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.

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.

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.

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.

Objective: To explore the longitudinal correlation between smartphone multitasking and depressive symptoms, so as to provide an evidence based basis for promoting the mental health of college students. Methods: A total of 967 college students were recruited from one university in Taiyuan, Chongqing, and Shenzhen cities, China, by using multi stage randomized cluster sampling from October to December 2021 at baseline, and a follow up survey was conducted in May 2022. Smartphone multitasking behaviors were assessed by means of the Assessment of Smartphone Multitasking for Adolescents (ASMA), and depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9) among college students. Chi square tests were performed to compare the differences in depressive symptoms between different groups of demographic characteristics, and binary Logistic regression models were employed to analyze the associations between smartphone multitasking and depressive symptoms among college students. Results: The rates of depressive symptoms among college students at baseline and follow up were 35.2% and 42.3%, respectively. Compared to the low level smartphone multitasking index group at baseline, the moderate and high level groups were more likely to experience depressive symptoms at baseline (moderate level group: OR=1.74, 95%CI =1.22-2.50, high level group: OR=2.77, 95%CI =1.94-3.95) and followup (moderate level group: OR=1.41, 95%CI =1.01-1.95, high level group: OR=1.64, 95%CI =1.17-2.29) ( P <0.05). In addition, compared to the persistently low smartphone multitasking index, increased risk of depressive symptoms was associated with maintaining a moderate to high ( OR=2.94, 95%CI =1.83-4.71), and a higher ( OR=2.07, 95%CI =1.31-3.27) or lower smartphone multitasking index ( OR=2.02, 95%CI =1.27-3.19) ( P <0.05). Moreover, higher smartphone multitasking index scores were positively associated with the risk of new-onset depressive symptoms at follow up ( OR=1.87, 95%CI=1.07-3.27, P <0.05). Conclusions Smartphone multitasking behaviors are find to be associated with an increased risk of depressive symptoms in college students. There is a need to reduce smartphone multitasking in order to decrease depressive symptoms and promote students mental health.

Objective: To explore the association among neck-shoulder pain (NSP), low back pain (LBP) and co occurring symptoms with mental sub health in adolescents, so as to provide evidence for improving physical and mental health of adolescents. Methods: Stratified cluster random sampling method was used to select 7 986 students from 12 middle and high schools in Shenzhen, Nanchang, and Shenyang cities from October to December 2019. The Assessment of Spinal Health of Youth (ASHY) and the Brief Instrument on Psychological Health of Youth (BIOPHY) were used to assess NSP, LBP and mental sub health. Binary Logistic regression model was used to analyze the association between NSP, LBP and co occurring symptoms with mental sub health in adolescents. Results: The detection rates of adolescents with NSP, LBP and co occurring symptoms and mental sub health were 9.1% , 9.8%, 9.5%, and 10.0%, respectively. The co occurring rate of neck shoulder pain, low back pain and mental sub health was 3.2%. After adjusting for confounding variables such as gender, age, being an only child, family residence, and parental education level, NSP ( OR=6.01, 95%CI =5.02-7.19), LBP ( OR=5.08, 95%CI =4.25-6.07), and co occurring symptoms ( OR= 5.96 , 95%CI =4.98-7.12) in adolescents were positively correlated with mental sub health risk ( P <0.01). Stratifying the gender, boys with NSP, LBP and co occurring symptoms ( OR =6.84, 5.80, 6.74)had a higher risk of mental sub health compared to girls ( OR =5.52, 4.65, 5.49) ( P <0.01). Conclusions NSP, LBP and co occurring symptoms in adolescents are associated with mental sub health. The mental health status of boys is more affected by NSP, LBP and their co occurring symptoms. Measures should be taken to improve spinal health in adolescents to reduce the incidence of mental sub health.