Abstract The issue of multimorbidity in children and adolescents is becoming increasingly prominent, but there is no consensus on the definition of multimorbidity. As research deepens, issues related to the comparability and standardization of relevant findings are gradually emerging. As a solution, a systematic review of both domestic and international research on multimorbidity is conducted, and a classification system for defining the concept of multimorbidity is proposed, offering more convenient conditions for the advancement of future research and cross study exchange.

Objective: To analyze the association and dose response relationship between physical activity and inflammatory markers in college students, so as to provide a reference for promoting cardiometabolic health in college students. Methods: A cluster random sampling method was used to select 747 college students from two universities in Hefei, Anhui Province and Shangrao, Jiangxi Province from April to May 2019. Physical activity was assessed by using the International Physical Activity Questionnaire-Short Form (IPAQ-SF), and peripheral blood was collected to detect plasma inflammatory factor levels [including hypersensitive C reactive protein (hsCRP), interleukin-10 (IL-10), interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)]. The differences between the groups were compared by using the χ 2 test and the Kruskal-Wallis rank sum test, and the association between physical activity and inflammatory markers was analyzed by using the Generalized Linear Model. The dose response relationship between physical activity and inflammatory markers was analyzed using the Restricted Cubic Spline Model. Results: The proportions of low physical activity, moderate physical activity, and high physical activity groups of college students were 15.9%, 53.7% and 30.4%, respectively. The levels of hsCRP, IL-10, IL-1β, IL-6 and TNF-α in the high physical activity group were 0.38(0.21, 1.10)mg/L, 70.74(47.90, 116.43)pg/mL, 1.75(1.21, 2.64)pg/mL, 4.33(2.93, 6.82) pg/mL , 5.27(3.89, 7.30)pg/mL,the levels in the low physical activity group were 0.80(0.31, 1.30)mg/L, 73.88 (47.90, 124.24)pg/mL, 1.88(1.42, 2.81) pg/mL, 4.82 (3.64, 6.67) pg/mL, 5.63 (4.34, 7.62)pg/mL, the levels in the moderate physical activity group were 0.63(0.25, 1.30)mg/L, 89.78(58.21, 127.65)pg/mL, 2.21(1.59, 3.27)pg/mL, 5.15( 3.72 , 7.72)pg/mL, 5.87( 4.63 , 8.00)g/mL, and the differences were statistically significant ( H=10.66, 11.38, 27.79, 14.13, 9.44, P <0.05). After adjusting for variables such as gender, body mass index, smoking, alcohol consumption and health status, the results of Generalized Linear Model showed that compared with the high physical activity group, the low physical activity group ( OR=2.20, 95%CI = 1.46- 3.31) and the moderate physical activity group ( OR=1.65, 95%CI =1.22-2.25) were more likely to have high levels of hsCRP, and the moderate physical activity group was more likely to have high levels of IL-1β ( OR=1.85, 95%CI =1.36-2.51), IL-6 ( OR=1.44, 95%CI =1.06-1.96), and TNF-α ( OR=1.43, 95%CI =1.05-1.94) ( P <0.05). The Restricted Cubic Spline Model showed that there was no linear dose response relationship between the time of moderate to vigorous physical activity weekly and IL-10, IL-6, II-1β, and TNF-α ( P <0.05). Conclusion There is an association between physical activity and inflammation in college students, and moderate to high intensity per week could reduce inflammation levels to promote cardiometabolic health in college students.

Objective: To describe the association of different sleep characteristics and cardiometabolic risk among college students, so as to provide reference for health promotion of college students. Methods: By random cluster sampling method, a questionnaire survey and physical examination including blood pressure, waist circumference and blood lipid indicators, which were conducted in April and May of 2019 among a total of 1 179 college students from the first grade in two universities in Hefei City of Anhui Province and Shangrao City of Jiangxi Province. A total of 729 college students with valid questionnaires were included into analysis. The Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI) were used to investigate sleep behavior, and the Morning And Evening Questionnaire-5 (MEQ-5) was used to investigate sleep characteristics. The cardiometabolic risk score was derived using the sum of the standardized sex specific Z scores of waist circumference, mean arterial pressure, HDL cholesterol (multiplied by -1), triglycerides, and insulin resistance index. The rank sum tests were used to compare differences in cardiometabolic risk scores across demographic characteristics. Generalized linear models were used to compare the association of different sleep characteristics with cardiometabolic risk scores among college students. Results: The average cardiovascular metabolic risk score of college students was -0.32(-2.03, 1.58). There were statistically significant differences in cardiovascular metabolic risk scores among college students in variables such as smoking, health status, and physical activity levels ( t/F=-3.41, 12.88, 51.07, P <0.01). The results of the generalized linear model showed that nighttime preference ( B=1.89, 95%CI =1.02-3.49), insomnia symptoms ( B=3.25, 95%CI =1.79-5.90), and short or long sleep duration ( B=1.92, 95%CI =1.21-3.05) were positively correlated with the cardiovascular metabolic risk score of college students ( P <0.05). Conclusions Poor sleep patterns among college students are positively correlated with the risk of cardiovascular metabolism. The sleep behavior of college students should be actively changed to reduce the risk of cardiovascular disease.

Refractive error is a common ophthalmic disease in children. It refers to the mismatch between the axial length and the refractive power that results in visual blur, which is usually driven by the interaction of genetic and environmental factors. The impacts of pregnancy and puerperium-related factors on refractive error in children have gradually gained attention. According to the different stages of pregnancy, this review summarizes the impacts of four aspects on refractive error in children, including lifestyle during pregnancy, complications and comorbidities during pregnancy, adverse pregnancy outcomes and other factors, which aims to provide perinatal healthcare clues for the prevention and control of refractive error in children, achieve prevention beforehand and reduce the public health burden of refractive error in children.

Objective:To understand the prevalence of occasional hypertension in preschool children in three provinces in the middle and lower reaches of the Yangtze River in China, and analyze the relationship between their sleep status and occasional hypertension.Methods:From October to November 2017, a total of 24 842 preschool children from 109 kindergartens in 11 cities in Hubei, Anhui and Jiangsu provinces were selected by intentional sampling method. A self-made questionnaire was used to collect basic information about the subjects, and the sleep status data was collected by the Children′s Sleep Habits Questionnaire. Physical examinations were performed on the subjects, and height, weight and blood pressure were measured on-site. The difference in occasional hypertension detection rate among preschool children with different characteristics was compared, and the correlation between sleep status and occasional hypertension detection rate was analyzed by the multivariate logistic regression model.Results:The age of the subjects was (4.4±1.0) years, including 12 729 boys (51.2%). The prevalence of occasional hypertension was 31.8% (7 907/24 842). The prevalence of occasional hypertension among preschool children in three provinces of the middle and lower reaches of the Yangtze River was 31.8%. There were statistically significant differences in the detection rate of occasional hypertension among preschool children of different genders, age groups, family residence, family economic status and parents′ education level (all P values<0.05). The detection rate of occasional hypertension in children with less than 10 hours of sleep was higher than those with sufficient sleep, and the difference was statistically significant ( P<0.05). The results of multivariate logistic regression analysis showed that after adjusting for factors such as gender, age, family residence, family economic status, parental education level, parental smoking history, and physical constitution, the ORs (95% CI) for less than 10 hours of sleep, turning on the lights while sleeping, and poor sleep quality were 1.09 (1.03-1.15), 1.17 (1.07-1.28) and 1.04 (0.91-1.18), respectively, compared with the corresponding reference group. Conclusion:The detection rate of occasional hypertension is high in preschool children in the middle and lower reaches of the Yangtze River and there is a positive correlation between insufficient sleep and turning on the light when sleeping and occasional hypertension in preschool children.

Objective To investigate the influencing factors of peripheral infections of knee joint tumor prosthesis as well as the value of serum D-D and TLR2 in predicting the infection risks so as to provide a reference for early diagnosis of tumorous periprosthetic infection(PJI)of knee joint.Methods The patients who were treated and followed up in our department from January 2008 to June 2020 were selected.According to the inclusion and exclusion criteria,136 of the patients were selected.The data including age,gender,BMI,history of diabetes,smoking history,tumor location,stage of malignant tumor,operation time,osteotomy length,intraoperative bleed-ing,and the percentage of neutrophils,leukocytes,serum D-dimer,and serum TLR value 3 days after operation were collected.The risk factors of PJI and the diagnostic value of serum D-dimer and serum TLR were analyzed.Results The incidence of PJI was 11.76%.Postoperative chemotherapy and operation time≥180 min were the risk factors of PJI(P<0.05).The area under curve(AUC)of the combination of two indicators,serum D-dimer and serum TLR2 were 0.917,0.894 and 0.778,respectively.The AUC of TLR2 was lower than that of the combina-tion of two indicators(P<0.05);The sensitivity was 0.975,0.908 and 0.708,respectively,and the specificity was 0.75,0.75,and 0.812,respectively.Conclusion Postoperative chemotherapy and operation time≥180 min are the risk factors of PJI.The combination of D-dimer and TLR2 has good diagnostic value.

Objective: To describe the prevalence and the association of sleep quality trajectory, social jetlag and comorbid symptoms of anxiety and depression among college students, in order to provide a theoretical basis for improving the comorbid symptoms of anxiety and depression in college students. Methods: A questionnaire survey was conducted among 1 135 college students from two universities in Shangrao, Jiangxi Province and Hefei, Anhui Province from April to May 2019, and were followed up once every one year for a total of three times, with a valid sample size of 1 034 individuals after matching with the baseline survey. A selfassessment questionnaire was used to investigate the social jetlag of college students, the Generalized Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire 9 (PHQ-9) were used to evaluate anxiety and depression symptoms, respectively, while the Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. College students with GAD-7 score ≥5 and PHQ-9 score ≥5 were defined as having comorbid anxiety and depression symptoms. Latent class growth model (LCGM) was employed to analyze the sleep quality trajectory of college students, and binary Logistic regression was used to analyze the relationship between social jetlag, sleep quality trajectory and comorbid symptoms of anxiety and depression. Results: The detection rate of comorbid symptoms of anxiety and depression among college students was 16.9%, and the detection rate of social jetlag ≥2 h was 13.8%. The sleep quality showed an overall improvement trend, and the two trajectories were good sleep quality (81.6%) and poor sleep quality (18.4%). Binary Logistic regression model showed that poor sleep quality and social jetlag ≥2 h were positively correlated with comorbid symptoms of anxiety and depression (OR=5.94, 1.84, P<0.05). Conclusions Poor sleep quality and social jetlag ≥2 h in college students increase the risk of comorbid symptoms of anxiety and depression. Early screening and intervention of sleep quality and reduction of social jetlag are crucial for enhancing the mental health of college students.

Objective: To analyze the association between sleep chronotype and suicidal psychological behaviors among middle school students, so as to provide a scientific basis for the prevention and control of middle school students suicide. Methods: In October 2021 and November 2022, a multistage cluster sampling method was used to conduct baseline and followup surveys in Shenyang, Zhengzhou, Nanchang, and Taiyuan cities in China, and a total of 6 656 middle and high school students were included as the research subjects. The Chisquare test was used to analyze the groups differences, and generalized estimating equation was used to analyze the associations between middle school students sleep chronotype and suicide ideation, suicide plan and suicide attempt, and the grade stratification was carried out. Results: Baseline detection of suicide ideation, suicide plan, and suicide attempt were 26.3%, 12.6%, and 5.3%, respectively, with followup rates of 21.0%, 10.0%, and 4.8% for each, and varied significantly by gender, academic stress, smoking or alcohol use, and anxiety or depressive symptoms among middle school students (χ2=11.93-880.20, P<0.05). After adjusting for gender, academic stress, physical activity, smoking, alcohol use, anxiety and depressive symptoms, generalized estimating equations showed that compared with the morning sleep chronotype, the OR(95%CI) for suicide ideation, suicide plan and suicide attempt were 1.61(1.36-1.89), 1.66(1.35-2.05) and 1.41(1.06-1.88) among evening chronotype students, and were higher among junior 1.78(1.39-2.27), 2.00(1.48-2.69) and senior middle school students 1.84(1.44-2.35), 1.67(1.20-2.33) (P<0.05). Conclusion There is a positive association between evening sleep chronotype and middle school students suicidal psychological behavior, and improving sleep chronotype may be one of the effective measures to prevent middle school students suicide.

Abstract: To analyze the relationship between parenting behaviors and sleep problems of preschool children, so as to provide a strategic decision support for child growth and parenting behavior improvement. Methods: Using the questionnaire data of 27 200 preschool children parents selected from 11 cities in Hubei, Anhui and Jiangsu provinces in October 2017, parents parenting behavior was assessed by Parent Behavior Inventory (PBI), and children s sleep problems were assessed by Children s Sleep Habits Questionnaire (CSHQ). Data were analyzed using descriptive statistics and Logistic regression models. Results: The reporting rate of sleep problems among preschool children was 15.3%. After adjusting for confounding factors, maternal hostile/coercive parenting behavior scores (medium level: OR=1.38; high level: OR=1.86) and paternal hostile/coercive parenting behavior scores (medium level: OR=1.17; high level: OR=1.59) were positively correlated with sleep problems (P<0.05). Hostile/coercive parenting behaviors by their parents (maternal high level: the OR values were 1.75, 2.97, 1.86, and 2.75 respectively; paternal high level: OR values were 1.79, 1.91, 1.69, and 1.79 respectively) were positively associated with sleep problems in preschool children aged 3, 4, 5, and 6. Scores of parental support/engaged (fathers of 4yearold children medium level: OR=0.84; fathers of 5yearold children medium and high level: OR=0.84, 0.82) were negatively correlated with children aged 4 and 5 (P<0.05). High level maternal supportive/engaged and paternal hostile/coercive scores were positively associated with child sleep problems (OR=1.93); high level maternal hostile/coercive and paternal supportive/engaged scores were positively associated with child sleep problems (OR=1.93); high scores of parental hostile/coercive were positively correlated with child sleep problems (OR=2.60) (P<0.05). Conclusion Sleep problems among children are related to parenting behaviors, especially hostile/coercive parenting behaviors that increases the risk of sleep problems among children.

Abstract Dry eye is a multifactorial ocular surface disease characterized by tear film homeostasis imbalance, which usually causes eye discomfort and visual impairment. With the change of environment and lifestyle, the incidence of dry eye in children and adolescents has risen steadily. Epidemiological studies have confirmed that the incidence of dry eye is closely related to unhealthy lifestyle. Prevention should be given great priority to in avoiding lifestyle related dry eye. The review summarizes the definition, epidemiology, risk factors and preventive measures of lifestyle related dry eye, so as to provide a theoretical basis for improving the diagnosis, treatment and prevention of lifestyle related dry eye in children and adolescents.