Genetic and healthy lifestyle factors in relation to the incidence and prognosis of severe liver disease in the Chinese population / 中华医学杂志(英文版)

BACKGROUND@#Severe liver disease (SLD), including cirrhosis and liver cancer, constitutes a major disease burden in China. We aimed to examine the association of genetic and healthy lifestyle factors with the incidence and prognosis of SLD.@*METHODS@#The study population included 504,009 participants from the prospective China Kadoorie Biobank aged 30-79 years. The individuals were from 10 diverse areas in China without a history of cancer or liver disease at baseline. Cox regression was used to estimate adjusted hazard ratios (HRs) for incident SLD and death after SLD diagnosis associated with healthy lifestyle factors (smoking, alcohol, physical activity, and central adiposity). Additionally, the contribution of genetic risk for hepatitis B virus (HBV, assessed by genetic variants in major histocompatibility complex, class II, DP/DQ [ HLA - DP / DQ ] genes) was also estimated.@*RESULTS@#Compared with those with 0-1 healthy lifestyle factor, participants with 2, 3, and 4 factors had 12% (HR 0.88 [95% confidence interval [CI] 0.85, 0.92]), 26% (HR 0.74 [95%CI: 0.69, 0.79]), and 44% (HR 0.56 [95%CI: 0.48, 0.65]) lower risks of SLD, respectively. Inverse associations were observed among participants with both low and high genetic risks (HR per 1-point increase 0.83 [95%CI: 0.74, 0.94] and 0.91 [95%CI: 0.82, 1.02], respectively; Pinteraction = 0.51), although with a non-significant trend among those with a high genetic risk. Inverse associations were also observed between healthy lifestyle factors and liver biomarkers regardless of the genetic risk. Despite the limited power, healthy lifestyle factors were associated with a lower risk of death after incident SLD among participants with a low genetic risk (HR 0.59 [95%CI: 0.37, 0.96]).@*CONCLUSIONS@#Lifestyle modification may be beneficial in terms of lowering the risk of SLD regardless of the genetic risk. Moreover, it is also important for improving the prognosis of SLD in individuals with a low genetic risk. Future studies are warranted to examine the impact of healthy lifestyles on SLD prognosis, particularly among individuals with a high genetic risk.

Ideal cardiovascular health and mortality: pooled results of three prospective cohorts in Chinese adults / 中华医学杂志(英文版)

BACKGROUND@#Evidence on the relations of the American Heart Association's ideal cardiovascular health (ICH) with mortality in Asians is sparse, and the interaction between behavioral and medical metrics remained unclear. We aimed to fill the gaps.@*METHODS@#A total of 198,164 participants without cancer and cardiovascular disease (CVD) were included from the China Kadoorie Biobank study (2004-2018), Dongfeng-Tongji cohort (2008-2018), and Kailuan study (2006-2019). Four behaviors (i.e., smoking, physical activity, diet, body mass index) and three medical factors (i.e., blood pressure, blood glucose, and blood lipid) were classified into poor, intermediate, and ideal levels (0, 1, and 2 points), which constituted 8-point behavioral, 6-point medical, and 14-point ICH scores. Results of Cox regression from three cohorts were pooled using random-effects models of meta-analysis.@*RESULTS@#During about 2 million person-years, 20,176 deaths were recorded. After controlling for demographic characteristics and alcohol drinking, hazard ratios (95% confidence intervals) comparing ICH scores of 10-14 vs. 0-6 were 0.52 (0.41-0.67), 0.44 (0.37-0.53), 0.54 (0.45-0.66), and 0.86 (0.64-1.14) for all-cause, CVD, respiratory, and cancer mortality. A higher behavioral or medical score was independently associated with lower all-cause and CVD mortality among the total population and populations with different levels of behavioral or medical health equally, and no interaction was observed.@*CONCLUSIONS@#ICH was associated with lower all-cause, CVD, and respiratory mortality among Chinese adults. Both behavioral and medical health should be improved to prevent premature deaths.

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.

Minimal improvement in coronary artery disease risk prediction in Chinese population using polygenic risk scores: evidence from the China Kadoorie Biobank / 中华医学杂志(英文版)

BACKGROUND@#Several studies have reported that polygenic risk scores (PRSs) can enhance risk prediction of coronary artery disease (CAD) in European populations. However, research on this topic is far from sufficient in non-European countries, including China. We aimed to evaluate the potential of PRS for predicting CAD for primary prevention in the Chinese population.@*METHODS@#Participants with genome-wide genotypic data from the China Kadoorie Biobank were divided into training ( n = 28,490) and testing sets ( n = 72,150). Ten previously developed PRSs were evaluated, and new ones were developed using clumping and thresholding or LDpred method. The PRS showing the strongest association with CAD in the training set was selected to further evaluate its effects on improving the traditional CAD risk-prediction model in the testing set. Genetic risk was computed by summing the product of the weights and allele dosages across genome-wide single-nucleotide polymorphisms. Prediction of the 10-year first CAD events was assessed using hazard ratios (HRs) and measures of model discrimination, calibration, and net reclassification improvement (NRI). Hard CAD (nonfatal I21-I23 and fatal I20-I25) and soft CAD (all fatal or nonfatal I20-I25) were analyzed separately.@*RESULTS@#In the testing set, 1214 hard and 7201 soft CAD cases were documented during a mean follow-up of 11.2 years. The HR per standard deviation of the optimal PRS was 1.26 (95% CI:1.19-1.33) for hard CAD. Based on a traditional CAD risk prediction model containing only non-laboratory-based information, the addition of PRS for hard CAD increased Harrell's C index by 0.001 (-0.001 to 0.003) in women and 0.003 (0.001 to 0.005) in men. Among the different high-risk thresholds ranging from 1% to 10%, the highest categorical NRI was 3.2% (95% CI: 0.4-6.0%) at a high-risk threshold of 10.0% in women. The association of the PRS with soft CAD was much weaker than with hard CAD, leading to minimal or no improvement in the soft CAD model.@*CONCLUSIONS@#In this Chinese population sample, the current PRSs minimally changed risk discrimination and offered little improvement in risk stratification for soft CAD. Therefore, this may not be suitable for promoting genetic screening in the general Chinese population to improve CAD risk prediction.

Multimorbidity patterns and association with mortality in 0.5 million Chinese adults / 中华医学杂志(英文版)

BACKGROUND@#Few studies have assessed the relationship between multimorbidity patterns and mortality risk in the Chinese population. We aimed to identify multimorbidity patterns and examined the associations of multimorbidity patterns and the number of chronic diseases with the risk of mortality among Chinese middle-aged and older adults.@*METHODS@#We used data from the China Kadoorie Biobank and included 512,723 participants aged 30 to 79 years. Multimorbidity was defined as the presence of two or more of the 15 chronic diseases collected by self-report or physical examination at baseline. Multimorbidity patterns were identified using hierarchical cluster analysis. Cox regression was used to estimate the associations of multimorbidity patterns and the number of chronic diseases with all-cause and cause-specific mortality.@*RESULTS@#Overall, 15.8% of participants had multimorbidity. The prevalence of multimorbidity increased with age and was higher in urban than rural participants. Four multimorbidity patterns were identified, including cardiometabolic multimorbidity (diabetes, coronary heart disease, stroke, and hypertension), respiratory multimorbidity (tuberculosis, asthma, and chronic obstructive pulmonary disease), gastrointestinal and hepatorenal multimorbidity (gallstone disease, chronic kidney disease, cirrhosis, peptic ulcer, and cancer), and mental and arthritis multimorbidity (neurasthenia, psychiatric disorder, and rheumatoid arthritis). During a median of 10.8 years of follow-up, 49,371 deaths occurred. Compared with participants without multimorbidity, cardiometabolic multimorbidity (hazard ratios [HR] = 2.20, 95% confidence intervals [CI]: 2.14 - 2.26) and respiratory multimorbidity (HR = 2.13, 95% CI:1.97 - 2.31) demonstrated relatively higher risks of mortality, followed by gastrointestinal and hepatorenal multimorbidity (HR = 1.33, 95% CI:1.22 - 1.46). The mortality risk increased by 36% (HR = 1.36, 95% CI: 1.35 - 1.37) with every additional disease.@*CONCLUSION@#Cardiometabolic multimorbidity and respiratory multimorbidity posed the highest threat on mortality risk and deserved particular attention in Chinese adults.

Frequency of bowel movements and risk of Parkinson’s disease: a prospective cohort study in adults in China / 中华流行病学杂志

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.

Association of body mass index and waist circumference with major chronic diseases in Chinese adults / 中华流行病学杂志

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/m2), the HR (95%CI) of overweight (BMI 24.0-28.0 kg/m2) and obesity (BMI≥28.0 kg/m2) 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.

The cut-off points of body mass index and waist circumference for predicting metabolic risk factors in Chinese adults / 中华流行病学杂志

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/m2 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/m2 both in men and women, with the range of 27.0 to 28.9 kg/m2.@*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/m2 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.

Impact of menarche age on the near-term and long-term obesity of adult females / 中华流行病学杂志

Objective To study the relationship between the age of menarche and the nearterm/long-term obesity in adult women.Methods We analyzed the baseline data of 30 895 women with complete data on menarche and body measurement that was from the China Kadoorie Biobank (CKB) study from 2004 to 2008.The age of menarche was divided into three groups:≤12,13-16 and ≥ 17 years old.Prematurity was set at age ≤ 12 years.Multivariate logistic regression was used to analyze the effects of menarche age on the near/long-term obesity in female adults.Results The average menarche age of respondent appeared as (15.64 ± 1.92) years old,with prematurity number as 1 421,accounting for 4.6％ of the total numbers.Regarding the postponing of dates of birth,the age of menarche in women showed an advancing tendency.Among all the adult women under study,803 developed near-term obesity,with the prevalence as 2.6％,while the number of long-term obesity was 3 738,accounting for 12.1％.Refining factors of age,lifestyle,menopausal status,hypertension and diabetes showed that the menarche age was related to the risks of both short-term and long-term obesity in women and the ORs (95％CI) were 2.45 (1.74-3.45) and 1.99 (1.69-2.34),respectively.There was no multiplicative interaction shown between the menarche age and menopausal status on long-term obesity (P=0.324).Conclusion Premature menarche appeared a risk factor for near-term/long-term obesity in adult females.

Prevalence of'healthy lifestyle'in Chinese adults / 中华流行病学杂志

Objective To examine the prevalence of'healthy lifestyle'from data extracted from the China Kadoorie Biobank (CKB) of 0.5 million adults from ten areas across China.Methods After excluding participants with self-reported histories of coronary heart disease,stroke or cancer,a total of 487 198 participants at baseline (2004-2008) and 22 604 participants at second survey (2013-2014),were included for analysis.'Healthy lifestyle'was defined as haing the following characteristics:a) never smoking or having stopped smoking for reasons other than illness;b) alcohol drinking ＜25 g/day (men)/＜ 15 g/day (women);c) diet rich in vegetables,fruits,legumes and fish,but low in red meat;d) upper quarter of the physical activity level;e) body mass index of 18.5-23.9 kg/m2 and waist circumstance ＜85 cm (men)/80 cm (women).We calculated the healthy lifestyle scores (HLS) by counting the number of all the healthy lifestyle factors,with a range from 0 to 6.Results At baseline,prevalence rates of the above five healthy lifestyles (except physical activity) were 70.6％,92.6％,8.7％,52.6％ and 59.0％,respectively,with the mean HLS being 3.1± 1.2.Most participants (81.4％) had 2-4 healthy components,while only 0.7％ (0.2％ in men and 1.0％ in women) of all the participants had all six healthy lifestyles.Participants who were women,at younger age,with more schooling and rural residents,were more likely to adhere to the healthy lifestyle.After ten years,the mean HLS showed a slight decrease.Conclusion The prevalence of optimal lifestyles in Chinese adults appeared extremely low.Levels of'healthy lifestyle'varied greatly among those populations with different socio-demographic characteristics across the ten areas in China.

Relationship between educational level and long-term changes of body weight and waist circumference in adults in China / 中华流行病学杂志

Objective To evaluate the association of educational level with anthropometric measurements at different adult stages and their long-term changes in adults who participated in the second re-survey of China Kadoorie Biobank (CKB).Methods The present study excluded participants who were aged ＞65 years,with incomplete or extreme measurement values,or with major chronic diseases at baseline survey or re-survey.The weight at age 25 years was self-reported.Body height,body weight and waist circumference at baseline survey (2004-2008) and re-survey (2013-2014) were analyzed.Results The present study included 3 427 men and 6 320 women.Both body weight and waist circumference (WC) increased with age.From age 25 years to baseline survey (mean age 45.2 ± 6.5),the mean weight change per 5-year was (1.70 ± 2.63) kg for men and (1.27 ± 2.10) kg for women.From baseline survey to re-survey (53.2± 6.5),the mean changes per 5-year for body weight were (1.12±2.61) kg for men and 0.90±2.54) kg for women;and that for WC was (3.20±3.79) cm for men and (3.83 ± 3.85) cm for women.Among women,low educational level was consistently associated with higher body mass index (BMI) and WC at age 25 years,baseline survey and re-survey.Among men,low educational level was associated with higher BMI at age 25 years.At baseline survey and re-survey,the educational level in men was not statistically associated with BMI;but men who completed junior or senior high school showed slight higher WC and increase of WC from baseline survey to re-survey than other male participants.Conclusions Body weight and WC increased with age for both men and women.The associations of educational level with BMI and WC were different between men and women.

Study on genetic structure differences and adjustment strategies in different areas of China / 中华流行病学杂志

Objective To describe the genetic structure of populations in different areas of China,and explore the effects of different strategies to control the confounding factors of the genetic structure in cohort studies.Methods By using the genome-wide association study (GWAS) on data of 4 500 samples from 10 areas of the China Kadoorie Biobank (CKB),we performed principal components analysis to extract the fast and second principal components of the samples for the component two-dimensional diagram generation,and then compared them with the source of sample area to analyze the characteristics of genetic structure of the samples from different areas of China.Based on the CKB cohort data,a simulation data set with cluster sample characteristics such as genetic structure differences and extensive kinship was generated;and the effects of different analysis strategies including traditional analysis scheme and mixed linear model on the inflation factor (λ) were evaluated.Results There were significant genetic structure differences in different areas of China.Distribution of the principal components of the population genetic structure was basically consistent with the geographical distribution of the project area.The first principal component corresponds to the latitude of different areas,and the second principal component corresponds to the longitude of different areas.The generated simulation data showed high false positive rate (λ =1.16),even if the principal components of the genetic structure was adjusted or the area specific subgroup analysis was performed,λ could not be effectively controlled (λ ＞ 1.05);while,by using a mixed linear model adjusting for the kinship matrix,λ was effectively controlled regardless of whether the genetic structure principal component was further adjusted (λ =0.99).Conclusions There were large differences in genetic structure among populations in different areas of China.In molecular epidemiology studies,bias caused by population genetic structure needs to be carefully treated.For large cohort data with complex genetic structure and extensive kinship,it is necessary to use a mixed linear model for association analysis.

Impact of menarche age on the near-term and long-term obesity of adult females / 中华流行病学杂志

Objective To study the relationship between the age of menarche and the nearterm/long-term obesity in adult women.Methods We analyzed the baseline data of 30 895 women with complete data on menarche and body measurement that was from the China Kadoorie Biobank (CKB) study from 2004 to 2008.The age of menarche was divided into three groups:≤12,13-16 and ≥ 17 years old.Prematurity was set at age ≤ 12 years.Multivariate logistic regression was used to analyze the effects of menarche age on the near/long-term obesity in female adults.Results The average menarche age of respondent appeared as (15.64 ± 1.92) years old,with prematurity number as 1 421,accounting for 4.6％ of the total numbers.Regarding the postponing of dates of birth,the age of menarche in women showed an advancing tendency.Among all the adult women under study,803 developed near-term obesity,with the prevalence as 2.6％,while the number of long-term obesity was 3 738,accounting for 12.1％.Refining factors of age,lifestyle,menopausal status,hypertension and diabetes showed that the menarche age was related to the risks of both short-term and long-term obesity in women and the ORs (95％CI) were 2.45 (1.74-3.45) and 1.99 (1.69-2.34),respectively.There was no multiplicative interaction shown between the menarche age and menopausal status on long-term obesity (P=0.324).Conclusion Premature menarche appeared a risk factor for near-term/long-term obesity in adult females.

Prevalence of'healthy lifestyle'in Chinese adults / 中华流行病学杂志

Objective To examine the prevalence of'healthy lifestyle'from data extracted from the China Kadoorie Biobank (CKB) of 0.5 million adults from ten areas across China.Methods After excluding participants with self-reported histories of coronary heart disease,stroke or cancer,a total of 487 198 participants at baseline (2004-2008) and 22 604 participants at second survey (2013-2014),were included for analysis.'Healthy lifestyle'was defined as haing the following characteristics:a) never smoking or having stopped smoking for reasons other than illness;b) alcohol drinking ＜25 g/day (men)/＜ 15 g/day (women);c) diet rich in vegetables,fruits,legumes and fish,but low in red meat;d) upper quarter of the physical activity level;e) body mass index of 18.5-23.9 kg/m2 and waist circumstance ＜85 cm (men)/80 cm (women).We calculated the healthy lifestyle scores (HLS) by counting the number of all the healthy lifestyle factors,with a range from 0 to 6.Results At baseline,prevalence rates of the above five healthy lifestyles (except physical activity) were 70.6％,92.6％,8.7％,52.6％ and 59.0％,respectively,with the mean HLS being 3.1± 1.2.Most participants (81.4％) had 2-4 healthy components,while only 0.7％ (0.2％ in men and 1.0％ in women) of all the participants had all six healthy lifestyles.Participants who were women,at younger age,with more schooling and rural residents,were more likely to adhere to the healthy lifestyle.After ten years,the mean HLS showed a slight decrease.Conclusion The prevalence of optimal lifestyles in Chinese adults appeared extremely low.Levels of'healthy lifestyle'varied greatly among those populations with different socio-demographic characteristics across the ten areas in China.

Relationship between educational level and long-term changes of body weight and waist circumference in adults in China / 中华流行病学杂志

Objective To evaluate the association of educational level with anthropometric measurements at different adult stages and their long-term changes in adults who participated in the second re-survey of China Kadoorie Biobank (CKB).Methods The present study excluded participants who were aged ＞65 years,with incomplete or extreme measurement values,or with major chronic diseases at baseline survey or re-survey.The weight at age 25 years was self-reported.Body height,body weight and waist circumference at baseline survey (2004-2008) and re-survey (2013-2014) were analyzed.Results The present study included 3 427 men and 6 320 women.Both body weight and waist circumference (WC) increased with age.From age 25 years to baseline survey (mean age 45.2 ± 6.5),the mean weight change per 5-year was (1.70 ± 2.63) kg for men and (1.27 ± 2.10) kg for women.From baseline survey to re-survey (53.2± 6.5),the mean changes per 5-year for body weight were (1.12±2.61) kg for men and 0.90±2.54) kg for women;and that for WC was (3.20±3.79) cm for men and (3.83 ± 3.85) cm for women.Among women,low educational level was consistently associated with higher body mass index (BMI) and WC at age 25 years,baseline survey and re-survey.Among men,low educational level was associated with higher BMI at age 25 years.At baseline survey and re-survey,the educational level in men was not statistically associated with BMI;but men who completed junior or senior high school showed slight higher WC and increase of WC from baseline survey to re-survey than other male participants.Conclusions Body weight and WC increased with age for both men and women.The associations of educational level with BMI and WC were different between men and women.

Study on genetic structure differences and adjustment strategies in different areas of China / 中华流行病学杂志

Objective To describe the genetic structure of populations in different areas of China,and explore the effects of different strategies to control the confounding factors of the genetic structure in cohort studies.Methods By using the genome-wide association study (GWAS) on data of 4 500 samples from 10 areas of the China Kadoorie Biobank (CKB),we performed principal components analysis to extract the fast and second principal components of the samples for the component two-dimensional diagram generation,and then compared them with the source of sample area to analyze the characteristics of genetic structure of the samples from different areas of China.Based on the CKB cohort data,a simulation data set with cluster sample characteristics such as genetic structure differences and extensive kinship was generated;and the effects of different analysis strategies including traditional analysis scheme and mixed linear model on the inflation factor (λ) were evaluated.Results There were significant genetic structure differences in different areas of China.Distribution of the principal components of the population genetic structure was basically consistent with the geographical distribution of the project area.The first principal component corresponds to the latitude of different areas,and the second principal component corresponds to the longitude of different areas.The generated simulation data showed high false positive rate (λ =1.16),even if the principal components of the genetic structure was adjusted or the area specific subgroup analysis was performed,λ could not be effectively controlled (λ ＞ 1.05);while,by using a mixed linear model adjusting for the kinship matrix,λ was effectively controlled regardless of whether the genetic structure principal component was further adjusted (λ =0.99).Conclusions There were large differences in genetic structure among populations in different areas of China.In molecular epidemiology studies,bias caused by population genetic structure needs to be carefully treated.For large cohort data with complex genetic structure and extensive kinship,it is necessary to use a mixed linear model for association analysis.

Family History, Tobacco Smoking, and Risk of Ischemic Stroke / 대한뇌졸중학회지

BACKGROUND AND PURPOSE: Both genetic factors and smoking are associated with ischemic stroke (IS) risk. However, little is known about the potential interaction of these factors. We aimed to assess whether smoking and a positive family history interact to increase the risk of IS. METHODS: The nationwide prospective study recruited 210,000 men and 300,000 women in 2004 to 2008 at ages 30 to 79 years. During 9.7 years of follow-up, we documented 16,923 and 20,656 incident IS cases in men and women without major chronic diseases at baseline, respectively. Multivariable Cox regression models were used to examine associations between family history and IS. Likelihood ratio tests were used to test the smoking-family history interactions on IS. RESULTS: About 67.8% (n=135,168) of men ever smoked regularly compared with 2.7% (n=7,775) of women. Among men, a significant interaction between family history and smoking on IS was observed (P for interaction=0.03), with more pronounced association between family history and IS among ever-regular smokers (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.16 to 1.27) than among never-smokers (HR, 1.11; 95% CI, 1.01 to 1.23). The association between family history and IS among ex-smokers after more than 10 years of cessation (HR, 1.01; 95% CI, 0.85 to 1.20) appeared similar to that among never-smokers. Among women, a similar but not significant interaction between family history and smoking on IS was observed. Ever-regular smokers who had a family history of stroke had the highest risk of IS. CONCLUSIONS: Among Chinese men, the association of family history with IS was accentuated by smoking, and such accentuation tended to be lowered by cessation.

Study on correlation between alcohol consumption and obesity in adults in China / 中华流行病学杂志

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.

Epidemiological characteristics and correlated factors of habitual snoring among Chinese aged 30 to 79 year-old / 中华流行病学杂志

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/m2 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.

Association between fruit consumption and stroke in adults in Qingdao: a prospective study / 中华流行病学杂志

Objective@#To understand the fruit consumption of adults of Qingdao and examine the association between fruit consumption and stroke.@*Methods@#We analyzed baseline data and stroke incidence of the participants who were aged 30-79 years and had been enrolled into the China Kadoorie Biobank (CKB) study from Qingdao city. Cox proportional hazards regression model was conducted to estimate the association of fruit consumption with risk of stroke.@*Results@#A total of 35 509 participants were investgated in the baseline survey. Ratio of male to female was 1∶1.27, and the average age was (50.3±10.2) years. Respondents with higher frequency of fruit consumption were younger, more women, with higher education level and higher income (P<0.05). A total of 1 011 new cases of stroke were observed, with a stroke incidence of 387.63/100 000 person-years. Multivariate Cox regression analysis showed that fruit consumption had a protective effect on stroke incidence. Compared to the respondents who never consumed fruit, respondents who consumed fruit more than 4 days per week had a 44% lower risk of stroke incidence (HR=0.56, 95%CI: 0.50-0.62, P<0.05), and the risk reduced by 46% (HR=0.54, 95%CI: 0.46-0.64, P<0.05) and 42% (HR=0.58, 95%CI: 0.52-0.69, P<0.05) in male and female, respectively. Further adjustment for WC, BMI, SBP and random blood glucose did not change the association.@*Conclusion@#Increasing fruit consumption can effectively decrease the risk of stroke. People should increase fruit consumption advisably to set up reasonable and healthy dietary habits.