[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.

P5505Inflammation implicated in the aetiology of major vascular and non-vascular diseases in East Asians

Background

Mendelian randomisation (MR) studies using genetic variants in the IL6R gene encoding the interleukin-6 (IL-6) receptor have demonstrated that IL-6 plays a causal role in the aetiology of coronary heart disease (CHD) in European populations, with implications for the development of drugs targeting inflammation-related pathways. It is less clear whether IL-6 signalling plays a causal role in vascular disease or major non-vascular diseases in East Asians.

Purpose

Using an MR approach, we investigated associations of altered IL-6 signalling with subtypes of CHD, stroke, cancer and respiratory disease in a large East Asian cohort.

Methods

In approximately 150,000 Chinese adults from the China Kadoorie Biobank, we investigated associations of rs7529229 (in strong linkage disequilibrium, r2=0.99, with the IL6R Asp358Ala variant rs2228145) with blood biomarkers and selected disease events in which inflammation has previously been implicated. First, we used linear regression to quantify the per-allele association of rs7529229 with levels in plasma of log-transformed C-reactive protein (CRP) (n=17,866), fibrinogen (n=9,255), and IL-6 protein (n=633). Second, we used logistic regression to evaluate the association of rs7529229 with incidence of CHD, stroke, cancer, and respiratory disease events. All models were adjusted for age, age-squared, sex (except breast cancer), and case ascertainment (for CRP and fibrinogen), and stratified by recruitment region. We assessed significance at a 5% false discovery rate.

Results

IL6R rs7529229 C-allele was associated with lower log CRP (–0.11 SDs per C-allele; p=4.9x10–25) and log fibrinogen (–0.07 SDs; p=2.2x10–7), and higher log IL-6 (0.15 SDs; p=0.011) (Figure 1), mimicking therapeutic blockade of IL6R. IL6R rs7529229 was associated with a lower risk of acute myocardial infarction (n=4,047 cases; OR: 0.92 [95% CI 0.88–0.96] per C-allele; p=2.8x10–4), with the association similar for fatal and non-fatal cases (Figure 2). There was no evidence of association with ischaemic stroke (n=18,315; OR: 1.00 [0.98–1.03]; p=0.90) or intracerebral haemorrhage (n=7,372; OR: 1.03 [0.99–1.07]; p=0.10). For non-cardiovascular diseases, the IL6R rs7529229 was associated with a lower risk of oesophageal (n=824; OR: 0.88 [0.79–0.97] per C-allele; p=0.013) and colorectal (n=1,151; OR: 0.89 [0.82–0.97]; p=8.3x10–3) cancers, but a higher risk of tuberculosis (n=1,017; OR: 1.15 [1.05–1.26]; p=2.4x10–3).

Conclusion

The results of the present study are consistent with a causal role for the IL-6 signalling pathway in the aetiology of myocardial infarction and some cancers, but not of stroke. These findings provide further genetic support for drug development targeting inflammation in the prevention and treatment of coronary and selected cancer outcomes.

Acknowledgement/Funding

Kadoorie Charitable Foundation, UK Wellcome Trust, Chinese Ministry of Science and Technology, BHF, CRUK, NIHR

P2494Cardiovascular disease burden attributed to high blood pressure in Chinese adults with type 2 diabetes

Background

Cardiovascular diseases (CVD) are the most common cause of death among people with diabetes, reflecting in part co-existence with other CVD risk factors, including high blood pressure. However, controversy persists about the nature of the relationship of blood pressure with risk of CVD in individuals with diabetes, and about the associated disease burden.

Methods

We analysed data from 26,315 men and women aged 30–79 years with type 2 diabetes but no prior history of CVD, who were recruited into the China Kadoorie Biobank in 2004–2008 from 10 diverse areas in China. During ∼10 years' follow-up 1,190 major coronary events (MCE), 4,362 ischaemic stroke (IS), 469 intra-cerebral haemorrhage (ICH) events and 4,503 deaths (including 1,807 CVD deaths) were recorded. Usual systolic (SBP) and diastolic (DBP) blood pressure and uncontrolled hypertension were related to risks of incident CVD and all-cause mortality, after adjustment for relevant confounders.

Results

Overall, 75.7% of participants had prior doctor-diagnosed (24.8%) or screen-detected (67.7%) hypertension, compared with 54.3% among those without diabetes. The age-adjusted prevalence of hypertension was higher among men and in rural areas. Among those with previously diagnosed hypertension, 39.3% reported use of anti-hypertensive medications (on average, 1 agent) and 8.5% had controlled hypertension (<130/80 mmHg). Usual SBP was continuously and positively associated with the risk of CVD, with no evidence of a threshold throughout the range examined (120–180 mmHg). Each 10 mmHg higher SBP was associated with a 27% higher risk for CVD death (HR 1.27, 95% CI 1.25–1.30). Strong positive associations were also seen for MCE (1.16, 1.12–1.21), IS (1.15, 1.13–1.18), and ICH (1.46, 1.34–1.60). Overall, uncontrolled hypertension accounts for an estimated 39% (32–45%), 30% (21–38%), 24% (20–28%) and 48% (34–58%) of CVD deaths, MCE, IS and ICH, respectively, among Chinese adults with diabetes.

Conclusion

Hypertension is common but frequently undetected and uncontrolled among adults with type 2 diabetes in China. Effective diagnosis and management of hypertension among individuals with diabetes would be expected to achieve substantial reductions in CVD morbidity and mortality.

Acknowledgement/Funding

Wellcome Trust, MRC, BHF, CR-UK, Kadoorie Foundation, MoST, NSFC

P2780Accuracy of electronic healthcare records for diagnosis of stroke types in a large community-based prospective cohort study in China

Background and purpose

Reliable assessment of the determinants of major pathological types of stroke is dependent on the accuracy of diagnosis in population-based studies. We evaluated the diagnostic accuracy of stroke types in a large community-based cohort study involving health records collected in China.

Methods

In 2004–08, >0.5 million adults aged 30–79 years were recruited from general populations of 10 diverse areas (5 urban, 5 rural) in China. During an approximate 7-year follow-up, 37,694 stroke cases had been reported by linkage to electronic health records from disease-specific and mortality registries and from national health insurance agencies. For all reported stroke cases, hospital medical records were retrieved systematically and relevant data extracted for subsequent adjudication by specialists using bespoke electronic platforms.

Results

Among all reported incident stroke cases, 80% were ischaemic stroke (IS), 17% were intracerebral haemorrhage (ICH), and 1% were subarachnoid haemorrhage (SAH). To date, medical records have been retrieved for 29,632 cases, with reports of stroke diagnosis verified by public health staff in 27,115 (92%) cases, of which 3,778 (14%) were secondary diagnoses. Evidence of neuroimaging was found in 92% of all verified stroke cases. Of 23,337 primary stroke cases sent for specialist adjudication, a diagnosis of pathological stroke type was confirmed in 19,718 cases with the positive predictive values being 82.4% (95% confidence interval [CI], 82.0% - 82.8%) for IS, 97.8% (97.6 - 97.9) for ICH, and 98.2% (98.1 - 98.3) for SAH. Overall, the strength of association of systolic blood pressure was over 6-fold greater for confirmed than non-confirmed stroke cases and was nearly 3-fold greater for confirmed ICH than IS cases.

Diagnostic accuracy by stroke type Reported Retrieved Verified Adjudicated Confirmed Approximate 95% CI n n % n % n % n PPV, % IS 30,143 25,477 85 23,551 92 20,045 85 16,515 82.4 (82.0–82.8) ICH 6,484 3,486 54 3,079 88 2,919 95 2,854 97.8 (97.6–97.9) SAH 557 397 71 326 82 279 86 274 98.2 (98.1–98.3) Other 510 272 53 159 59 94 59 75 79.8 (79.4–80.2) IS indicates ischaemic stroke; ICH, intracerebral haemorrhage; SAH, subarachnoid haemorrhage; and PPV, positive predictive value.

Conclusions

The overall diagnostic accuracy of pathological stroke types obtained from hospital records in China is comparable to reports from Western populations. Despite advances in electronic healthcare records, reliable classification of stroke types requires clinical adjudication using additional relevant investigations.

Acknowledgement/Funding

Kadoorie Charitable Foundation, UK Wellcome Trust & National Natural Science Foundation and National Key Research and Development Program of China

[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.

Analyzing risk factors for recurrence of developmental coxa vara after surgery

PURPOSE

To evaluate the risk factors for developmental coxa vara (DCV) recurrence following valgus osteotomy of the proximal femur.

METHODS

We retrospectively reviewed records of 32 DCV patients (46 hips) treated surgically (2005 to 2012). Recurrence-related factors, including age at initial surgery, side, sex, fixation methods, diagnosis of coxa vara, premature capital femoral physeal closure and postoperative Hilgenreiner epiphyseal (HE) angle, head-shaft (HS) angle, medial femoral offset and posterior slope angle (PSA) were analyzed.

RESULTS

At 4.7-year mean follow-up, 12 hip deformities recurred (26%). Postoperative HE angle > 41° and negative offset were statistically significant univariate and multivariate risk factors for the deformity recurrence. Increased PSA was common preoperatively, which accounted for 59% of hips. Postoperative PSA > 20° was associated with a high recurrence rate in the univariate analysis. Age was another univariate risk factor for the recurrence. Recurrence rate was 52% in the < 6.5-year age group versus 4% in the > 6.5-year age group. Other factors were not statistically significantly related to recurrence.

CONCLUSION

DCV is a 3D deformity. To prevent recurrence, HE angle should be restored to < 41° in the coronal plane. Sagittal malalignment (abnormal PSA) should be corrected concurrently, so that, the direction of surgical correction is along the true deformity plane. During valgus osteotomy, the distal fragment should be lateralized to maintain a normal mechanical axis.

LEVEL OF EVIDENCE

IV.

Vascular endothelial growth factor A/Vascular endothelial growth factor receptor 2 axis promotes human dental pulp stem cell migration via the FAK/PI3K/Akt and p38 MAPK signalling pathways

AIM

To investigate the effects of vascular endothelial growth factor A (VEGFA) and the underlying molecular mechanisms on the migration of human dental pulp stem cells (hDPSCs).

METHODOLOGY

The expression of VEGFA in inflammatory pulp tissue and lipopolysaccharide (LPS)-stimulated dental pulp cells was examined by immunofluorescence staining and qRT-PCR. The migration of hDPSCs was detected using transwell migration and wound healing assays. The activation of FAK, PI3K, Akt and p38 signalling was evaluated by Western blot analysis. Silence RNA (siRNA) technology was utilized to knockdown the expression of VEGFR1 (Flt-1) and VEGFR2 (Flk-1/KDR). PF573228 (inhibitor of FAK), LY294002 (inhibitor of PI3K), SB203580 (inhibitor of p38) and SU5416 (inhibitor of VEGFR2) were employed to investigate the effect of VEGFA on the migratory mechanism of hDPSCs. Data were analysed statistically using the Student's t-test or one-way ANOVA.

RESULTS

The expression levels of VEGFA in inflammatory pulp tissue in vivo and LPS-stimulated dental pulp cells in vitro were significantly greater than those in the control groups (P < 0.05). Vascular endothelial growth factor A promoted the migration of hDPSCs in a concentration-dependent manner. Several signalling pathways, including FAK, PI3K, Akt and p38, were activated by VEGFA in a dose- and time-dependent manner in hDPSCs. The VEGFA-induced migration of hDPSCs was significantly inhibited with drug inhibitors such as PF573228, LY294002, SB203580 or SU5416 (P < 0.05). These signalling pathways activated by VEGFA stimulation were significantly suppressed by pre-treatment with inhibitor of VEGFR2 (SU5416) or transfection with siRNA of VRGFR2 (P < 0.05) but not VEGFR1 siRNA.

CONCLUSIONS

Vascular endothelial growth factor A/VEGFR2 axis promoted the migration of hDPSCs via the FAK/PI3K/Akt and p38 MAPK signalling pathways. These findings reveal a novel molecular mechanism for cell migration of hDPSCs, which may contribute to the remodelling of pulp tissue and dentine.

Lipopolysaccharide-induced DNA damage response activates nuclear factor κB signalling pathway via GATA4 in dental pulp cells

AIM

To investigate the role of GATA-binding protein 4 (GATA4) in the inflammatory response induced by DNA double-strand breaks (DSBs) in human dental pulp cells (hDPCs).

METHODOLOGY

Lipopolysaccharide (LPS) was used for stimulating inflammation in dental pulp tissue in vivo and hDPCs in vitro. Expression levels of GATA4 and γ-H2A.X (a marker for DSBs) were detected at different stages of pulpitis in a rat model and human pulp tissues by immunohistochemistry. Real-time quantitative polymerase chain reaction and Western blot were performed to assess expression of GATA4 and γ-H2A.X and the activation of nuclear factor κB (NF-κB) in hDPCs stimulated by LPS. The comet assay was used for detecting the extent of DSBs in hDPCs. Immunocytochemistry and Western blot were utilized to evaluate expression of γ-H2A.X and GATA4 and activation of NF-κB in hDPCs pre-treated with inhibitors of DNA damage response or transfected with GATA4 small interfering RNA before the treatment of LPS. Data were analysed statistically using one-way anova or Kruskal-Wallis tests.

RESULTS

The expression of GATA4 and activation of DNA damage response and NF-κB in inflamed pulp tissue and LPS-treated hDPCs were identified. Significantly decreased expression of GATA4 and significantly decreased inflammatory processes in hDPCs were demonstrated via suppression of DNA damage response (P < 0.05). In GATA4-knockdown cells, the expression of γ-H2A.X did not change, but nuclear translocation of p65 was significantly suppressed (P < 0.05) upon induction by LPS.

CONCLUSIONS

Lipopolysaccharide-induced DSBs activated the NF-κB signalling pathway in hDPCs, and GATA4 acts as a positive moderator of the progress. The involvement of GATA4 in this pathology may serve as a therapeutic target in pulpitis.

Antifibrotic Potential of MiR-335-3p in Hereditary Gingival Fibromatosis

Hereditary gingival fibromatosis (HGF) is a highly genetically heterogeneous disease, and current therapeutic method is limited to surgical resection with a high recurrence rate. MicroRNAs (miRNAs) are able to fine-tune large-scale target genes. Here we established a simple but effective computational strategy based on available miRNA target prediction algorithms to pinpoint the most potent miRNA that could negatively regulate a group of functional genes. Based on this rationale, miR-335-3p was top ranked by putatively targeting 85 verified profibrotic genes and 79 upregulated genes in HGF patients. Experimentally, downregulation of miR-355-3p was demonstrated in HGF-derived gingival fibroblasts as well as in transforming growth factor β–stimulated normal human gingival fibroblasts (NHGFs) compared to normal control. Ectopic miR-335-3p attenuated, whereas knockdown of miR-335-3p promoted, the fibrogenic activity of human gingival fibroblasts. Mechanically, miR-335-3p directly targeted SOS1, SMAD2/3, and CTNNB1 by canonical and noncanonical base paring. In particular, different portfolios of fibrotic markers were suppressed by silencing SOS1, SMAD2/3, or CTNNB1, respectively. Thus, our study first proposes a novel miRNA screening approach targeting a functionally related gene set and identifies miR-335-3p as a novel target for HGF treatment. Mechanically, miR-335-3p suppresses the fibrogenic activity of human gingival fibroblasts by repressing multiple core molecules in profibrotic networks. Our strategy provides a new paradigm in the treatment for HGF as well as other diseases.

[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.

[Interpretation for the group standards in technical specification of management for field survey in large population-based cohort study]

Large population-based cohort study is an important resource for population disease prevention and control, the results of which provide scientific basis for individualized treatment and precise prevention, and it is also the key strategic content of precision medicine. The Chinese Preventive Medicine Association coordinated experienced researchers from the Chinese Academy of Medical Sciences and other professional institutes to write up the group standard entitled Technical specification of management for field investigation in large population-based cohort study (T/CPMA 001-2019). Based on the research of large population-based cohort study in China and the principle of scientific, normative, applicable, and feasible, the standard proposed six aspects of management requirements including institutional arrangement, personnel composition, equipment, materials, documents and finance, as well as the basic requirements of the on-site investigation, the requirements of each position and the overall quality control requirements, etc.. 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 scientific research level, accelerate scientific research output and provide localization basis for disease prevention and control in China.

[Association between fruit consumption and stroke in adults in Qingdao: a prospective study]

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.

[Levels of skeletal muscle mass and handgrip strength in adults from 10 regions of China]

Objective: To describe the regional and population-related differences in skeletal muscle mass and handgrip strength across the 10 regions of China. Methods: 24 533 participants aged 38-88 years from the second resurvey of China Kadoorie Biobank were included in our analyses. Appendicular and trunk skeletal muscle mass were assessed using the bioelectrical impedance analysis (TANITA). Handgrip strength was measured using Jamar hand-held dynamometer. Low muscle mass and low muscle strength were defined as the lowest quintile of height-adjusted appendicular muscle mass or handgrip strength according to the Consensus Report of the Asian Working Group for Sarcopenia. We analyzed the mean value of absolute muscle mass, height-adjusted muscle mass, weight-adjusted muscle mass and handgrip strength. We also reported the prevalence of low muscle mass and low muscle strength. Results: The average appendicular and total skeletal muscle mass were (22.0±0.02) kg and (49.7±0.05) kg in men, which were higher than in women [(15.9±0.02) kg and (37.2±0.04) kg, respectively]. The handgrip strength was (32.6±0.06) kg in men, which was higher than (19.9±0.05) kg in women. The absolute muscle mass was higher in north area and urban region (P<0.001). The weight-adjusted muscle mass showed reverse patterns of regional difference compared with height-adjusted muscle mass. Both muscle mass and handgrip strength decreased by age (trend P<0.001), with a larger decline observed in handgrip strength. According to AWGS criteria, the proportions of low muscle mass and strength increased by age. Among participants over 80 years old, the prevalence of low muscle mass and strength were 56.2% and 74.5% in men, and 35.7% and 66.0% in women. Conclusions: Levels of skeletal muscle mass and strength varied greatly among people from 10 regions and among participants with different demographic characteristics. The prevalence of low muscle mass and strength was extremely high in elderly.

[Association between the frequency of bowel movements and the risk of colorectal cancer in Chinese adults]

Objective: To examine the association between the frequencies of bowel movement (BMF) and the risk of colorectal cancer (CRC). Methods: In this study, 510 134 participants from the China Kadoorie Biobank (CKB) were included, after excluding those who reported as having been diagnosed with cancer at the baseline survey. The baseline survey was conducted from June 2004 to July 2008. The present study included data from baseline and follow-up until December 31, 2016. We used the Cox proportional hazards regression models to estimate the HR and the 95%CI of incident CRC with BMF. Results: During an average follow-up period of 9.9 years, 3 056 participants were documented as having developed colorectal cancer. In the site-specific analysis, 1 548 colon cancer and 1 475 rectal cancer were included. Compared with participants who had bowel movements on the daily base, the multivariable-adjusted HR (95%CI) for those who had more than once of BMF were 1.24 (1.12-1.39) for CRC, 1.12 (0.95-1.31) for colon cancer, and 1.37 (1.18-1.59) for rectal cancer. We further examined the association between BMF and CRC, according to the stages of follow-up, the corresponding HR (95%CI) for CRC, colon and rectal cancer were 1.59 (1.36-1.86), 1.43 (1.14- 1.80), and 1.76 (1.41-2.19) for the first five years, while such associations became statistically insignificant in the subsequent follow-up (P for all interactions were <0.05), as time went on. As for CRC, colon or rectal cancers among participants who had lower bowel movements, the risks were not significantly different from those who had bowel movements everyday. Conclusions: Participants who had BMF more than once a day, appeared an increased risk of CRC in the subsequent five years. Since abnormal increase of bowel movements is easily recognizable, programs should be set up on health self- management and early screening for CRC.

[Association between tea drinking and stroke in adults in Zhejiang province: a prospective study]

Objective: To prospectively explore the association between tea drinking and incidence of stroke of adults of Zhejiang province. Methods: After excluding participants with heart disease, stroke, cancer and diabetes at baseline study, 53 916 participants aged 30-79 years in the China Kadoorie Biobank (CKB) study from Tongxiang were included for final analysis. Cox regression model was used to estimate the hazard ratio (HR) for the association of tea drinking with incident stroke. Results: The main type of drinking tea was black tea (79.78%), followed by green tea (20.08%). Of the 53 916 participants, the proportion of participants who drank tea at least once per week was 31.27%. The corresponding proportions for men and women were 60.24% and 10.30%, respectively. Among 391 512 person-years of the follow-up program (median 7.26 years), a total of 1 487 men and 1 769 women were diagnosed with stroke. After adjusting for socio-demographic status, lifestyle, BMI, waist circumference, and systolic blood pressure, HR for incident stroke decreased with the increase of daily average tea consumption amount (P=0.000 6). Compared with participants who did not drink tea weekly, the HRs for incident stroke in those consuming tea 0.1-, 3.0- and ≥5.0 g/d were 0.93 (95%CI: 0.85-1.00), 0.88 (95%CI: 0.77-0.99) and 0.79 (95%CI: 0.69-0.89), respectively. The HRs for incident stroke in smokers and non-smokers who consumed tea ≥5.0 g/d were 0.71 (95%CI: 0.59-0.86) and 0.97 (95%CI: 0.77-1.21), respectively, compared with current smokers and non-smokers who did not drink tea weekly (P=0.040 0). The corresponding HRs for alcohol drinkers and non-drinkers were 0.96 (95%CI: 0.76-1.22) and 0.70 (95%CI: 0.58-0.84), respectively (P=0.040 0). The corresponding HRs for central obese persons and non-central obese persons were 0.60 (95%CI: 0.44-0.81) and 0.86 (95%CI: 0.73-1.01), respectively (P=0.040 0). Conclusion: Tea drinking had an effect on reducing the possibility of incident stroke, especially among those who were current smokers, non-alcohol drinkers and central obese.

Effects of different fencing regimes on community structure of degraded desert grasslands on Mu Us desert, China

Grazing is one of the major anthropogenic driving factors influencing community structure and ecological function of grasslands. Fencing has been proved to be one of the main measures for rehabilitating degraded grasslands in northwestern China. However, data from combined empirical studies on the effects of different management regimes in desert grasslands are lacking. So we selected long-term fencing (fenced since 1991), mid-term fencing and seasonal fencing (fenced since 2002), and adjacent free-grazing grasslands to investigate vegetation and soil properties on southwest Mu Us desert. Our results showed that fencing increased plant cover, height, aboveground biomass (AGB) of different plant life-form groups, Shannon-Wiener diversity index, Evenness index, Simpson index, total soil nitrogen, total soil phosphorus, and soil organic matter, but decreased plant density, species richness, Richness index, soil bulk density, water content, and pH. However, 22-24 years of long-term complete fencing might cause redegradation of vegetation and soil nutrients, characterized by the reduction of some vegetation properties, biodiversity, total AGB, and some soil properties. Seasonal fencing with 11-13 year was more beneficial to vegetation restoration than that with completely fencing measures. Our study suggests that appropriate artificial disturbances, such as seasonal fencing (winter grazing and summer fencing), should be used after long-term fencing in order to maintain grassland productivity and biodiversity. These findings will help to provide theoretical support for vegetation restoration and sustainable management in grassland under grazing prohibition at Mu Us desert.

[Epidemiological characteristics of household fuel use in 10 areas of China]

Objective: To describe the characteristics of cooking and heating fuel use in participants from the China Kadoorie Biobank (CKB) study. Methods: The CKB study recruited 512 891 adults from 10 areas in China during 2004-2008. Information on cooking fuel and heating fuel was collected using a questionnaire in baseline survey. The proportions of various fuels used in different areas, in different populations, and at different time points were calculated and compared. Results: Overall, 52.1% participants used solid fuel for cooking or heating. Rural areas had higher prevalence of solid fuel use than urban areas. The percentage of participants using solid fuel for cooking was 36.1% (coal 20.1%, wood/charcoal 16.0%); The percentage of participants using solid fuel for heating was 36.7% (coal 22.7%, wood/charcoal 14.0%). The prevalence of solid fuel use and the fuel type mainly used varied widely across 10 areas. The proportion of clean fuel use was lower in less-educated and lower-income people. Household coal and wood/charcoal use showed a declining trend, which was more remarkable in urban areas. Conclusion: There are still a large number of rural residents and people with low income relying on solid fuel in China, which is a serious public health concern.

[Impact of menarche age on the near-term and long-term obesity of adult females]

Objective: To study the relationship between the age of menarche and the near-term/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]

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/m(2) 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%) had2-4 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.

Tea consumption and bone health in Chinese adults: a population-based study

Tea is a worldwide drink with controversial effect on bone health. The sex-specific associations are unrevealed among general population. This study showed that prolonged moderate tea consumption benefited bone health in women, while no additional benefit with stronger tea. However, tea consumption was not associated with bone health in men.

INTRODUCTION

Tea consumption has been shown a potentially beneficial effect on bone health in postmenopausal women. However, little is known about such association in men, and whether stronger tea instead harms bone health due to elevated urinary excretion of calcium associated with caffeine in the tea. The aim of this study was to examine the association between various metrics of tea consumption and bone health.

METHODS

The present study included 20,643 participants from the China Kadoorie Biobank (CKB), who have finished both baseline survey (2004-2008) and a re-survey (2013-2014). They were aged 38-86 years at re-survey. Tea consumption was self-reported at both baseline and re-survey. Bone mineral density (BMD) was measured using calcaneal quantitative ultrasound once at re-survey.

RESULTS

Compared with non-consumers, prolonged weekly tea consumers in women was associated with higher calcaneus BMD measures, with β (95% CI) of 0.98 (0.22, 1.74) for BUA, 4.68 (1.74, 7.61) for SOS, and 1.95 (0.81, 3.10) for SI. Among prolonged weekly tea consumers, no linear increase in BMD measures with the amount of tea leaves added was observed. The SOS and SI were higher in consumers with tea leaves 3.0-5.9 g/day than in those with < 3.0 g/day, but were reduced to non-significant for those with ≥ 6.0 g/day. Tea consumption was not associated with calcaneus BMD measures in men.

CONCLUSION

Prolonged moderate tea consumption benefited bone health in women but not in men. For stronger tea consumption with more tea leaves added, neither benefit nor harm to bone health was observed.

[Interpretation for the group standards in data management for large population-based cohorts]

Precision medicine became the key strategy in development priority of science and technology in China. The large population-based cohorts become valuable resources in preventing and treating major diseases in the population, which can contribute scientific evidence for personalized treatment and precise prevention. The fundamental question of the achievements above, therefore, is how to construct a large population-based cohort in a standardized way. The Chinese Preventive Medicine Association co-ordinated experienced researchers from Peking University and other well-known institutes to write up two group standards Technical specification of data processing for large population-based cohort study (T/CPMA 001-2018) and Technical specification of data security for large population-based cohort study (T/CPMA 002-2018), on data management. The standards are drafted with principles of emphasizing their scientific, normative, feasible, and generalizable nature. In these two standards, the key principles are proposed, and technical specifications are recommended in data standardization, cleansing, quality control, data integration, data privacy protection, and database security and stability management in large cohort studies. The standards aim 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.

[Relationship between educational level and long-term changes of body weight and waist circumference in adults in China]

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.