Progress in research of risk prediction model for chronic kidney disease / 中华流行病学杂志

Chronic kidney disease (CKD) is an important global public health problem that greatly threatens population health. Application of risk prediction model is a crucial way for the primary prevention of CKD, which can stratify the risk for developing CKD and identify high-risk individuals for more intensive interventions. By now, more than twenty risk prediction models for CKD have been developed worldwide. There are also four domestic risk prediction models developed for Chinese population. However, none of these models have been recommended in clinical guidelines yet. The existing risk prediction models have some limitations in terms of outcome definition, predictors, strategies for handling missing data, and model derivation. In the future, the applications of emerging biomarkers and polygenic risk scores as well as advances in machine learning methods will provide more possibilities for the further improvement of the model.

Epidemiological characteristics and research progress of monkeypox in 2022 / 中华流行病学杂志

Monkeypox is a zoonosis caused by monkeypox virus. Monkeypox was endemic mainly in central and western Africa in the past. Since May 7, 2022, monkeypox outbreaks have been reported in many non-epidemic countries and regions around the world. As of December 25, 2022, monkeypox cases have been detected in 110 countries and areas. Moreover, human to human transmission, especially among men who have sex with men, has aroused high global concern. The incidence, transmission route and clinical characteristics of monkeypox in 2022 seemed different from those in the past. Therefore, this paper summarizes the progress in research of the changes of epidemiological characteristics of monkeypox, the clinical characteristics of monkeypox and its prevention and treatment to provide scientific evidence for the prevention and control of monkeypox.

Prevalence of chronic kidney disease and its association with lifestyle factors in adults from 10 regions of China / 中华流行病学杂志

Objective: To investigate the distribution of chronic kidney disease (CKD) in participants from the China Kadoorie Biobank (CKB) study and evaluate the association between lifestyle risk factors and CKD. Methods: Based on the baseline survey data and follow-up data (as of December 31, 2018) of the CKB study, the differences in CKD cases' area and population distributions were described. Cox proportional hazards regression model was used to estimate the association between lifestyle risk factors and the risk of CKD. Results: A total of 505 147 participants, 4 920 cases of CKD were recorded in 11.26 year follow up with a incidence rate of 83.43/100 000 person-years. Glomerulonephropathy was the most common type. The incidence of CKD was higher in the urban area, men, and the elderly aged 60 years and above (87.83/100 000 person-years, 86.37/100 000 person-years, and 132.06/100 000 person-years). Current male smokers had an increased risk for CKD compared with non-smokers or occasional smokers (HR=1.18, 95%CI: 1.05-1.31). The non-obese population was used as a control group, both general obesity determined by BMI (HR=1.19, 95%CI: 1.10-1.29) and central obesity determined by waist circumference (HR=1.27, 95%CI: 1.19-1.35) were associated with higher risk for CKD. Conclusion: The risks for CKD varied with area and population in the CKB cohort study, and the risk was influenced by multiple lifestyle factors.

Progress in research of epidemiology of 2019-nCoV reinfection / 中华流行病学杂志

Continuous evolution of Omicron variant of 2019-nCoV has resulted in a rapid and simultaneous emergences of novel sub-variants with increased immune escape ability, higher reinfection risk and shorter time interval between infections. Compared with the first infection, the reinfection would still pose exceed risk to people's health although the clinical manifestations of the reinfection might be milder and the risk for severe illness or death is lower. The reinfection is highly associated with people's vaccination status, immunity level, age, working and residential factors. Those who have not received 2019-nCoV vaccination, the elderly and those with comorbidities, especially the previous 2019-nCoV patients with severe/critical illness, are at high risk for the reinfection. Booster doses of vaccine might play an additional role in the prevention of the reinfection and severe illness on the basis of natural immunity.

Research progress of Eubacterium and its metabolite short-chain fatty acids in regulating type 2 diabetes mellitus / 中华预防医学杂志

Intestinal flora and its metabolites are closely related to the progression of type 2 diabetes mellitus(T2DM). Eubacterium is one of the dominant intestinal flora, and its metabolites short-chain fatty acids (SCFAs) play a leading role in regulating intestinal metabolic balance. It has been reported that SCFAs can regulate the secretion of glucagon-like peptide-1, improve the function of pancreatic β cells, participate in bile acids metabolism and regulate the production of inflammatory factors in T2DM. Based on the above research background, this article mainly reviews the relationship between Eubacterium and its metabolite SCFAs and T2DM and its regulatory mechanism.

Prospective association between physical activity and mortality in patients with chronic kidney disease / 中华流行病学杂志

Objective: To investigate the prospective association of physical activity with all-cause, cardiovascular disease (CVD), and chronic kidney disease (CKD) mortality in CKD patients in China. Methods: Cox proportional hazard models were used to evaluate the association of total, domain-specific, and intensity-specific physical activity with the risk of all-cause, CVD, and CKD mortality based on data from the baseline survey of China Kadoorie Biobank. Results: During a median follow-up of 11.99 (11.13, 13.03) years, there were 698 deaths in 6 676 CKD patients. Compared with the bottom tertile of total physical activity, participants in the top tertile had a lower risk of all-cause, CVD, and CKD mortality, with hazard ratios (HRs) (95%CIs) of 0.61 (0.47-0.80), 0.40 (0.25-0.65), and 0.25 (0.07-0.85), respectively. Occupational, commuting, and household physical activity were negatively associated with the risk of all-cause and CVD mortality to varying degrees. Participants in the top tertile of occupational physical activity had a lower risk of all-cause (HR=0.56, 95%CI: 0.38-0.82) and CVD (HR=0.39, 95%CI: 0.20-0.74) mortality, those in the top tertile of commuting physical activity had a lower risk of CVD mortality (HR=0.43, 95%CI: 0.22-0.84), and those in the top tertile of household physical activity had a lower risk of all-cause (HR=0.61, 95%CI: 0.45-0.82), CVD (HR=0.44, 95%CI: 0.26-0.76) and CKD (HR=0.03, 95%CI: 0.01-0.17) mortality, compared with the bottom tertile of corresponding physical activity. No association of leisure-time physical activity with mortality was observed. Both low and moderate-vigorous intensity physical activity were negatively associated with the risk of all-cause, CVD and CKD mortality. The corresponding HRs (95%CIs) were 0.64 (0.50-0.82), 0.42 (0.26-0.66) and 0.29 (0.10-0.83) in the top tertile of low intensity physical activity, and the corresponding HRs (95%CIs) were 0.63 (0.48-0.82), 0.39 (0.24-0.64) and 0.23 (0.07-0.73) in the top tertile of moderate-vigorous intensity physical activity. Conclusion: Physical activity can reduce the risk of all-cause, CVD, and CKD mortality in CKD patients.

A descriptive analysis of hyperlipidemia in adult twins in China / 中华流行病学杂志

Objective: To describe the distribution characteristics of hyperlipidemia in adult twins in the Chinese National Twin Registry (CNTR) and explore the effect of genetic and environmental factors on hyperlipidemia. Methods: Twins recruited from the CNTR in 11 project areas across China were included in the study. A total of 69 130 (34 565 pairs) of adult twins with complete information on hyperlipidemia were selected for analysis. The random effect model was used to characterize the population and regional distribution of hyperlipidemia among twins. The concordance rates of hyperlipidemia were calculated in monozygotic twins (MZ) and dizygotic twins (DZ), respectively, to estimate the heritability. Results: The age of all participants was (34.2±12.4) years. This study's prevalence of hyperlipidemia was 1.3% (895/69 130). Twin pairs who were men, older, living in urban areas, married,had junior college degree or above, overweight, obese, insufficient physical activity, current smokers, ex-smokers, current drinkers, and ex-drinkers had a higher prevalence of hyperlipidemia (P<0.05). In within-pair analysis, the concordance rate of hyperlipidemia was 29.1% (118/405) in MZ and 18.1% (57/315) in DZ, and the difference was statistically significant (P<0.05). Stratified by gender, age, and region, the concordance rate of hyperlipidemia in MZ was still higher than that in DZ. Further, in within-same-sex twin pair analyses, the heritability of hyperlipidemia was 13.04% (95%CI: 2.61%-23.47%) in the northern group and 18.59% (95%CI: 4.43%-32.74%) in the female group, respectively. Conclusions: Adult twins were included in this study and were found to have a lower prevalence of hyperlipidemia than in the general population study, with population and regional differences. Genetic factors influence hyperlipidemia, but the genetic effect may vary with gender and area.

A descriptive analysis on hypertension in adult twins in China / 中华流行病学杂志

Objective: To describe the distribution characteristics of hypertension among adult twins in the Chinese National Twin Registry (CNTR) and to provide clues for exploring the role of genetic and environmental factors on hypertension. Methods: A total of 69 220 (34 610 pairs) of twins aged 18 and above with hypertension information were selected from CNTR registered from 2010 to 2018. Random effect models were used to describe the population and regional distribution of hypertension in twins. To estimate the heritability, the concordance rates of hypertension were calculated and compared between monozygotic twins (MZ) and dizygotic twins (DZ). Results: The age of all participants was (34.1±12.4) years. The overall self-reported prevalence of hypertension was 3.8%(2 610/69 220). Twin pairs who were older, living in urban areas, married, overweight or obese, current smokers or ex-smokers, and current drinkers or abstainers had a higher self-reported prevalence of hypertension (P<0.05). Analysis within the same-sex twin pairs found that the concordance rate of hypertension was 43.2% in MZ and 27.0% in DZ, and the difference was statistically significant (P<0.001). The heritability of hypertension was 22.1% (95%CI: 16.3%- 28.0%). Stratified by gender, age, and region, the concordance rate of hypertension in MZ was still higher than that in DZ. The heritability of hypertension was higher in female participants. Conclusions: There were differences in the distribution of hypertension among twins with different demographic and regional characteristics. It is indicated that genetic factors play a crucial role in hypertension in different genders, ages, and regions, while the magnitude of genetic effects may vary.

Association between fresh fruit consumption and the risk of chronic obstructive pulmonary disease-related hospitalization and death in Chinese adults: A prospective cohort study / 中华医学杂志(英文版)

BACKGROUND@#Existing evidence suggests that fruit consumption is a significant influencing factor for chronic obstructive pulmonary disease (COPD), but this is unclear in the Chinese population. We examined the association of fresh fruit consumption with the risk of COPD-related hospitalization and death in a nationwide, population-based prospective cohort from China.@*METHODS@#Between 2004 and 2008, the China Kadoorie Biobank recruited >0.5 million adults aged 30 to 79 years from ten diverse regions across China. After excluding individuals diagnosed with major chronic diseases and prevalent COPD, the prospective analysis included 421,428 participants. Cox regression was used to calculate the hazard ratios (HRs) for the association between fresh fruit consumption and risk of COPD-related hospitalization and death, with adjustment for established and potential confounders.@*RESULTS@#During a mean follow-up of 10.9 years, 11,292 COPD hospitalization events and deaths were documented, with an overall incidence rate of 2.47/1000 person-years. Participants who consumed fresh fruit daily had a 22% lower risk of COPD-related hospitalization and death compared with non-consumers (HR = 0.78, 95% confidence interval [CI]: 0.71-0.87). The inverse association between fresh fruit consumption and COPD-related hospitalization and death was stronger among non-current smokers and participants with normal body mass index (BMI) (18.5 kg/m 2 ≤ BMI < 24.0 kg/m 2 ); the corresponding HRs for daily fresh fruit consumption were 0.78 (95% CI: 0.68-0.89) and 0.69 (95% CI: 0.59-0.79) compared with their counterparts, respectively.@*CONCLUSIONS@#High-frequency fruit consumption was associated with a lower risk of COPD in Chinese adults. Increasing fruit consumption, together with cigarette cessation and weight control, should be considered in the prevention and management of COPD.

Structural Design and Penumbra Analysis of Dynamic Multi-leaf Collimator Leaf End / 中国医疗器械杂志

Dynamic multi-leaf collimator, which has the function of radiation beam shaping, is a key executive component of tumor precise radiotherapy, and plays a core role in improving the accuracy, efficiency and quality of radiotherapy. A new type of collimator leaf end structure with circular arc and plane combination was studied, and collimator penumbra performance analysis model combining analytical expression and graphic analysis was developed. The influence of leaf end structure on penumbra was analyzed quantitatively, and a set of three-dimensional structure design of dynamic multi-leaf collimator was completed. The feasibility of the structural design and analysis model was verified through experimental measurements.

Progress on genome-wide association studies on mosaic chromosomal alterations / 中华流行病学杂志

Mosaic chromosomal alteration (mCA) is referred to as large-scale somatic mutations on chromosomes, which results in diverse karyotypes in body. The mCA is regarded as one of the phenotypes of aging. Studies have revealed its associations with many chronic diseases such as hematopoietic cancers and cardiovascular diseases, but its genetic basis (e.g. genetic susceptibility variants) is still under-investigated. This paper reviews GWAS studies for mCA on autosomal chromosomes and sex chromosomes [mosaic loss of the Y chromosome (mLOY) and mosaic loss of the X chromosome (mLOX)] based on large population, respectively. Most of the genetic susceptibility loci found in studies for autosomal mCA were associated with copy-neutral loss of heterozygosity. The study of sex chromosome mCA focused on mosaic loss mutations. The number of genetic susceptibility loci for mLOY was high (up to 156), but it was relatively less for mLOX.

Tea consumption and cancer: a Mendelian randomization study / 中华流行病学杂志

Objective: A Mendelian randomization (MR) analysis was performed to assess the relationship between tea consumption and cancer. Methods: There were 100 639 participants with the information of gene sequencing of whole genome in the China Kadoorie Biobank. After excluding those with cancer at baseline survey, a total of 100 218 participants were included in this study. The baseline information about tea consumption were analyzed, including daily tea consumption or not, cups of daily tea consumption, and grams of daily tea consumption. We used the two-stage least square method to evaluate the associations between three tea consumption variables and incidence of cancer and some subtypes, including stomach cancer, liver and intrahepatic bile ducts cancer, colorectal cancer, tracheobronchial and lung cancer, and female breast cancer. Multivariable MR and analysis only among nondrinkers were used to control the impact of alcohol consumption. Sensitivity analyses were also performed, including inverse variance weighting, weighted median, and MR-Egger. Results: We used 54, 42, and 28 SNPs to construct non-weighted genetic risk scores as instrumental variables for daily tea consumption or not, cups of daily tea consumption, and grams of daily tea consumption, respectively. During an average of (11.4±3.0) years of follow-up, 6 886 cases of cancer were recorded. After adjusting for age, age2, sex, region, array type, and the first 12 genetic principal components, there were no significant associations of three tea consumption variables with the incidence of cancer and cancer subtypes. Compared with non-daily tea drinkers, the HR (95%CI) of daily tea drinkers for cancer and some subtypes, including stomach cancer, liver and intrahepatic bile ducts cancer, colorectal cancer, tracheobronchial and lung cancer, and female breast cancer, are respectively 0.99 (0.78-1.26), 1.17 (0.58-2.36), 0.86 (0.40-1.84), 0.85 (0.42-1.73), 1.39 (0.85-2.26) and 0.63 (0.28-1.38). After controlling the impact of alcohol consumption and performing multiple sensitivity analyses, the results were similar. Conclusion: There is no causal relationship between tea consumption and risk of cancer in population in China.

Epidemiological distribution characteristics of peripheral blood mosaic chromosomal alteration in adults from 10 regions of China / 中华流行病学杂志

Objective: To describe the epidemiological distribution characteristics of peripheral blood mosaic chromosomal alteration (mCA) in community adults aged 30-79 years in 10 regions of China. Methods: A total of 100 297 participants with complete baseline information (demographic characteristics, lifestyle, physical examination, etc.) and genotyping data of blood-derived DNA in ten regions of the China Kadoorie Biobank study were included. The mCAs were detected with the Mosaic Chromosomal Alterations pipeline, and logistic regression models were used to compare the differences in the detection rate of mCAs in different regions and populations. Results: A total of 5 810 mCA carriers were detected, with the detection rate of 5.8%. The standardized detection rate was 5.1%. The baseline detection rate of mCA increased with age, which were 3.4%, 5.0%, and 9.4% in those aged 30-, 51-, and >60 years, respectively (trend test P<0.001). A more significant proportion of mCAs were found in men (8.0%) than women (4.0%), as well as in urban areas (6.4%) than in rural areas (5.3%), the difference was significant (P<0.001). After adjusting for age and gender, the detection rate of mCA was higher in current smokers or people quitting smoking due to illness and people with low physical activity level, and the mCA detection rate was lower in obesy people (5.3%) than that in people with normal body weight (5.9%) (P=0.006). Conclusions: The detection rate of mCAs varied with region and population in community adults aged 30-79 years in 10 regions of China. The study results might contribute to the molecular identification of aging populations and guide precision prevention of age-related diseases such as cancers.

A review on cardiovascular disease risk prediction models in the elderly / 中华流行病学杂志

Risk prediction models play an important role in the primary prevention of cardiovascular diseases (CVD) in the elderly population. There are fifteen papers about CVD risk prediction models developed for the elderly domestically and internationally, of which the definitions of disease outcome vary widely. Ten models were reported with insufficient information about study methods or results. Ten models were at high risk of bias. Thirteen models presented moderate discrimination in internal validation, and only four models have undertaken external validation. The CVD risk prediction models for the elderly differed from those for the general population in terms of model algorithm and the effect size of association between predictor and outcome, and the prediction performance of the models for the elderly attenuated. In the future, high-quality external validation researches are necessary to provide more solid evidence. Different ways, including adding new predictors, using competing risk model algorithms, machine learning methods, or joint models, and altering the prediction time horizon, should be explored to optimize the current models.

Incidence of chronic obstructive pulmonary disease and risk factors in the Suzhou cohort / 中华流行病学杂志

Objective: To understand the incidence of chronic obstructive pulmonary disease (COPD) in the Suzhou cohort, and explore the risk factors for the development of COPD in Suzhou, and provide a scientific basis for COPD prevention. Methods: This study was based on the China Kadoorie Biobank project in Wuzhong District, Suzhou. After excluding individuals with airflow obstruction and self-reported chronic bronchitis, emphysema, or pulmonary heart disease at baseline, 45 484 individuals were finally included in the analysis. Cox proportional risk models were used to analyze risk factors of COPD and calculate hazard ratios and 95% confidence interval (CI) in the Suzhou cohort. The effect modifications of smoking on the association between other risk factors and COPD were evaluated. Results: Complete follow-up was available through December 31, 2017. Participants were followed up for a median of 11.12 years, and 524 individuals were diagnosed with COPD during the follow-up period; the incidence was 105.54 per 100 000 person-years. Multivariate Cox proportional risk regression models showed that age (HR=3.78, 95%CI:3.32-4.30), former smoking (HR=2.00, 95%CI:1.24-3.22), current smoking (<10 cigarettes/day, HR=2.14, 95%CI:1.36-3.35;≥10 cigarettes/day, HR=2.69, 95%CI:1.60-4.54), history of respiratory disease (HR=2.08, 95%CI:1.33-3.26), daily sleep duration ≥10 hours (HR=1.41, 95%CI:1.02-1.95) were associated with increased risk of COPD. However, education level of primary school and above (primary or junior high school, HR=0.65, 95%CI:0.52-0.81; high school and above, HR=0.54, 95%CI:0.33-0.87), consuming fresh fruit daily (HR=0.59, 95%CI:0.42-0.83) and consuming spicy food weekly (HR=0.71, 95%CI:0.53-0.94) were associated with reduced risk of COPD. Conclusions: The incidence of COPD is low in Suzhou. Older age, smoking, history of respiratory disease, and long sleep duration were risk factors for the development of COPD in the Suzhou cohort.

A case-control study on the association between a healthy lifestyle and obesity among adult twins in Shanghai / 中华流行病学杂志

Objective: To investigate the associations between the numbers of healthy lifestyles and overweight/obesity and abdominal obesity in adult twins in Shanghai. Methods: Based on the Shanghai Twin Registry System Phase Ⅱ survey data in 2017-2018, a case-control study was conducted to analyze the association between healthy lifestyles and obesity and further adjusted for confounders by a co-twin control study. Results: A total of 7 864 adult twins (3 932 pairs) were included. In the co-twin case-control analysis for monozygotic twins, compared with participants with 0 to 2 healthy lifestyles, those with 3 and 4 to 5 healthy lifestyles had a 49% (OR=0.51, 95%CI: 0.28-0.93) and 70% (OR=0.30, 95%CI: 0.13-0.69) lower risk of overweight/obesity, respectively, and a 17% (OR=0.83, 95%CI: 0.44-1.57) and 66% (OR=0.34, 95%CI: 0.14-0.80) lower risk of abdominal obesity, respectively. For each additional healthy lifestyle, the risk of developing overweight/obesity was reduced by 41% (OR=0.59, 95%CI: 0.42-0.85), and the risk of developing abdominal obesity was reduced by 37% (OR=0.63, 95%CI: 0.44-0.90). Conclusion: An increasing number of healthy lifestyles was associated with a marked decreased risk for both overweight/obesity and abdominal obesity.

The correlation of sleep duration and insomnia with low muscle mass, strength and quality in Chinese adults / 中华流行病学杂志

Objective: To explore the relationship of sleep duration and insomnia with muscle mass, strength, and quality in Chinese adults. Methods: Based on the second resurvey of China Kadoorie Biobank (CKB) in 2013-2014, logistic regression models were used to analyze the correlation of sleep duration, insomnia, and its duration with low muscle mass, handgrip strength, and muscle quality. Results: The average sleep duration of the study population was (7.4±1.5) hours. Morbidities of short sleep duration (<6 hours), long sleep duration (≥9 hours), and insomnia were 9.3%,17.4%,and 29.9%,respectively. Compared with those who slept for 7- hours, those who slept for ≥9 hours were more likely to have low muscle mass, low handgrip strength,and low arm muscle quality (AMQ), and the OR (95%CI) of low appendicular skeletal muscle mass index (ASMI), low total skeletal muscle mass index (TSMI), low grip strength and low AMQ were 1.32 (1.18-1.48),1.26 (1.13-1.41), 1.33 (1.18-1.49) and 1.16 (1.03-1.30), respectively. Compared with participants without insomnia, insomnia patients were more likely to have low muscle mass,and the longer the duration of insomnia,the higher the risk (P for trend <0.001). Participants who reported <6 hours sleep duration and insomnia had a higher proportion of low ASMI and low TSMI,compared with those who slept for 7- hours and without insomnia, the OR (95%CI) were 1.26 (1.08-1.47) and 1.25 (1.07-1.46), respectively. Conclusions: Participants who reported ≥9 hours sleep duration were more likely to have low muscle mass,low handgrip strength,and low AMQ. Participants with insomnia had lower muscle mass, and the longer the duration of insomnia, the higher the proportion of low ASMI and low TSMI.

Spicy food consumption and risk of lip, oral cavity and pharynx cancers: a prospective cohort study of Chinese adults / 中华流行病学杂志

Objective: To explore the association of spicy food consumption and risk of lip, oral cavity, and pharynx cancers (LOCPs) in Chinese adults. Methods: Based on the baseline survey and long-term follow-up of the China Kadoorie Biobank (CKB) study, Cox proportional hazard regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) for associations between spicy food consumption and LOCPs incidence. Results: Of the 510 145 participants included at baseline, 30.1% reported daily spicy food consumption. During a mean follow-up of 10.8 (2.0) years, we documented 767 LOCPs cases. Multivariate adjusted analyses showed that the risk of LOCPs incidence decreased with the frequency of spicy food intake (trend P=0.003), with HR of 0.69 (95%CI:0.54-0.88) for daily spicy food consumers, compared with never or occasional consumers. Participants who preferred moderate pungency degrees had the lowest risk of LOCPs, with a 33%[0.67(95%CI:0.52-0.87)] reduced risk compared to those who consumed spicy food less than once per week. The later the starting age, the lower the risk (trend P=0.004). Those who started eating spicy food after 18 years old had the lowest risk of LOCPs incidence, with adjusted HR (95%CI) of 0.70(0.54-0.92). Conclusions: Spicy food intake might be associated with a decreased risk of LOCPs incidence. Such association was independent of healthy lifestyles. Advocating moderate-pungency spicy food consumption and healthy lifestyles might help prevent LOCPs.

The correlation of physical activity and sedentary leisure time with low muscle mass, strength, and quality in Chinese adults / 中华流行病学杂志

Objective: To explore the relationship of physical activity and sedentary leisure time with muscle mass, strength, and quality in Chinese adults. Methods: Based on the second resurvey of China Kadoorie Biobank (CKB) in 2013-2014, logistic regression models were used to analyze the correlation of physical activity and sedentary leisure time with low muscle mass, grip strength, and muscle quality. Results: A total of 24 245 participants were included in the analysis. The average daily physical activity level was (18.3±13.8) MET-h/d, and the sedentary leisure time was (4.4±1.9) hours. We took the lowest physical activity quartile as the reference and found that the participants' physical activity was negatively correlated to low muscle mass, strength, and quality. The ORs (95%CIs) of low appendicular skeletal muscle mass index (ASMI), low total skeletal muscle mass index (TSMI), low grip strength and low arm muscle quality (AMQ) were 0.68 (0.60-0.77), 0.66 (0.58-0.75), 0.82 (0.72-0.94) and 0.84 (0.74-0.95), respectively. The subtypes of physical activity, including those related to work, transportation, housework, and leisure, also showed negative correlations with low muscle mass, strength, and quality to varying degrees. Compared with participants with the shortest sedentary leisure time, those who had the longest were more likely to have low TSMI (OR=1.13, 95%CI: 0.99-1.30). Conclusions: Physical activity was negatively correlated with a lower risk of low muscle mass and strength, while longer sedentary leisure time positively correlated with low muscle mass.

Associations of body mass index and waist circumference with hospitalization risk of kidney stones in Chinese adults / 中华流行病学杂志

Objective: To evaluate the associations of body mass index (BMI) and waist circumference with hospitalization risk of kidney stones in Chinese adults. Methods: This study used long-term follow-up data from China Kadoorie Biobank. After excluding participants with chronic kidney disease, cancer, and extreme BMI or waist circumference values at baseline, 502 096 participants were included in the present analysis. Cox proportional hazards regression models were used to estimate the associations of BMI and waist circumference with hospitalization risk of kidney stones. Results: During an average follow-up period of (10.7±2.2) years, 12 396 participants were hospitalized for the first time with kidney stones. Using the participants with BMI (kg/m2) of 20.5-22.4 as reference, the multivariable-adjusted HR (95%CI) for those with BMI of <18.5, 18.5-20.4, 22.5-23.9, 24.0-25.9, 26.0-27.9, 28.0-29.9, and ≥30.0 were 0.96 (0.87-1.05), 0.94 (0.88-1.00), 1.11 (1.05-1.17), 1.25 (1.18-1.32), 1.29 (1.21-1.37), 1.39 (1.28-1.50), and 1.54 (1.40-1.71), respectively. For every 1 kg/m2 increase in BMI, the HR of kidney stones hospitalization increased by 4% (HR=1.04, 95%CI: 1.04-1.05). Using the participants with waist circumference (cm) of 75.0-79.9 as reference, the multivariable-adjusted HR (95%CI) for those with waist circumference of <65.0, 65.0-69.9, 70.0-74.9, 80.0-84.9, 85.0-89.9, 90.0-94.9, and ≥95.0 were 0.82 (0.74-0.91), 0.85 (0.80-0.92), 0.95 (0.89-1.00), 1.16 (1.09-1.22), 1.22 (1.15-1.30), 1.28 (1.19-1.38), and 1.46 (1.35-1.58), respectively. For every 5 cm increase in waist circumference, the HR of kidney stones hospitalization increased by 9% (HR=1.09, 95%CI: 1.08-1.10). After mutually adjusting for BMI and waist circumference in the above models, the association between BMI and hospitalization risk of kidney stones disappeared. In contrast, the association between waist circumference and hospitalization risk of kidney stones remained unchanged. Conclusions: BMI and waist circumference were positively associated with hospitalization risk of kidney stones. The increased waist circumference was an independent risk factor for kidney stones among Chinese adults.