Yanxia Luo

Measures of Adiposity and Risk of Stroke in China: A Result from the Kailuan Study

Objective The objective of this study was to explore the association between adiposity and risk of incident stroke among men and women. Methods We studied the relationship between adiposity and stroke among 94,744 participants (18–98 years old) in the Kailuan study. During a follow-up of 4 years, 1,547 ischemic or hemorrhagic strokes were recorded. Measurements of adiposity included body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHpR), and waist-to-height ratio (WHtR). Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated from Cox regression models and each model fit was assessed using −2log-likelihood. Results Every measurement of adiposity was associated with the risk for total stroke and ischemic stroke, but not for hemorrhagic stroke. After adjusting for confounders and intermediates, the HR (comparing the mean of the highest quintile with that of the lowest quintile) for total stroke was 1.34(1.13–1.60) for BMI, 1.26(1.06–1.52) for WC, 1.29(1.08–1.56) for WHpR, and 1.38(1.15–1.66) for WHtR. The HR for ischemic stroke was 1.52(1.24–1.88) for BMI, 1.46(1.17–1.81) for WC, 1.40(1.12–1.74) for WHpR, and 1.62(1.29–2.04) for WHtR. The model fit for each of the indices was similar. Conclusions Adiposity increases the total risk of stroke and ischemic stroke, but not of hemorrhagic stroke. No clinically meaningful differences among the associations between BMI, WC, WHpR, and WHtR and stroke incidence were identified in this study.

Resting heart rate and risk of hypertension: results of the Kailuan cohort study.

Objective: Resting heart rate (RHR) is a predictive risk factor of the development of cardiovascular diseases, but its association with arterial hypertension has remained unclear. This study investigated the relationship between RHR and new-onset hypertension (NOH) in an Asian population. Methods: The Kailuan study is a prospective longitudinal cohort study on cardiovascular risk factors and cardiovascular or cerebrovascular events. Hazard ratios with 95% confidence intervals (CIs) were calculated using Cox regression modelling. Results: Out of 101 510 individuals originally included into the Kailuan study, 31 507 participants (mean age: 46.3 ± 11.5 years) were selected with no previous arterial hypertension or cardiac arrhythmias. After a mean follow-up period of 3.5 ± 0.9 years, 12 565 (39.88%) individuals developed arterial hypertension. Incidence of hypertension was 104.4, 109.7, 114.2 and 124.6 per 1000 person-years for each RHR quartile. In multivariate analysis with adjustment for blood pressure, blood lipids, diabetes mellitus and other parameters, hazard ratios for NOH increased significantly (P < 0.0001) with increasing RHR quartile. Increase in RHR by 10 beats/minute was associated with an 8% increase in NOH. Individuals in the highest RHR quartile as compared with participants in the lowest quartile demonstrated a 16% greater risk of developing NOH [hazard ratio 1.16; 95% confidence interval (CI) 1.11–1.23]. There were no significant interactions between RHR and prehypertension, diabetes mellitus, age and BMI in terms of NOH risk, respectively. Conclusion: Independently of other baseline parameters such as blood pressure, blood lipids and diabetes mellitus, elevated RHR significantly increases the risk of incident hypertension. Measuring RHR is helpful in predicting the risk of eventual arterial hypertension.

PM2.5 Spatiotemporal Variations and the Relationship with Meteorological Factors during 2013-2014 in Beijing, China

Objective Limited information is available regarding spatiotemporal variations of particles with median aerodynamic diameter < 2.5 μm (PM2.5) at high resolutions, and their relationships with meteorological factors in Beijing, China. This study aimed to detect spatiotemporal change patterns of PM2.5 from August 2013 to July 2014 in Beijing, and to assess the relationship between PM2.5 and meteorological factors. Methods Daily and hourly PM2.5 data from the Beijing Environmental Protection Bureau (BJEPB) were analyzed separately. Ordinary kriging (OK) interpolation, time-series graphs, Spearman correlation coefficient and coefficient of divergence (COD) were used to describe the spatiotemporal variations of PM2.5. The Kruskal-Wallis H test, Bonferroni correction, and Mann-Whitney U test were used to assess differences in PM2.5 levels associated with spatial and temporal factors including season, region, daytime and day of week. Relationships between daily PM2.5 and meteorological variables were analyzed using the generalized additive mixed model (GAMM). Results Annual mean and median of PM2.5 concentrations were 88.07 μg/m3 and 71.00 μg/m3, respectively, from August 2013 to July 2014. PM2.5 concentration was significantly higher in winter (P < 0.0083) and in the southern part of the city (P < 0.0167). Day to day variation of PM2.5 showed a long-term trend of fluctuations, with 2–6 peaks each month. PM2.5 concentration was significantly higher in the night than day (P < 0.0167). Meteorological factors were associated with daily PM2.5 concentration using the GAMM model (R 2 = 0.59, AIC = 7373.84). Conclusion PM2.5 pollution in Beijing shows strong spatiotemporal variations. Meteorological factors influence the PM2.5 concentration with certain patterns. Generally, prior day wind speed, sunlight hours and precipitation are negatively correlated with PM2.5, whereas relative humidity and air pressure three days earlier are positively correlated with PM2.5.

Resting Heart Rate and Risk of Cardiovascular Diseases and All-Cause Death: The Kailuan Study

Background Resting heart rate (RHR) predicts both cardiovascular and noncardiovascular death in different populations. However, the results of the association between RHR and cardiovascular diseases (CVDs) are inconsistent, especially for each subtype of CVDs. Objective The aim of this study was to prospectively explore the relationship between RHR and CVDs including myocardial infarction (MI), ischemic stroke, and hemorrhagic stroke and all-cause death in a general population. Methods The Kailuan study is a prospective longitudinal cohort study on cardiovascular risk factors and cardiovascular or cerebrovascular events. Hazard ratio (HR) with 95% confidence intervals (CI) were calculated using Cox regression modeling. Results We analyzed 92,562 participants (18–98 years old) in the Kailuan Study. CVDs were developed in 1,903 people during follow-ups. In multivariate analysis with adjustment for major traditional cardiovascular risk factors, HRs of the highest quintile group compared with the lowest quintile group of RHR for all-cause CVDs, MI, any stroke, ischemic stroke, hemorrhagic stroke, and all-cause death were 1.03 (95% CI, 0.98–1.07), 1.10 (95% CI, 1.01–1.20), 1.01 (95% CI, 0.97–1.06), 1.02 (95% CI, 0.96–1.07), 1.01 (95% CI, 0.92–1.11) and 1.18, (95% CI, 1.13–1.23), respectively. Conclusions The elevated RHR was independently associated with the increased risk for MI and all-cause death, but not for all-cause CVDs, any stroke, ischemic stroke, nor hemorrhagic stroke. This indicates that the elevated RHR might be a risk marker for MI and all-cause death in general populations.

Particulate Matter and Hospital Admissions for Stroke in Beijing, China: Modification Effects by Ambient Temperature.

Background The impact of particulate matter (PM) on stroke may vary by particle size, stroke subtype, and patient characteristics and temperature. We examined the association of stroke admissions with PM in different subgroups in Beijing, China, during 2013–2014. Methods and Results A time‐stratified case‐crossover design was used to assess the relation between PM of different particle sizes and hospital admissions for ischemic and hemorrhagic stroke. Stratified analyses were performed by age, sex, and temperature. In total, there were 147 624 stroke admissions during the study period. In the whole‐period analysis, both PM2.5 and PM10 were positively associated with ischemic stroke admissions on the day of hospital admission and negatively associated with ischemic stroke at lag2 and lag3 day. In warm days (>13.5°C), the odds ratios of ischemic stroke admissions were 2.071 (95% CI 1.959–2.190), 1.470 (95% CI 1.391–1.554), and 1.590 (95% CI 1.493–1.694) per IQR increase in the same‐day PM2.5 (82.0 μg/m3), PM2.5–10 (36.6 μg/m3), and PM10 (93.5 μg/m3), respectively. For hemorrhagic stroke, the corresponding values were 1.941 (95% CI 1.658–2.273), 1.590 (95% CI 1.366–1.851), and 1.527 (95% CI 1.278–1.826). The positive associations were also observed in the other lag structures and were higher than in cold days (≤13.5°C). Conclusions This study suggests that the associations of PM2.5, PM2.5–10, and PM10 with stroke admissions differed across levels of temperature. Short‐term exposure to PM2.5, PM2.5–10, and PM10 was positively associated with hospital admissions for ischemic and hemorrhagic stroke on warm days (>13.5°C).

Prevalence of metabolic syndrome and optimal waist circumference cut-off points for adults in Beijing

BACKGROUND In the modified ATP III definition for metabolic syndrome (MS), the cut-off values for central obesity were set to > or =90 cm for male and > or =80 cm for women. Recently, a new Chinese definition for central obesity was set to > or =90 cm for male and > or =85 cm for women according to the corresponding BMI value of 25 kg/m(2). OBJECTIVE The purpose of this study was to explore the optimal WC cut-off points to reflect the cluster of multiple risk factors for adults in Beijing. METHOD The data collected during the surveillance of risk factors for non-communicable diseases in Beijing 2005 were used, with a total of 16,711 adults studied. Subjects with two or more components from the modified ATP III definition other than central obesity were considered to have multiple risk factors. RESULTS The optimal WC cut-off points were 87 cm in men and 80 cm for women. When applied the WC advised definition for MS, the age-standardized prevalence was 38.0% for male and 32.3% for women, which is significantly higher than using the original one for men (34.7% vs 32.3%, P<0.001). CONCLUSION The present study indicated that optimal waist circumference cut-off points were lower than that proposed in the modified ATP III definition, especially for men.

Risk Factors of Myopic Shift among Primary School Children in Beijing, China: A Prospective Study.

Objective: To evaluate factors associated with myopic shift among primary school children. Methods: In a one-year prospective school-based study, 5052 children from ten schools were enrolled using a multi-stage random cluster approach. The baseline examination included non-cycloplegic auto-refractometry and questionnaire interview. Measurements were repeated at the follow-up. Results: Among 5052 students at baseline investigated, 4292 students (85.0%) returned for the follow-up examination. The mean refractive error (-1.13±1.57 diopters) had changed -0.52±0.73 diopters from the baseline to the follow-up examination. 2170 (51.0%) had a rate of significant myopic shift (significant myopic shift is defined as the change of spherical equivalent of the refraction ≤ -0.50D between the follow-up and baseline measures). We confirmed that common associated factors (older age, parental myopia, lower refractive status at baseline, shorter reading distance and lower frequency of outdoor activities during class recesses) were associated with greater shift towards myopia. After controlling for age, sex, region of habitation, parental myopia and refractive status at baseline, greater shift towards myopia was independently associated with distance from near-work (OR=1.48 , 95% CI=1.26-1.74, P<0.001) and longer time outdoors for leisure (OR=0.87, 95% CI=0.78-0.97, P<0.013). Conclusion: Greater shift towards myopia was independently associated with modifiable factors (distance from near-work and longer time outdoors for leisure) might suggest that encouraging children to go outside for outdoor activities during class recess and after school may be a promising and feasible intervention against myopia development.

Impact of proteinuria and glomerular filtration rate on risk of ischaemic and intracerebral hemorrhagic stroke: a result from the Kailuan study.

Persons with chronic kidney disease, defined by a reduced estimated glomerular filtration rate and proteinuria, have an increased risk of cardiovascular disease including stroke. However, data from developing countries are limited. Our aim was to assess the relationship between chronic kidney disease and risk of stroke and its subtypes in a community‐based population in China.

Prevalence and risk factors for cervical neoplasia: a cervical cancer screening program in Beijing

BackgroundCervical cancer is the second most common cancer and cause of cancer-related death for women worldwide. The aims of this study were to investigate the prevalence of cervical neoplasia and examine factors associated with high-grade cervical squamous intraepithelial lesions (HSIL) among women taking part in a cervical cancer screening program in Beijing.MethodsWomen aged 25–65 years were screened using the ThinPrep cytologic test and gynecologic examination. Univariate and multivariate logistic regressions were conducted to investigate factors associated with HSIL.ResultsAmong 728,704 women screened, the prevalence of cervical intraepithelial neoplasia (CIN) I, II, III was 50.2, 34.0, and 36.4 per 100,000, respectively. Prevalence of cervical cancer was 12.2 per 100,000. Risk factors for HSIL included being in age group of 46–55 years (adjusted odds ratio [aOR] = 1.15, 95% CI: 1.07–1.44, compared with the 25–35 age group), bleeding after intercourse (aOR = 2.08, 95% CI: 1.40–3.10), and presence of trichomonas vaginalis infection (aOR = 2.62, 95% CI: 1.35–5.07), cervical inflammation (aOR = 4.22, 95% CI: 3.39–5.26), and genital warts (aOR = 3.89, 95% CI: 2.54–7.70). High education level (college and above compared with junior middle school or lower) was found to be protective (aOR = 0.79, 95% CI: 0.37–0.90).ConclusionsThe prevalence of cervical neoplasia is relatively high in Beijing. Women aged 46–55 years, those with a lower education level, those reporting bleeding after intercourse, and those affected by Trichomonas vaginalis infection, cervical inflammation and genital warts are at higher risk for HSIL. Particular efforts should be made to ensure these women are included in cervical cancer screening programs.

Hypertriglyceridemic waist phenotype and risk of cardiovascular diseases in China: Results from the Kailuan Study

BACKGROUND While some case-control studies have showed the correlation between the hypertriglyceridemic waist (HTGW) phenotype (increased WC and hypertriglyceridemia) and cardiovascular disease (CVD) events, there are few data regarding this correlation in cohort studies, especially in Asian populations that have a higher prevalence of central obesity than other populations. OBJECTIVE The aim of this study was to explore the relationship between HTGW phenotype and risk of incident CVD events among men and women in China. METHODS We analyzed 95,015 participants (18-98 years old) in the Kailuan Study. CVDs developed in 1958 people during follow-up. The cutoffs for defining HTGW phenotype were a waist circumference (WC) of 90 cm or more and a triglyceride level of 2.0 mmol/L or more for men and a WC of 85 cm or more and a triglyceride level of 1.5 mmol/L or more for women. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated from Cox regression models. RESULTS Compared with participants who had a normal WC and a normal triglyceride level (NWNT), those with HTGW phenotype had a higher WC, body mass index, prevalence of hypertension and diabetes mellitus; and a lower level of high-density lipoprotein cholesterol. The HTGW group had an unadjusted HR of 1.76 (95% CI=1.55-1.99) for future CVDs compared with the NWNT group. After adjustment for confounders, the HR still remained significant (HR=1.24, 95% CI=1.07-1.44). CONCLUSIONS HTGW phenotype was associated with the risk of CVDs independently. HTGW phenotype might be a simple but useful tool to screen the individuals at a high risk for future CVDs, and it might be recommended in most clinical practices.