Objective:To investigate the cognition and learning habits of different types of postgraduates and evaluate learning effect and its potential risk factors on clinical epidemiology in a medical college, so as to provide relevant data for improving the teaching method and learning effect of clinical research methods for postgraduates.Methods:A cross-sectional study design was conducted to enroll all the postgraduates of Grade 2020 in a military medical school. A self-filled questionnaire was adopted to collect data. The discrepancy of cognition and learning habits between different types of postgraduates was evaluated by univariate analysis. Discussion was conducted to clarify the potential risk factors of learning effect. t tests or Mann-Whitney U tests were conducted to test the differences between groups for continuous variables. Chi-squared tests or McNemar tests were applied to evaluate the difference between groups for categorical variables. Results:A total of 652 postgraduate students were enrolled for analysis, including 409 master students (62.7) and 243 doctoral students (37.3). The proportion of doctoral students who have heard of clinical epidemiology ( χ2=19.99, P<0.001), who have learned clinical epidemiology ( χ2=9.20, P=0.002), who are interested in ( χ2=11.41, P=0.001) and think the course is important ( χ2=10.71, P=0.001), who previewed before class( χ2=11.21, P=0.001), reviewed after class ( χ2=3.29, P=0.001) and actively discuss in class ( χ2=11.64, P=0.001) is significantly higher than that of master students, the difference was statistically significance. The average score of all the postgraduates was (5.50±1.62) points before teaching and (7.47±1.90) points after teaching, the difference was statistically significant ( t=-23.49, P<0.001). After teaching, the grades of full-time students improved more than that of part-time graduate students, there was statistical significance in the master group ( t=4.41, P<0.001), while not in the doctor group ( t=0.94, P=0.351). Conclusions:The mastery of key points on clinical epidemiology have significantly improved after teaching among the postgraduates of different types. Different teaching methods and processes should be adopted to the variety of postgraduates according to their knowledge foundations and shortcomings. Besides, standardizing their learning habits are of certain significance to improve the learning effect.

Objective:To investigate the distribution characteristics of cognition-related lifestyles of elderly in communities and explore the integrated effects on early cognitive decline.Methods:The participants were from the Project of Prevention and Intervention of Neurodegenerative Disease for Elderly in China. A total of 2 537 older adults aged ≥60 years without dementia in the 2015 baseline survey and the 2017 follow-up survey were included. The information about their cognition-related lifestyles, including physical exercise, social interaction, leisure activity, sleep quality, smoking status, and alcohol consumption, were collected through questionnaire survey and the integrated scores were calculated. Multivariate logistic regression analysis was used to assess the association between integrated cognition-related lifestyle score and early cognitive decline.Results:In the 2 537 older adults surveyed, 28.7% had score of 5-6, while only 4.8% had high scores for all 6 healthy lifestyles. Significant differences in healthy lifestyle factor distributions were observed between men and women. Multivariate logistic regression model showed that the risks for early cognitive decline in the older adults who had lifestyle score of 4 and 5-6 were lower than that in those with lifestyle score of 0-3 ( OR=0.683, 95% CI: 0.457-1.019; OR=0.623, 95% CI: 0.398-0.976; trend P=0.030). In the women, the risks for early cognitive decline was lower in groups with score of 4 and 5-6 than in group with score of 0-3 ( OR=0.491, 95% CI: 0.297-0.812; OR=0.556, 95% CI: 0.332-0.929; trend P=0.024). Conclusion:Cognition-related healthy lifestyles are associated with significantly lower risk for early cognitive decline in the elderly, especially in women.

ObjectiveTo provide scientific support for the compilation of high-quality anti-nuclear， biological， and chemical （NBC） medical textbooks in China by retrieving books in the field of biological weapons defense in China， summarizing the publication time and distribution of publishing institutions， and categorizing content and key points of related books. MethodsRelevant subject terms in the field of biological weapons defense were searched through the official website of China National Digital Library and other websites， up until December 31， 2023， and were limited to books. Topic analysis was conducted on the introductions and contents of the books using the latent Dirichlet allocation （LDA） model. The number of topics was determined based on perplexity， and topics were identified according to the intertopic distance map， followed by a qualitative description of the core content of each topic. ResultsA total of 104 books were included in this study， among which four were identified as higher educational textbooks. The volume of publications increased during the periods 2002‒2004 and 2020‒2023. Research institutions accounted for the highest percentage of publishers （37.78%）， and 56.67% of the publishers were military institutions. The study identified six topics： "distribution， defense， and response to biological weapons"， "category， diagnosis， and treatment of biological warfare agents"， "response to biological public health emergencies"， "status of nuclear， biological， and chemical weapons internationally"， "biosafety risk management and prevention and control"， and "technologies and equipment related to biological hazard identification". ConclusionThere are few books in the field of biological weapons defense in China and the content is relatively outdated. In the future， the preparation of teaching materials should be aimed at practical emergency handling techniques for biological weapons， enhance the emphasis on biological weapons detection and biological warfare early warning， improve the fundamental theories at different training levels， and timely update the current research status in the field.

Centenarians are known as the "model population" in the study of healthy aging. Understanding their characteristics of health and longevity and its related influencing factors would facilitate the exploration of the possible path to achieve health and longevity under the background of population aging in China. In recent years, the population based observational studies, including China Hainan Centenarian Cohort Study (CHCCS), have found the main health characteristics of centenarians and their relationship with quality of life. This paper summarizes the relevant research results from CHCCS in recent years, and compare them with the results of similar domestic studies. The main health indicators include blood pressure, blood lipid, blood glucose, hemoglobin, body measurement and renal function. The health outcomes including diet, nutrition, health-related quality of life, activities of daily living, geriatric syndrome. The results are expected to provide epidemiological evidence for the development of healthy aging policies.

Objective:To explore the association between parathyroid hormone (PTH) and all-cause death in the centenarians in Hainan Province.Methods:The study was based on China Hainan Centenarian Cohort Study, a total of 1 002 centenarians were included in the baseline survey, the follow up was conducted to collect the information about their death outcome. The association between baseline PTH level and all-cause death was analyzed by Cox proportional risk regression model using continuous variables, dichotomous variables, and quad variables as independent variables of the centenarians.Results:As of May 31 st, 2021, a total of 522 centenarians had died in the follow up period, the median of the follow up time was 4.16 (1.31,5.04) years, and the mortality rate was 52.10%. After fully adjusting the covariates, the multiple Cox proportional hazards regression analyses showed that the risk of all-cause death increased by 3.7% for every 10 pg/ml increase in PTH value, the HR was 1.037 (95% CI: 1.007-1.067) in all the centenarians. The risk of death in the centenarians in the highest PTH group was 1.458 (95% CI: 1.131-1.878) times higher than that in the lowest PTH group. Conclusions:Higher parathyroid hormone level was associated with the elevated risk for all-cause death in the centenarians in Hainan. PTH can be used as a reference index for the prediction of the death risk of long-lived elderly in community.

Objective:To examine the association between depression and all-cause death in centenarians in Hainan Province.Methods:Based on China Hainan Centenarian Cohort Study, 1 002 centenarians with integral data were included in the baseline survey, follow up was conducted to collect the information about their survival status and death outcome. Depression was evaluated by the 15-item Geriatric Depression Scale (GDS-15) and based on the evaluation scores, the mental status of the centenarians was classified as: severe depressive disorder (MDD; score ≥10), minor depressive disorder (MnDD; score 6-9), and normal status (score ≤5). Multivariable-adjusted Cox proportional hazards regression models was used to estimate the hazard ratios ( HRs) and 95% CIs. Results:As of May 31 st, 2021, a total of 522 deaths had been reported, with a mortality density of 152.39/1 000 person-years and a median follow up time M( Q1, Q3) of 4.16 (1.31, 5.04) years, in the centenarians. After adjusting the factors of socio-demographic characteristics and lifestyle, multivariate Cox regression analysis showed that the risk of all-cause mortality increased by 3.1% for every 1-point increase in GDS-15 score ( HR=1.031, 95% CI: 1.002-1.061). Compared with centenarians with normal status, the risk of mortality in the centenarians with MDD increased by 35.9% ( HR=1.359, 95% CI: 1.023-1.806), the centenarians with MDD had an average 1.94 years of life lost. Among the female centenarians, the risk of mortality in MnDD group and MDD group increased by 29.3% ( HR=1.293, 95% CI: 1.053-1.590) and 42.3% ( HR=1.423, 95% CI: 1.047-1.935) compared with normal group, those with MDD had an average 1.71 years of life lost. Conclusions:Depression was related to the increased risk of all-cause death and life lost in the centenarians in Hainan.

Objective:To describe and analyze the relationship between traditional and new obesity related anthropometric indicators and all-cause death in centenarians in Hainan, the traditional and new obesity related anthropometric indicators included BMI, waist circumference (WC), waist hip ratio (WHR), waist height ratio, calf circumference (CC), waist-calf ratio (WCR), lipid accumulation product (LAP), visceral adiposity index (VAI), Chinese visceral adiposity index (CVAI), a body shape index (ABSI), a body shape index of Chinese (CABSI) and body roundness index.Methods:A total of 1 002 centenarians in Hainan were selected by cluster sampling. The M( Q1,Q3) follow-up time was 4.16 (1.31, 5.04) years and the outcome was all-cause death. Multiple Cox regression model was used to analyze the relationship between the obesity related anthropometric indicators and all-cause death, and the area under receiver operating characteristic curve was used for comparison. Results:In all the centenarians, CC had the strongest power to predict death, with area under curve (AUC) of 0.61 (95% CI:0.57-0.64), the gender specific results were consistent with that in overall population ( P<0.05), followed by WCR with AUC of 0.58, and then BMI, LAP and WC with AUC of 0.55, 0.55 and 0.54 respectively, while CABSI, WHR and VAI had the weaker power to predict death with AUC of 0.51, 0.50 and 0.50 respectively. Conclusions:This was the first study to prospectively compare and analyze the association between 12 obesity related anthropometric indicators and all-cause death in a large sample cohort of centenarians in China. It was found that CC had the best prediction power for death, and the risk for death decreased with the increase of CC value in a dose-response manner. It is suggested that CC can be used as a reference index for death risk monitoring in the elderly.

Objective:To understand the associations of various levels of systolic and diastolic blood pressure levels and related factors with all-cause death in the centenarians in Hainan Province.Methods:The data were obtained from China Hainan Centenarian Cohort Study, a prospective cohort study which included 1 002 centenarians. Cox proportional risk regression models were used to analyze the associations of blood pressure and related factors with all-cause death in the centenarians.Results:As of May 31, 2021, with the median of the follow-up time of 4.16 years, and the mortality density had reach 15.24 per 100 person-years. After grouping by SBP and DBP quartiles, the Q1 of SBP and Q2 of DBP caused the lowest mortality density (12.73 per 100 person-years and 14.10 per 100 person-years relatively). In all the centenarians, compared with the Q1 of SBP (≤137 mmHg, 1 mmHg=0.133 kPa), Q2, Q3 and Q4 were all positively associated with all-cause death. In the female population, the HRs of SBP's Q2, Q3 and Q4 were 1.343, 1.355 and 1.420 respectively ( Q1 as reference), and the HRs of DBP's Q1, Q3 and Q4 were 1.468, 1.800 and 1.504 respectively ( Q2 as reference), showing a roughly U-shaped association. Interactive analysis showed multiplicative interaction between SBP and BMI. Conclusions:In the centenarians in Hainan, different levels of systolic and diastolic blood pressure were associated with all-cause death. In the centenarians, DBP might have a suitable level or range in which the risk of death is relatively low. Different BMI status might affect the associations of blood pressure levels with death outcomes.

Objective:To explore the association between nutritional status and all-cause death in the centenarians in Hainan Province.Methods:Based on the survey data of China Hainan Centenarian Cohort Study from 2014 to 2021, a total of 1 002 Hainan centenarians with complete baseline data were included in this study, and their survival status and death outcome were surveyed. According to the Mini Nutritional Assessment Short-Form (MNA-SF), the centenarians were divided into three groups: well-nourished (12-14), at risk of malnutrition (8-11), and malnutrition (0-7). The survival status of the centenarians was evaluated by Kaplan-Meier curve. Cox proportional hazards regression model was used to assess the association between nutritional status and all-cause death.Results:After the follow-up on May 31, 2021, we had found that 522 centenarians died, with an all-cause mortality rate of 52.10% (522/1 002). Compared with the well-nourished group, the average life lost caused by malnutrition was 0.62 years. Kaplan-Meier survival analysis showed that all-cause mortality rate was higher in the malnourished centenarians than in other groups ( χ2=16.45, P<0.001). Multivariate Cox proportional hazards regression model showed that the risk of all-cause mortality rate in malnourished centenarians was higher than that in well-nourished centenarians ( HR=1.65, 95% CI: 1.18-2.31). Subgroup analysis found that the association in female centenarians was more significant. Conclusions:Malnutrition was associated with a high risk of all-cause death in Hainan centenarians. It is suggested that we should timely evaluate and pay attention to the impact of nutritional status of centenarians on their health and longevity, and death, especially in the female elderly.

Objective:To investigate the distribution characteristics of sex hormones and their relationship with all-cause mortality in Hainan female centenarians.Methods:All the subjects were from China Hainan Centenarian Cohort Study. A total of 717 female centenarians were included in the final analysis. Kaplan-Meier method was used to draw the survival curve, and Cox proportional hazard regression was used to analyze the relationship between sex hormones and survival time.Results:The M( Q1, Q3) of estradiol and progesterone among female centenarians was 32.60 (18.40, 58.70) pmol/L and 0.62 (0.32, 1.01) nmol/L. The estradiol (pmol/L) and progesterone (nmol/L) in the survival and death groups were 26.65 vs.37.80, 0.54 vs.0.69, respectively, with statistical differences ( P<0.05). Cox multivariate analysis showed that estradiol and progesterone were significantly associated with death ( P<0.05), the hazard ratio ( HR) of estradiol Q4 was 1.58 (95% CI: 1.17-2.15), and the HR of progesterone Q3 was 1.53 (95% CI: 1.10-2.12), HR for Q4 was 1.63 (95% CI: 1.15-2.32). Subgroup and cross-analysis showed that estradiol was statistically significant with hypertension, diabetes, and low high-density lipoprotein cholesterol ( P<0.05), and progesterone interacted with diabetes ( P=0.016), while testosterone interacted with low high-density lipoprotein cholesterol ( P=0.034). Conclusion:It is suggested that the estrogen levels of female centenarians in Hainan were associated with a higher mortality risk and an increased risk of cardiovascular metabolic disease (such as diabetes, hypertension, and abnormal lipid metabolism).