Yanrui Jiang

Relationship between Duration of Sleep and Hypertension in Adults: A Meta-Analysis.

OBJECTIVES Epidemiologic studies have shown that chronic short sleep may be associated with the development of hypertension; however, the results are controversial. This meta-analysis was conducted to determine whether the duration of sleep is associated with hypertension. METHODS Reference databases (PubMed, EmBase, the Cochrane Library, Chinese Biological Medicine database) were searched for studies related to sleep duration and hypertension. Sleep duration categories (≤ 5 h, 6 h, 7 h, 8 h, ≥ 9 h) and prevalence or incidence of hypertension in each sleep category were extracted. A general analysis and subgroup analyses stratified by gender, age, study design, and different definitions of sleep duration were conducted to evaluate the relationship between sleep duration and hypertension. RESULTS Thirteen articles out of a total of 1,628 articles involving 347,759 participants met the inclusion criteria. A U-shaped change in pooled odds ratios (ORs) for hypertension due to the change of sleep duration was observed. The unadjusted OR for hypertension of individuals who slept ≤ 5 h vs. 7 h was 1.61, 95% CI = 1.28-2.02; those who slept ≥ 9 h vs. 7 h was 1.29, 95% CI = 0.97-1.71. The pooled ORs were still significant after adjusted by age and gender. Women deprived of sleep (sleep time ≤ 5 h vs. 7 h, OR = 1.68, 95% CI = 1.39-2.03) had a higher risk of hypertension than men (OR = 1.30, 95% CI = 0.93-1.83). CONCLUSION Excessively longer and shorter periods of sleep may both be risk factors for high blood pressure; these associations are stronger in women than men.

Investigating the relationship between precocious puberty and obesity: a cross-sectional study in Shanghai, China

Objectives Obesity is reported to be closely relevant to early sexual development but the relationship between sexual precocity and obesity or central obesity is still inconsistent, especially in boys. We aimed to investigate the relationship between precocious puberty and obesity as well as central obesity. Design A large population-based cross-sectional study using multistage, stratified cluster random sampling. Setting Data from the Shanghai Children’s Health, Education and Lifestyle Evaluation (SCHEDULE) study in June 2014. Participants 17 620 Chinese children aged 6–12 years. Primary and secondary outcome measures Obesity was defined by WHO Child Growth Standards. Central obesity was defined by sex-specific waist-to-height ratio (WHtR) cut-offs (WHtR ≥0.48 for boys, WHtR ≥0.46 for girls). Precocious puberty was identified by Tanner stage of breast, pubic hair and testicle development. A χ2 test was performed to compare rates. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the association between precocious puberty and general obesity and central obesity. Probit analysis was used for estimating the median age at entry into Tanner stage 2 or greater for breast, pubic hair and testicle development. Linear regression was utilised to compare the effects of WHtR and body mass index (BMI) on sex development indicators. Results 25.98% and 38.58% of boys with precocious puberty were respectively accompanied by obesity (OR=2.15, 95% CI=1.31 to 3.50) or central obesity (OR=2.10, 95% CI=1.46 to 3.03); meanwhile, 13.86% and 29.42% of girls with precocious puberty were respectively accompanied by obesity (OR=9.00, 95% CI=5.60 to 14.46) or central obesity (OR=5.40, 95% CI=4.10 to 7.12). The median ages of breast, pubic hair and testicle development decreased with BMI increase and median ages of thelarche and testicular development rather than pubarche were earlier in children with central obesity. Conclusions Earlier pubertal development was positively associated with obesity and central obesity in Chinese children.

The Relation Among Sleep Duration, Homework Burden, and Sleep Hygiene in Chinese School-Aged Children

Insufficient sleep in school-aged children is common in modern society, with homework burden being a potential risk factor. The aim of this article is to explore the effect of sleep hygiene on the association between homework and sleep duration. Children filled out the Chinese version of the Adolescent Sleep Hygiene Scale, and parents filled out a sociodemographic questionnaire. The final sample included 363 boys and 371 girls with a mean age of 10.82 ± 0.38 years. Children with more homework went to bed later and slept less. Better sleep hygiene was associated with earlier bedtimes and longer sleep duration. Findings suggest that homework burden had a larger effect on sleep duration than sleep hygiene. Fifth-grade children in Shanghai have an excessive homework burden, which overwrites the benefit of sleep hygiene on sleep duration.

Association between Physical Activity and Teacher-Reported Academic Performance among Fifth-Graders in Shanghai: A Quantile Regression

Introduction A growing body of literature reveals the causal pathways between physical activity and brain function, indicating that increasing physical activity among children could improve rather than undermine their scholastic performance. However, past studies of physical activity and scholastic performance among students often relied on parent-reported grade information, and did not explore whether the association varied among different levels of scholastic performance. Our study among fifth-grade students in Shanghai sought to determine the association between regular physical activity and teacher-reported academic performance scores (APS), with special attention to the differential associational patterns across different strata of scholastic performance. Method A total of 2,225 students were chosen through a stratified random sampling, and a complete sample of 1470 observations were used for analysis. We used a quantile regression analysis to explore whether the association between physical activity and teacher-reported APS differs by distribution of APS. Results Minimal-intensity physical activity such as walking was positively associated with academic performance scores (β = 0.13, SE = 0.04). The magnitude of the association tends to be larger at the lower end of the APS distribution (β = 0.24, SE = 0.08) than in the higher end of the distribution (β = 0.00, SE = 0.07). Conclusion Based upon teacher-reported student academic performance, there is no evidence that spending time on frequent physical activity would undermine student’s APS. Those students who are below the average in their academic performance could be worse off in academic performance if they give up minimal-intensity physical activity. Therefore, cutting physical activity time in schools could hurt the scholastic performance among those students who were already at higher risk for dropping out due to inadequate APS.

Pre- and postnatal risk factors in relation to allergic rhinitis in school-aged children in China.

Objective The objective of this study was to investigate the relationship between prenatal and postnatal risk factors and the prevalence of allergic rhinitis (AR) in Chinese children of specific ages. Study Design This study was a cross-sectional survey. Students from 8 metropolitan cities in China were studied in November and December, 2005. There were 20,803 elementary-school Chinese children (49.6% boys, mean age, 9.19 years) enrolled. Questions from the standard questionnaire of the International Study of Asthma and Allergies in Children were completed to enable us to examine the pattern of current AR. The potential confounders and pre-and postnatal risk factors were analyzed using logistic regression. Results The overall prevalence of AR was found in this study to be 9.8%. After adjusting for several likely confounders, there was a higher likelihood of AR in school-aged children who were not exclusively breastfed in the first 4 months of their lives (odds ratio [OR]: 1.28; 95% confidence interval [CI]: 1.16–1.41), children who were born post-term (OR: 1.34; 95% CI: 1.12–1.60), children delivered by cesarean section (OR: 1.07; 95% CI: 1.00–1.19), or children born to mothers who experienced depressive symptoms during the pre- and postnatal periods (OR: 1.28; 95% CI: 1.15–1.42). Conclusions AR in school-aged children was found to be associated with pre- and postnatal events. These findings indicate that strategies to reduce exposure to risk factors during pre- and postnatal periods for childhood allergies might be warranted.

Somatic growth of lean children: the potential role of sleep

BackgroundDespite the current obesity pandemic, childhood malnutrition remains an urgent, public health concern. Similar to the obesity pandemic, childhood malnutrition is influenced by genetic and a number of social, environmental and biological factors. In this study, we investigated the association between sleep duration and somatic growth in lean children.MethodsA stratified, randomly clustered sampling design was used to select fifth grade students from 10 primary schools in Shanghai. Based on a body mass index below the 15th percentile a subsample of 143 lean children aged 10–11 years old was defined. Sleep duration and other potential confounders were surveyed through parental or self-report questionnaires. Body measurements were collected and used to calculate the Z score of weight, height, body mass index as well as body fat percentage.ResultsCompared with children who slept <9 hours, those who slept for ≥10 hours grew taller and gained more weight after adjusting for confounding factors. When children slept 9–10 hours, they had significantly higher Z score of weight and body mass index.ConclusionsProlonged sleep not only benefits weight gain but also improves height in lean children. Our findings might provide important public health advice such that prolonged sleep may be an effective modifier of nutritional problems in childhood.

Cesarean section without medical indication and risks of childhood allergic disorder, attenuated by breastfeeding

Caesarean section (CS) may increase the risk of asthma and allergic diseases in children, but previous studies could not preclude the potential confounding effect of underlying medical indications for CS. We aim to assess the association between CS itself (without indications) and risks of asthma and allergic rhinitis in children. The 2014 Shanghai Children’s Health, Education and Lifestyle Evaluation was a large population-based survey with cluster random probability sampling in 26 primary schools in Shanghai, China, in 2014. The mode of delivery and child history of asthma and allergic rhinitis were reported by parents. We included 12639 children in our analysis. CS without medical indication was associated with an increased risk of childhood asthma. CS without medical indication and CS for fetal complications were associated with increased risks of childhood allergic rhinitis, respectively. In children fed by exclusive breastfeeding or mixed feeding in the first four months after birth, these risks were not significant. In contrast, in children fed by exclusive formula milk, CS was highly significantly associated with childhood asthma and allergic rhinitis. In conclusion, CS without medical indication was associated with increased risks of both childhood asthma and allergic rhinitis. Breastfeeding in early infancy may attenuate these risks.

Differences in sleep problems between Japanese and Chinese preschoolers: a cross-cultural comparison within the Asian region.

STUDY OBJECTIVES Previous studies have performed cross-cultural comparisons of differences in childhood sleep problems between Asian and Western countries. However, whether such differences can be observed among Asian countries remains unclear. The present study aimed to investigate differences in the pattern of sleep problems between Japanese and Chinese preschoolers. METHODS Data were collected from one city in Japan and 10 cities in China. The present study recruited 438 Japanese and 1020 Chinese preschoolers aged four and five years. Sleep problems and patterns were assessed on the basis of parental reports using the Childrens Sleep Habits Questionnaire (CSHQ). RESULTS Analysis of covariance revealed no significant difference in total CSHQ scores between Japanese and Chinese preschoolers, thus indicating that the total severity of sleep problems did not differ between the groups. Japanese preschoolers exhibited higher scores on the bedtime resistance subscale of the CSHQ than Chinese preschoolers. Conversely, Chinese preschoolers exhibited higher subscale scores for night wakings and sleep-disordered breathing. In addition, Japanese preschoolers exhibited earlier bedtimes and wake times and shorter total sleep times than Chinese preschoolers. CONCLUSIONS Our findings indicate that the patterns of sleep problems in preschoolers differ between Japan and China and that such differences may be due to differences in cosleeping practices, bedtime routines, and/or environmental conditions. Thus, investigators studying sleep in preschoolers should consider regional differences in the pattern of sleep problems, even among Asian countries.

Association of Sleep and Circadian Activity Rhythm with Emotional Face Processing among 12-month-old Infants

Sleep and circadian rhythmicity both play an important role in human’s cognitive functioning, yet the way in which early development of sleep and circadian rhythm affects cognitive processes and social learning in infants remains less understood. We examined the association of sleep and circadian activity rhythm (CAR) with face and emotional information processing in 12-month old infants. Face processing was measured by eye tracking, whereby infants’ scanning patterns and pupil dilations were calculated when they were presented with neutral, pleasant and unpleasant faces. Infants with better sleep quality (i.e., less waking after sleep onset) and lower sleep-wake pattern variability (i.e., higher inter-daily stability) exhibited a higher eyes over mouth fixation ratio (EMR). Infants with longer total sleep time showed larger pupil diameter changes in response to emotional facial expressions, more closely resembling the responses of adults. Our findings suggest the role of sleep and circadian rhythm in waking cognition and have implications for understanding the early development of social learning in young children.

Cesarean section and risks of overweight and obesity in school-aged children: a population-based study

Background Obesity puts a great health burden in the world. Previous studies suggest that caesarean section (CS) may increase the risk of obesity in children, but it is still uncertain whether this association is causal or due to residual confounding by medical indication. Aim To assess the association between CS, CS without medical indications in particular and the risk of overweight and obesity in school-aged children. Design Cross-sectional survey. Methods The 2014 Shanghai Child Health, Education and Lifestyle Evaluation was a large population-based survey with cluster random probability sampling in 26 primary schools in Shanghai, China, in 2014. The mode of delivery was reported by parents. The height, weight and waist circumference of the children were measured. Logistic regression models with SURVEYLOGISTIC procedure were used to estimate the risk of childhood obesity. Pupils delivered vaginally were served as the reference group. Results A total of 17 571 pupils completed this survey, and 13 724 of them who were singleton, born term and between 5 and 13 years old were included in our analysis. CS was associated with increased risks of overweight and obesity (BMI: adjusted OR = 1.28 [95%CI 1.13-1.45] and 1.44 [1.26-1.66], respectively; weight for height ratio [WHtR] >0.46: 1.33 [1.20-1.48]). Similar results were found in CS without medical indication (BMI: overweight = 1.24 [1.05-1.47], obesity = 1.43 [1.19-1.72]; WHtR > 0.46: 1.30 [1.13-1.50]). Conclusions CS overall and CS without medical indications were associated with increased risks of overweight and obesity in primary school children.