[Associations of body mass index and waist circumference with risk of chronic kidney disease in adults in China].

Objective: To examine the associations of BMI and waist circumference (WC) with the risk of chronic kidney disease (CKD) and its subtypes in adults in China. Methods: The data from the China Kadoorie Biobank were used. After excluding those with cancer, coronary heart disease, stroke, or CKD at baseline survey, 480 430 participants were included in this study. Their body height and weight, and WC were measured at baseline survey. Total CKD was defined as diabetic kidney disease (DKD), hypertensive nephropathy (HTN), glomerulonephritis (GN), chronic tubulointerstitial nephritis (CTIN), obstructive nephropathy (ON), CKD due to other causes, and chronic kidney failure. Cox proportional hazards regression model was used to estimate the associations between exposure factors and risks of outcomes. Results: During a follow-up period of (11.8±2.2) years, 5 486 cases of total CKD were identified, including 1 147 cases of DKD, 340 cases of HTN, 1 458 cases of GN, 460 cases of CTIN, 598 cases of ON, 418 cases of CKD due to other causes, and 1 065 cases of chronic kidney failure. After adjusting for socio-demographic factors, lifestyle factors, baseline prevalence of hypertension and diabetes, and WC and compared to participants with normal BMI (18.5-23.9 kg/m2), the hazard ratios (HRs) of total CKD for underweight (<18.5 kg/m2), overweight (24.0-27.9 kg/m2), and obese (≥28.0 kg/m2) were 1.42 (95%CI: 1.23-1.63), 1.00 (95%CI: 0.93-1.08) and 0.98 (95%CI: 0.87-1.10), respectively. Stratification analysis by WC showed that BMI was negatively associated with risk for total CKD in non-central obese participants (WC: <85.0 cm in men and <80.0 cm in women) (HR=0.97, 95%CI: 0.96-0.99), while the association was positive in central obese participants (≥90.0 cm in men and ≥85.0 cm in women) (HR=1.03, 95%CI: 1.01-1.05). The association between BMI and GN was similar to that of total CKD. BMI was associated with an increased risk for HTN, with a HR of 1.12 (95%CI: 1.06-1.18) per 1.0 kg/m2 higher BMI. After adjusting for potential confounders and BMI, compared to participants with non-central obesity, the HRs for pre-central obesity (WC: 85.0-89.9 cm in men and 80.0-84.9 in women) and central obesity were 1.26 (95%CI: 1.16-1.36) and 1.32 (95%CI: 1.20-1.45), respectively. With the exception of HTN and CTIN, WC was positively associated with risks for all CKD subtypes. Conclusions: BMI-defined underweight and central obesity were independent risk factors for total CKD, and BMI and WC had different associations with risks for disease subtypes.

[Prospective association study of sleep status and risk of coronary heart disease in adults in Suzhou].

Objective: To investigate the association between sleep status and the risk for coronary heart disease in adults in Suzhou. Methods: Using the baseline and follow up information of 53 269 local residents aged 30-79 years in China Kadoorie Biobank conducted in Wuzhong District, Suzhou, 51 929 subjects were included in this study after excluding those reporting coronary heart disease, stroke and cancer at the baseline survey. A Cox proportional hazards regression model was used to analyze the association of healthy sleep score (0-3 points) and sleep factors (snoring, insomnia, long sleep duration and nap) with the risk for coronary heart disease. Results: The median follow-up time was 11.12 years, and 1 304 individuals were diagnosed with coronary heart disease during the follow-up. After adjusting for potential confounders, occasional snoring (HR=1.20, 95%CI: 1.04-1.38), usual snoring (HR=1.17, 95%CI: 1.02-1.33), insomnia disorder (HR=1.41, 95%CI: 1.12-1.78), daytime dysfunction (HR=1.56, 95%CI: 1.20-2.03) and perennial nap (HR=1.37, 95%CI: 1.19-1.59) were associated with increased risk of coronary heart disease. Compared with those with sleep score of 0 - 1 (low sleep quality), the people with sleep score of 3 had reduced risk of coronary heart disease by 26% (HR=0.74, 95%CI: 0.63-0.87). Stratified analysis showed that the association of healthy sleep score 3 with risk of coronary heart disease was stronger in low physically active individuals (interaction P<0.05). Conclusions: Snoring, insomnia disorders, daytime dysfunction, and perennial napping were all associated with increased risk for coronary heart disease, and keep healthy sleep mode might reduce the risk for coronary heart disease in adults.

[Distribution and influencing factors of lipoprotein (a) levels in non-arteriosclerotic cardiovascular disease population in China].

Objective: To describe the distribution of lipoprotein (a) [Lp(a)] levels in non-arteriosclerotic cardiovascular disease (ASCVD) population in China and explore its influencing factors. Methods: This study was based on a nested case-control study in the CKB study measured plasma biomarkers. Lp(a) levels was measured using a polyclonal antibody-based turbidimetric assay certified by the reference laboratory and ≥75.0 nmol/L defined as high Lp(a). Multiple logistic regression model was used to examine the factors related to Lp(a) levels. Results: Among the 5 870 non-ASCVD population included in the analysis, Lp(a) levels showed a right-skewed distribution, with a M (Q1, Q3) of 17.5 (8.8, 43.5) nmol/L. The multiple logistic regression analysis found that female was associated with high Lp(a) (OR=1.23, 95%CI: 1.05-1.43). The risk of increased Lp(a) levels in subjects with abdominal obesity was significantly reduced (OR=0.68, 95%CI: 0.52-0.89). As TC, LDL-C, apolipoprotein A1(Apo A1), and apolipoprotein B(Apo B) levels increased, the risk of high Lp(a) increased, with OR (95%CI) for each elevated group was 2.40 (1.76-3.24), 2.68 (1.36-4.93), 1.29 (1.03-1.61), and 1.65 (1.27-2.13), respectively. The risk of high Lp(a) was reduced in the HDL-C lowering group with an OR (95%CI) of 0.76 (0.61-0.94). In contrast, an increase in TG levels and the ratio of Apo A1/Apo B(Apo A1/B) was negatively correlated with the risk of high Lp(a), with OR (95%CI) of 0.73 (0.60-0.89) for elevated triglyceride group, and OR (95%CI) of 0.60 (0.50-0.72) for the Apo A1/B ratio increase group (linear trend test P≤0.001 except for Apo A1). However, no correlation was found between Lp(a) levels and lifestyle factors such as diet, smoking, and physical activity. Conclusions: Lp(a) levels were associated with sex and abdominal obesity, but less with lifestyle behaviors.

[Progress in research of relationship between marital status and cancer].

In recent 30 years, the global burden of cancer has become more serious, and one of social problem is population aging, plus declining birth rate, declining marriage rate and increasing divorce rate. Marriage is one of the most intimate and long-term social relations, and previous research had piecemeal reports of its impact on cancer morbidity and mortality without systematic review of evidence in high-quality population based epidemiological research. This paper summarizes the progress in research of the relationship between marital status and cancer to provide reference for future research and cancer prevention and control.

[An observational and Mendelian randomization study of the associations of body mass index with plasma amino acids and acylcarnitines in Chinese adults].

Objective: To explore the relationship between BMI and levels of plasma amino acids and acylcarnitines in Chinese adults. Methods: Based on 2 182 individuals with targeted mass spectrometry metabolomic measurements from the first resurvey of the China Kadoorie Biobank, we assessed the linear and nonlinear associations between BMI and plasma levels of 20 amino acids and 40 acylcarnitines using linear regression models and restricted cubic spline models, and identified BMI-related metabolic pathways. We conducted one-sample Mendelian randomization (MR) with BMI genetic risk scores as the instrumental variable further to explore the potential causal relationships between BMI and 20 amino acids and 40 acylcarnitines, and tested for horizontal pleiotropy using the MR-Egger method. Results: Observational analyses found that BMI was associated with increased plasma levels of 3 branched-chain amino acids (isoleucine, leucine, and valine), 2 aromatic amino acids (phenylalanine and tyrosine), 3 other amino acids (cysteine, glutamate, lysine), and 7 acylcarnitines (C3, C4, C5, C10, C10:1, C14, and C16), and with decreased circulating levels of asparagine, serine, and glycine. Pathway analysis identified 7 BMI-related amino acids metabolic pathways (false discovery rate corrected all P<0.05), including branched-chain amino acids and aromatic amino acids biosynthesis, glutathione metabolism, etc. BMI showed a nonlinear relationship with leucine, valine, and threonine, and a linear relationship with other amino acids and acylcarnitines. One-sample MR analyses revealed that BMI was associated with elevated levels of tyrosine and 4 acylcarnitines [C5-DC(C6-OH), C5-M-DC, C12-DC, and C14], with tyrosine and acylcarnitine C14 positively correlated with BMI in both observational [the ß values (95%CIs) were 0.057 (0.044-0.070) and 0.018 (0.005-0.032), respectively] and One-sample MR analyses [the ß values (95%CIs) were 0.102 (0.035-0.169) and 0.104 (0.036-0.173), respectively]. The MR analyses of the current study satisfied the 3 core assumptions of instrumental variable. Conclusions: BMI was associated with circulating 11 amino acids and 7 acylcarnitines in Chinese adults, involving several pathways such as branched-chain amino acid and aromatic amino acid metabolism, fatty acid metabolism, and oxidative stress. There may be a causal relationship between BMI and tyrosine and acylcarnitine C14.

[A prospective study on association between sleep duration and the risk of chronic obstructive pulmonary disease in adults in Suzhou].

Objective: To investigate the prospective association of sleep duration with the development of chronic obstructive pulmonary disease (COPD) in adults in Suzhou. Methods: The study used the data of 53 269 participants aged 30-79 years recruited in the baseline survey from 2004 to 2008 and the follow-up until December 31, 2017 of China Kadoorie Biobank (CKB) conducted in Wuzhong District, Suzhou. After excluding participants with airflow limitation, self-reported chronic bronchitis/emphysema/coronary heart disease history at the baseline survey and abnormal or incomplete data, a total of 45 336 participants were included in the final analysis. The association between daily sleep duration and the risk for developing COPD was analyzed by using a Cox proportional hazard regression model, and the hazard ratio (HR) values and their 95%CI were calculated. The analysis was stratified by age, gender and lifestyle factors, and cross-analysis was conducted according to smoking status and daily sleep duration. Results: The median follow-up time was 11.12 years, with a total of 515 COPD diagnoses in the follow-up. After adjusting for potential confounders, multifactorial Cox proportional hazard regression analysis showed that daily sleep duration ≥10 hours was associated with higher risk for developing COPD (HR=1.42, 95%CI: 1.03-1.97). The cross analysis showed that excessive daily sleep duration increased the risk for COPD in smokers (HR=2.49, 95%CI: 1.35-4.59, interaction P<0.001). Conclusion: Longer daily sleep duration (≥10 hours) might increase the risk for COPD in adults in Suzhou, especially in smokers.

[A prospective study of association between physical activity and ischemic stroke in adults].

Objective: To explore the prospective associations between physical activity and incident ischemic stroke in adults. Methods: Data of China Kadoorie Biobank study in Tongxiang of Zhejiang were used. After excluding participants with cancers, strokes, heart diseases and diabetes at baseline study, a total of 53 916 participants aged 30-79 years were included in the final analysis. The participants were divided into 5 groups according to the quintiles of their physical activity level. Cox proportional hazard regression models was used to calculate the hazard ratios (HR) for the analysis on the association between baseline physical activity level and risk for ischemic stroke. Results: The total physical activity level in the participants was (30.63±15.25) metabolic equivalent (MET)-h/d, and it was higher in men [(31.04±15.48) MET-h/d] than that in women [(30.33±15.07) MET-h/d] (P<0.001). In 595 526 person-years of the follow-up (average 11.4 years), a total of 1 138 men and 1 082 women were newly diagnosed with ischemic stroke. Compared to participants with the lowest physical activity level (<16.17 MET-h/d), after adjusting for socio-demographic factors, lifestyle, BMI, waist circumference, and SBP, the HRs for the risk for ischemic stroke in those with moderate low physical activity level (16.17-24.94 MET-h/d), moderate physical activity level (24.95-35.63 MET-h/d), moderate high physical activity level (35.64-43.86 MET-h/d) and the highest physical activity level (≥43.87 MET-h/d) were 0.93 (95%CI: 0.83-1.04), 0.87 (95%CI: 0.76-0.98), 0.82 (95%CI: 0.71-0.95) and 0.76 (95%CI: 0.64-0.89), respectively. Conclusion: Improving physical activity level has an effect on reducing the risk for ischemic stroke.

[Physical activity and its influencing factors in patients with diabetes mellitus: a comparative study between China and the United Kingdom].

Objective: To compare the differences in low-level physical activity (PA) and related influencing factors in patients with diabetes mellitus in China and the United Kingdom (UK). Methods: Using baseline survey data from the China Kadoorie Biobank and the UK Biobank, we analyzed the association between diabetes mellitus and low-level PA using logistic regression, with the participants' self-reported whether they had diabetes mellitus as the independent variable, and low-level PA as the dependent variable. Results: We included 509 254 Chinese adults and 359 763 British adults in the analysis. After adjusting for multiple factors, we found that both Chinese and British patients with diabetes mellitus were at elevated risk for low-level PA, with corresponding ORs (95%CIs) of 1.15 (1.12-1.19) and 1.37 (1.32-1.41), respectively. Patients with diabetes mellitus with longer disease duration and poorer glycemic control were at greater risk of having low-level of PA. Female, rural-distributed, employed, never-smoking Chinese diabetics, and male, urban-distributed, retired/unemployed, quit-smoking British diabetics were more likely to have low-level PA. Conclusions: Chinese and British patients with diabetes mellitus were more likely to have low-level PA compared with the general population, but the risk of low-level PA for patients in both countries varied by population characteristics. Therefore, PA guidelines and intervention measures should be based on the characteristics of individuals in the target countries and regions, which could improve PA levels among patients with diabetes mellitus.

[A prospective cohort study of factors associated with longevity in older adults in 10 areas of China].

Objective: To evaluate the associations of sociodemographic characteristics and lifestyle factors with longevity status in older adults in China. Methods: After excluding those born after 31st December 1938, a total of 51 870 older adults from the China Kadoorie Biobank (CKB) were included. The attained age was defined according to the survival age or age on 31st December 2018. According to the attained age, the old persons were categorized into non-longevity (died before age 80 years) and longevity (attained age ≥80 years). The longevity group was further divided into two groups: longevity with death occurring before 2019, and longevity and survival to 2019. The information about socio-demographic characteristics and lifestyles was collected at the 2004-2008 baseline survey. Multinomial logistic regression models were used to analyze the associations between exposure factors and outcomes by taking the non-longevity group as the reference group. Results: A total of 51 870 older adults aged 65-79 years in the baseline survey were included for analysis. During a follow-up for (10.2±3.5) years, 38 841 participants were longevity, and 30 354 participants still survived at the end of 2018. Compared to men, rural populations, non-married individuals, those with an annual household income of less than 10 000 yuan, and those with education levels of primary school or below, the adjusted ORs(95%CI) for longevity and survival to 2019 in women, urban residents, married individuals, those with annual household incomes ≥20 000 yuan, and those with education levels of college or university were 1.68 (1.58-1.78), 1.69 (1.61-1.78), 1.15 (1.10-1.21), 1.44 (1.36-1.53), and 1.32 (1.19-1.48), respectively. The OR (95%CI) for longevity and survival to 2019 was 1.09 (1.08-1.10) for those with an increase of 4 MET-hour/day in total physical activity level. With those who never or almost never smoked, had no alcohol drinking every week, had normal weight (BMI: 18.5-23.9 kg/m2), and WC <85 cm (man)/<80 cm (woman) as the reference groups, the ORs(95%CI) of longevity and survival to 2019 were 0.64 (0.60-0.69) for those smoking ≥20 cigarettes per day, 1.29 (1.14-1.46) for those with alcohol drinking every week, 1.13 (1.01-1.26) for those with pure alcohol drinking <30 g per day, 0.56 (0.52-0.61) for those being underweight, 1.27 (1.19-1.36) for those being overweight, 1.23 (1.11-1.36) for those with obesity, and 0.86 (0.79-0.93) for those with central obesity. Further stratified analysis by WC was performed. In the older adults with WC <85 cm (man)/<80 cm (woman), the ORs (95%CI) of longevity and survival was 1.80 (1.69-1.92) for those with each 5 kg/m2 increase in BMI and 1.02 (0.96-1.08) for those with WC ≥85 cm (man)/≥80 cm (woman). There was a statistically significant difference in the association between BMI and longevity between the two WC groups (interaction test P<0.001). Conclusion: This study showed that women, the married, those with higher socioeconomic status and education level, and those with healthy lifestyles were more likely to achieve longevity.

[Epidemiological distribution of mosaic loss of chromosome Y in adult men in 10 areas in China and its prospective association with lung cancer].

Objective: To detect the prevalence of mosaic loss of chromosome Y in adult men in ten study areas in China, describe the epidemiological distribution of mosaic loss of chromosome Y (mLOY) carriers and assess its prospective association with lung cancer. Methods: Based on the data from baseline survey, genetic analysis and follow-up (as of December 31, 2018) from China Kadoorie Biobank, we used Mosaic Chromosomal Alterations pipeline to detect mLOY carriers in 10 areas in China and described the epidemiological characteristics of mLOY carriers in adult men, including age, area distribution, lifestyle and disease history. We used multivariate logistic regression model to identify the potential relevant factor of mLOY. Cox proportional hazard regression model was fitted to assess the prospective association of mLOY with lung cancer. Stratification analysis were conducted to evaluate the potential modification effects of smoking and age. We also conducted mediation analysis to assess the mediating effect of mLOY in the association between smoking and lung cancer. Results: A total of 42 859 adult men were included in our analysis, in whom 2 458 mLOY carriers were detected (5.7%). The detection rate increased with age (P<0.05). The detection rate was higher in urban area (7.3%±0.2%) than that in rural area (4.7%±0.1%). The results of logistic regression analysis indicated that smoking might be a risk factor for the detection of mLOY (OR=1.49, 95%CI:1.36-1.64). After follow-up for average 11.1 years, 1 041 lung cancer cases were observed. The prospective analysis showed that mLOY carriers had an increased risk for lung cancer by 24% compared with non-mLOY carriers (HR=1.24, 95%CI:1.01-1.52) and expanded mLOY carriers (mLOY cell proportion ≥10%) had an increased risk for lung cancer by 50% (HR=1.50, 95%CI:1.13-2.00). Stratification analysis showed no modification effects of smoking and age in the association between mLOY and lung cancer (interaction P>0.05). Mediation analysis showed that mLOY could be a mediating factor in the association between smoking and lung cancer, the estimated effect was 0.09 (0.01-0.17). Conclusions: There were significant differences in the detection rate of mLOY in adult men with different social-economic characteristics and lifestyles in ten areas in China. Besides, mLOY carriers, especially expanded mLOY carriers, had increased risk for lung cancer and mLOY might be a mediating factor in the association between smoking and lung cancer.

[Comparative study on physical activity and its influencing factors in patients with chronic pulmonary obstructive disease between China and the United Kingdom].

Objective: To compare physical activity and its influencing factors in patients with chronic obstructive pulmonary disease (COPD) between China and the United Kingdom. Methods: We analyzed baseline data from China Kadoorie Biobank and the United Kingdom Biobank among COPD patients who were diagnosed with a one-second rate (FEV1/FVC) less than 70%. Physical activity level was calculated as metabolic equivalent (MET) and divided into three levels: low, medium, and high, according to tertiles stratified by gender and age. Multiple logistic regression was used to estimate ORs and 95%CIs for COPD and Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade about physical activity level, and subgroup analysis was conducted. Results: A total of 506 073 Chinese adults and 231 884 British adults were included. After adjusting for potential confounders, COPD was associated with lower physical activity levels in both Chinese and British COPD patients, with OR (95%CI) of 1.07(1.03-1.10) and 1.03(1.01-1.06) compared with non COPD patients, respectively. The GOLD grade was inversely correlated with physical activity level, particularly in a dose-response manner in the CKB population (trend test P<0.001). The negative relationship was stronger among the elderly, people with less education and lower economic status, and those with a smoking or chronic disease history. Chinese rural COPD patients were at high risk of decline of physical activity. Conclusions: Physical activity is inversely related to COPD, with a dose-response connection to GOLD grade. Therefore, physical activity maintenance and improvement should be encouraged and promoted in COPD patients, especially in high-risk groups.

[Epidemiological distribution characteristics of peripheral blood mosaic chromosomal alteration in adults from 10 regions of China].

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.

[Tea consumption and cancer: a Mendelian randomization study].

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.

[Progress on genome-wide association studies on mosaic chromosomal alterations].

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.

[Characteristics of daytime napping and its correlation with chronic diseases in Chinese adults].

Objective: To describe the prevalence of daytime nap habit in participants of the China Kadoorie Biobank (CKB) study, across 10 study regions and explore its correlation with prevalence of major chronic diseases. Methods: Participants with a self-reported pre-diagnosis of any cancer at baseline survey were excluded. Logistic regression models were used to analyze the differences in study regions and age distribution of the prevalence daytime nap habit, and its correlation with the prevalence of diabetes, hypertension, coronary heart disease (CHD), stroke, chronic obstructive pulmonary disease (COPD), and chronic liver diseases. Results: Among 510 145 participants, 39.9% had daytime nap habit in summer and 20.8% had daytime nap habit all the year round. Urban-rural differences were observed in the prevalence of summer nap habit and perennial nap habit. Daytime nap in summer was common in rural areas and Suzhou, with prevalence ranged from 32.9% to 73.3%. Haikou and Liuzhou had higher prevalence of perennial nap (60.4% and 63.3%). The proportion of people with daytime nap habit all the year round increased with age (P for trend <0.001), the proportion was highest in those aged 70- years (31.9%). Daytime nap habit in summer was positively correlated with the prevalence of diabetes, hypertension, CHD and chronic liver disease with OR of 1.10 (95%CI: 1.07-1.14), 1.03 (95%CI:1.02-1.05), 1.07 (95%CI: 1.02-1.12) and 1.07 (95%CI:1.00-1.14), respectively. Daytime nap habit all the year round was positively correlated with the prevalence of diabetes, hypertension, CHD, stroke, COPD and chronic liver disease with OR of 1.33 (95%CI: 1.29-1.37), 1.11 (95%CI: 1.09-1.13), 1.39 (95%CI: 1.33-1.45), 1.33 (95%CI: 1.26-1.41), 1.12 (95%CI: 1.08-1.16) and 1.27 (95%CI:1.18-1.37) respectively. Conclusion: There were regional and age differences in prevalence of daytime nap habit among CKB participants. Daytime nap habit, especially daytime nap habit all the year round, was positively correlated with the prevalence of major chronic diseases.

[Associations between sleep status and risk for kidney stones in Chinese adults: a prospective cohort study].

Objective: To analyze the associations between sleep status and the risk for kidney stone in Chinese adults. Methods: This study used baseline and long-term follow-up data of China Kadoorie Biobank. After excluding those with self-reporting of diagnosed chronic kidney disease and cancer and those with extreme values of sleep duration at baseline survey, 501 701 participants were included in this study. The information about their sleep status were collected, including insomnia symptoms, daytime sleepiness, nap habit, snoring and sleep duration. The sleep score was constructed based on insomnia symptoms, daytime sleepiness, and sleep duration, ranging from 0 to 3. Cox proportional hazards regression models were used to evaluate the association of sleep status with the risk for kidney stone, including individual sleep factors and combined sleep score. Results: During the follow-up for average (10.7±2.2) years, 12 381 cases of kidney stone were recorded for the first time. Compared with participants without insomnia symptoms, the multivariable-adjusted HR of kidney stone in those with difficulty falling asleep and waking up early were 1.12 (95%CI: 1.06-1.18) and 1.06 (95%CI: 1.00-1.12), respectively. There was no statistically significant association of kidney stone risk with sleeping pill use, daytime sleepiness, nap habit, or snoring. Compared with participants with sleep duration ≥7 hours per day, the HR of kidney stone in those with sleep duration <7 hours per day was 1.13 (95%CI: 1.08-1.18). Compared with participants with sleep score of 3 (highest sleep quality), the HR of kidney stone in those with sleep score of 2, 1, and 0 were 1.08 (95%CI: 1.03-1.13), 1.16 (95%CI: 1.10-1.23), and 1.19 (95%CI: 1.03-1.37), respectively. Conclusion: In China, adults with insomnia symptoms or short sleep duration have increased risk for kidney stone.

[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 of lifestyle and cardiometabolic risk factors with epigenetic age acceleration in adults in China].

Objective: To explore the association of lifestyle and cardiometabolic risk factors with five epigenetic age acceleration (AA) indices. Methods: This study included 980 participants of China Kadoorie Biobank, for whom genome-wide DNA methylation of peripheral blood cells had been detected in baseline survey. Five indices of DNA methylation age (DNAm age) were calculated, i.e. Horvath clock, Hannum clock, DNAm PhenoAge, GrimAge and Li clock. Epigenetic AA was defined as the residual of regressing DNAm age on chronological age. Lifestyle factors studied included smoking status, alcohol consumption, eating habits, physical activity level and body shape defined by a combination of BMI and waist circumference. Cardiometabolic risk factors included blood pressure, blood glucose level and total cholesterol level. Linear regression model was used to analyze the association of lifestyle and cardiometabolic risk factors with AA (ß). Results: GrimAge_AA was associated with smoking status, alcohol consumption, physical activity level and BMI. Compared with non-smokers, non-drinkers, or participants with BMI of 18.5- 23.9 kg/m2, the smokers who smoked 1-14 cigarettes/day (ß=0.71, 95%CI: 0.57-0.86), 15-24 cigarettes/day (ß=0.88, 95%CI: 0.73-1.03), and ≥25 cigarettes/day (ß=0.99, 95%CI: 0.81-1.18), respectively, heavy drinkers with daily pure alcohol consumption ≥60 g (ß=0.33, 95%CI: 0.11-0.55) and participants with BMI<18.5 kg/m2 (ß=0.23, 95%CI: 0.03-0.43) showed accelerated aging. Compared with those in the lowest quintile of physical activity level, participants in the top three quintile of physical activity level showed decelerated aging (ß=-0.13, 95%CI: -0.26-0.01, ß=-0.12, 95%CI: -0.26-0.02, and ß=-0.14, 95%CI: -0.27- -0.00, respectively). GrimAge_AA decreased with the increase of the number of healthy lifestyle factors (P<0.001). Compared with the participants with 0 to 1 healthy lifestyle factor, the ß of those with 2, 3, or 4 to 5 healthy lifestyle factors were -0.30 (95%CI: -0.47- -0.12), -0.47 (95%CI: -0.65- -0.30) and -0.72 (95%CI: -0.90- -0.53), respectively. The other four indices were not statistically significantly associated with most lifestyle factors. None of the five indices of AA was associated with blood pressure, blood glucose level or total cholesterol level. Conclusion: People with unhealthy lifestyle showed accelerated epigenetic aging, that is, the predicted DNAm age is older than their own chronological age.

[Gene-lifestyle interaction on coronary heart disease in adult twins of China].

Objective: To explore the gene-lifestyle interaction on coronary heart disease (CHD) in adult twins of China. Methods: Participants were selected from twin pairs registered in the Chinese National Twin Registry (CNTR). Univariate interaction model was used to estimate the interaction, via exploring the moderation effect of lifestyle on the genetic variance of CHD. Results: A total of 20 477 same-sex twin pairs aged ≥25 years were recruited, including 395 CHD cases, and 66 twin pairs both had CHD. After adjustment for age and sex, no moderation effects of lifestyles, including current smoking, current drinking, physical activity, intake of vegetable and fruit, on the genetic variance of CHD were found (P>0.05), suggesting no significant interactions. Conclusion: There was no evidence suggesting statistically significant gene-lifestyle interaction on CHD in adult twins of China.

[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.