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Background and aims Janus kinase 2 (JAK2) play an important role in the energy metabolism. Whether there is a causal relationship between JAK2 methylation levels and obesity remains unclear. Based on the instrumental variables of 5 SNP sites, this study was aimed to explore the causal relationship between JAK2 methylation levels and obesity by Mendelian randomization analysis. Methods and results A total of 1021 participants (511 cases and 510 controls defined by body mass index (BMI) ≥ 28.0 kg/m2) was conducted from the Henan Rural Cohort study. SNPscan® was performed to test the SNP genotyping and MethylTarget™ was applied to detect the DNA methylation level. The logistic regression model was used to evaluate the associations between SNP or methylation of JAK2 and obesity (according to BMI). Mendelian randomization analysis was used to assess the potential causal association between JAK2 methylation and obesity. According to the logistic regression model, 1 CpG sit in the promotor was related to an increased risk of obesity (P Conclusions This study supported that the methylation degree of JAK2 has a complex relationship with obesity, which might be related to the region of methylation. A causal relationship exists between the methylated level of JAK2 and obesity.

Current studies have shown the controversial effect of genetic risk scores (GRSs) in hypertension prediction. Machine learning methods are used extensively in the medical field but rarely in the mining of genetic information. This study aims to determine whether genetic information can improve the prediction of incident hypertension using machine learning approaches in a prospective study. The study recruited 4592 subjects without hypertension at baseline from a cohort study conducted in rural China. A polygenic risk score (PGGRS) was calculated using 13 SNPs. According to a ratio of 7:3, subjects were randomly allocated to the train and test datasets. Models with and without the PGGRS were established using the train dataset with Cox regression, artificial neural network (ANN), random forest (RF), and gradient boosting machine (GBM) methods. The discrimination and reclassification of models were estimated using the test dataset. The PGGRS showed a significant association with the risk of incident hypertension (HR (95% CI), 1.046 (1.004, 1.090), P = 0.031) irrespective of baseline blood pressure. Models that did not include the PGGRS achieved AUCs (95% CI) of 0.785 (0.763, 0.807), 0.790 (0.768, 0.811), 0.838 (0.817, 0.857), and 0.854 (0.835, 0.873) for the Cox, ANN, RF, and GBM methods, respectively. The addition of the PGGRS led to the improvement of the AUC by 0.001, 0.008, 0.023, and 0.017; IDI by 1.39%, 2.86%, 4.73%, and 4.68%; and NRI by 25.05%, 13.01%, 44.87%, and 22.94%, respectively. Incident hypertension risk was better predicted by the traditional+PGGRS model, especially when machine learning approaches were used, suggesting that genetic information may have the potential to identify new hypertension cases using machine learning methods in resource-limited areas. The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). http://www.chictr.org.cn/showproj.aspx?proj=11375 .

Although obesity reflected by BMI can enhance the association of air pollution with increase blood pressures (BP) and prevalent hypertension in susceptible population, there remains lack evidence on interactive effects of different obesity indices and air pollutants on BP and prevalent hypertension in rural adults. 39,259 individuals were recruited from the Henan Rural Cohort. Concentrations of air pollutants (PM1, PM2.5, PM10 and NO2) were evaluated by a spatio-temporal model based on satellites data. Independent associations of air pollutants and obesity reflected by BMI, WC, WHR, WHtR, BFP and VFI on BP indicators (SBP, DBP, MAP and PP) and prevalent hypertension were analyzed by linear regression and logistic regression models, respectively. Furthermore, their additive effects were quantified by RERI, AP and S. Six obesity indices enhanced the associations of four air pollutants and BP indicators. Individuals with high PM1 concentrations plus obesity classified by BMI, WC, WHR, WHtR, BFP and VFI had a 4.18-fold (95% CI: 3.86, 4.53), 3.58-fold (95% CI: 3.34, 3.84), 3.53-fold (95% CI: 3.28, 3.81), 4.02-fold (95% CI: 3.72, 4.35), 3.89-fold (95% CI: 3.59, 4.23), 3.87-fold (95% CI: 3.62, 4.14) increase in prevalent hypertension, respectively, compared to non-obese individuals with low PM1 concentrations; similar results were observed for combined effect of PM2.5, PM10 or NO2 and obesity indices on prevalent hypertension. The significant values of RERI, AP and S indicated additive effects of air pollutants and obesity indices on hypertension. Obesity amplified the effects of exposure to high levels of air pollutants on increased BP values and prevalent hypertension, implying that obese individuals may be susceptible to elevate BP and prevalent hypertension in relation to air pollution exposure. CLINICAL TRIAL REGISTRATION: The Henan Rural Cohort study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699, http://www.chictr.org.cn/showproj.aspx?proj=11375).

Background and aims To assess the associations of sedentary time, suppressor of cytokine signaling (SOCS)-3 DNA methylation with type 2 diabetes mellitus (T2DM), and further identify the role of SOCS3 methylation in mediating the association of sedentary time with T2DM in a Chinese rural population. Methods and results A case–control study including 1032 participants from the Henan Rural Cohort study was conducted. Restricted cubic spline analysis and logistic regression model were performed to evaluate the associations between sedentary time, SOCS3 methylation and T2DM. The mediation effect of SOCS3 methylation on the association between sedentary time and T2DM was assessed. Sensitivity analysis was conducted by excluding individuals with diagnosed T2DM. Linear dose–response relationships were found between sedentary time, methylation level of Chr17:76356190 (one novel site on SOCS3) and T2DM. Compared with the first quartile (less than 5 h/d) of sedentary time, the adjusted odds ratio (OR, 95% confidence interval, 95%CI) for those in the third (7–10 h/d) and fourth (≥10 h/d) quartiles were 1.87 (1.22–2.85) and 3.54 (2.14–5.85), respectively. Participants in the fourth quartile of methylation level of Chr17:76356190 had lower risk of T2DM than those in the first quartile (OR (95%CI): 0.23 (0.14–0.38)). Mediation analysis showed 9.66% (6.38%–14.80%) of the association between sedentary time and T2DM was attributable to Chr17:76356190. The comparable effect estimates were observed between sedentary time, methylation level of Chr17:76356190 and undiagnosed T2DM. Conclusion Sedentary time and methylation level of Chr17:76356190 were both independently associated with T2DM in the Chinese rural population. Furthermore, Chr17:76356190 appeared to partially mediate the effect of sedentary time on T2DM. Chinese Clinical Trial Registration ChiCTR–OOC–15006699 (URL: http://www.chictr.org.cn/showproj.aspx?proj=11375 ).

Background Although exposure to ambient air pollution (AAP) increases the risk for arteriosclerotic cardiovascular disease (ASCVD), evidence on the association of solid fuel use with ASCVD and its association modified by ambient air pollution remains limited. Methods A total of 16,779 adults were derived from the Henan Rural Cohort Study. Concentrations of ambient air pollutants (PM1, PM2.5, PM10, and NO2) were estimated by a spatiotemporal model based on satellites data. Solid fuel use was assessed by a self-reported questionnaire. The associations of solid fuel use with high 10-year ASCVD risk and the modified association by exposure to air pollutants were explored using logistic regression models. Results There were positive associations of AAP exposure with high 10-year ASCVD risk among individuals with self-cooking. The joint associations between high AAP exposures and solid fuel use with high 10-year ASCVD risk were found. Compared to clean fuel user with low PM2.5 exposure, the odds ratios (ORs) and 95% confidence intervals (CIs) of high 10-year ASCVD risk was 1.25 (1.09, 1.42) for solid fuel user with low PM2.5 exposure, 1.93 (1.75, 2.12) for clean fuel user with high PM2.5 exposure, and 3.08 (2.67, 3.54) for solid fuel user with high PM2.5 exposure, respectively. Their additive effect on high 10-year ASCVD risk was observed (relative excess risk due to interaction (RERI): 0.90 (95 %CI: 0.50, 1.30), attributable proportion due to interaction (AP): 0.29 (95 %CI: 0.19, 0.40), and synergy index (SI): 1.77 (95 %CI: 1.38, 2.26)). Conclusion This study showed a synergistic effect of AAP and household air pollution reflected by solid fuel use on high 10-year ASCVD risk, suggesting that reducing solid cooking fuels and controlling air pollution may have a joint effect on public health improvement.

Evidence on the association of snoring, daily sleep duration (daytime napping and night sleep duration) with hyperuricemia (HUA) was limited, especially in the resources-poor areas. This study aimed to investigate the independent effect of snoring frequency and daily sleep duration on HUA prevalence in rural Chinese adults.29,643 participants aged 18-79 years were included in the final cross-sectional analysis from the Henan Rural Cohort Study. Multivariate logistic regression and linear regression models with HUA and serum uric acid (SUA) levels as dependent variables were conducted, respectively. Of the 29,643 included adults, 3498 suffered from HUA. Compared to never snoring, the adjusted odds ratio (OR) and 95% confidence interval (CI) of HUA for rare snoring, occasional snoring, and habitual snoring were 1.35 (1.17, 1.56), 1.30 (1.14, 1.47), and 1.59 (1.47, 1.73), respectively (P for trend0.001). Compared with no napping, participants who had daytime napping of 61-90 and 91 min were associated with a 29% and 30% increase in the prevalence of HUA, respectively (P for trend0.001). But in night sleep duration groups, no significant associations were observed. The positive associations between snoring and HUA were attenuated in people aged ≥65 and people with type 2 diabetes mellitus (both P for interaction0.05).Habitual snoring or longer daytime napping was independently associated with increased HUA prevalence and SUA levels in rural Chinese adults, which indicates the significance of early intervention and treatment of snoring and longer daytime napping to prevent hyperuricemia.

Residential greenness may be beneficial for cardiovascular health, but the evidence is still scarce, especially in developing countries. This study aimed to assess the associations between exposure to residential greenness and 10-year atherosclerotic cardiovascular disease (ASCVD) risk in a large rural Chinese adult population. This was a cross-sectional study based on 31,162 participants aged 35–74 years with complete data on predictors of the 10-year ASCVD risk from the Henan Rural Cohort Study. The satellite-derived Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) were used to quantify residential greenness in a buffer radius of 500 m, 1000 m, and 3000 m. The high 10-years ASCVD risk was defined as the estimated risk ≥10% based on prediction equations from the China-PAR Project for Chinese populations. Multivariable-adjusted logistic regression models were performed to estimate the associations of greenness exposures with high 10-year ASCVD risk, and mediation analyses were employed to the potential mediators. For per interquartile range (IQR) increase in NDVI500−m, NDVI1000−m, NDVI3000−m, EVI500−m, EVI1000−m, and EVI3000−m, the adjusted OR (95% CI) of high 10-years ASCVD risk was 0.828 (0.793–0.866), 0.850 (0.817–0.885), 0.823 (0.792–0.855), 0.848 (0.809–0.889), 0.863 (0.826–0.901), 0.843 (0.805–0.883), respectively. Strong associations of NDVI500−m and EVI500−m with high 10-years ASCVD risk were found among participants with lower education level and lower averaged monthly income. The associations of greenness exposures with high 10-year ASCVD risk were partially explained by particulate matter with an aerodynamic diameter ≤1 µm, BMI, and physical activity. Enhancing residential greenness exposure may be beneficial for reducing the high 10-year ASCVD risk in rural Chinese adults.

Background Familial hypercholesterolemia (FH) is a common monogenic disease, while studies about the epidemiology for the general population in China was scarce. Aim of the study was to estimate the prevalence of FH and explore related factors by the Chinese modified Dutch Lipid Clinic Network (DLCN) definition. Methods A total of 39,205 participants (15,463 males and 23,742 females) aged 18–79 years old were enrolled from the Henan Rural Cohort Study. FH was defined by the Chinese modified DLCN definition, and score > 5 was classified as FH. Logistic regression analysis was used to calculate the odds ratio and 95% confidence interval. Results Crude prevalence of probable/definite FH was 0.35% (0.29–0.41%), estimated by the Chinese modified DLCN definition. Prevalence in female was 0.38%, and in male, it was 0.32%. Age-standardized prevalence in female increased significantly around the age of 50 years. Moreover, there were no FH patients getting low-density lipoprotein cholesterol controlled to the recommended level. Multivariate logistic regression identified that older, overweight/obesity were positively associated with FH. Conclusions The current study indicated that FH was not rare in rural area of China (1 in 286). Effective early detection and timely control of FH must be strengthened to reduce disease burden. Electronic supplementary material The online version of this article (10.1186/s12889-019-7212-4) contains supplementary material, which is available to authorized users.

Objective To estimate the prevalence of poor sleep quality and identify related factors by gender in the Chinese rural population. Methods Overall, 27424 subjects (10881 males and 16543 females) aged 18–79 years were enrolled from the Henan Rural Cohort Study. Sleep quality was evaluated by the standard Pittsburgh Sleep Quality Index (PSQI) and global score>5 was classified as poor sleep quality. Logistic regression analysis was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). A meta-analysis including 14 studies was used to validate the result of the cross-sectional study. Results The average PSQI score was 3.78 ± 2.72 in total, and the score of females (4.10 ± 2.90) was significantly higher than males (3.29 ± 2.33). The crude and age-standardized prevalences of poor sleep quality were 21.62% and 15.80%, respectively. The crude prevalence in females (25.73%) was significantly higher than males (15.38%). The results of meta-analysis showed that the pooled prevalence of poor sleep quality was 25.0% (18.8%–31.2%) in total sample, 31.7% (24.9%–38.5%) in male, and 38.2% (29.7%–46.7%) in females. Multivariate logistic regression identified that older age, being female, unmarried/divorced/widowed, low education level, low income, drinking, depression and dyslipidemia could increase the odds of poor sleep quality. Conclusions More than one fifth of the participants in a rural area of China slept poorly and the prevalence in females was significantly higher than males. Effective interventions are urgently needed to improve the sleep quality in resource limited areas. Clinical trial registration The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). http://www.chictr.org.cn/showproj.aspx?proj=11375 .

Obesity and ambient air pollution are independent risk factors of type 2 diabetes mellitus (T2DM), however, the evidence regarding their joint associations on T2DM was sparsely studied in low-middle income countries.A total of 38,841 participants were selected from Henan Rural Cohort study which was carried out during 2015-2017. Obesity was identified by body mass index (BMI), WC (waist circumstance), WHR (waist-to-hip ratio), WHtR (waist-to-height ratio), BFP (body fat percent), and VFI (visceral fat index). Three-year averaged-concentrations of NOPositive associations of six obesity measures and four air pollutants with FBG levels and prevalent T2DM were observed. Obese participants measured by BMI plus high exposure to NOThe synergistic associations of obesity and air pollutants on FBG levels and prevalent T2DM were observed, indicating that obese participants were at high risk for prevalent T2DM in highly polluted rural regions.

Background The risk allele frequency of rs1378942 of c-src tyrosine kinase (CSK) gene is much higher in Asians (~ 0.80) than that in Europeans (~ 0.35), and the association between rs1378942 and blood pressure is controversial in Asians. Thus, the review and meta-analysis was performed to explore the effects of rs1378942 polymorphism on systolic blood pressure (SBP), diastolic blood pressure (DBP) levels and hypertension in Asians. Methods A literature search was conducted in electronic databases up to September 1, 2018. Beta, Odds Ratio (OR) and corresponding 95% confidence intervals (95%CI) were calculated to estimate the effects of rs1378942 on SBP, DBP and hypertension. Quanto software was used to estimate the statistical power. Results The results showed that the rs1378942 polymorphism significantly affected blood pressure levels in Asians, the C allele carriers had higher SBP and DBP levels: beta (95%CI): 0.71(0.38–1.04), P = 2.579 × 10−5, I2 = 43.5%, and beta (95%CI): 0.33(0.18–0.49), P = 2.092 × 10−5, I2 = 28.3%, respectively. This association was also found in East Asians, but not in South Asians. Furthermore, no significant association was observed with hypertension: OR (95%CI): 1.10 (0.97–1.25), P = .129, I2 = 81.2%. Conclusion The meta-analysis demonstrates that the C allele of the CSK rs1378942 is associated with higher SBP and DBP levels in East Asians.

The study aimed to explore the relationship between visceral fat index (VFI) and dyslipidemia and evaluate the efficiency of VFI as a marker for identifying dyslipidemia in Chinese rural adults. The cross-sectional study recruited 35,832 aged 18–79 years eligible participants from The Henan Rural Cohort Study. VFI was measured by bioelectrical impendence methods and classified into sex-specific quartiles. Fasting blood samples were collected. Logistic regression models with VFI as a categorical variable and restricted cubic spline regression models with VFI as a continuous variable were performed to obtain odds ratios (ORs) and 95% confidence intervals (CIs). Receiver-operating characteristic (ROC) curve was conducted to evaluate the identifying performance of VFI. The age-standardized prevalence of dyslipidemia was 29.80% and 26.01% in male and female, respectively. Increasing VFI quartiles were significantly positively related to the risk of dyslipidemia and its components (P for trend

Objective:The purpose of the current study was to investigate associations between spicy food intake and serum lipids levels in Chinese rural population.Design:Information on spicy food flavour and intake frequency was obtained using a two-item questionnaire survey. Dietary data were collected using a validated thirteen-item FFQ. Fasting blood samples were collected and measured for total cholesterol (TC), TAG, HDL-cholesterol and LDL-cholesterol. Multivariate linear and logistic regression models were employed to examine the relationship between spicy food and serum lipids levels according to the spicy food flavour and intake frequency, respectively.Setting:A cross-sectional study in Henan Province.Participants:38 238 participants aged 18–79 years old.Results:Spicy flavour and intake frequency were consistently associated with decreased TC and non-HDL-cholesterol levels but mildly associated with elevated TAG levels. Each level increment in spicy flavour was inversely associated with high TC (OR: 0·91; 95 % CI 0·88, 0·93) and high non-HDL-cholesterol (OR: 0·88; 95 % CI 0·85, 0·91) but positively associated with high TAG (OR: 1·04; 95 % CI 1·01, 1·07). Similarly, 1-d increment in spicy food intake frequency was also inversely associated with high TC (OR: 0·92; 95 % CI 0·91, 0·94) and high non-HDL-cholesterol (OR: 0·91; 95 % CI 0·89, 0·93) but positively associated with high TAG (OR: 1·04; 95 % CI 1·02, 1·06).Conclusions:Spicy food intake was mildly associated with increased risk of abnormal TAG level, significantly associated with decreased risk of abnormal TC and non-HDL levels. Spicy food intake may be contribute to the management of lipid levels.

Long-term exposure to air pollutants and residential greenness related to advanced fibrosis have been sparsely studied in low- and middle-income countries. A total of 29883 participants were selected from a cross-sectional survey of the Henan Rural Cohort. Concentrations of air pollutants (particulate matter with an aerodynamic diameter ≤ 1.0 μm (PM1), ≤ 2.5 μm (PM2.5), ≤ 10 μm (PM10) and nitrogen dioxide (NO2)) for participants were predicted by using a spatiotemporal model. Residential greenness of each participant was indicated by Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI). Independent and joint associations of air pollutants and residential greenness indices with prevalent advanced fibrosis reflected by fibrosis-4 score (FIB4), aspartate-to-platelet-ratio index (APRI) and ALT/AST ratio were analyzed by generalized linear mixed models and their interactive effect on prevalent advanced fibrosis were visualized by using the interplot method. Long-term exposure to PM1, PM2.5, PM10 and NO2 were positively related to FIB4 or APRI as well as prevalent intermediate-high advanced fibrosis; EVI was negatively related to FIB4 or APRI as well as prevalent intermediate-high advanced fibrosis. Negative associations of residential greenness indices (EVI or NDVI) with prevalent advanced fibrosis were decreased as increased air pollutants (PM1, PM2.5, PM10 or NO2) (P < 0.05 for all). This study indicated that residential greenness may partially attenuate negative effect of long-term exposure to air pollutants related to increased prevalent intermediate-high advanced fibrosis, implying that residential greenness may be an effective strategy to reduce the burden of prevalent hepatic fibrosis and its related disease in association with exposure high levels of air pollutants. The Henan Rural Cohort study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699, http://www.chictr.org.cn/showproj.aspx?proj=11375 )

Background Low socio-economic status (SES) and exposure to single-air pollutant relate to increased prevalent atherosclerotic cardiovascular diseases (ASCVD), however, interactive effect between SES and exposure to single- or multiple-air pollutants on high 10-year ASCVD risk remains unclear. Methods A total of 31,162 individuals were derived from the Henan Rural Cohort Study. Concentrations of air pollutants (particulate matter with an aerodynamic diameter ≤ 1.0 μm (PM1), ≤2.5 μm (PM2.5) or ≤10 μm (PM10), nitrogen dioxide (NO2)) were assessed using a spatiotemporal model based on satellites data. Independent and joint associations of SES, single- and multiple- air pollutants with high 10-year ASCVD risk were evaluated using logistic regression models, quantile g-computation and structural equation models. The interactive effects of SES and exposure to single- or multiple air pollutants on high 10-year ASCVD risk were visualized by using Interaction plots. Results Exposure to single air pollutant (PM1, PM2.5, PM10 or NO2) related to increased high 10-year ASCVD risk among individuals with low education level or personal average monthly income, compared to the ones with high education level or personal average monthly income. Furthermore, similar results of exposure to mixture of air pollutants with high 10-year ASCVD risk were observed. Positive interactive effects between low SES and exposure to high single air pollutant or the mixture of air pollutants on high 10-year ASCVD risk were observed. Conclusion Positive association of low SES with high 10-year ASCVD risk was amplified by exposure to high levels of single air pollutant or a mixture of air pollutants, implying that individuals with low SES may more susceptible to air pollution-related adverse health effect.

Background Previous reports about health-related quality of life (HRQoL) of type 2 diabetes mellitus (T2DM) concentrated on general patients rather than patients in rural areas with poor infrastructure and limited resources. Thus, the aims of this study were to evaluate the HRQoL of diabetics in the countryside and explore its influencing factors. Methods A total of 23 053 participants aged from 18 to 79 years were drawn from the Henan Rural Cohort Study for this cross-sectional study. The HRQoL of participants were assessed by utility index and VAS-score of European Quality of Life Five Dimension Five Level Scale (EQ-5D-5L) instrument. Binary logistic regression, generalized linear and tobit regression models were used to estimate the potential influencing factors on HRQoL. Results This study (23 053 participants) included 2231 T2DM patients with a crude prevalence of 9.68%. The utility index and VAS-score in health group were 0.96 ± 0.10 and 78.85 ± 14.53, while in T2DM group were 0.93 ± 0.15 and 74.09 ± 16.09, respectively. In total, most diabetics reported problem about pain/discomfort dimension. Being old, poverty, low physical activity, and with comorbidities was negatively related to HRQoL of diabetics, while high educational level was positively related to HRQoL. Conclusion HRQoL of rural T2DM patients depended on several sociodemographic factors. More attention should be paid to diabetics with poor socioeconomic status in rural areas. Clinical trial registration The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699) http://www.chictr.org.cn/showproj.aspx?proj=11375.

Background There are few studies on the hyperuricemia (HUA) and moderate to vigorous intensity physical activity (PA) and also hardly regarding sitting time (ST). The purpose of this study was to examine the independent and interactive association of PA and ST with HUA. Methods A cross-sectional analysis was performed on 38,855 participants (aged 18–79) enrolled from the Henan Rural Cohort Study at baseline (2015 to 2017). PA and ST levels were assessed by using the International Physical Activity Questionnaire (IPAQ). HUA was defined as a serum uric acid level of > 7.0 mg/dL for males and > 6.0 mg/dL for females. Multivariable logistic regression and linear regression models were applied to examine the independent association between PA or ST and HUA and serum uric acid level. Interaction plots were used to visualize the interaction effects of PA and ST on HUA. Results PA level was inversely related with serum uric acid level (β − 0.15, 95% confidence interval (CI) − 0.22, − 0.07), but ST was positively related with uric acid level (β 2.12, 95% CI 1.90, 2.34). Metabolic equivalent (MET-hour/day) was associated with decreased prevalence of HUA (odds ratio (OR) 0.97, 95% CI 0.96, 0.99), while per hour increased for ST was associated with increased HUA (OR 1.05, 95% CI 1.04, 1.06). The interaction of PA and ST was significant (P Conclusion Exposure to higher ST was independently related to increased prevalence of HUA, while vigorous PA with a decreased HUA prevalence. Meanwhile, higher daily ST might attenuate the protective effect of PA on HUA. Trial registration The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699).

Additional file: 1 Table S1. The weight of 21 SNPs based on our population. Table S2. Simple Cox regression analysis of risk factors for developing dyslipidaemia in the raining set. Table S3. Other statistics of the conventional model and conventional+GRS model. Table S4. Performance of models without blood lipid indexes. Fig. S1. Flowchart of the study population and model constitution and evaluation.

Background: Although independent association of socioeconomic status (SES) or physical activity (PA) with obesity has been well-documented in urban settings, their independent and joint associations on obesity measures are limited in rural regions.Methods: Almost 38,000 (n = 37,922) individuals were included from the Henan Rural Cohort Study. The International Physical Activity Questionnaire (IPAQ) was used to evaluate PA. Obesity was reflected by body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat percentage (BFP), and visceral fat index (VFI). The independent and interactive effects of SES and PA on obesity were analyzed by logistic regression models and generalized linear regression models, respectively.Results: Compared with high education level, the OR (95%CI) of obesity defined by BMI with low education level was 1.466 (1.337, 1.608), 1.064 (0.924, 1.225), and 1.853 (1.625, 2.114) in total population, men and women, respectively. Besides, the OR (95%CI) of obesity defined by BMI associated with per capita monthly income were 1.089 (1.015, 1.170), 1.192 (1.055, 1.347), 1.038 (0.951, 1.133) in total population, men and women, respectively. Similar results had been observed in other obesity measures. Negative interactive association of low education level and PA on obesity measures were observed only in women (all P < 0.05).Conclusions: This study suggests that women are more susceptible to obesity concerning low SES and that adequate PA may be a potential target for mitigating the negative effect of low SES on obesity in women.Clinical Trial Registration: The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699) http://www.chictr.org.cn/showproj.aspx?proj=11375.

Additional file 1: Table S1. Association of physical activity level and sitting time with serum uric acid level by gender. Table S2. Association of physical activity level and sitting time with prevalence of hyperuricemia by gender. Table S3. Joint effects of hyperuricemia by different combinations of physical activity level and sitting time. Figure S1. Joint associations of physical activity level and sitting time with hyperuricemia.

Background: Few studies have developed risk models for dyslipidemia, especially for rural population. Further, the performance of genetic factors in predicting dyslipidemia was not explored. The purpose is to develop and evaluate the prediction models with and without genetic factor for dyslipidemia in Chinese rural population.Methods: A total of 3596 individuals from the Henan Rural Cohort study were included in this study. All subjects were divided into training set and testing set in a ratio of 7:3. The conventional models and conventional+GRS models were developed with COX regression, artificial neural network (ANN), random forest (RF), and gradient boosting machine (GBM) classifiers in training set. Area under the receiver operating characteristic curve (AUC), net reclassification index (NRI), and integrated discrimination index (IDI) were used to assess the discrimination ability of models and the calibration curve was used to show calibration ability in testing set.Results: Compared to the lowest GRS quartile, HR (95%CI) of individuals in the highest GRS quartile was 1.23(1.07, 1.41) in total population. Age, family history of diabetes, physical activity, BMI, TG, HDL-C, and LDLC-C were included and developed the conventional models, and the AUC of COX, ANN, RF, and GBM classifiers were 0.702(0.673, 0.729), 0.736(0.708, 0.762), 0.787 (0.762, 0.811), and 0.816(0.792, 0.839), respectively. After adding GRS, the AUC increased by 0.005, 0.018, 0.023, and 0.015 with COX, ANN, RF, and GBM classifiers, respectively. The corresponding NRI and IDI were 25.6%, 7.8%, 14.1%, 18.1% and 2.3%, 1.0%, 2.5%, 1.8%, respectively.Conclusion: Genetic factors could improve the predictive ability for dyslipidemia risk model, suggesting genetic information could be provided as a potential predictor to screen clinical dyslipidemia.Trial RegistrationThe Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register. (Trial registration: ChiCTR-OOC-15006699. Registered 6 July 2015 - Retrospectively registered) http://www.chictr.org.cn/showproj.aspx?proj=11375

Although solid-fuel use or smoking is associated with obesity measured by body mass index (BMI), research on their interactive effects on general and central obesity is limited. Data of 20,140 individuals in the Henan Rural Cohort Study was examined the independent and combined associations of solid-fuel use and smoking with prevalent obesity, which was measured by BMI, waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat percentage (BFP), and visceral fat index (VFI). Multiple adjusted logistic regression models showed that the OR (95% CI) of prevalent obesity measured by BMI associated with exposure to solid fuels alone or with smoking was 0.78 (0.70, 0.86) or 0.46 (0.32, 0.66), compared with neither smoking nor solid-fuel exposure. Similar results had been found in other obese anthropometric indices and in the results of linear regression analysis. The results indicated that solid-fuel use and smoking have a synergistic effect on reduction in obesity indices. The effects of household air pollution from solid-fuel use and smoking on obesity should be considered when exploring the influencing factors of obesity.

Background The relationship of spicy food intake with hyperuricemia remains unknown. The objective of this study was to examine the association between spicy food intake and hyperuricemia, and whether this association was mediated by body mass index (BMI) in Chinese rural population. Methods 38, 027 adults aged 18–79 years were recruited from the Henan Rural Cohort Study. Information on spicy food intake was obtained using a validated questionnaire survey. Multivariable logistic regression model was used to estimate the association between spicy food intake and hyperuricemia, multiple linear regression model was performed to estimate the relationships between spicy food intake, BMI and serum urate level. BMI was used as a mediator to evaluate the mediation effect. Results After adjusting for potential confounders, compared with no spicy food flavor, the odds ratio (OR) and 95% confidence interval (CI) of mild, middle, and heavy flavor for hyperuricemia were 1.09 (1.00–1.19), 1.10 (0.97–1.24), and 1.21 (1.10–1.46), respectively (Ptrend = 0.017). Similarly, compared with those without intake in spicy food, the multivariable adjusted OR (95% CI) of 1-2 days/week, 3–5 days/week, and 6–7 days/week were 1.15 (1.01–1.31), 1.14 (1.01–1.30) and 1.15 (1.05–1.26), respectively (Ptrend = 0.007). However, when we further controlling for BMI, the associations were substantially attenuated. Furthermore, mediation analysis showed that BMI play a full mediating role in the relationship of spicy food intake with hyperuricemia. Conclusion Spicy food flavor and intake frequency are positively related with hyperuricemia in Chinese rural population. BMI may play a full mediating role in the relationship. Trial registration The Henan Rural Cohort Study registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 2015-07-06.

Evidence from numerous epidemiological studies for the relationship between mental disorder and sleep quality was inconclusive and few studies assessed the modification effect of exposure to ambient air PM

Background. Evidence on the association of snoring, daytime napping or sleep duration with hyperuricemia (HUA) was limited, especially in the resources-poor areas. This study aimed to investigate the independent and joint effect of snoring frequency, daytime napping and sleep duration with prevalence of HUA in rural Chinese adults. Methods. 29,643 participants aged 18-79 years were included from baseline survey of the Henan Rural Cohort Study. Sleep variables were assessed using the Pittsburgh Sleep Quality Index (PSQI). Multivariate logistic regression and linear regression models with HUA and serum uric acid level as dependent variables were conducted, respectively. Results. Of the 29,643 included adults, 3498 suffered from HUA. Compared to never snoring, the adjusted odds ratio (OR) and 95% confidence interval (CI) of HUA for rare snoring, occasional snoring and habitual snoring were 1.35 (1.17, 1.56), 1.30 (1.14, 1.47) and 1.59 (1.47, 1.73), respectively. Compared with no napping, participants who had daytime napping of 61-90 and >91 min were associated with 29% and 30% increase in prevalence of HUA, respectively. But in night sleep duration groups, no significant associations were observed (all P>0.05). The positive associations between snoring and HUA were attenuated in older, female adults and those with chronic disease conditions. The joint of habitual snoring and longer daytime napping (≥61min) increased 63% prevalence on HUA. Conclusion. Snoring or daytime napping may independently increase the prevalence of HUA and serum uric acid (SUA) level. Moreover, habitual snoring and longer daytime napping might be jointly associated with a higher prevalence of HUA.Clinical Trial Registration The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). http://www.chictr.org.cn/showproj.aspx?proj=11375

Background: Although long-term exposure to air pollution and physical inactivity are linked to increased risk for atherosclerotic cardiovascular diseases (ASCVD), however, the interactive effect of air pollution and physical activity (PA) on high 10-year ASCVD risk is largely unknown. Methods: A total of 31,162 individuals aged 35–74 years were derived from the Henan Rural Cohort Study, after individuals with personal histories of ASCVD or missing data on predictors of high 10-year ASCVD risk were excluded. Concentrations of air pollutants (nitrogen dioxide (NO2), particulate matter with an aerodynamics diameters ≤ 1.0 µm (PM1), ≤2.5 µm (PM2.5) or ≤10 µm (PM10)) of individuals were estimated using a spatiotemporal model based on satellites data. The metabolic equivalent (MET) of PA of each individual was evaluated using the formula: duration (hour/time) × frequency/week × MET coefficient of each type of activity. Logistic regression models were used to analyze associations between air pollutants, PA and high 10-year ASCVD risk. Interaction plots were used to describe interactive effects of air pollutants and PA on high 10-year ASCVD risk. Results: Each 1 µg/m3 increase in PM1, PM2.5, PM10 and NO2 were related to a 4.4% (odds ratio (OR): 1.044, 95% confidence interval (CI): 1.034, 1.056), 9.1% (OR: 1.091, 95% CI: 1.079, 1.104), 4.6% (OR: 1.046, 95% CI: 1.040, 1.051) or 6.4% (OR: 1.064, 95% CI: 1.055, 1.072) increase in high 10-year ASCVD risk (all p

Background Long-term exposure to air pollutants relate to increase risk of cardiovascular diseases that may be partially attributable to platelet dysfunction. Physical activity (PA) may attenuate inflammation to modulate platelet function. Thus, this study aimed to evaluate associations of air pollutants and PA with platelet traits of cardiovascular risk. Methods A total of 31,282 participants were obtained from the Henan Rural Cohort (n = 39,259). The concentrations of particulate matter (PM) (PM with an aerodynamic diameter ≤1.0 μm (PM1), ≤2.5 μm (PM2.5), or ≤10 μm (PM10)) and nitrogen dioxide (NO2) were evaluated by using a spatiotemporal model incorporated into satellites data. Independent and combined effects of air pollutants and PA on platelet traits were analyzed by linear mixed models. Results Positive associations of PM1, PM2.5, PM10 and NO2 with platelet indices (mean platelet volume (MPV), platelet distribution width (PDW) and platelet large cell ratio (P-LCR), the MPV to platelet counts (PLT) ratio (MPVP)) were observed, whereas negative associations of PM10 and NO2 with PLT or plateletcrit (PCT) were observed; negative interaction effects of PM2.5 PM10 and NO2 and PA on MPV, PDW or P-LCR were found; negative interaction effects of PM1, PM2.5 and PM10 and PA on PCT were observed. Conclusions Long-term exposure to air pollutants were related to increase platelet size and these associations were attenuated by increased PA, implying that PA is a costless and affordable method to decrease adverse effects on platelet traits in relation to air pollutants.

Background: Long-term exposure to ambient air pollution and physical activity are linked to metabolic syndrome (MetS). However, the joint effect of physical activity and ambient air pollution on MetS remains largely unknown in rural Chinese adult population. Methods: In this study, 39 089 individuals were included from the Henan Rural Cohort study that recruited 39 259 individuals at the baseline. Participants' exposure to air pollutants (including particulate matter with an aerodynamic diameter ≤ 1.0 µm (PM1), ≤2.5 µm (PM2.5), or ≤ 10 µm (PM10) and nitrogen dioxide (NO2)) were evaluated by using a spatiotemporal model based on satellites data. Individuals were defined as MetS according to the recommendation of the Joint Interim Societies. Physical activity-metabolic equivalent (MET) was calculated based on the formula of MET coefficient of activity × duration (hour per time) × frequency (times per week). Generalized linear models were used to analyze the individual air pollutant or physical activity and their interaction on MetS. Interaction effects of individual air pollutant and physical activity on MetS were assessed by using Interaction plots which exhibited the estimated effect of physical activity on MetS as a function of individual air pollutant. Results: The prevalence of MetS was 30.8%. The adjusted odd ratio of MetS with a per 5 µg/m3 increase in PM1, PM2.5, PM10, NO2 or a 10 MET (hour/day) of physical activity increment was 1.251(1.199, 1.306), 1.424(1.360, 1.491), 1.228(1.203, 1.254), 1.408(1.363, 1.455) or 0.814(0.796, 0.833). The protective effect of physical activity on MetS was decreased with accompanying air pollutant concentrations increased. Conclusions: The results indicated that long-term exposure to ambient air pollutants related to increased risk of MetS and physical activity attenuated the effects of ambient air pollutants on increased risk for MetS. Keywords: Particulate matter, Gaseous pollutants, Physical activity, Metabolic syndrome, Rural population

We have previously shown that serum testosterone was associated with impaired fasting glucose (IFG) and type 2 diabetes (T2D). Testosterone can be acting through binding the androgen receptor (AR). Therefore, we aimed to explore the independent associations of AR DNA methylation (ARm) with IFG and T2D and the moderation effects of serum testosterone on the associations.A case-control study with 1065 participants including 461 men and 604 women was performed. ARm in peripheral blood sample and serum testosterone were measured using pyrosequeuncing and liquid chromatography-tandem mass, respectively. Multivariable logistic regression was performed to estimate the associations of ARm (including 2 cytosine-phosphoguanine [CpG] islands and average methylation levels) with different glucose status. Serum testosterone was used as a moderator to estimate the moderation effect.After multivariate adjustment, CpG 1, 2 and CpG average methylation were all significantly associated with IFG (CpG 1: Odds ratio (OR) = 4.80, 95% confidence interval (CI): 2.24-10.27; CpG 2: OR = 4.35, 95% CI: 2.50-7.58; CpG average: OR = 11.73, 95% CI: 5.36-25.67) in women. In addition, testosterone played negative moderation effects in above associations. Moreover, no significant independent associations of methylation levels with T2D was observed both in men and women.Our findings demonstrate that ARm was positively associated with IFG in women and the associations would be weakened by testosterone. The individuals experiencing low testosterone and ARm levels reported a lower state of IFG than those who experienced high levels of testosterone and ARm in women.背景: 我们之前的研究显示血清睾酮与空腹血糖受损(impaired fasting glucose，IFG)和2型糖尿病(type 2 diabetes, T2D)相关。睾酮可以通过与雄激素受体(androgen receptor, AR)结合发挥作用。因此，我们旨在探讨AR DNA甲基化与IFG和T2D的关系，以及血清睾酮对上述关联的调节作用。 方法: 本研究采用病例对照研究设计，共纳入1065名研究对象，其中包括461名男性和604名女性。分别采用焦磷酸测序和液相色谱串联质谱法测定外周血样品中的AR DNA甲基化和血清睾酮水平。通过多变量logistic回归评估AR DNA甲基化(包括2个胞嘧啶-磷酸鸟嘌呤(cytosine-phosphoguanine, CpG)岛和平均甲基化水平)与不同葡萄糖状态的相关性。此外，血清睾酮被用作调节因子来评估其调节效应。 结果: 经过多变量调整后，在女性中，CpG 1、2和CpG平均甲基化水平均与IFG显著相关(CpG 1: OR=4.80, 95% CI: 2.24-10.27；CpG 2: OR = 4.35, 95% CI: 2.50-7.58；CpG平均值: OR = 11.73, 95% CI: 5.36-25.67)。此外，睾酮在上述相关性中发挥了负向调节作用。另外，无论在男性还是女性中，均未观察到甲基化水平与T2D之间存在显著的关联。 结论: 我们的研究结果表明，在女性中，AR DNA甲基化水平与IFG呈正相关，而这种相关性会被睾酮削弱。与那些睾酮水平和AR DNA甲基化水平较高的人相比，睾酮和AR DNA甲基化水平较低的人，其IFG患病概率较低。.

Additional file 1: Table S1. Pairwise correlations between the adiposity indices. Table S2. Adjusted estimates for BMD per SD increase of the adiposity indices after removed. Table S3. Adjusted OR high osteoporosis risk associated with a SD increase of the adiposity indices after excluding medium osteoporosis risk patients. Table S4. Odd ratios for osteoporosis with a SD increase of the adiposity indices.