. The current study aims to investigate the significance of BMI trajectories over childhood and the risk of asthma phenotypes. Methods. The current study is a prospective cohort of children aged 0-2 years who were followed every two years for eight years through cycles one to five in the National Longitudinal Survey of Children and Youths (NLSCY). Statistical analysis: a latent class growth modelling (LCGM) method was used to identify BMI trajectory patterns from cycles one to five. Multiple imputation (number of imputations=5) was carried out to impute children with missing values on height or weight information. Sampling weights and 1,000 bootstrap weights were used in SAS PROC SURVEYLOGISTIC to examine the association between BMI trajectory and asthma phenotypes (persistent or transient asthma) in a multivariate analysis. Results. The study consisted of 571,790 males and 549,230 females. Among them, 46% of children showed an increasing trajectory in terms of change in BMI percentile during childhood, followed by the stable-trajectory group (41%) and decreasing-trajectory group (13%). After controlling for confounding factors, females in the increasing BMI trajectory group were four times more likely to be associated with persistent asthma (OR = 4.09; 95% CI:1.04-16.15; p = 0.0442) than females in the stable BMI trajectory group. No such relationship was found in males. The BMI trajectory was not significantly associated with risk of transient asthma for either sex. Conclusion. We report a female-specific association between increasing adiposity, measured by BMI, and persistent asthma.

BACKGROUND: PYY is an appetite suppressing hormone. Low circulating PYY has been linked to greater BMI. However data is controversial and this association has not been verified in large human populations. OBJECTIVE: The purpose of this study was to investigate if fasting serum total PYY is associated with obesity status and/or adiposity at the population level. DESIGN: A total of 2094 subjects (Male-523, Female-1571) participated in this investigation. Total PYY was measured in fasting serum by enzyme-linked immunosorbent assay. Obesity status (NW-normal-weight, OW-overweight and OB-obese) was determined by the Bray Criteria according to body fat percentage measured by dual-energy x-ray absorptiometry and the WHO criteria according to BMI. One-way ANOVA and multiple regression was used to assess the adiposity-specific association between PYY and the following; weight, BMI, waist-circumference, hip-circumference, waist-hip ratio, percent body fat (%BF), trunk fat (%TF), android fat (%AF) and gynoid fat (%GF). RESULTS: PYY was not significantly different among NW, OW and OB groups defined by neither %BF nor BMI for both men and women. However among women, fasting PYY was positively associated with adiposity measures. Women with the highest (Top 33%) waist-circumference, %BF and %TF had significantly higher PYY (10.5%, 8.3% and 9.2% respectively) than women with the lowest (Bottom 33%). Age, smoking, medication use and menopause were all positively associated with PYY levels in women but not in men. CONCLUSION: To our knowledge this is the largest population based study, with the most comprehensive analysis and measures of confounding factors, to explore the relationship of circulating PYY with obesity. Contrary to initial findings in the literature we discovered that PYY was positively associated with body fat measures (waist-circumference, %BF and %TF) in women. Although the effect size of the positive association of PYY with obesity in women is small, and potentially negligible, it may in fact represent a protective response against significant weight gain.

'Food addiction' shares a similar neurobiological and behavioral framework with substance addiction. However whether, and to what degree, 'food addiction' contributes to obesity in the general population is unknown.to assess 1) the prevalence of 'food addiction' in the Newfoundland population; 2) if clinical symptom counts of 'food addiction' were significantly correlated with the body composition measurements; 3) if food addicts were significantly more obese than controls, and 4) if macronutrient intakes are associated with 'food addiction'.A total of 652 adults (415 women, 237 men) recruited from the general population participated in this study. Obesity was evaluated by Body Mass Index (BMI) and Body Fat percentage measured by dual-energy X-ray absorptiometry. 'Food addiction' was assessed using the Yale Food Addiction Scale and macronutrient intake was determined from the Willet Food Frequency Questionnaire.The prevalence of 'food addiction' was 5.4% (6.7% in females and 3.0% in males) and increased with obesity status. The clinical symptom counts of 'food addiction' were positively correlated with all body composition measurements across the entire sample (p

Magnesium plays a role in glucose and insulin homeostasis and evidence suggests that magnesium intake is associated with insulin resistance (IR). However, data is inconsistent and most studies have not adequately controlled for critical confounding factors.The study investigated the association between magnesium intake and IR in normal-weight (NW), overweight (OW) and obese (OB) along with pre- and post- menopausal women.A total of 2295 subjects (590 men and 1705 women) were recruited from the CODING study. Dietary magnesium intake was computed from the Willett Food Frequency Questionnaire (FFQ). Adiposity (NW, OW and OB) was classified by body fat percentage (%BF) measured by Dual-energy X-ray absorptiometry according to the Bray criteria. Multiple regression analyses were used to test adiposity-specific associations of dietary magnesium intake on insulin resistance adjusting for caloric intake, physical activity, medication use and menopausal status.Subjects with the highest intakes of dietary magnesium had the lowest levels of circulating insulin, HOMA-IR, and HOMA-ß and subjects with the lowest intake of dietary magnesium had the highest levels of these measures, suggesting a dose effect. Multiple regression analysis revealed a strong inverse association between dietary magnesium with IR. In addition, adiposity and menopausal status were found to be critical factors revealing that the association between dietary magnesium and IR was stronger in OW and OB along with Pre-menopausal women.The results of this study indicate that higher dietary magnesium intake is strongly associated with the attenuation of insulin resistance and is more beneficial for overweight and obese individuals in the general population and pre-menopausal women. Moreover, the inverse correlation between insulin resistance and dietary magnesium intake is stronger when adjusting for %BF than BMI.

Adiponectin is an adipose tissue derived hormone which strengthens insulin sensitivity. However, there is little data available regarding the influence of a positive energy challenge (PEC) on circulating adiponectin and the role of obesity status on this response.The purpose of this study was to investigate how circulating adiponectin will respond to a short-term PEC and whether or not this response will differ among normal-weight(NW), overweight(OW) and obese(OB).We examined adiponectin among 64 young men (19-29 yr) before and after a 7-day overfeeding (70% above normal energy requirements). The relationship between adiponectin and obesity related phenotypes including; weight, percent body fat (%BF), percent trunk fat (%TF), percent android fat (%AF), body mass index (BMI), total cholesterol, HDLc, LDLc, glucose, insulin, homeostatic model assessment insulin resistance (HOMA-IR) and β-cell function (HOMA-β) were analyzed before and after overfeeding.Analysis of variance (ANOVA) and partial correlations were used to compute the effect of overfeeding on adiponectin and its association with adiposity measurements, respectively. Circulating Adiponectin levels significantly increased after the 7-day overfeeding in all three adiposity groups. Moreover, adiponectin at baseline was not significantly different among NW, OW and OB subjects defined by either %BF or BMI. Baseline adiponectin was negatively correlated with weight and BMI for the entire cohort and %TF, glucose, insulin and HOMA-IR in OB. However, after controlling for insulin resistance the correlation of adiponectin with weight, BMI and %TF were nullified.Our study provides evidence that the protective response of adiponectin is preserved during a PEC regardless of adiposity. Baseline adiponectin level is not directly associated with obesity status and weight gain in response to short-term overfeeding. However, the significant increase of adiponectin in response to overfeeding indicates the physiological potential for adiponectin to attenuate insulin resistance during the development of obesity.

Ghrelin is a 28-amino acid orexigenic peptide synthesized mainly in the stomach. Acute administration of ghrelin has been found to decrease insulin secretion. However, little data is available regarding whether ghrelin contributes to the long-term regulation of insulin resistance at the population level. The aim of this study is to investigate the association between circulating ghrelin and insulin resistance in a large population based study.A total of 2082 CODING study (Complex Diseases in the Newfoundland population: Environment and Genetics) subjects were assessed. Subjects were of at least third generation Newfoundland descent, between the ages of 20 and 79 years, and had no serious metabolic, cardiovascular, or endocrine diseases. Ghrelin was measured with an Enzyme Immunoassay method. Insulin and fasting glucose were measured by Immulite 2500 autoanalyzer and Lx20 clinical chemistry analyzer, respectively. Homeostatic Model Assessment of β cell function (HOMA-β) and Insulin Resistance (HOMA-IR) and Quantitative Insulin-sensitivity Check Index (QUICKI) were used for measurement of insulin resistance.Partial correlation analyses showed a significant negative correlation between circulating ghrelin and insulin level and insulin resistance in the entire cohort and also in men and women separately. The aforementioned correlation was independent of age, percentage of trunk fat and HDL-cholesterol. According to menopausal status, only pre-menopausal women revealed negative correlations.Our results suggest that except for postmenopausal women, high circulating ghrelin level is associated with lower insulin resistance in the general population.

Ghrelin, an orexigenic gut hormone secreted primarily from the stomach, is involved in energy homeostasis. However, little data is available regarding its response to energy surplus and the development of human obesity.The present study investigated the response of circulating acylated ghrelin to a 7-day positive energy challenge.A total of 68 healthy young men were overfed 70% more calories than required, for 1-week. Subjects were classified based on percent body fat (measured by dual-energy X-ray absorptiometry) as normal weight, overweight, and obese. Serum acylated ghrelin concentration was measured before and after the positive energy challenge. Additionally, the relationship between acylated ghrelin and obesity-related phenotypes including weight, body mass index, percent body fat, cholesterol, HDL-c, LDL-c, glucose, insulin and homeostasis model assessment of insulin resistance and β-cell function at baseline and change due to overfeeding, were assessed.Contrary to our expectations, serum acylated ghrelin was significantly increased in response to overfeeding and the increase was independent of obesity status. There was no significant difference in fasting acylated ghrelin between normal weight, overweight, and obese men at baseline. Acylated ghrelin was negatively correlated with weight and BMI for normal weight and with BMI in overweight men. Also ghrelin was correlated with change in weight and BMI in overweight (negative relationship) and obese (positive relationship) groups.Our results showed that circulating acylated ghrelin was increased after a 7-day positive energy challenge regardless of adiposity status. However, acylated ghrelin was correlated with change in weight and BMI in opposing directions, in overweight and obese subjects respectively, thus dependent on obesity status.