Objective To investigate the quality of life of acute coronary syndrome patients(ACS)preoperatively to 6 months postoperatively percutaneous coronary intervention(PCI)and analyze its changing trend and influencing factors so as to provide reference for the improvement of ACS patients after PCI and direct for patient health management.Methods The patients with ACS were investigated for their sociodemographic characteristics,disease data,behavior and lifestyle and quality of life with the Seattle Angina Scale(SAQ)of PCI before PCI,1 month,3 months and 6 months after the surgery by means of medical records,face-to-face or telephone follow-up.Results A total of 235 ACS patients were surveyed before PCI,and 213(90.6％)of them who were successfully followed up to 6 months after PCI were included in this study,with a mean age of(62.67±9.18)years,and 76.1％being male.The results of the generalized estimation equation analysis showed that all the scores of the five dimensions of SAQ before PCI to 6 months after surgery,i.e.,physical limitation(Wald x2=83.118,P＜0.001),angina stabilizaton stability(Wald x2=289.369,P＜0.001),angina frequency(Wald x2=219.458,P＜0.001),treatment satisfaction(Wald x2=159.055,P＜0.001),and disease perception(Wald x2=130.839,P＜0.001)increased overall(all P＜0.001).However,the scores of physical limitation,angina stability and disease perception were only moderate at 6 months after surgery.The results of generalized linear model analysis showed that the factors affecting the quality of life before PCI to 6 months after PCI were gender,educational level,type of ACS,time to diagnosis,in-stent restenosis(ISR),tobacco smoking,and alcohol drinking.Conclusion The quality of life of the ACS patients gradually improved at 6 months after PCI,but the improvement effect of physical activity,angina stability and cognitive level was not ideal.Being female,low-level education,unstable angina,onset to diagnosis time 6 months or longer,occurrence of ISR,and postoperative tobacco smoking and alcohol drinking made patients have relatively low quality of life;therefore,more attention and guidance should be given to this group of population.

Objective By comparing the prevalence and mortality of dementia among rural people in Xi'an in 1997 and 2014 to clarify the epidemiological changes of dementia among rural people in the city over 17 years.Methods In 1997 and 2014,people aged 55 and above in villages in Xi'an were selected by random cluster sampling method,and face-to-face questionnaire survey was conducted by combining centralized and home visits.Dementia and its subtypes were diagnosed by"the three-step method";the changes of dementia prevalence and mortality were compared between the two surveys.Results The prevalence of dementia among rural residents aged 55 and above in Xi'an was 3.49％in 1997,with age-gender standardized prevalence of 2.08％.In 2014,the prevalence of dementia was 4.25％,with age-gender standardized prevalence of 2.78％.Over the 17 years,the prevalence of dementia increased by 1.79 times(OR=1.79,95％CI:1.20-2.65,P=0.004),with a 1.9-fold increase in females and a 1.67-fold increase in males.The mortality of dementia patients was 61.76‰ and age-gender standardized mortality was 60.20‰ in 1997,while the mortality was 35.71‰ and age-gender standardized mortality was 34.18‰ in 2014.The mortality of dementia decreased by 33％over the 17 years(HR=0.33,95％CI:0.15-0.74,P=0.007).Conclusion The prevalence of dementia in rural areas of Xi'an increased significantly over the 17 years,but the mortality rate decreased,and this trend was more obvious in women.

Objective To investigate the quality of life of acute coronary syndrome patients(ACS)preoperatively to 6 months postoperatively percutaneous coronary intervention(PCI)and analyze its changing trend and influencing factors so as to provide reference for the improvement of ACS patients after PCI and direct for patient health management.Methods The patients with ACS were investigated for their sociodemographic characteristics,disease data,behavior and lifestyle and quality of life with the Seattle Angina Scale(SAQ)of PCI before PCI,1 month,3 months and 6 months after the surgery by means of medical records,face-to-face or telephone follow-up.Results A total of 235 ACS patients were surveyed before PCI,and 213(90.6％)of them who were successfully followed up to 6 months after PCI were included in this study,with a mean age of(62.67±9.18)years,and 76.1％being male.The results of the generalized estimation equation analysis showed that all the scores of the five dimensions of SAQ before PCI to 6 months after surgery,i.e.,physical limitation(Wald x2=83.118,P＜0.001),angina stabilizaton stability(Wald x2=289.369,P＜0.001),angina frequency(Wald x2=219.458,P＜0.001),treatment satisfaction(Wald x2=159.055,P＜0.001),and disease perception(Wald x2=130.839,P＜0.001)increased overall(all P＜0.001).However,the scores of physical limitation,angina stability and disease perception were only moderate at 6 months after surgery.The results of generalized linear model analysis showed that the factors affecting the quality of life before PCI to 6 months after PCI were gender,educational level,type of ACS,time to diagnosis,in-stent restenosis(ISR),tobacco smoking,and alcohol drinking.Conclusion The quality of life of the ACS patients gradually improved at 6 months after PCI,but the improvement effect of physical activity,angina stability and cognitive level was not ideal.Being female,low-level education,unstable angina,onset to diagnosis time 6 months or longer,occurrence of ISR,and postoperative tobacco smoking and alcohol drinking made patients have relatively low quality of life;therefore,more attention and guidance should be given to this group of population.

Objective By comparing the prevalence and mortality of dementia among rural people in Xi'an in 1997 and 2014 to clarify the epidemiological changes of dementia among rural people in the city over 17 years.Methods In 1997 and 2014,people aged 55 and above in villages in Xi'an were selected by random cluster sampling method,and face-to-face questionnaire survey was conducted by combining centralized and home visits.Dementia and its subtypes were diagnosed by"the three-step method";the changes of dementia prevalence and mortality were compared between the two surveys.Results The prevalence of dementia among rural residents aged 55 and above in Xi'an was 3.49％in 1997,with age-gender standardized prevalence of 2.08％.In 2014,the prevalence of dementia was 4.25％,with age-gender standardized prevalence of 2.78％.Over the 17 years,the prevalence of dementia increased by 1.79 times(OR=1.79,95％CI:1.20-2.65,P=0.004),with a 1.9-fold increase in females and a 1.67-fold increase in males.The mortality of dementia patients was 61.76‰ and age-gender standardized mortality was 60.20‰ in 1997,while the mortality was 35.71‰ and age-gender standardized mortality was 34.18‰ in 2014.The mortality of dementia decreased by 33％over the 17 years(HR=0.33,95％CI:0.15-0.74,P=0.007).Conclusion The prevalence of dementia in rural areas of Xi'an increased significantly over the 17 years,but the mortality rate decreased,and this trend was more obvious in women.

【Objective】 To analyze the association of sexual development characteristics and phases with the cognitive and behavioral development of adolescents aged 10 to 14 in rural areas of Shaanxi Province, in order to provide scientific reference for enhancing adolescent health. 【Methods】 The study population was selected from a birth cohort study′s follow-up data for the adolescent phase. The Tanner quintile method was used to assess sexual development, the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-Ⅳ) was used to assess cognitive development, and the Youth Self-Rating Scale(YSR-2001) was used to assess behavioral development. Generalized linear models was used to examine the association of the stages of adolescent sexual development with their cognitive and behavioral development. 【Results】 A total of 1 887 adolescents were enrolled in this study, with 1 111 (58.9%) boys. The proportion of boys and girls who have started sexual development was 78.22% and 89.30%, respectively. The detection rate of behavioral problems in adolescents was 9.70%, with 11.80% in boys and 6.70% in girls, and the gender difference was significant (χ²=13.517, P<0.001). Compared to adolescents in Tanner stage Ⅰ, adolescents in stage Ⅲ had a higher total cognitive score of 2.19 (95%CI: 0.15 - 4.23), and a higher total score of 3.84 (95%CI: 0.85 - 6.83,P<0.05) in stages Ⅳ-Ⅴ. The detection rate of total behavioral problems of children in Tanner stages Ⅳ-Ⅴ was 2.63 times (95%CI:1.27 - 5.46,P<0.05) higher than that in stage Ⅰ. In boys, the rate of detection of internalizing problems was 3.96 times(95%CI:1.60 - 9.81,P<0.01) higher than that in stage Ⅰ, and the detection rate of internalizing problems was 2.88 times(95%CI:1.19 - 7.01,P<0.05) higher than that in stage Ⅰ. 【Conclusions】 There is a significant correlation of sexual developmental phrase with cognitive and behavioral development among adolescents aged 10 - 14 years in rural Shaanxi Province. The detection rate of adolescent behavioral problems increases with the increase of sexual development level and cognitive level, and there are significant gender differences.

【Objective】 To explore the impact of intrapartum antibiotic prophylaxis (IAP) on antibiotic resistance genes (ARGs) in the gut microbiota of infants up to 6 months of age and their longitudinal changes, in order to provide theoretical basis for the rational use of antibiotics and antibiotic resistance control. 【Methods】 Fecal samples were collected within 3 days, 2 months, and 6 months from a maternal and birth cohort conducted between January 2018 and June 2019. A panel of 6 common ARGs (aac(6′)-Ib, qnrS, blaTEM, ermB, mecA, tetM) were tested, the absolute abundance and positive detection rate by qPCR were calculated. Nonparametric and linear mixed model (LMM) analysis were used to assess the influence of IAP on the absolute abundance of antibiotic resistance genes and the longitudinal changes in their abundance at the three time points. 【Results】 A total of 157 samples from 65 singleton infants were analyzed, including 15 mothers (23.1%) who received IAP. The detection rate of ARGs was high in infants up to six months of age, and the abundance of ARGs tended to increase over time. IAP significantly increased the abundance of the mecA gene in the gut microbiota of vaginally delivered infants at 6 months of age (6.1±1.1 in the VDIAP group vs. 3.8±4.6 in the VDno-IAP group, P=0.046). Additionally, in cesarean section infants, there was a significant increase in the abundance of aac(6′)-Ib genes at 2 months (β=3.81, ,P<0.05), P<0.05] and 6 months of age (β=4.89, ,P<0.001), P<0.001) compared to 3 days of age. 【Conclusions】 The findings suggest that IAP can increase the abundance of ARGs in 6-month-old infants, and this effect is still significant after stratifying by delivery mode. Therefore, the rational and standardized use of intrapartum antibiotics may help reduce the development of antibiotic resistance.

【Objective】 To assess the prevalence of chronic diseases and associated influencing factors among residents in Ali so as to provide reference for local prevention and control of chronic diseases. 【Methods】 Stratified cluster random sampling was used to investigate the prevalence of chronic diseases and their influencing factors among permanent residents over 18 years of age in Aili. 【Results】 Totally 606 subjects were included, with a prevalence of chronic diseases of 39.93% and the highest prevalence of rheumatoid arthritis of 14.03%. The prevalence of chronic diseases was significantly different among ethnicity, age, education, occupation, personnel category, family living standard, amateur physical exercise, fuel type and self-rated health (P<0.05). Logistic regression showed that the risk of chronic diseases among the residents aged 50 years and above was 2.656 (95% CI: 1.439-4.901) times higher than that of residents under 30 years; the risk of chronic diseases among the residents with elementary school education and below was 3.528 (95% CI: 1.519-8.197) times higher than that of residents with college education and above; housework personnel could reduce the risk of chronic diseases (OR=0.365, 95% CI: 0.161-0.828); residents with poor self-rated health had 5.814 (95% CI: 3.243-10.423) times higher risk of chronic diseases than those with good self-rated health; and those with a weight gain of more than 2.5 kg in the past year could increase the risk of chronic diseases (OR=2.029, 95% CI: 1.226-3.358). 【Conclusion】 The prevalence of chronic diseases is high in residents of Ali. Attention should be paid to the elderly population with poor self-rated health and tendency of weight gain. Personalized behavioral lifestyle health education is helpful in preventing the occurrence of chronic diseases.

Cohort study is one of the important research methods in analytical epidemiology because of its clear time sequence relationship, which is better than other observational studies in demonstrating causal association. However, screening diagnosis or other methods are often used to exclude the individuals with outcome events during the enrollment process of the subjects in cohort studies. The accuracy of screening diagnosis and the effectiveness of exclusion will affect the accuracy of the baseline status assessment of the subjects included in the study, which may lead to the causal time sequence reversal of exposure-outcome in the estimation of causal effect. Landmark analysis can be used to control reverse causality by excluding subjects with potentially unknown expose-outcome timing. In this paper, we describe the basic principles and analytical steps of landmark analysis, and use data from the Chinese Longitudinal Healthy Longevity Survey to explore the relationship between physical activity and frailty, and introduce the specific application of landmark analysis for the purpose of facilitating its application and inferring causal effects more accurately in cohort studies.

With completing a baseline survey of a large natural population cohort, conducting regular follow-up has become a key factor in further improving the quality of cohort construction and ensuring its sustainable development. Typical cohort follow-up methods include repeat surveys, routine monitoring, and community-oriented surveillance. However, in practical applications, there are often issues such as high costs, difficulty, and high error rates. Telephone follow-up is an important supplementary method to the methods mentioned above, as it has the characteristics of low cost, fast response, and high quality. However, the with difficult organization, quality control is challenging, response rates are low, and management levels vary widely, which limits its widespread use in large-scale population cohort studies. Given the above problems, this study draws on customer relationship management based on the actual needs of the China Northwest Cohort follow-up. It relies on the REDCap electronic data collection platform to build a telephone follow-up management and quality control system. Targeted solutions are provided for key issues in telephone follow-up implementation, including organizational structure, project management, data collection, and process quality control, to improve the quality control level of telephone follow-up comprehensively and thereby enhance the quality and efficiency of follow-up. We hope to provide standardized follow-up programs and efficient quality control tools for newly established and existing cohort studies.

【Objective】 To clarify the hematological characteristics and current situation of chronic mountain sickness among Tibetan residents in extreme high altitude area (more than 5 000 m above the sea level) of Ali district based on the analysis of physical examination and blood test results. 【Methods】 Totally 250 Tibetan residents were selected by convenient sampling for blood oxygen saturation (SpO2), heart rate, and blood routine examination. Chronic mountain sickness was determined according to the hemoglobin (Hb) level and SpO2. 【Results】 The red blood cell (RBC), Hb and hematocrit (HCT) of the Tibetan residents at 5 200-meter altitude were all higher than the normal physiological reference range of China. Mean red blood cell volume (MCV), mean red blood cell hemoglobin content (MCH), mean red blood cell hemoglobin concentration (MCHC), white blood cell (WBC) and platelet (PLT) were in the upper limit of the reference value. The RBC, Hb, HCT and MCHC of male Tibetan residents were higher than those of females, while PLT was lower than that of females, with significant differences. There were no statistical differences in MCV, MCH or WBC among different genders of Tibetan residents. The SpO2 of the Tibetan residents was about 85% of the normal value, and the males had higher SpO2 than the females in the same age group, and the difference was statistically significant, but the heart rate did not differ significantly. The prevalence rate of chronic mountain sickness in this area was as high as 16.4%, and the prevalence rate of heavy manual workers was significantly higher than that of light manual workers, with significant differences. 【Conclusion】 The high-altitude anoxic environment causes the changes in red blood cells, hemoglobin, and oxygen saturation of local residents, and the prevalence of chronic mountain sickness increases significantly. Labor intensity is one of the risk factors for chronic mountain sickness in high-altitude areas.