[A prospective cohort study of premature death and influencing factors in adults aged 56-69 years from 10 regions of China]

Objective: To describe and analyze the epidemiological characteristics of premature death (death before age of 70 years) and related risk factors in approximate 100 000 adults recruited from 10 regions of China during a 10-year follow-up. Methods: Data, including demographic characteristics, lifestyle and physical indicators as well as health outcomes as of December 31, 2017, were obtained from baseline survey and long-term follow-up of the China Kadoorie Biobank (CKB) study. All-cause and cause-specific premature death in different areas, in men and women and in people with different lifestyles were analyzed. Cox proportional risk model was used to analyze the associations between baseline factors and premature death. Results: A total of 99 993 participants aged 56-69 years were included in the study. During 10 years of follow-up, 7 530 premature deaths were recorded and the premature death rate was 7.15 per 1 000 person-years. The main causes of premature death were cancer and cardiovascular and cerebrovascular diseases. The premature mortality rate was higher in rural areas, in northern region and in men, and decreased with age (P<0.05). Premature death was more likely to occur in smokers, and a dose-response relationship was observed. Compared with non-drinkers, the risk for premature death was higher in ex-drinkers (HR: 1.25 [95%CI:1.16-1.36]) and heavy drinkers (average alcohol consumption ≥60 g/d) (HR: 1.20 [95%CI:1.08-1.34]). The risk for premature death decreased with the increase of physical activity. Low body weight and central obesity were independently associated with increased risk for premature death (HR: 1.67 [95%CI:1.55-1.81] and 1.13 [95%CI:1.05-1.21], respectively). Conclusions: The main causes of premature death in adults aged 56-69 years in China during 10-year follow-up were cancer and cardiovascular and cerebrovascular diseases. The premature mortality rate varied with socioeconomic and demographic characteristics. The risk for premature death was influenced by multi factors, such as lifestyle and physical conditions.

[Association between genetic predisposition to childhood obesity and the risk of adult ischemic heart disease in China]

Objective: To examine the associations of childhood obesity, assessed by genetic variations of childhood body mass index (BMI), with the risk of adult ischemic heart disease (IHD) and major coronary event (MCE). Methods: More than 69 000 participants from the China Kadoorie Biobank were genotyped. After excluding those with coronary heart disease, stroke, or cancer at baseline, a total of 64 454 participants were included in this study. Based on genome-wide significant single nucleotide polymorphisms (SNPs), childhood BMI genetic risk score were constructed for every participant and divided into quintiles, with the lowest quintile as the low genetic risk group and the highest quintile as the high genetic risk group. Cox proportional hazards regression models were used to estimate the association between genetic predisposition to childhood obesity and the risk of ischemic heart disease. Results: During a median of 10.7 years of follow-up, 7 073 incident cases of IHD and 1 845 cases of MCE were documented. After adjusting for sex, age, region, and the first ten genetic principal components, the HRs (95%CIs) for IHD and MCE in the high genetic risk group were 1.10 (1.02-1.18) and 1.10 (0.95-1.27), compared with the low genetic risk group. IHD risk increased by 4% (2%-6%) for each one standard deviation increase in genetic risk score (trend P=0.001). After further adjustment for baseline BMI, the differences between genetic risk groups were not statistically significant, but there was still a linear trend between genetic risk score and IHD risk (trend P=0.019). Conclusions: IHD risk increased with genetic predisposition to childhood obesity, suggesting that childhood obesity is an important risk factor for the development of IHD in China. As an easily identifiable feature, changes of childhood BMI should be monitored regularly to realize early intervention of IHD in adults.

[Association between tea consumption and all-cause mortality in Chinese adults]

Objective: To investigate the association between tea consumption and the risk of all-cause and cause-specific mortality among Chinese adults. Methods: This study was based on China Kadoorie Biobank (CKB). Tea consumption information was self-reported by participants at baseline. Death was mainly identified by linkage to the death registry system. Cox proportional hazard regression models estimated HR and 95%CI. Results: With a median follow-up of 11.1 years, there were 34 661 deaths in 438 443 participants. Compared with those who never drink tea, all-cause mortality HR(95%CI) were 0.89(0.86-0.91) and 0.92(0.88-0.95) for non-daily tea drinkers and daily tea drinkers, respectively. A statistically significant difference was found in the association of tea consumption and the risk of all-cause mortality between men and women(interaction P<0.05). The protective effect was mainly seen in men. Compared with those who never drink tea, daily tea drinkers had a reduced risk of death from ischemic heart disease, ischemic stroke, hemorrhagic stroke, cancer, respiration diseases and other causes of death, and the corresponding HR(95%CI) were 0.83(0.76-0.92), 0.82(0.69-0.97), 0.86(0.78-0.94), 1.03(0.97-1.09), 1.00(0.87-1.16), 0.84(0.78-0.90). Among never smokers and non-excessive drinkers, there was no statistically significant association between daily tea drinking and the risk of death from cancer. While smokers and excessive drinkers had an increased risk of death from cancer (interaction P<0.001). Conclusions: Tea consumers had reduced risks of all-cause mortality and partial cause-specific mortality, but not for the risk of death from cancer. On the contrary, daily tea drinkers with smoking habits and excessive alcohol drinking had an increased risk of death from cancer.

[Associations of body mass index and waist circumference with hospitalization risk of kidney stones in Chinese adults]

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.

[The correlation of physical activity and sedentary leisure time with low muscle mass, strength, and quality in Chinese adults]

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.

[Spicy food consumption and risk of lip, oral cavity and pharynx cancers: a prospective cohort study of Chinese adults]

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 sleep duration and insomnia with low muscle mass, strength and quality in Chinese adults]

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.

[Correlation between chronic diseases and low muscle mass, strength and quality in adults in China]

Objective: To explore the correlation between chronic diseases and muscle mass, strength and quality in adults in China. Methods: Based on the second resurvey of China Kadoorie Biobank (CKB) in 2013-2014, logistic regression models were used to analyze the correlation of different types, number and duration of chronic diseases with low muscle mass, handgrip strength and muscle quality. Results: The prevalence rate of diabetes, coronary heart disease (CHD), stroke and chronic obstructive pulmonary disease (COPD) were 9.6%, 5.8%, 3.2% and 26.8%, respectively, and 38.8% of the participants had at least one disease, and they were more likely to have low handgrip strength and low arm muscle quality (AMQ), and the longer the chronic diseases duration, the higher the risk. The ORs (95%CIs) for low handgrip strength and low AMQ in patients with 1 chronic disease for more than 10 years was 1.64 (1.42-1.90) and 1.83 (1.60-2.10), respectively. The ORs (95%CIs) for low handgrip strength were 1.26 (1.17-1.37), 1.42 (1.23-1.64) and 2.27 (1.55-3.32) and the ORs (95%CIs) for low AMQ were 1.28 (1.18-1.38), 1.67 (1.46-1.92) and 2.41(1.69-3.45), respectively, in patients with 1, 2, ≥3 chronic diseases, the correlation showed a linear trend (P for trend <0.001). Diabetes, CHD and stroke were positively correlated with low handgrip strength and low AMQ. Compared with participants without COPD, COPD patients were more likely to have low appendicular skeletal muscle mass index (ASMI), low total skeletal muscle mass index (TSMI) and low handgrip strength, and the risk was positively correlated with disease duration. Conclusions: Patients with chronic diseases were more likely to have lower muscle strength and muscle quality, especially the patients with multi diseases and longer disease duration. The proportion of low handgrip strength and low AMQ was higher in patients who reported multi-prevalence and longer duration of chronic diseases.

[Comparison of Fried phenotype and frailty index and their associations with risk of mortality]

Objective: To compare the consistency of frailty status measured by Fried phenotype and frailty index composed of different numbers of deficits, and their prospective associations with risk of mortality. Methods: Data of 23 615 participants from the second resurvey of the China Kadoore Biobank (CKB) was used. Fried phenotype was constructed using five phenotypes, and frailty indexes (FI) were constructed using 28 and 40 deficits, respectively. We calculated the Weighted Kappa coefficient to compare the consistency of three measures in the classification of frailty status. Cox regression was performed to analyze the association of frailty status with risk of mortality. Results: The frailty prevalence calculated by Fried phenotype, FI-28, and FI-40 were 5.4%, 7.9%, and 4.0%, respectively. The Kappa coefficients of Fried phenotype with FI-28 and FI-40 were 0.357 and 0.408, respectively. The Kappa coefficients of FI-28 and FI-40 was 0.712. During an average of (3.9±0.5) years of follow-up, 755 participants died. When Fried phenotype was used, compared with the robust participants, the prefrail and frail participants had increased risk of mortality, the multivariable-adjusted HRs were 1.60 (95%CI: 1.32-1.94) and 2.90 (95%CI: 2.25-3.73), respectively. When FI-28 was used, the corresponding HRs were 1.71 (95%CI: 1.39-2.11) and 2.52 (95%CI:1.95-3.27) for prefrail and frail participants, and when FI-40 was used, the corresponding HRs were 1.98 (95%CI:1.60-2.44) and 3.71 (95%CI: 2.80-4.91). The association of frailty status with mortality differed in different age groups, with the association stronger in younger adults than in older adults. Conclusion: Fried phenotype and frailty index constituted with different numbers of deficits showed good consistency; which can be used to well predict the risk of mortality.

[Prevalence of heart failure and its association with smoking behavior in adults from 10 regions of China]

Objective: To describe the prevalence of heart failure in China and to explore the prospective association between smoking behavior and the risk of incident heart failure. Methods: The subjects were from the China Kadoorie Biobank (CKB) and the baseline survey was conducted from June 2004 to July 2008. A total of 487 197 subjects were included in this study, after excluding those with missing BMI information, lost follow-up immediately after baseline investigation, and self-reported coronary heart disease, stroke, or malignant tumor at baseline. This study included data from baseline and follow-up until December 31, 2016. Cox proportional hazards regression models were used to estimate the association between smoking behavior and the risk of heart failure. Results: The median follow-up time was 10.15 years, during which a total of 4 208 new cases of heart failure occurred, with a crude incidence rate of 0.87/1 000 person-years and a cumulative incidence rate of 0.86%. The higher the age at baseline, the higher the incidence of heart failure. The incidence of heart failure in high age group, rural area and male was higher than that in low age group, urban area and female population respectively. Compared with non-smokers, there was no significant difference in the risk of heart failure in occasional smokers (HR=1.05; 95%CI: 0.91-1.22), while former smokers (HR=1.48; 95%CI:1.31-1.67) and current smokers (HR=1.34;95%CI:1.22-1.49) increased risk. Former smokers (HR=1.33;95%CI:1.21-1.46) and current smokers (HR=1.46; 95%CI:1.31-1.64) had higher risk of heart failure than non-smokers or occasional smokers. No dose-response relationship was observed between the number of cigarettes smoked per day and the risk of heart failure in current and former smokers (for trend P=0.347 and 0.066). Compared with non-smokers or occasional smokers, the hazard ratios of <5, 5-, 10- and ≥20 years since quit smoking were 1.61 (95%CI: 1.36-1.92), 1.55 (95%CI: 1.27-1.90), 1.24 (95%CI: 1.02-1.51) and 1.35 (95%CI: 1.08-1.68), respectively (for trend P=0.091). The hazard ratios of quitting smoking due to disease and other reasons were 1.62 (95%CI:1.41-1.86) and 1.23 (95%CI: 1.04-1.45). Healthy smoking behaviors had a significant protective effect on heart failure compared with non-healthy smoking behaviors (HR=0.75, 95%CI:0.69-0.81). Area and family history of coronary heart disease, and the smoking behaviors interacted with the risk of heart failure (for all interactions were P<0.05). Conclusions: The incidence of heart failure in China is higher in males than females, higher in rural areas than in urban areas, and increases with age. Both former smokers and current smokers had a higher risk of heart failure than nonsmokers or occasional smokers, regardless of the frequency, amount, duration, and reason for quitting. Smoking is an important risk factor for heart failure and comprehensive anti-smoking measures should be maintained.

[Prevalence, patterns and long-term changes of multimorbidity in adults from 10 regions of China]

Objective: To describe the prevalence of multimorbidity and its secular trend, and to explore the common patterns of multimorbidity in Chinese adults. Methods: A total of 25 033 participants who attended the second resurvey of China Kadoorie Biobank (CKB) were included in the study. We used data collected both at baseline (2004-2008) and at resurvey (2013-2014). A total of 13 chronic conditions were included, defined by self-reported, physical examination, and blood sample testing. Multimorbidity was defined as co-existence of two or more chronic conditions. Patterns of multimorbidity were explored using hierarchical cluster analysis. Results: The mean age of participants was (51.5±10.1) years at baseline and (59.5±10.2) years at second resurvey. The prevalence of multimorbidity increased from 33.5% to 58.1% over (8.0±0.8) years of follow-up. The average number of chronic conditions per person increased from 1.15 to 1.82 and all participants increased 0.42 conditions per 5 years on average. Participants who were older, less educated or lived in urban areas had a higher prevalence of multimorbidity and a higher increase in the number of chronic conditions. The increase in the number of chronic conditions was also higher among smokers and heavy alcohol drinkers. The most common multimorbidity pattern in the present population consisted of obesity, hypertension, diabetes, stroke, and heart disease. Conclusions: The prevalence of multimorbidity in Chinese adults is increasing rapidly due to ageing population. Populations of different sociodemographic background and lifestyle habits may have different prevalence of multimorbidity and changes in rates over time.

[Descriptive analysis of fracture hospitalization rate in adults from 10 regions of China]

Objective: To analyze the epidemiological distributions of fracture hospitalization. Methods: The present study included participants who participated in the baseline survey of China Kadoorie Biobank (CKB) and excluded participants who were lost to follow up or died before 2009, leaving a total of 506 004 participants. Negative binomial regression models were used to analyze the epidemiological distribution of any fracture and fracture at five specific body sites (upperlimb, lowerlimb, spine, pelvis and hip) from 2009 to 2016 in 10 regions. Results: During a median follow-up of (7.7±1.2) years (total person-years 3 899 814), we documented 17 118 cases of fracture hospitalizations. The crude fracture hospitalization rate was 4.39/1 000 person-years. After controlling for the increasing age of the fixed cohort, the hospitalization rates of fractures at various body sites increased from 2009 to 2016, with an annual growth rate (95%CI) of 9.1% (8.3%-9.9%) for any fracture. The fracture hospitalization rate was higher in rural than in urban areas except for hip fractures (P<0.05) and the hospitalization rate of any fracture were 5.42/1 000 and 3.24/1 000 person-years in rural and urban areas, respectively. Fracture hospitalization rate increased by age. In participants aged <50 years, men had higher fracture hospitalization rates than women except for pelvis fracture, while in those aged ≥50 years, women had higher fracture hospitalization rates than men. Conclusions: Fracture hospitalization rates increased by age and also showed upward selular trends. As China has begun the aging process, fractures impose a heavier burden on society. It is of great significance to prevent osteoporosis-related and injury-related fractures in order to reduce fractures incidence.

[The correlation of dietary patterns with low muscle mass, strength and quality in adults from 10 regions of China]

Objective: To evaluate the correlation of dietary patterns with low muscle mass, strength and quality in Chinese adults. Methods: Based on the second resurvey of China Kadoorie Biobank, factor analysis was conducted to derive dietary patterns from 20 food groups. Low muscle mass, strength, and quality were defined as the sex-specific lowest quintile of appendicular skeletal muscle mass index (ASMI), total skeletal muscle mass index (TSMI), handgrip strength and arm muscle quality (AMQ) according to Asian Working Group for Sarcopenia recommendations. Logistic regression models were used to evaluate the correlation of dietary patterns with low muscle mass, strength, and quality. Results: Two major dietary patterns were extracted. The balanced dietary pattern was characterized by the intake of a variety of foods, whereas the rice-meat dietary pattern was characterized by high intakes of rice, meat, poultry and fish. Individuals who had the highest quintile score of the balanced dietary pattern were less likely to have low TSMI, handgrip strength or AMQ(OR=0.83, 95%CI: 0.74-0.95 for low TSMI; OR=0.64, 95%CI: 0.56-0.74 for low handgrip strength; OR=0.82, 95%CI: 0.72-0.93 for low AMQ; for trend P<0.05). And those who scored higher on the rice-meat dietary pattern had lower risk of low muscle mass and strength (OR=0.67, 95%CI: 0.55-0.82 for low ASMI; OR=0.69, 95%CI: 0.56-0.85 for low TSMI; OR=0.74, 95%CI: 0.60-0.91 for low handgrip strength; for trend P<0.05). Conclusion: Individuals followed the balanced dietary pattern, as well as those who followed the rice-meat dietary pattern, had better levels of skeletal muscle mass, strength and quality.

[Polygenic risk score in personalized screening of lung cancer: a prospective cohort study in Chinese]

Objective: To explore how to personalize lung cancer screening programs for prevention in Chinese populations based on individual genetic risk score. Methods: We constructed the lung cancer polygenic genetic risk score (PRS-19) based on the 19 previously published genetic variations, using 100 615 participants with genotyping data from the China Kadoorie Biobank (CKB). Using the 5-year absolute risk of lung cancer in a population (55 years old with at least 30-pack-year history of smoking) as reference, the trend of 5-year absolute risk in different genetic risk groups was calculated in smokers and non-smokers, respectively. Distribution curves of 5-year absolute risk were also described to determine the theoretical age or smoking dose when different genetic risk groups reached the reference values. Given the overall findings, the specific start age for lung cancer screening were suggested for different genetic risk groups. Results: The 5-year absolute risk of lung cancer was 0.67% in 55-year-old smokers with 30 packs per year in the CKB. Among smokers, 5-year absolute risk of participants increased as the genetic risk increased. Hence, it was recommended that people at high genetic risk should start screening earlier. For the highest genetic risk populations (the top 1% of PRS), the start age might be changed to 50 years old. If the start age remained at 55-year-old, the smoking dose should be set lowered in high genetic risk populations. For the highest genetic risk populations, they should be included in lung cancer screening regardless of the cumulative smoking exposure. Among nonsmokers, it was also valuable to screen people with high genetic risk, considering the start age of 62 for the highest genetic risk populations and 74 for the lowest genetic risk populations (the bottom 5% of PRS). Conclusions: PRS-19 can be effectively used in developing lung cancer screening program for individualized prevention in China. For smokers with high genetic risk, the recommended starting age and smoking dose could be lowered for lung cancer screening, and non-smokers with high genetic risk could also be included in the screening programs.

[Study on the mechanisms of the intestinal tight-junction destruction caused by Blastocystis hominis infection in rats]

OBJECTIVE

To explore the mechanism of the intestinal barrier damage caused by Blastocystis hominis infections in rats.

METHODS

Thirty SD rats were randomly divided into the control group, and the 1-, 3-, 6- and 9-week-infection groups, of 6 rats in each group. Rats in each infection group were orally infected with B. hominis trophozoites at a density of 2 × 10⁸ parasites per rat, and the control group was given an equal volume of phosphate buffered saline solution. The 7-hour urine samples were collected 1, 3, 6 and 9 weeks post-infection for the measurement of the intestinal permeability. Then, rats were sacrificed using the cervical dislocation method, and the cecum specimens were collected for the detection of the intestinal epithelial cell permeability. The expression of tight junction-related Occludin and Claudin - 1 genes and apoptosis-related Bcl - 2 and Bax genes was quantified in cecum epithelial cells using the real-time fluorescent quantitative PCR (qPCR) assay, and cell apoptosis was detected in the rat cecum using the TdT-mediated dUTP nick-end labeling (TUNEL) assay.

RESULTS

The median urinary lactolose to mannitol ratios were 0.29, 0.72, 0.44, 0.46 and 0.38 in the control group, and the 1-, 3-, 6- and 9-week-infection groups, respectively, and the difference was statistically significant (H = 12.09, P < 0.05). B. hominis invasion and epithelial injury were observed in intestinal epithelial cells of rats infected with B. hominis, and transmission electron microscopy displayed the destruction of tight junctions between intestinal epithelial cells. The relative expression of Occludin, Claudin-1, Bcl-2 and Bax genes was 1.04, 0.62, 0.71, 0.68 and 0.96; 1.03, 0.61, 0.63, 0.76 and 0.86; 1.08, 0.70, 0.75, 0.74 and 1.03; and 1.00, 1.57, 1.33, 1.35 and 1.10 in the control group and the 1-, 3-, 6- and 9-week-infection groups, respectively, and all differences were statistically significant (F = 2.86, 2.85, 3.37 and 4.45, all P values < 0.05). The median number of positive staining cells were 1.00, 13.00, 9.00, 3.50 and 1.00 in rat cecum specimens in the control group, and the 1-, 3-, 6- and 9-week-infection groups, respectively, and the difference was statistically significant (H = 22.95, P < 0.01).

CONCLUSIONS

B. hominis infection may cause an increase in the rat intestinal permeability through triggering the apoptosis of intestinal epithelial cells to destroy the tight junction between intestinal epithelial cells, thereby destroying the intestinal barrier function.

[The diagnostic value of chromosome microarray analysis technique in the genetic causes of children with intellectual disability or global developmental delay]

Objective: To study the value of chromosome microarray analysis (CMA) application in children with developmental delay (DD), intellectual disability (ID), autistic spectrum disorder (ASD) and multiple congenital anomalies (MCA). Methods: Genomic DNA was extracted from peripheral blood samples. Array-based comparative genomic hybridization (array-CGH) analysis and single nucleotide polymorphism array (SNP-array) were performed in 1 320 children with DD/ID, ASD, with or without epilepsy and MCA who were admitted to Peking University First Hospital from 2014 to 2019. The results of genetic etiology test of CMA in children with mental retardation or global DD was summarized. Results: Of 1 320 samples, there were 10 cases of aneuploid abnormality, 6 cases of uniparental disomy and one case of mosaicism, respectively. Pathogenic copy number variations (CNVs) were found in 320 cases and pathogenic CNVs were detected in 23 cases, with a combined detection rate of 26% (343/1 320). CNVs of uncertain clinical significance occurred in 107 cases, accounting for 8.1% (107/1 320). There were 25 cases of possible benign CNVs, accounting for 2% (25/1 320), while benign CNVs were reported in 20 cases, accounting for 1.5% (20/1 320). The detection rate of MCA with DD/ID was 39.8% (130/327). Conclusions: CMA has the advantages of high resolution and covering the whole genome. It can detect the chromosomal abnormalities, microdeletions and duplications seen under the microscope, thus the genetic etiology of children with mental retardation or global DD can be diagnosed.

[Regional and demographic differences on passive smoking among non-smokers aged 30-79 years in 10 regions of China]

Objective: To describe the regional and demographic differences on passive non-smokers from 10 regions involved in the China Kadoorie Biobank (CKB) study. Methods: Detailed information regarding passive smoking behaviors related to 317 486 non-smokers who were 30-79 years old from the 10 study regions were gathered and analyzed. Results: Following the standardization of the 2010 China national population, the prevalence rate of passive smoking was 56.7%, and the prevalence rate of living with smokers was 66.5% among the Chinese adults. Both of the aforementioned rates were higher in rural than in urban areas. Meanwhile, the regional distribution of weekly passive smoking frequency and cumulative duration of passive smoking per week and cumulative duration of passive smoking per day were significantly different. The cumulative passive smoking duration per week increased along with the weekly frequency in people living in urban areas. Among women, the weekly passive smoking frequency was the highest, and the cumulative durations per week and per day appeared the lowest in Hunan, opposite to the situation in Henan. The prevalence of passive smoking among participants living with smokers was 2.27 times (95%CI: 2.24-2.29) of those who were not and the association appeared stronger in women (OR=2.61, 95%CI: 2.58-2.64) but not in men (OR=1.01, 95%CI: 0.95-1.06). Almost all the indicators seemed higher in women than those in men, except for the cumulative duration per day. Furthermore, these indicators appeared higher among those who were at younger age or with less education. The prevalence rates of passive smoking and living with smokers were lower but the cumulative duration per day was higher among those with lower household income. And the two rates were higher in married women and lower in married men, as compared to their counterparts. Conclusion: Regional and demographic differences in passive smoking were noticed among study population of CKB in the 10 regions.

[Association between height loss and calcaneus bone mineral density in Chinese adults]

Objective: To examine the association between height loss and calcaneus bone mineral density (BMD) through data gathered from the China Kadoorie Biobank (CKB). Methods: The present study included 24 231 participants who attended the CKB resurvey during 2013-2014, in which calcaneus BMD was measured by quantitative ultrasound method for the first time. Height loss was calculated according to the differences appeared in height measurement between baseline and resurvey. We used linear regression models to estimate the association between height loss and BMD measures. Results: The mean interval between baseline and resurvey was (8.0±0.8 ) years. 33.0% of the participants showed a height loss of ≥1.0 cm, and another 3.7% were with height loss of ≥3.0 cm. After adjustment for potential confounders, there was a linear correlation seen between height loss and BMD (P for all linear trend were <0.001). The βs (95%CIs) for each 1.0 cm of height loss were -0.79 (-0.95--0.63) for broadband ultrasound attenuation (BUA), -2.74 (-3.35--2.13) for speed of sound (SOS), and -1.29 (-1.54--1.04) for stiffness index (SI). Compared with participants with stable height, the multivariate-adjusted βs (95%CIs) for those with height loss of ≥3.0 cm were -3.29 (-4.08--2.50) for BUA, -10.70 (-13.66--7.73) for SOS, and -5.16 (-6.36--3.96) for SI, respectively. According to the subgroup analyses, the association of height loss with BMD measures seemed to be more apparent among females, in those aged ≥55 years, and those being less physically active. Conclusions: BMD became lower with the increase of height loss. Regular height measurement may contribute to the early diagnosis and prevention of osteoporosis.

[The cut-off points of body mass index and waist circumference for predicting metabolic risk factors in Chinese adults]

Objective: To assess the association of BMI and waist circumference (WC) with metabolic risk factors, and confirm the appropriate cut-off points of BMI and WC among Chinese adults. Methods: After excluding participants with missing or extreme measurement values, as well as individuals with self-reported histories of cancer, a total of 501 201 adults in baseline and 19 201 adults in the second re-survey from the China Kadoorie Biobank were included. The associations of BMI and WC with metabolic risk factors were estimated. Receiver operating characteristic (ROC) analyses were conducted to assess the appropriate cut-off values of BMI and WC to predict the risk of hypertension, diabetes, dyslipidemia and clustering of risk factors. Results: The prevalence of hypertension, diabetes, dyslipidemia and clustering of risk factors all presented ascending trends with the increasing levels of BMI or WC. Defined as the points on the ROC curve where Youden's index reached the highest, the appropriate overweight cut-off points of BMI were around 24.0 kg/m(2) both in men and women, and the points of WC were around 85 cm in men and 80 to 85 cm in women. With specificity 90% for identification of risk factors, the appropriate obese cut-off points of BMI were around 28.0 kg/m(2) both in men and women, with the range of 27.0 to 28.9 kg/m(2). Conclusions: The cut-off points for overweight and obesity recommended by Coorperative Meta-analysis Group of China Obesity Task Force was verified in the large sample survey conducted more recently. The cut-off points of BMI were 24.0 and 28.0 kg/m(2) for overweight and obesity, and the cut-off point of WC was 85 cm in men and 80 to 85 cm in women for central obesity.

[Association of body mass index and waist circumference with major chronic diseases in Chinese adults]

Objective: To examine the association of BMI with major chronic diseases morbidity and all-cause mortality in Chinese adults. Methods: This study is based on China Kadoorie Biobank. Anthropometric indexes were objectively measured at the baseline survey during 2004-2008. After excluding participants with heart disease, stroke, cancer, COPD and diabetes, 428 113 participants aged 30 to 79 years were included in the analysis. Cox regression models were used to investigate the associations of BMI and waist circumference with incidence of major chronic diseases (including cardiovascular disease, cancer, COPD, and type 2 diabetes) and all-cause mortality. Results: Over an average of 10 years, 131 454 participants developed any one of major chronic diseases. A total of 26 892 all-cause deaths were reported. The risk of major chronic diseases increased with BMI. Compared with normal BMI (18.5-24.0 kg/m(2)), the HR (95%CI) of overweight (BMI 24.0-28.0 kg/m(2)) and obesity (BMI≥28.0 kg/m(2)) were 1.26 (95%CI: 1.24-1.27) and 1.59 (95%CI: 1.57-1.62) respectively. Underweight and obesity were both associated with risk of all-cause mortality. Waist circumference was positively associated with risk of major chronic diseases and all-cause mortality. According to recommended cut-off points of BMI and waist circumference for Chinese adults, maintaining a healthy body weight would prevent 12% incident cases of major chronic diseases. Conclusion: General and central obesity were risk factors for major chronic disease among Chinese adults.

[Frequency of bowel movements and risk of Parkinson's disease: a prospective cohort study in adults in China]

Objective: To evaluate the association between the frequency of bowel movement (BMF) and the risk of Parkinson's disease (PD). Methods: In this study, 510 134 participants from the China Kadoorie Biobank (CKB) were included after excluding those who reported to had been diagnosed with cancer at baseline survey. The baseline survey was conducted from 2004 to 2008. The study used the data from the baseline survey and follow-up until December 31, 2016. Cox proportional hazards regression models were used to estimate the HRs and the 95%CIs of risk of PD diagnosis with BMF. Results: During an average follow-up period of (9.9±1.9) years, 808 participants were diagnosed with PD. Compared with participants who had bowel movements every day, the multivariable-adjusted HR (95%CI) for those who had bowel movements<3 times/week, once every 2-3 days, and>1 time/day were 3.62 (2.88-4.54), 2.13 (1.74-2.60), and 0.81 (0.63-1.05), respectively. The linear trend test results of the association between BMF and risk of PD diagnosis was significant (P<0.001). Compared with the participants who had bowel movements ≥1 time/day, the multivariable-adjusted HR (95%CI) for those who had bowel movements<1 time/day was 3.13 (2.32-4.23) within the 5 years of follow- up and was 2.48 (2.05-3.01) beyond the 5 years of follow-up. The gender specific results were similar. The association of BMF<1 time/day with risk of PD diagnosis was stronger in older participants. Conclusions: The participants with low BMF at baseline survey would have higher risk for PD diagnosis in the subsequent 10 years on average. Since abnormal decrease of BMF is easy to be found, programs could be set up for the early screening of PD in older people, along with other early symptoms of PD.

Fenretinide, Tocilizumab, and Reparixin Provide Multifaceted Disruption of Oral Squamous Cell Carcinoma Stem Cell Properties: Implications for Tertiary Chemoprevention

Locoregional recurrence of oral squamous cell carcinoma (OSCC) dramatically reduces patient survival. Further, as many OSCC recurrences are inoperable, radiotherapy and chemotherapy with or without biological adjuncts are the remaining treatment options. Although the tumors may initially respond, radiotherapy- and chemotherapy-resistant cancer stem cells (CSC) can readily repopulate OSCC tumors. Currently, following the initial OSCC treatment, patients are closely monitored until a recurrence or a second primary is detected. Identification of agents with complementary mechanisms to suppress CSC tumorigenic functions could change this passive approach. The goals of this study were twofold: (1) develop and validate CSC-enriched (CSCE) OSCC cell lines and (2) identify chemopreventive agents that obstruct multiple CSCE protumorigenic pathways. CSCE cultures, which were created by paclitaxel treatment followed by three tumorsphere passes, demonstrated CSC characteristics, including increased expression of stem cell and inflammatory genes, increased aldehyde dehydrogenase (ALDH) activity, and enhanced in vitro/in vivo proliferation and invasion. Three chemopreventives, fenretinide, tocilizumab, and reparixin, were selected due to their distinct and complementary CSC-disruptive mechanisms. The CSCE selection process modulated the cells' intermediate filaments resulting in an epithelial-predominant (enhanced cytokeratin, proliferation, IL6 release) line and a mesenchymal-predominant (upregulated vimentin, invasive, IL8 release) line. Our results confirm that 4HPR binds with appreciably higher affinity than Wnt at the Frizzled binding site and significantly inhibits CSC-enabling Wnt-β-catenin downstream signaling. Notably, combination fenretinide-tocilizumab-reparixin treatment significantly suppressed IL6 and IL8 release, stem cell gene expression, and invasion in these diverse CSCE populations. These promising multiagent in vitro data provide the basis for our upcoming in vivo CSCE tertiary chemoprevention studies.

[Epidemiological characteristics and correlated factors of habitual snoring among Chinese aged 30 to 79 year-old]

Objective: To describe the characteristics of habitual snoring among adults from 10 regions engaged in the China Kadoorie Biobank (CKB) study. Methods: The baseline survey of CKB was conducted from 2004 to 2008. Data was collected regarding the information on socio- demographic characteristics, lifestyle, sleeping habits, and results from the physical examination of the participants. Logistic regression models were used to compare the regional differences and to estimate the associations of other baseline characteristics on snoring habit. Results: A total of 512 713 participants were included in this study. The overall prevalence of habitual snoring was 21.2%, higher among men, in south regions and urban areas, but no difference observed among people with different socioeconomic status after adjusting for age, regions, BMI, waist circumference or lifestyle factors. Results showed that the prevalence of habitual snoring under the multivariable adjusted model increased among current and ever smokers, also among current and ever alcohol consumers. The risk of habitual snoring was increased by 19% per 1 kg/m(2) and 6% per 1 cm increment in BMI or waist circumference, respectively. Among participants with similar BMI, central obese individuals were more likely to be habitual snorers. For individuals with similar waist circumference, the prevalence of habitual snoring was higher among those with higher BMI. Conclusion: The prevalence of habitual snoring varied across regions. Substantial differences in habitual snoring were also seen among people with different lifestyles and body sizes.

[Interpretation for the group standards in technical specification of long-term follow-up for end point in large population-based cohort study]

Long-term follow-up for end point is an extremely important and arduous task in large population-based cohort studies, which is also the key to the success of large cohort studies. Thus, the fundamental question of the achievements above is how to construct a large population- based cohort in a standardized way. The Chinese Preventive Medicine Association coordinated experienced researchers from Zhejiang Provincial Center for Disease Control and Prevention and other professional institutes to write up the group standard entitled Technical specification of long-term follow-up for end point in large population-based cohort study (T/CPMA 002-2019). The standard is drafted with principles of emphasizing the scientific, normative, applicability, and feasible nature. This group standard recommended the follow-up target population, time, content, methods, quality control, and indicators assessment. The standard aims to guide the large population-based cohorts that have been or intended to be established in China, including national cohorts, regional population cohorts, and special population cohorts, hence, to improve domestic scientific research level and the international influence, and to support decision-making and practice of disease prevention and control.

[Study on correlation between alcohol consumption and obesity in adults in China]

Objective: To evaluate the correlation between alcohol consumption and obesity in adults in China. Methods: The information about alcohol consumption were collected at the baseline survey of the China Kadoorie Biobank. The general obesity and central obesity were defined by BMI and waist circumference (WC) respectively. Logistic regression model was employed to examine the relationship of drinking behavior with general obesity and central obesity. Results: A total of 249 873 adults were included. A J-shaped relationship was observed between alcohol consumption and obesity measurement index (BMI and WC) in men. Compared with non-drinkers, the proportion of general obesity and central obesity were lower in light drinkers (men: OR=0.65, 95%CI: 0.59-0.71 and OR=0.93, 95%CI: 0.88-0.98; women: OR=0.77, 95%CI: 0.65-0.91 and OR=0.89, 95%CI: 0.80-0.99). In men, the proportion of general obesity and central obesity was highest in heavy drinkers (OR=1.21, 95%CI: 1.12-1.32; OR=1.33, 95%CI: 1.27-1.40). BMI and WC were higher in those with a drinking frequency of 3-5 d/week, with largest of proportion of central obesity (men: OR=1.23, 95%CI: 1.16-1.31; women: OR=1.13, 95%CI: 0.99-1.28). The risk for central obesity in men who began drinking every week before 20 years old was 1.24 times higher than non-drinkers (95%CI: 1.16-1.33). Those who drank beer had lower proportion of general obesity (men: OR=0.74, 95%CI: 0.67-0.82; women: OR=0.54, 95%CI: 0.43-0.68). Conclusion: The proportion of obesity was lower in light drinkers but higher in heavy drinkers; and the earlier drinking started, the higher the risk for obesity was.