Objective: To assess the status of handgrip strength of elderly population from longevity areas in China, and to analyze the correlative factors of handgrip strength of elderly people. Methods: Data from Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2012 was used, from which1 967 participants aged ≥60 years old with valid data of grip strength value from 8 Chinese longevity areas were included. Information on demographics characteristic, life style and health status was collected using questionnaires. The handgrip strength of both left and right hands were measured by grip dynamometer. The different characteristics of group of participants with different grip strength were compared and then analyzed by adopting the Cumulative odds Logistic regression model to identify main factors associated with hand grip strength. Results: The P₅₀ (P₂₅-P₅₀) of hand grip strength of elderly people from the eight longevity areas was 20 (11-28) kg; The hand grip strength of males was 26 (18-34) kg, which was higher than that of females(14 (9-20) kg) (P<0.001). Cumulative odds Logistic regression model showed that the hand grip strength of females was lower than males, whose β value (95%CI) was-1.22 (-1.43--1.00). The elderly who was at a higher age, smoking, drinking or with anemia, had a comparatively lower handgrip strength, whose β (95%CI) value were separately-0.08(-0.09~-0.07),-0.29(-0.56~-0.02),-0.54(-0.80~-0.28), and-0.41(-0.62~-0.20). And the elderly who had a higher boby mass index, drinking tea and outdoor activities, had a comparatively higher handgrip strength, whose β(95%CI) value were separately 0.28 (0.15-0.40), 0.25(0.03-0.47) and 0.51(0.30-0.71). Conclusion Age and gender were the main correlative factors, lifestyles and physical conditions might also be correlative factors of hand grip strength of the elderly from longevity areas in China.

Objective: To discuss the relationship between body mass index (BMI) and cognitive impairment among elderly adults aged ≥65 years old from longevity areas of China. Methods: A total of 2 439 elderly adults from 8 longevity areas were included in our baseline survey by answering questionnaire and taking body measurements and blood biochemical examinations in 2012. In the follow-up study in 2014, we studied the cognitive impairment status among the 1 135 elderly adults aging ≥65 years old. Multivariate logistic regression model was used to analyze the relationship between BMI and cognitive impairment risk. Results: 113 participants were defined as cognitive impairment, with a positive rate at 10.0%. The positive rate in group of underweight, normal weight, and overweight and obese elderly were 22.2% (51/230), 7.5% (47/629), 5.4% (15/276). The rate of cognitive impairment in groups of low BMI (<19.7 kg/m²), middle BMI (19.7-23.1 kg/m²) and high BMI (>23.1 kg/m²) were separately 17.7% (66/372), 7.1% (27/379) and 5.2% (20/384) (P<0.001). Every 1.0 kg/m² increase in BMI, the risk of cognitive impairment would significantly decreased by 7% (RR(95%CI): 0.93(0.87-0.99)). Compared with participants with middle BMI level, the group of low BMI participants was associated with a significantly increased risk of cognitive impairment (RR (95% CI): 1.98(1.14-3.44)); while there was no significant association was observed in the high BMI group (RR(95%CI): 1.15(0.57-2.32)). Compared with elderly in normal weight, the elderly with under weight was in higher risk of cognitive impairment (RR (95%CI: 2.19(1.31-3.66)) and there was no significant association found between the elderly with overweight (RR(95%CI): 1.18(0.58-2.38)). Conclusion Among the elderly ≥65 years old from longevity area, low BMI level and underweight were associated with the increased risk of cognitive impairment.

Objective: To explore the relationship between successful aging (SA) index and the survival status among elderly from longevity areas of China. Methods: A total of 2 296 old people aged ≥65 years old from 8 longevity areas were enrolled in our baseline survey in 2012. The information of demographics characteristic, life style, self-assessed health and mood or emotional state, cognitive function, abilities of daily living and physical activity were collected by questionnaire. There were 891 SA people in total, whose SA score was 4-5. 891 SA and 1 396 non-SA participated in the follow-up study in 2014. Finally, 860 SA and non-SA people were matched by orientation analysis. A Cox proportional hazards model was used to explore the relationship between successful aging index and survival status. Results: After 2 years of follow-up, a total of 1 442 elderly survived, with an average baseline age at (83.69±10.81) years old and 278 elderly people died, with an average baseline age at (93.41±9.05) years old. The mortality rate was 16.16% (278/1 720) in total, and it was 13.14% (113/860) in SA group, which was lower than it in non-SA group (19.19%, 165/860), and the difference was statistically significant (P=0.001). The analysis of the multivariate Cox regression showed that SA was the protective factor of the survival of the elderly after age and sex adjusted. Compared to the non-SA group, the risk of mortality rate in SA group decreased by 38%, the HR (95% CI) was 0.62 (0.49-0.79). Conclusion The mortality rate in the SA group was low in the longevity areas in China; compared with non-SA group, the death rate in SA group reduced by 38%.

Objective To explore the association between anemia and 3-year all-cause mortality among the oldest old people in longevity areas in China. Methods In August 2012, questionnaire survey,health examination and blood test were conducted among 929 old people aged≥80 years in 7 longevity areas in China,who were included in Chinese Longitudinal Healthy Longevity Survey(CLHLS)2009. Cox regression model was used to evaluate the association between anemia or different hemoglobin levels and mortality. Results Among the 929 subjects,the prevalence of anemia was 49.6%,the main form of anemia was normocytic anemia. During the three year follow-up period,a total of 447 subjects died,the overall mortality was 49.8%(56.0%in subjects with anemia and 43.3% in subjects without anemia). Compared with the subjects without anemia,the mortality risk increased by 25% in the subjects with anemia after adjusting confounding factors(HR=1.25, 95%CI:1.03-1.52). Macrocytic anemia,simplex microcytic anemia and microcytic hypochromic anemia were all associated with the increased mortality in the oldest old people. Compared with the subjects with low hemoglobin concentration,the subjects with high hemoglobin concentration had a lower mortality risk,and the association was more obvious in women. Conclusion Anemia and low hemoglobin concentration were associated with higher mortality risk in the oldest old people in China, indicating the importance of anemia prevention and treatment among this population.

Objective To explore association between serum albumin level and cognitive performance in elderly Chinese.Methods All the subjects aged ≥65 years in the 8 longevity areas in Chinese longitudinal health longevity survey (CLHLS) were invited to participate the biomedical in-depth CLHLS study,information about subjects' demographic characteristics,lifestyle,prevalence of diseases and health status was collected through household-interview.The cognitive performance was assessed with Mini Mental State Evaluation (MMSE) scale.Health examination was conducted by medical personnel and fasting venous blood samples were collected to detect the levels of triglycerides,total cholesterol,fasting glucose,creatine and blood albumin.MMSE score was compared and the trend was analyzed with generalized linear model.Association between albumin concentration and cognitive impairment was analyzed by logistic regression model.Results Generalized linear model showed that adjusted MMSE score increased from 23.22 in the lowest quartile group to 25.07 in the highest quartile group (P for linear trend ＜0.001).Logistic regression analysis results showed that the higher albumin level was associated with the lower risk of cognitive impairment (P＜ 0.001),the OR decreased linearly with the increasing level of albumin (P＜0.01),with the OR (95％CI) for the lower,higher and highest quartile groups was 0.64(0.45-0.91),0.60(0.40-0.89) and 0.43 (0.27-0.69),respectively,compared with the lowest quartile group.Conclusion High level of serum albumin was associated with low risk of cognitive impairment.

Objective: To explore the association between biomarkers and activities of daily living (ADL) in the elderly over 65 years old from longevity areas in China. Methods: A total of 2 439 people from 8 longevity areas were included in our baseline survey in 2012. Using questionnaires, body measurements, and blood biochemical examinations, information on demographics characteristic, life style, ADL, blood pressure and biomarkers were collected. Based on these six items of ADL (bathing, dressing, indoor activities, toileting, eating, bowel and bladder control), we constructed a dichotomous indicator for ADL. A respondent was defined as ADL disabled if any difficulty in one or more of the above six activities was reported. Information were collected in the follow-up in 2014 using the same questionnaires and examinations. We excluded information on the elderly who lacked ADL or biomarkers test results or with ADL disability at baseline study. Finally 938 elderly people over 65 years old were included in this analysis. Multivariate logistic regression model was used to analyze the influence factors of ADL disability. Results: During the 2-year follow-up, 100 (10.7%) participants developed into ADL disability, with a rate at 10.7%. Multivariate logistic regression analysis indicated that each year increase in age or each 1 mmHg (1 mmHg=0.133 kPa) increase in systolic blood pressure (SBP) would cause the risk of ADL disability to increase 9% or 1%, whose OR (95%CI) were separately 1.09 (1.06-1.12), 1.01 (1.00-1.02). Han nationality or cognitive impairment increased the risk of ADL disability, whose OR (95%CI) values were separately 4.90 (1.13-21.24), 2.47 (1.44-4.25), while increased lymphocyte count (>1.60×10⁹/L), being married, or participating in recreational activities decreased the risk of ADL disability, whose OR (95%CI) values were separately 0.51 (0.31-0.82), 0.52 (0.28-0.96), 0.43 (0.23-0.80). Conclusion In the elderly elevated lymphocyte count was associated with lower risk of ADL disability. In addition, incresed age, increased SBP, unmarried, Han nationality or cognitive impairment were associated with the increasing risk of ADL disability in older people, while participating in recreational activities would reduce the risk.

Objective: To investigate the influence factors of survival outcome among elderly aged ≥80 years old. Methods: In baseline survey in 2009, 930 participants aged ≥80 years old were enrolled from 7 longevity areas, to collect the information of socioeconomic factors, life style, cognitive function, activities of daily living and diseases, as well as physical examination to test biomarkers of blood and urine. The survival status was followed up at 2012 and 2014 survey. Stepwise Cox proportional hazards models were used to screen influence factors of 5-year survival. Results: During 5 years of follow-up, 571 participants died, 133 participants were lost to follow up, and the all-cause mortality was 63.4%. In stepwise Cox proportional hazards models, male, unmarried, self-reported poor life quality, disability in daily life, cognitive impairment, cardiovascular and cerebrovascular diseases, chronic kidney diseases were risk factors for elderly survival outcome, with the HR (95%CI) at 1.75 (1.40-2.12), 1.49 (1.10-2.03), 1.40 (1.16-1.69), 1.37 (1.11-1.70), 1.51 (1.22-1.88), 1.62 (1.18-2.23) and 1.48 (1.23-1.77) respectively. Each 1 year increase in age corresponded to 4% increase in mortality risk (HR (95%CI)=1.04 (1.02-1.05)); each 1 kg/m² increase in BMI corresponded to 5% increase in mortality risk (HR (95%CI)=0.95 (0.93-0.98)); each 1.0×10⁹/L increase in total lymphocyte count (TLC) corresponded to 13% increase in mortality risk (HR (95%CI)=0.87 (0.76-0.99)). Additionally, the mortality risk decreased 19% (HR (95%CI)=0.81 (0.66-0.98)) in participants with regularly physical exercise compared to those without; and the mortality risk decreased 41% (HR (95% CI)=0.59 (0.40-0.88)) in participants with elevated triglycerides (TG, ≥2.26 mmol/L) compared to those without. Conclusion In Chinese longevity areas, some nutritional and immune indices such as relatively higher level of BMI, TLC and TG were independent protective factors for 5-year survival outcome, which was different from general adults and younger elderly.

Objective: To investigate the association of ambient fine particulate matters (PM_2.5) exposure with anxiety in middle-aged and elderly people in China. Methods: Using a stratified random sampling method, 5 997 middle-aged and elderly people (aged 40-89) who resided in the region for more than 2 years and had no hearing or language impairment were selected from 32 districts/counties in the key areas for air pollution prevention and control in China from October 10^th, 2017 to February 7^th, 2018. Information about demographic characteristics, socioeconomic factors and health status were collected by questionnaire survey and physical examination. The anxiety symptoms were assessed by 7-item Generalized Anxiety Disorder Scales. Three-year moving average concentrations of PM_2.5 were calculated to estimate exposure level. The multivariate logistic regression model was conducted to assess the association between PM_2.5 exposure and anxiety. The interaction of age, gender, overweight, education, smoking, drinking and chronic diseases was also analyzed by likelihood ratio test. Results: There were 2 995 (49.94%) males subjects, 4 092 (68.23%) subjects with education of secondary school or above and 2 576 (42.95%) subjects with self-reported chronic diseases among the 5 997 middle-aged and elder participants. The prevalence of anxiety was 6.64% (n=398). The mean±SD of 3-year moving average concentrations of PM_2.5, O₃ and SO₂ were (53.50±13.38), (90.58±13.26) and (40.29±12.56) μg/m³, respectively. PM_2.5 had significantly association with anxiety, and the corresponding OR value was 1.17 (95%CI: 1.05,1.31) with a 10 μg/m³ increment of 3-year moving average concentrations of PM_2.5. Compared with female (OR (95%CI)=1.07 (0.93,1.23)), those with no chronic diseases (OR (95%CI)=1.06 (0.93,1.20)) and those with primary school degree or below (OR (95% CI)=0.90 (0.75,1.09)), the association between PM_2.5 and anxiety was stronger among male (OR (95%CI)=1.35 (1.12,1.63)) and those with chronic diseases (OR (95%CI)=1.77 (1.31,2.38)), middle school education (OR (95%CI)=1.43 (1.22,1.67)), college education and above (OR (95%CI)=1.68 (1.05, 2.67)), all the P interaction values were <0.05. Conclusion PM_2.5 exposure has significantly positive association with anxiety. The associations are stronger in male, people with higher educational qualifications and patients with chronic diseases.

Restricted cubic spline Cox proportional hazard regression model analysis is an important method of epidemiological multivariate survival analysis. By comparing the typical Cox regression model and the restricted cubic spline Cox regression model, this study expounds the limitations of the typical Cox regression model, and explains the basic principles and implementation process of the restricted cubic spline Cox proportional hazard regression model. When the follow-up data does not meet the application conditions of the typical Cox regression model, this method can be used to realize the correlation analysis between continuous exposure and outcomes.

Objective:To explore the association between resting heart rate(RHR) and all-cause mortality among the Chinese oldest-old aged more than 80.Methods:Using a total of seven surveys or follow-ups data (1998, 2000, 2002, 2005, 2008, 2011 and 2014) from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A total of 17 886 elderly over 80 years old were selected as subjects, their resting heart rate were measured though baseline survey and the survival outcome and death time of the subjects were followed up. The subjects were divided into 6 groups according to their resting heart rate. Cox regression model was used to estimate the effect of resting heart rate on mortality risk. The interaction of age, gender and resting heart rate was also analyzed by likelihood ratio test.Results:The age of subjects M( P25, P75) was 92 (86, 100) years old, including 10 531 females (58.9%) and there were 13 598 participants died, the mortality rate was 195.5 per 1 000 person-years. Multivariate Cox regression analysis showed that compared to the control group (60-69 pbm/min), the hazard ratio of the elderly are 1.06 (95% CI: 1.02, 1.11), 1.09 (95% CI: 1.04, 1.15), 1.23 (95% CI: 1.14, 1.34), 1.25 (95% CI: 1.08, 1.44) in the group of RHR between 70-79, 80-89, 90-99 and ≥100 pbm/min and Pvalues are all less than 0.05. Likelihood ratio test showed that RHR and age had an interaction effect. ( P for interaction=0.011). Conclusion:The risk of all-cause death increased with the increase of resting heart rate and this relationship was stronger between the 80-89 years old people.