Cellular localization and associations of the major lipolytic proteins in human skeletal muscle at rest and during exercise

Lipolysis involves the sequential breakdown of fatty acids from triacylglycerol and is increased during energy stress such as exercise. Adipose triglyceride lipase (ATGL) is a key regulator of skeletal muscle lipolysis and perilipin (PLIN) 5 is postulated to be an important regulator of ATGL action of muscle lipolysis. Hence, we hypothesized that non-genomic regulation such as cellular localization and the interaction of these key proteins modulate muscle lipolysis during exercise. PLIN5, ATGL and CGI-58 were highly (>60%) colocated with Oil Red O (ORO) stained lipid droplets. PLIN5 was significantly colocated with ATGL, mitochondria and CGI-58, indicating a close association between the key lipolytic effectors in resting skeletal muscle. The colocation of the lipolytic proteins, their independent association with ORO and the PLIN5/ORO colocation were not altered after 60 min of moderate intensity exercise. Further experiments in cultured human myocytes showed that PLIN5 colocation with ORO or mitochondria is unaffected by pharmacological activation of lipolytic pathways. Together, these data suggest that the major lipolytic proteins are highly expressed at the lipid droplet and colocate in resting skeletal muscle, that their localization and interactions appear to remain unchanged during prolonged exercise, and, accordingly, that other post-translational mechanisms are likely regulators of skeletal muscle lipolysis.

Associations between sedentary behaviour and body composition, muscle function and sarcopenia in community-dwelling older adults

Summary: While previous studies have reported detrimental associations of sedentary behaviours with cardiometabolic disorders and mortality, in this study, we report that higher levels of sitting time were associated with a greater risk of sarcopenia, with increased television (TV) viewing negatively associated with lean mass, independent of physical activity.

Associations between dietary iron and zinc intakes, and between biochemical iron and zinc status in women

Iron and zinc are found in similar foods and absorption of both may be affected by food compounds, thus biochemical iron and zinc status may be related. This cross-sectional study aimed to: (1) describe dietary intakes and biochemical status of iron and zinc; (2) investigate associations between dietary iron and zinc intakes; and (3) investigate associations between biochemical iron and zinc status in a sample of premenopausal women aged 18–50 years who were recruited in Melbourne and Sydney, Australia. Usual dietary intakes were assessed using a 154-item food frequency questionnaire (n = 379). Iron status was assessed using serum ferritin and hemoglobin, zinc status using serum zinc (standardized to 08:00 collection), and presence of infection/inflammation using C-reactive protein (n = 326). Associations were explored using multiple regression and logistic regression. Mean (SD) iron and zinc intakes were 10.5 (3.5) mg/day and 9.3 (3.8) mg/day, respectively. Median (interquartile range) serum ferritin was 22 (12–38) μg/L and mean serum zinc concentrations (SD) were 12.6 (1.7) μmol/L in fasting samples and 11.8 (2.0) μmol/L in nonfasting samples. For each 1 mg/day increase in dietary iron intake, zinc intake increased by 0.4 mg/day. Each 1 μmol/L increase in serum zinc corresponded to a 6% increase in serum ferritin, however women with low serum zinc concentration (AM fasting < 10.7 μmol/L; AM nonfasting < 10.1 μmol/L) were not at increased risk of depleted iron stores (serum ferritin <15 μg/L; p = 0.340). Positive associations were observed between dietary iron and zinc intakes, and between iron and zinc status, however interpreting serum ferritin concentrations was not a useful proxy for estimating the likelihood of low serum zinc concentrations and women with depleted iron stores were not at increased risk of impaired zinc status in this cohort.

Parents' food choice motives and their associations with children's food preferences

Objective The objective was to investigate parents' motives for selecting foods for their children and the associations between these motives and children's food preferences. Design Cross-sectional survey. A modified version of the Food Choice Questionnaire was used to assess parents' food choice motives. Parents also reported children's liking/disliking of 176 food and beverage items on 5-point Likert scales. Patterns of food choice motives were examined with exploratory principal component analysis. Associations between motives and children's food preferences were assessed with linear regression while one-way and two-way ANOVA were used to test for sociodemographic differences. Setting Two Australian cities. Subjects Parents (n 371) of 2-5-year-old children. Results Health, nutrition and taste were key motivators for parents, whereas price, political concerns and advertising were among the motives considered least important. The more parents' food choice for their children was driven by what their children wanted, the less children liked vegetables (β =-0·27, P<0·01), fruit (β=-0·19, P<0·01) and cereals (β=-0·28, P<0·01) and the higher the number of untried foods (r=0·17, P<0·01). The reverse was found for parents' focus on natural/ethical motives (vegetables β=0·17, P<0·01; fruit β=0·17, P<0·01; cereals β=0·14, P=0·01). Health and nutrition motives bordered on statistical significance as predictors of children's fruit and vegetable preferences. Conclusions Although parents appear well intentioned in their motives for selecting children's foods, there are gaps to be addressed in the nature of such motives (e.g. selecting foods in line with the child's desires) or the translation of health motives into healthy food choices.

Do sedentary behaviors mediate associations between socio-demographic characteristics and BMI in women living in socio-economically disadvantaged neighborhoods?

Women living in deprived neighborhoods are a risk group for overweight and obesity, particularly during the childbearing years. Several socio-demographic characteristics may compound this risk, but little is known about why this might be the case. Sedentary behaviors are emerging as a socio-demographically patterned risk factor for obesity. The purpose of the present study was to assess socio-demographic differences in sedentary behaviors, and to examine whether these behaviors could explain the relation between socio-demographic variables and BMI (BMI) in this risk group.

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: 2002/03) and follow-up waves (T2: 2005/06) 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 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 physical activity' 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 (OR=2.8; 95% CI: 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 three 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.International Journal of Obesity accepted article preview online, 24 April 2015. doi:10.1038/ijo.2015.66.

Demographic and psychographic associations of consumer intentions to purchase healthier food products

Objective: This study investigated the associations of nutrition concerns, demographics, universalism (community oriented) values, perceived control over personal health and food buying, and perceived influence over the food system with intentions to purchase low fat, sugar and salt (LFSS) food products. Methods: A national online survey of 2204 Australian consumers administered in November 2011. Structural equation modeling was used to examine associations of LFSS purchasing intentions with demographic, values, perceived control, and influence factors. Results: Nutrition concern, perceived influence over the food system, and universalism values were key predictors of LFSS purchasing intentions. Almost two thirds (64.6%) of the variance associated with LFSS purchasing was explained by the structural equation model. Conclusion: Communication programs which focus on universalism values, nutrition concern and perceived influence over the food system are likely to increase LFSS purchasing and perhaps reduce the demand for energy dense, nutrient poor foods.

Associations of diet quality with health-related quality of life in older Australian men and women

This study investigated associations between diet quality measures and quality of life two years later. Adults 55-65 years participating in the Wellbeing, Eating and Exercise for a Long Life (WELL) study in Victoria, Australia (n = 1150 men and n = 1307 women) completed a postal survey including a 111-item food frequency questionnaire in 2010. Diet quality in 2010 was assessed via the dietary guideline index (DGI), recommended food score (RFS) and Mediterranean diet score (MDS). The RAND 36-item survey assessed health-related quality of life in 2012. Associations were assessed using logistic regression adjusted for covariates. In men, DGI and RFS were associated with better reported energy (OR = 1.79, CI: 1.25, 2.55 and OR = 1.56, CI: 1.11, 2.19 respectively), and DGI was additionally associated with better general health (OR = 1.54, 95% CI: 1.08, 2.20), and overall mental component summary scale (OR = 1.51, CI: 1.07, 2.15) in the fully adjusted model. In women, associations between two indices of diet quality (DGI, RFS) physical function (OR = 1.66, CI: 1.19, 2.31 and OR = 1.70, CI: 1.21, 2.37 respectively) and general health (OR = 1.83, CI: 1.32, 2.54 and OR = 1.54, CI: 1.11, 2.14 respectively) were observed. DGI was also associated with overall physical component summary score (OR = 1.56, CI: 1.12, 2.17). Additional associations between emotional wellbeing and DGI (OR = 1.40, CI: 1.01, 1.93) and RFS (OR = 1.44, CI: 1.04, 1.99), and MDS and energy (OR = 1.53, CI: 1.11, 2.10) were observed in the fully adjusted model, in women only. Older adults with better quality diets report better health-related quality of life, with additional associations with emotional wellbeing observed in women.

Tracking of maternal self-efficacy for limiting young children's television viewing and associations with children's television viewing time: a longitudinal analysis over 15-months

BACKGROUND: Mothers' self-efficacy for limiting their children's television viewing is an important correlate of this behaviour in young children. However, no studies have examined how maternal self-efficacy changes over time, which is potentially important during periods of rapid child development. This study examined tracking of maternal self-efficacy for limiting young children's television viewing over 15-months and associations with children's television viewing time. METHODS: In 2008 and 2010, mothers (n = 404) from the Melbourne InFANT Program self-reported their self-efficacy for limiting their child's television viewing at 4- and 19-months of age. Tertiles of self-efficacy were created at each time and categorised into: persistently high, persistently low, increasing or decreasing self-efficacy. Weighted kappa and multinomial logistic regression examined tracking and demographic and behavioural predictors of change in self-efficacy. A linear regression model examined associations between tracking categories and children's television viewing time. RESULTS: Tracking of maternal self-efficacy for limiting children's television viewing was low (kappa = 0.23, p < 0.001). Mothers who had persistently high or increasing self-efficacy had children with lower television viewing time at 19-months (β = -35.5; 95 % CI = -54.4,-16.6 and β = 37.0; 95 % CI = -54.4,-19.7, respectively). Mothers of children with difficult temperaments were less likely to have persistently high self-efficacy. Mothers who met adult physical activity guidelines had 2.5 greater odds of increasing self-efficacy. CONCLUSIONS: Interventions to increase and maintain maternal self-efficacy for limiting children's television viewing time may result in lower rates of this behaviour amongst toddlers. Maternal and child characteristics may need to be considered when tailoring interventions.

Lunch frequency among adolescents: associations with sociodemographic factors and school characteristics

Objective: To investigate: (i) how lunch frequency of adolescents varies between schools and between classes within schools; (ii) the associations between frequency of lunch and individual sociodemographic factors and school characteristics; and (iii) if any observed associations between lunch frequency and school characteristics vary by gender and age groups. Design: Cross-sectional study in which students and school headmasters completed self-administered questionnaires. Associations were estimated by multilevel multivariate logistic regression. Setting: The Danish arm of the Health Behaviour in School-Aged Children study 2010. Subjects: Students (n 4922) aged 11, 13 and 15 years attending a random sample of seventy-three schools. Results: The school-level and class-level variations in low lunch frequency were small (intraclass correlation coefficient <2·1 %). At the individual level, low lunch frequency was most common among students who were boys, 13- and 15-year-olds, from medium and low family social class, descendants of immigrants, living in a single-parent family and in a reconstructed family. School-level analyses suggested that having access to a canteen at school was associated with low lunch frequency (OR=1·47; 95% CI 1·14, 1·89). Likewise not having an adult present during lunch breaks was associated with low lunch frequency (OR=1·44; 95% CI 1·18, 1·75). Cross-level interactions suggested that these associations differed by age group. Conclusions: Lunch frequency among Danish students appears to be largely influenced by sociodemographic factors. Additionally, the presence of an adult during lunch breaks promotes frequent lunch consumption while availability of a canteen may discourage frequent lunch consumption. These findings vary between older and younger students.

Associations between skill perceptions and young children's actual fundamental movement skills

-Given that children with low movement skill competence engage in less physical activity, it is important to understand how children's perceptions relate to actual movement competence. This study examined relationships between (i) children's self-perception and objective assessments of their movement skills (object control and locomotor) and (ii) parents' perceptions of the children's movement skills and objective assessment. Children's skill perceptions were assessed using the Pictorial Scale of Perceived Movement Skill Competence for Young Children. Parent perceptions of their child's skills were assessed using a modified version of this instrument. The Test of Gross Motor Development-2nd edition assessed children's skills objectively. Participants were 136 Australian children (51% boys; M = 6.5 yr., SD = 1.1) and 133 parents. Regression analyses (by sex) examined the relationship between perceptions and children's scores for actual skilled performance. Boys' perceptions were associated with their actual object control ability. Parents accurately perceived boys' object control ability and girls' locomotor ability, but not the reverse. This suggests interventions aiming to improve children's movement skills could target parents and be designed to teach parents how to recognize good and poor skill performance in their children.

Associations of obsessive-compulsive symptoms with clinical and neurocognitive features in schizophrenia according to stage of illness

This study aimed to investigate the association of obsessive-compulsive symptoms with clinical and neurocognitive features in patients with schizophrenia. This study enrolled 163 people with schizophrenia who were receiving risperidone monotherapy. Comorbid obsessive-compulsive symptoms were assessed using the Yale-Brown Obsessive-Compulsive Scale, and subjects with a score≥10 constituted the obsessive-compulsive symptom group (n=30, 18.4%). The learning index was significantly higher in patients with obsessive-compulsive symptoms than in those without such symptoms after adjusting for age, stage (early and chronic), duration of illness, and CDSS score. However, there was no significant interaction between obsessive-compulsive symptoms and stage of illness. Scores on Positive and Negative Syndrome Scale, Calgary Depression Scale for Schizophrenia, and Beck Depression Inventory were significantly higher in the obsessive-compulsive symptom group. In addition, the Subjective Well-being under Neuroleptic Treatment score was significantly lower in the obsessive-compulsive symptom group. In conclusion, comorbid obsessive-compulsive symptoms in patients with schizophrenia were associated with a higher learning ability without a significant interaction with stage of illness. However, schizophrenia patients with obsessive-compulsive symptoms had more severe psychotic and depressive symptoms and poorer quality of life.

Associations of obsessive-compulsive symptoms with clinical and neurocognitive features in schizophrenia according to stage of illness

This study aimed to investigate the association of obsessive-compulsive symptoms with clinical and neurocognitive features in patients with schizophrenia. This study enrolled 163 people with schizophrenia who were receiving risperidone monotherapy. Comorbid obsessive-compulsive symptoms were assessed using the Yale-Brown Obsessive-Compulsive Scale, and subjects with a score ≥ 10 constituted the obsessive-compulsive symptom group (n=30, 18.4%). The learning index was significantly higher in patients with obsessive-compulsive symptoms than in those without such symptoms after adjusting for age, stage (early and chronic), duration of illness, and CDSS score. However, there was no significant interaction between obsessive-compulsive symptoms and stage of illness. Scores on Positive and Negative Syndrome Scale, Calgary Depression Scale for Schizophrenia, and Beck Depression Inventory were significantly higher in the obsessive-compulsive symptom group. In addition, the Subjective Well-being under Neuroleptic Treatment score was significantly lower in the obsessive-compulsive symptom group. In conclusion, comorbid obsessive-compulsive symptoms in patients with schizophrenia were associated with a higher learning ability without a significant interaction with stage of illness. However, schizophrenia patients with obsessive-compulsive symptoms had more severe psychotic and depressive symptoms and poorer quality of life.

Associations of sedentary time patterns and TV viewing time with inflammatory and endothelial function biomarkers in children

OBJECTIVE: Investigate associations of TV viewing time and accelerometry-derived sedentary time with inflammatory and endothelial function biomarkers in children.

METHODS: Cross-sectional analysis of 164 7-10-year-old children. TV viewing time was assessed by parental proxy report and total and patterns of sedentary time accumulation (e.g. prolonged bouts) were assessed by accelerometry. C-reactive protein (CRP), homeostasis model assessment of insulin resistance, interleukin-2, -6, -8, -10, tumour necrosis factor alpha, adiponectin, resistin, brain-derived neurotrophic factor, soluble intercellular and vascular adhesion molecule 1, plasminogen activator inhibitor 1 and soluble E-selectin were assessed. Generalised linear models assessed the associations of TV viewing and sedentary time with biomarkers, adjusting for sex, waist circumference, moderate- to vigorous-intensity physical activity and diet density.

RESULTS: Each additional h week(-1) of TV viewing was associated with 4.4% (95% CI: 2.1, 6.7) greater CRP and 0.6% (0.2, 1.0) greater sVCAM-1 in the fully adjusted model. The association between frequency and duration of 5-10 min bouts of sedentary time and CRP was positive after adjustment for sex and waist circumference but attenuated after adjustment for diet density.

CONCLUSIONS: This study suggests that TV viewing was unfavourably associated with several markers of inflammation and endothelial dysfunction. The detrimental association between 5 and 10 min bouts of sedentary time and CRP approached significance, suggesting that further research with a stronger study design (longitudinal and/or experimental) is needed to better understand how the accumulation of sedentary time early in life may influence short and longer term health.

Cross-sectional and longitudinal associations between parents' and preschoolers' physical activity and TV viewing: the HAPPY Study

Background: Parental modelling has been shown to be important for school-aged children’s physical activity (PA) and television (TV) viewing, yet little is known about its impact for younger children. This study examined cross-sectional and three-year longitudinal associations between PA and TV viewing behaviours of parents and their preschool children. Method: In 2008-9 (T1), parents in the HAPPY cohort study (n=450) in Melbourne, Australia self-reported their weekly PA and TV viewing, and proxy-reported their partner’s PA and TV viewing, and their 3-5 year-old preschool child’s TV viewing. Children’s PA was assessed via accelerometers. Repeat data collection occurred in 2011-12 (T2). Results: Mothers’ and fathers’ PA were associated with PA among preschool girls at T1, but not boys. Parents’ TV viewing times were significant correlates of girls’ and boys’ TV viewing at T1. Longitudinally, mothers’ PA at baseline predicted boys’ PA at T2, while sex-specific associations were found for TV viewing, with mothers’ and fathers’ TV viewing at T1 associated with girls’ and boys’ TV viewing respectively at T2. Conclusions: The PA and TV viewing of both parents are significantly associated with these behaviours in preschool children. The influence of the sex-matched parent appears to be important longitudinally for children’s TV viewing&period.