Urine podocyte mRNA loss in preterm infants and related perinatal risk factors.

BACKGROUND: Preterm birth has been identified as a risk factor for development of long-term chronic kidney disease. Podocyte loss has been reported to contribute to this process in preterm animal models. However, details about podocyte loss in preterm infants and related perinatal risk factors have not been well clarified. METHODS: Forty full-term infants and 106 preterm infants were enrolled. Urine samples were collected from full-term infants within 4-7 days of birth and preterm infants at 37-40 weeks of corrected age. Levels of urine podocin mRNA, urine protein (UP), and urine microalbumin (UMA) were measured, and the relationship between these markers was evaluated. Clinical information in these infants was collected, and potential correlates that may lead to increased podocyte loss during the perinatal period were identified using linear regression analysis. RESULTS: Urine podocyte loss indicated by the urine podocin mRNA to creatinine ratio (UpodCR) was higher in preterm infants than in full-term infants. UpodCR was correlated with the levels of UP and UMA. Multiple linear regression analysis also showed that lower gestational age (GA) at birth and small for gestational age (SGA) were high risk factors for urine podocyte loss. CONCLUSIONS: Increasing urine podocyte loss was identified in preterm infants. Moreover, perinatal factors were associated with podocyte loss and may be a potential direction for comprehensive research and intervention in this field. A higher resolution version of the Graphical abstract is available as Supplementary information.

Environmental correlates of sedentary behaviors and physical activity in Chinese preschool children: A cross-sectional study.

OBJECTIVE: This cross-sectional study examined environmental correlates of sedentary behavior (SB) and physical activity (PA) in preschool children in the urban area of Tianjin, China. METHODS: Data were collected from the Physical Activity and Health in Tianjin Chinese Children study, involving healthy children 3-6 years old and their families. In all children (n = 980), leisure-time SB (LTSB) and leisure-time PA (LTPA) were reported in min/day by parents. In a subgroup (n = 134), overall sedentary time, light PA, and moderate-to-vigorous PA (MVPA) were objectively measured using ActiGraph accelerometry (≥3 days, ≥10 h/day). Environmental correlates were collected using a questionnaire that included home and neighborhood characteristics (e.g., traffic safety, presence of physical activity facilities) and children's behaviors. Potential correlates were identified using linear regression analysis. RESULTS: Multiple linear regression analysis showed that "having grandparents as primary caregivers" (ßs and 95% confidence intervals (95%CIs) for overall sedentary time: 29.7 (2.1-57.2); LTSB (ln): 0.19 (0.11-0.28)) and "having a television (for LTSB (ln): 0.13 (0.00-0.25)) or computer (for LTSB (ln): 0.13 (0.03-0.23)) in the child's bedroom" were both associated with higher SB. Furthermore, "having grandparents as primary caregivers" was associated with less MVPA (ß (95%CI): -7.6 (-14.1 to -1.2)), and "active commuting to school by walking" correlated with more MVPA (ß (95%CI): 9.8 (2.2-17.4)). The path model showed that "more neighborhood PA facilities close to home" was indirectly related to higher LTPA (ln), which was partly mediated by "outdoor play" (path coefficients (95%CI): 0.005 (0.002-0.008)) and "going to these facilities more often" (path coefficients (95%CI): 0.013 (0.008-0.018)). Traffic safety was not a correlate. CONCLUSION: Family structure and media exposure in the home maybe important factors in shaping preschoolers' PA patterns. Built environmental correlates could indirectly influence preschoolers' LTPA through parental help with engaging in active behaviors.

The association among SES, screen time, and outdoor play in children at different ages: The GECKO Drenthe study.

Introduction: This study examined the association among socioeconomic status (SES), screen time, and outdoor play in children at different ages in the GECKO Drenthe birth cohort study. Methods: Valid data were obtained from two surveys at ages 3-4 years and 10-11 years. Screen time (TV watching and computer use) and outdoor play were reported by parents. Childhood SES was derived by a synthetic "Equivalized Household Income Indicator," an estimated disposable income. Quantile regression models (cross-sectional analysis) and linear regression models (change between 3-4 and 10-11 years) were used. Results: In general, screen time increased strongly from a median of 51 min/day at 3-4 years (n = 888) to 122 min/day at 10-11 years (n = 1023), whereas time spent on outdoor play remained stable over age (77 min/day at 3-4 years and 81 min/day at 10-11 years). More time spent on outdoor play (50th quantile) was found in children with low SES families at 3-4 years, while at 10-11 years, more outdoor play was found in the high SES group. At 10-11 years, in the higher ranges of screen time, children from high SES had relatively lower screen time [50th quantile: -10.7 (-20.8; -0.6); 75th quantile: -13.6 (-24.4; -2.8)]. In the longitudinal analysis (n = 536), high SES was associated with an increasing time spent on outdoor play [11.7 (2.7; 20.8)]. Conclusion: Socioeconomic disparities in children's outdoor play and screen behavior may be more obvious with increasing age. Low SES may facilitate both outdoor play (at 3-4 years) and screen time (at 10-11 years); however, children from high SES families develop slightly more favorable behavior patterns with age.

The Association Between Sedentary Screen Time, Non-screen-based Sedentary Time, and Overweight in Chinese Preschool Children: A Cross-Sectional Study.

Introduction: Less is known about the effects of the different domains of sedentary behaviors on healthy weight in young children. This cross-sectional study examined the association between sedentary screen time (SST), non-screen-based sedentary time (NSST), and overweight (and obesity) in Chinese preschoolers. Methods: Data were collected from the Physical Activity and Health in Tianjin Chinese Children study (PATH-CC), involving healthy children 3-6 years old and their families. Children's overweight status was classified according to the international (IOTF) childhood BMI cut-offs. SST and NSST were reported in minutes/day by parents using the leisure-time sedentary behaviors questionnaire. Logistic regression models adjusted by sex, age, socioeconomic status, outdoor play, and sleep duration were used. Results: In a total of 971 children (55.4% boys), 11.8% were overweight. Generally, children spent 1 h/day in SST and 1 h/day in NSST. Multiple models showed that children who spent more time in SST were more likely to be overweight [OR and 95% CI: 1.22 (1.03-1.45)]. No correlation between time spent on NSST and children with overweight was found (P > 0.05). Conclusions: This study indicated that children who spent more time in SST were more likely to be overweight, but a null correlation between NSST and overweight was found. Longitudinal studies designed to identify associations between exposures to screen media and changes in metabolic parameters during a child's early years are needed.

Physical activity around the clock: objectively measured activity patterns in young children of the GECKO Drenthe cohort.

BACKGROUND: Given the widespread problem of physical inactivity, and the continued growth in prevalence of childhood and adolescent obesity, promotion of regular physical activity (PA) among young people has become a public priority. A greater understanding of children's PA patterns throughout the day is needed to effectively encourage children to be more physically active. Hence this study looking at the distribution of PA in young children throughout the day and its relevance to overweight. METHODS: Accelerometers (ActiGraph GT3X, weartime > 600 min/day, ≥3 days) were used to measure the PA of 958 children (aged 5.7 ± 0.8 years, 52% boys) enrolled in the GECKO Drenthe cohort. Levels of sedentary time (ST), light PA (LPA) and moderate-to-vigorous PA (MVPA) were recorded throughout the day and analysed in segments (07:00-09:00, 09:00-12:00, 12:00-15:00, 15:00-18:00, 18:00-21:00). Body mass index was measured by Preventive Child Healthcare nurses and Cole's (2012) definition of overweight was used. General linear mixed models, adjusted for age, sex and season, were used to analyse patterns of PA and ST throughout the day. RESULTS: Children were most sedentary in the early morning (07:00-09:00) and evening (18:00-21:00), and exhibited the most time spent engaged in LPA and MVPA in the afternoon (12:00-15:00) and late afternoon (15:00-18:00). The greatest inter-individual variation in ST, LPA and MVPA among the children occurred in the late afternoon and evening (approximately 40, 30 and 15 min difference per time segment between 25th and 75th percentile, respectively). The most active children (highest quartile of MVPA) were found to be more active and less sedentary throughout the entire day than the least active children (lowest quartile of MVPA). Furthermore, children with overweight were no less active than children without overweight. CONCLUSIONS: At this young age, the relevance of different PA patterns to childhood overweight was minimal. Children were most active in the afternoon and late afternoon. To encourage PA in general, ST can be reduced and PA increased in the early morning and evening. Targeted PA interventions to specifically stimulate the least active children could take place in the late afternoon or evening.

Objectively measured physical activity and psychosocial functioning in young children: The GECKO Drenthe cohort.

The global trend in inactivity in children may be related to psychosocial problems. We investigated the cross-sectional association between physical activity (PA) levels and psychosocial functioning in 3.4-7.3-year-old children. Children from the Dutch GECKO birth cohort (N = 898; 51.6% boys) had PA levels assessed objectively by accelerometry (ActiGraph GT3X) for at least three days. Linear regression analysis was used for associations with psychosocial functioning (parent report of the Strengths and Difficulties Questionnaire), controlling for gender, age and socio-economic status. Higher total and moderate-to-vigorous PA levels (MVPA) were associated with higher Total Difficulty scores, and sedentary time to lower Total Difficulty scores. More time spent in MVPA was significantly associated to "hyperactivity/inattention" in both boys (Standardized BBOYS = 0.192) and girls (Std.BGIRLS = 0.139) whereas for the time in sedentary behaviour, a reverse association was found only in boys (Std.BBOYS = -0.230). In boys only, more time in MVPA (Std.BBOYS = 0.154) and less time in sedentary behaviour (Std.BBOYS = -0.147), were significant determinants for 'behavioural problems'. When using objectively measured PA, parents report more hyperactivity/inattention and behavioural problems in the more active children, and less in the more sedentary children, most clearly for boys. High levels of PA might be an indicator of psychosocial problems in young children.

Environmental correlates of sedentary time and physical activity in preschool children living in a relatively rural setting in the Netherlands: a cross-sectional analysis of the GECKO Drenthe cohort.

OBJECTIVES: This study examined the relationship between environmental correlates and children's sedentary time (ST), light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) in preschool children. DESIGN: Cross-sectional study SETTING: A birth cohort in Drenthe, a northern province and relatively rural area of the Netherlands. PARTICIPANTS: Valid data both for the ActiGraph and the questionnaire were obtained from 505 child-parent pairs. PRIMARY AND SECONDARY OUTCOME MEASURES: ST, LPA and MVPA of children were objectively measured by ActiGraph accelerometry (minimum three wearing days, more than 10 hours/day). Environmental correlates were collected using a questionnaire reported by parents that included household characteristics, parental and children's PA behaviours and neighbourhood environment (eg, traffic safety, road network and presence of PA facilities). Potential correlates were identified using linear regression analysis, adjusted by age, gender, siblings, and maternal age and education level. Ordinary least square regression-based path analysis was used to estimate direct and indirect effects on activity outcomes in mediation models. RESULTS: Linear regression analysis showed that 'parents taking children to play sports' was related to less ST, more LPA and MVPA; more outdoor play was also related to less ST and more LPA, but not MVPA. Parents who perceived more PA facilities in their neighbourhood showed more support for 'taking children to play sports', and this was associated with less ST or more MVPA compared with children living with less PA facilities in their neighbourhood. No evidence was found for a relation between traffic safety or road network with ST, LPA and MVPA. CONCLUSIONS: This study indicated that parental support and child outdoor play may influence children's daily PA patterns. Convenient neighbourhood PA facilities, such as parks and playgrounds, had an indirect effect through parental support associated with lower children's ST and higher MVPA, even in relatively rural areas.

Factors of physical activity among Chinese children and adolescents: a systematic review.

BACKGROUND: Lack of physical activity is a growing problem in China, due to the fast economic development and changing living environment over the past two decades. The aim of this review is to summarize the factors related to physical activity in Chinese children and adolescents during this distinct period of development. METHODS: A systematic search was finished on Jan 10th, 2017, and identified 2200 hits through PubMed and Web of Science. English-language published studies were included if they reported statistical associations between factors and physical activity. Adapted criteria from the Strengthening The Reporting of OBservational studies in Epidemiology (STROBE) statement and evaluation of the quality of prognosis studies in systematic reviews (QUIPS) were used to assess the risk of bias of the included studies. Related factors that were reported in at least three studies were summarized separately for children and adolescents using a semi-quantitative method. RESULTS: Forty two papers (published 2002-2016) were included. Most designs were cross-sectional (79%), and most studies used questionnaires to assess physical activity. Sample size was above 1000 in 18 papers (43%). Thirty seven studies (88%) showed acceptable quality by methodological quality assessment. Most studies reported a low level of physical activity. Boys were consistently more active than girls, the parental physical activity was positively associated with children and adolescents' physical activity, children in suburban/rural regions showed less activity than in urban regions, and, specifically in adolescents, self-efficacy was positively associated with physical activity. Family socioeconomic status and parental education were not associated with physical activity in children and adolescents. CONCLUSIONS: The studies included in this review were large but mostly of low quality in terms of study design (cross-sectional) and methods (questionnaires). Parental physical activity and self-efficacy are promising targets for future physical activity promotion programmes. The low level of physical activity raises concern, especially in suburban/rural regions. Future research is required to enhance our understanding of other influences, such as the physical environment, especially in early childhood.