Haze weather and mortality in China from 2014 to 2020: Definitions, vulnerability, and effect modification by haze characteristics.

Haze weather, characterized by low visibility due to severe air pollution, has aroused great public concern. However, haze definitions are inconclusive, and multicentre studies on the health impacts of haze are scarce. We collected data on the daily number of deaths and environmental factors in 190 Chinese cities from 2014 to 2020. The city-specific association was estimated using quasi-Poisson regression and then pooled using meta-analysis. We found a negative association between daily visibility and non-accidental deaths, and mortality risk sharply increased when visibility was < 10 km. Haze weather, defined as a daily average visibility of < 10 km without a limit for humidity, produced the best model fitness and greatest effect on mortality. A haze day was associated with an increase of 2.53% (95% confidence interval [CI]:1.96, 3.10), 2.84 (95% CI: 2.13, 3.56), and 2.99% (95% CI: 1.94, 4.04) in all non-accident, cardiovascular and respiratory mortality, respectively. Haze had the greatest effect on lung cancer mortality. The haze-associated risk of mortality increased with age. Severe haze (visibility <2 km) and damp haze (haze with relative humidity >90%) had greater health impacts. Our findings can help in the development of early warning systems and effective public health interventions for haze.

Use of Virus Genotypes in Machine Learning Diagnostic Prediction Models for Cervical Cancer in Women With High-Risk Human Papillomavirus Infection.

Importance: High-risk human papillomavirus (hrHPV) is recognized as an etiologic agent for cervical cancer, and hrHPV DNA testing is recommended as the preferred method of cervical cancer screening in recent World Health Organization guidelines. Cervical cancer prediction models may be useful for screening and monitoring, particularly in low-resource settings with unavailable cytological and colposcopic examination results, but previous studies did not include women infected with hrHPV. Objectives: To develop and validate a cervical cancer prediction model that includes women positive for hrHPV infection and examine whether the inclusion of HPV genotypes improves the cervical cancer prediction ability. Design, Setting, and Participants: This diagnostic study included diagnostic data from 314 587 women collected from 136 primary care centers in China between January 15, 2017, and February 28, 2018. The data set was separated geographically into data from 100 primary care centers in 6 districts for model development (training data set) and 36 centers in 3 districts for model validation. A total of 24 391 women identified with positive hrHPV test results in the cervical cancer screening program were included in the study. Data were analyzed from January 1, 2022, to July 14, 2022. Main Outcomes and Measures: Cervical intraepithelial neoplasia grade 3 or worse (CIN3+) was the primary outcome, and cervical intraepithelial neoplasia grade 2 or worse (CIN2+) was the secondary outcome. The ability of the prediction models to discriminate CIN3+ and CIN2+ was evaluated using the area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. The calibration and clinical utility of the models were assessed using calibration plots and decision curves, respectively. Results: After excluding women without screening outcomes, the study included 21 720 women (median [IQR] age, 50 [44-55] years). Of 14 553 women in the training data set, 349 (2.4%) received a diagnosis of CIN3+ and 673 (4.6%) of CIN2+. Of 7167 women in the validation set, 167 (2.3%) received a diagnosis of CIN3+ and 228 (3.2%) of CIN2+. Including HPV genotype in the model improved the AUROC by 35.9% for CIN3+ and 41.7% for CIN2+. With HPV genotype, epidemiological factors, and pelvic examination as predictors, the stacking model had an AUROC of 0.87 (95% CI, 0.84-0.90) for predicting CIN3+. The sensitivity was 80.1%, specificity was 83.4%, positive likelihood ratio was 4.83, and negative likelihood ratio was 0.24. The model for predicting CIN2+ had an AUROC of 0.85 (95% CI, 0.82-0.88), with a sensitivity of 80.4%, specificity of 81.0%, positive likelihood ratio of 4.23, and negative likelihood ratio of 0.24. The decision curve analysis indicated that the stacking model provided a superior standardized net benefit when the threshold probability for clinical decision was lower than 23% for CIN3+ and lower than 17% for CIN2+. Conclusions and Relevance: This diagnostic study found that inclusion of HPV genotypes markedly improved the ability of a stacking model to predict cervical cancer among women who tested positive for hrHPV infection. This prediction model may be an important tool for screening and monitoring cervical cancer, particularly in low-resource settings.

The Risk Factors for Cervical Cytological Abnormalities Among Women Infected With Non-16/18 High-Risk Human Papillomavirus: Cross-sectional Study.

BACKGROUND: High-risk human papillomavirus (hrHPV) infection is a necessary cause of almost all cervical cancers. Relative to hrHPV 16/18 infection, non-16/18 hrHPV infection is of less concern. However, the increasing prevalence of non-16/18 hrHPV infections has become an important public health issue. The early identification and treatment of cervical cytological abnormalities in women infected with non-16/18 hrHPV reduces the incidence of cervical cancer. To date, no study has examined the risk factors for cytological abnormalities in this high-risk population. OBJECTIVE: This population-based, cross-sectional study aimed to identify the risk factors for cervical cytological abnormalities in women infected with non-16/18 hrHPV. METHODS: A total of 314,587 women from the general population were recruited for cervical cancer screening at 136 primary care hospitals in Xiangyang, China. Of these, 311,604 women underwent HPV genotyping, and 17,523 non-16/18 hrHPV-positive women were referred for cytological screening according to the screening program. A logistic regression model was used to assess the risk factors for cytological abnormalities among these non-16/18 hrHPV-positive women. A separate analysis was performed to determine the factors influencing high-grade cytological abnormalities. RESULTS: The non-16/18 hrHPV infection rate was 5.88% (18,323/311,604), which was 3-fold higher than that of hrHPV 16/18 (6068/311,604, 1.95%). Among the non-16/18 hrHPV-positive women who underwent ThinPrep cytologic test, the overall prevalence rates of cervical cytological abnormalities and high-grade cytological abnormalities were 13.46% (2359/17,523) and 1.18% (206/17,523), respectively. Multivariate logistic regression analysis revealed that women with middle or high school educational attainment were at a higher risk of having cytological abnormalities than those who received primary education (odds ratio [OR] 1.31, 95% CI 1.17-1.45; P<.001, and OR 1.32, 95% CI 1.14-1.53; P<.001, respectively). Living in rural areas (OR 2.58, 95% CI 2.29-2.90; P<.001), gravidity ≥3 (OR 2.77, 95% CI 1.19-6.45; P=.02), cervix abnormalities detected in pelvic examination (OR 1.22, 95% CI 1.11-1.34; P<.001), and having a cervical cancer screening 3 years ago (OR 0.79, 95% CI 0.62-1.00; P=.048) were associated with cytological abnormalities. The risk factors for high-grade cytological abnormalities included middle school education (OR 1.45, 95% CI 1.07-1.98; P=.02), living in rural regions (OR 1.52, 95% CI 1.10-2.10; P=.01), and cervix abnormality (OR 1.72, 95% CI 1.30-2.26; P<.001). CONCLUSIONS: The dominant epidemic of non-16/18 hrHPV infection is revealed in Chinese women. Multiple risk factors for cervical cytological abnormalities have been identified in women infected with non-16/18 hrHPV. These findings can provide important information for clinically actionable decisions for the screening, early diagnosis, intervention, and prevention of cervical cancer in non-16/18 hrHPV-positive women.

A nomogram for predicting mortality in patients with COVID-19 and solid tumors: a multicenter retrospective cohort study.

BACKGROUND: Individualized prediction of mortality risk can inform the treatment strategy for patients with COVID-19 and solid tumors and potentially improve patient outcomes. We aimed to develop a nomogram for predicting in-hospital mortality of patients with COVID-19 with solid tumors. METHODS: We enrolled patients with COVID-19 with solid tumors admitted to 32 hospitals in China between December 17, 2020, and March 18, 2020. A multivariate logistic regression model was constructed via stepwise regression analysis, and a nomogram was subsequently developed based on the fitted multivariate logistic regression model. Discrimination and calibration of the nomogram were evaluated by estimating the area under the receiver operator characteristic curve (AUC) for the model and by bootstrap resampling, a Hosmer-Lemeshow test, and visual inspection of the calibration curve. RESULTS: There were 216 patients with COVID-19 with solid tumors included in the present study, of whom 37 (17%) died and the other 179 all recovered from COVID-19 and were discharged. The median age of the enrolled patients was 63.0 years and 113 (52.3%) were men. Multivariate logistic regression revealed that increasing age (OR=1.08, 95% CI 1.00 to 1.16), receipt of antitumor treatment within 3 months before COVID-19 (OR=28.65, 95% CI 3.54 to 231.97), peripheral white blood cell (WBC) count ≥6.93 ×109/L (OR=14.52, 95% CI 2.45 to 86.14), derived neutrophil-to-lymphocyte ratio (dNLR; neutrophil count/(WBC count minus neutrophil count)) ≥4.19 (OR=18.99, 95% CI 3.58 to 100.65), and dyspnea on admission (OR=20.38, 95% CI 3.55 to 117.02) were associated with elevated mortality risk. The performance of the established nomogram was satisfactory, with an AUC of 0.953 (95% CI 0.908 to 0.997) for the model, non-significant findings on the Hosmer-Lemeshow test, and rough agreement between predicted and observed probabilities as suggested in calibration curves. The sensitivity and specificity of the model were 86.4% and 92.5%. CONCLUSION: Increasing age, receipt of antitumor treatment within 3 months before COVID-19 diagnosis, elevated WBC count and dNLR, and having dyspnea on admission were independent risk factors for mortality among patients with COVID-19 and solid tumors. The nomogram based on these factors accurately predicted mortality risk for individual patients.

Trends and seasonality in cause-specific mortality among children under 15 years in Guangzhou, China, 2008-2018.

BACKGROUND: This study analyzed the trends and seasonality in mortality among children aged 0-14 years in Guangzhou, China during 2008-2018. Understanding the epidemiology of this public health problem can guide policy development for children mortality prevention. METHODS: A population-based epidemiological retrospective study was conducted. Seven thousand two hundred sixty-five individual data of children mortality were obtained from the Guangzhou Center for Disease Control and Prevention (CDC). The Poisson regression was used to quantify the annual average reduction rate and the difference in mortality rate between sex and age groups. Incidence ratio with 95% confidence interval (CI) was estimated to determine the temperaol variations in mortality by month, season, school term, day of the week and between holidays and other days. RESULTS: Between 2008 and 2018, the children mortality rate in Guangzhou decreased from 54.0 to 34.3 per 100,000 children, with an annual reduction rate of 4.6% (95% CI: 1.1%-8.1%), especially the under-5 mortality rate decreased by 8.3% (95% CI: 4.8%-11.6%) per year. Decline trends varied by causes of death, even with an upward trend for the mortality of asphyxia and neurological diseases. The risk of death among males children was 1.33 times (95% CI: 1.20-1.47) of that of females. The distribution of causes of death differed by age group. Maternal and perinatal, congenital and pneumonia were the top three causes of death in infants and cancer accounted for 17% of deaths in children aged 1-14 years. Moreover, the injury-related mortality showed significant temporal variations with higher risk during the weekend. And there was a summer peak for drowning and a winter peak for asphyxia. CONCLUSIONS: Guangzhou has made considerable progress in reducing mortality over the last decade. The findings of characteristics of children mortality would provide important information for the development and implementation of integrated interventions targeted specific age groups and causes of death.

Comorbidity and its impact on 1590 patients with COVID-19 in China: a nationwide analysis.

BACKGROUND: The coronavirus disease 2019 (COVID-19) outbreak is evolving rapidly worldwide. OBJECTIVE: To evaluate the risk of serious adverse outcomes in patients with COVID-19 by stratifying the comorbidity status. METHODS: We analysed data from 1590 laboratory confirmed hospitalised patients from 575 hospitals in 31 provinces/autonomous regions/provincial municipalities across mainland China between 11 December 2019 and 31 January 2020. We analysed the composite end-points, which consisted of admission to an intensive care unit, invasive ventilation or death. The risk of reaching the composite end-points was compared according to the presence and number of comorbidities. RESULTS: The mean age was 48.9 years and 686 (42.7%) patients were female. Severe cases accounted for 16.0% of the study population. 131 (8.2%) patients reached the composite end-points. 399 (25.1%) reported having at least one comorbidity. The most prevalent comorbidity was hypertension (16.9%), followed by diabetes (8.2%). 130 (8.2%) patients reported having two or more comorbidities. After adjusting for age and smoking status, COPD (HR (95% CI) 2.681 (1.424-5.048)), diabetes (1.59 (1.03-2.45)), hypertension (1.58 (1.07-2.32)) and malignancy (3.50 (1.60-7.64)) were risk factors of reaching the composite end-points. The hazard ratio (95% CI) was 1.79 (1.16-2.77) among patients with at least one comorbidity and 2.59 (1.61-4.17) among patients with two or more comorbidities. CONCLUSION: Among laboratory confirmed cases of COVID-19, patients with any comorbidity yielded poorer clinical outcomes than those without. A greater number of comorbidities also correlated with poorer clinical outcomes.

Intravenous administration of adenosine triphosphate and phosphocreatine combined with fluoxetine in major depressive disorder: protocol for a randomized, double-blind, placebo-controlled pilot study.

BACKGROUND: Major depressive disorder (MDD) is a common psychiatric disorder. With systematic antidepressant treatment, 50-75% of patients have a treatment response but require 4-6 weeks to have their symptoms alleviated. Therefore, researchers anticipate the development of novel fast-acting antidepressants. Previous studies have revealed that the decrease of bio-energetic metabolism may contribute to the occurrence of depression, while our team has found adenosine triphosphate (ATP) and phosphocreatine (PCr) to be fast-acting antidepressants in the depressed-animal model. ATP and PCr have already been widely prescribed clinically as energy supplements for cells. This will be the first clinical attempt of the intravenous administration of ATP and PCr combined with orally administered fluoxetine in MDD. METHODS: This is a single-center, randomized, double-blind, placebo-controlled pilot study. A total of 42 patients will be divided randomly into three groups. Patients will receive an intravenous administration of ATP or PCr or saline twice daily combined with orally administered fluoxetine (20 mg/day) for the first 2 weeks and fluoxetine monotherapy for the following 4 weeks. Follow-up assessment will be completed at week 10. Feasibility outcomes will include percentages of patient eligibility, intention to use medication, willingness to participate, drug adherence, completion of the scheduled assessment, retention, drop-out, etc. Physical examination results, Side Effect Rating Scale, adverse events, results from blood tests, electroencephalogram, and electrocardiograph will be recorded for safety evaluation of the augmentation therapy. The trends of efficacy will be evaluated by the reduction rate of the Hamilton Depression Rating Scale, the mean change of the Clinical Global Impression Scale, and the Patients Health Questionaire-9 items. DISCUSSION: In our study, ATP and PCr will be given by intravenous infusion. Thus patients will be hospitalized for the initial 2 weeks for safety concern. Hospitalization will be an impact factor for the recruitment, participation, drop-out, efficacy, results, etc. The evaluation of our feasibility outcomes, study setting, safety of augmentation therapy and possible efficacy trends among groups, will facilitate a full-scale trial design and sample size calculation. TRIAL REGISTRATION: NCT03138681 . Registered on 3 May 2017. First patient: 4 May 2017.

Comparison of the clinical characteristics and comprehensive assessments of the 2011 and 2017 GOLD classifications for patients with COPD in China.

OBJECTIVE: Compared with the 2011 Global Initiative for Chronic Obstructive Lung Disease (GOLD), there have been significant changes in the 2017 GOLD classification. The purpose of this study was to analyze the changes in clinical characteristics of the new A-B-C-D system and to explore its role in comprehensive assessment of COPD. SUBJECTS AND METHODS: A total of 631 stable COPD patients were included in a cross-sectional survey. Data collected included baseline data and pulmonary function testing results, respiratory muscle strength, symptoms and quality of life, exercise capacity, nutritional status, and anxiety and depression as a comprehensive assessment. Based on the 2011 GOLD and 2017 GOLD classifications, patients were divided into Groups A1-D1 and Groups A2-D2, respectively. RESULTS: In the 2011 GOLD, 64 subjects in Group C1 were reclassified into Group A2 (41.6%), while 77 subjects in Group D1 were reclassified into Group B2 (27.1%). The old and new grading systems were somewhat consistent (Cohen's kappa=0.6963, P<0.001). Lung function was lower, while the body mass index, airflow obstruction, dyspnea, and exercise capacity index (BODE index) was higher in Group A2 than in Group A1 (P<0.001). In Group B2, lung function, 6-minute walking distance (6MWD), and respiratory muscle strength were significantly lower than in Group B1 (P<0.001), while the BODE index (P<0.001) was higher. In comprehensive assessment, subjects in Groups B2 and D2 had significantly lower lung function, 6MWD, respiratory muscle strength, quality of life, higher symptom scores, and BODE index than subjects in Group A2 (P<0.001). The differences between Group A2 and C2 were small. CONCLUSION: Compared with the 2011 GOLD, the 2017 GOLD reclassified more patients into Groups A and B, those with significantly worse lung function and higher BODE index. In the comprehensive assessment of the new classification, Groups B and D may have greater disease severity. However, the effectiveness of the new grading system in predicting patient prognosis, and its guidance on the use of drugs, remains to be explored in future studies.

Prevalence and Occupational and Environmental Risk Factors of Self-Reported Asthma: Evidence from a Cross-Sectional Survey in Seven Chinese Cities.

OBJECTIVE: Asthma is one of the most common chronic diseases and associated with significant morbidity and mortality. However, few data on occupational and environmental risk factors of asthma are available, particularly in Asian adults. Based on a national cross-sectional survey, we assessed the prevalence and risk factors of asthma in Chinese adults. METHODS: A total of 9974 participants aged 15 years and over in seven Chinese cities were selected using a stratified four-stage random sampling. All participants were interviewed face-to-face in their homes using a standardized self-administered questionnaire. Multivariate logistic regression analyses were adopted to determine various risk factors for asthma. RESULTS: The prevalence of self-reported lifetime asthma was 2.46% among the entire adult population, 3.02% among males and 1.93% among females. The prevalence varied by age group, ethnicity, marital status, education, and floor space per person (p < 0.05). After adjusting for socio-demographic variables and smoking, we found independent occupational and environmental determinants of asthma, including a clearance-related job (OR = 2.28, 95%CI: 1.07-4.89), occupational exposure to industrial or occupational poisonous gas (OR = 4.21, 95%CI: 2.43-7.30), having large amounts of carpet in the workplace (OR = 2.61, 95%CI: 1.20-5.69) and using coal for cooking (OR = 2.65, 95%CI: 1.26-5.57). CONCLUSIONS: Asthma is a serious public health problem in China. Our study provides important updated information on the prevalence of asthma and its associated risk factors, which may help us better understand the epidemiology of asthma and prevent this disorder.

Occupational and environmental risk factors for chronic rhinosinusitis in China: a multicentre cross-sectional study.

BACKGROUND: Chronic rhinosinusitis (CRS) is defined as a condition of inflammation in the paranasal sinus mucosa persisting for more than 12 weeks. We previously reported that the prevalence of CRS was about 8 % in China. Here, we aim to investigate the occupational and environmental risk factors associated with CRS. METHODS: Data were collected from seven Chinese cities: Urumqi, Changchun, Beijing, Wuhan, Chengdu, Huaian and Guangzhou. CRS was diagnosed according to the European Position Paper on Rhinosinusitis and Nasal Polyps (EP(3)OS) document. Participants were asked to complete a standardized questionnaire, which was developed by the Global Allergy and Asthma European Network (GA(2)LEN) project and covered sociodemographic characteristics, CRS-related symptoms and occupational and environmental exposures. We evaluated the association between CRS and various occupational and environmental factors using odds ratios (ORs) and 95 % confidence intervals (95 % CIs). RESULTS: The total study population consisted of 10,633 subjects, 850 (7.99 %) of whom were defined as having CRS according to the EP(3)OS criteria. We found that there were significant associations between occupational and environmental factors and CRS. Specifically, having a clearance-related job, occupational exposure to dust, occupational exposure to poisonous gas, a pet at home or carpet at home or at the workplace were risk factors for CRS. Additionally, the method used to keep warm in winter, the duration of time spent using air conditioning in summer and the frequency of exposure to mouldy or damp environments were significantly different in subjects with and without CRS. CONCLUSIONS: Our data showed that some occupational and environmental exposures are strongly associated with CRS, which aids in understanding the epidemiology of CRS.

Influence of self-reported chronic rhinosinusitis on health-related quality of life: a population-based survey.

Chronic rhinosinusitis (CRS) is a frequently occurring chronic respiratory disease. There is evidence that effective treatment of CRS can improve patients' quality of life, but the data regarding the extent to which CRS impairs patients' quality of life (QoL) is sparse. This study aimed to evaluate the effect of self-reported CRS on health-related QoL and to determine whether the influence was associated with gender, age and socio-economic status. A four-stage random sampling method was used to select the participants from the general population in Guangzhou, China. All participants were interviewed face-to-face at their homes using a standardized questionnaire. The health-related QoL of each participant was assessed using the SF-36 Health Survey. The scores of the SF-36 after adjusting for gender, age, socioeconomic conditions, smoking and some important comorbid conditions were compared between the CRS group and the non-CRS group using analysis of covariance. A multiple linear regression model with interaction terms was established to determine whether CRS affected QoL to the same degree across the different subpopulations. Among a total of 1,411 participants aged at least 15 years, 118 persons (8.4%) had self-reported CRS. Subjects with CRS had an increased prevalence of allergic rhinitis, chronic obstructive pulmonary disease and gout than subjects without CRS. The CRS group had lower scores in all eight domains and the physical and mental component summary than those without CRS (P<0.05), and the greatest differences were in role emotional function (RE), general health (GH) and role physical function (RP). The impairments of the CRS participants in RE and RP were greater among the females than the males. Moreover, physical domains were affected to greater degrees among the elderly and those with high-level education. In conclusion, CRS is a common chronic disorder. Persons with self-reported CRS perceived themselves as having impaired QoL in both the physical and mental domains. These findings shed new light on the health burden of CRS and should be taken into account by clinicians involved in the care of CRS patients.

Health-promoting lifestyles of university students in mainland China.

BACKGROUND: Health-promoting lifestyles of adolescents are closely related to their current and subsequent health status. However, few studies in mainland China have examined health-promoting behaviors among university students, notwithstanding the dramatic development of higher education over the past two decades. Moreover, no study has applied a standardized scale to such an investigation. The adolescent health promotion (AHP) scale has been developed and is commonly used for measuring adolescent health-promoting lifestyles in Taiwan. The aim of this study is to determine the appropriateness of the AHP for use in mainland China. METHODS: A cross-sectional study was performed on a total of 420 undergraduates, who were randomly selected using a two-stage stratified sampling method in a university in Guangzhou city, mainland China. The simplified Chinese version of the AHP scale, comprising six dimensions (Nutrition behavior, Social support, Life-appreciation, Exercise behavior, Health-responsibility and Stress-management), was used to measure health-promoting lifestyles among undergraduates. The reliability of the AHP scale was assessed using split-half reliability coefficients, intraclass correlation coefficients and Cronbach's alpha coefficient. Validity was assessed by factor analysis and correlation analysis. Factors associated with health-promoting lifestyles were identified using multiple linear regression. RESULTS: Cronbach's coefficients were greater than 0.7 in all dimensions of the AHP scale except for Nutrition behavior (0.684). Intraclass correlation coefficients ranged from 0.689 to 0.921. Split-half reliability coefficients were higher than 0.7 in three AHP dimensions (Social support, Life-appreciation and Exercise behavior). Our results were generally in accordance with the theoretical construction of the AHP scale. The mean score for each of the six dimensions was lower than 70. Gender and grade were the factors primarily associated with health-promoting lifestyles among undergraduates. CONCLUSION: The AHP is a valid and reliable instrument for assessing health-promoting lifestyles of undergraduates in mainland China, which remain at a low level. Health behavior education taking account of gender and grade differences may also be applied.

Short-term effects of particulate air pollution on male smokers and never-smokers.

BACKGROUND: Numerous studies have shown that ambient air pollution and smoking are both associated with increased mortality, but until now there has been little evidence as to whether the effects of these 2 factors combined are greater than the sum of their individual effects. We assessed whether smokers are subject to additional mortality risk from air pollution relative to never-smokers. METHODS: This study included 10,833 Chinese men in Hong Kong who died at the age of 30 or above during the period 1 January to 31 December 1998. Relatives who registered for deceased persons were interviewed about the deceased's smoking history and other personal lifestyle factors about 10 years before death. Poisson regression for daily number of deaths was fitted to estimate excess risks per 10 microg/m increase in particulate matter with aerodynamic diameter <10 microm (PM10) in male smokers and never-smokers in stratified data, and additional excess risk for smokers relative to never-smokers in combined data. RESULTS: In smokers there was a significant excess risk associated with PM10 for all natural causes and cardio-respiratory diseases for men age 30 years or older and men 65 or older. For all natural causes, greater excess risk associated with PM10 was observed for smokers relative to never-smokers: 1.9% (95% confidence interval = 0.3% to 3.6%) in men age 30 and older and 2.3% (0.4% to 4.3%) in those age 65 and older. CONCLUSIONS: Ambient particulate air pollution is associated with greater excess mortality in male smokers compared with never-smokers.

Does regular exercise protect against air pollution-associated mortality?

OBJECTIVES: To examine whether habitual exercise would modify the effects of air pollution on mortality. METHODS: This study included 24,053 Hong Kong Chinese who died at the age of 30 years or older in 1998. Individual information on frequency of exercise was obtained by interviewing their relatives at all four death registries. The deceased subjects were categorized as never-exercise ( or =once/month). Excess risks (ER) of mortality per 10 microg/m(3) increase of air pollutant were estimated separately by a Poisson regression model in the exercise and never-exercise groups. An interaction model was used to estimate the difference in ER between the two groups. RESULTS: In people aged 65 years or older and categorized as never-exercise group, there were significant ER of mortality for all natural causes attributed to nitrogen dioxide (p<0.05), ozone (p<0.05) and particulate matter with an aerodynamic diameter of 10 mum or smaller (p<0.01). When compared to the exercise group, the ER were significantly higher by 4.31% (95% confidence interval: 2.57%, 6.03%), 1.75% (0.25%, 3.23%), and 3.06% (1.74%, 4.37%), respectively. The estimates were insensitive to adjustment for socioeconomic, smoking and health status, and were non-linear by different exercise levels. CONCLUSIONS: The results of this study provide evidence that habitual exercise may prevent premature death attributable to air pollution.

First-trimester fetal limb biometry in Chinese population.

OBJECTIVES: To establish reference ranges for fetal limb biometry obtained by transabdominal ultrasound examination at 12-14 weeks of gestation in Chinese women. METHODS: A total of 1489 normal singleton fetuses between 12(+0) and 14(+6) weeks of gestation were examined transabdominally by two experienced observers. The gestation was ascertained by measurement of fetal crown-rump length (CRL) or biparietal diameter (BPD) and head circumference (HC). The lengths of the humerus and femur were prospectively worked out. RESULTS: Gestation-specific reference ranges for limb measurements were calculated. The femur length (FL) (mean +/- SD) was 9.15 +/- 1.44 mm at 12-12(+6) weeks, 11.45 +/- 1.35 mm at 13-13(+6) weeks, and 13.64 +/- 1.60 mm at 14-14(+6) weeks; the corresponding humerus length (HL) (mean +/- SD) was 9.63 +/- 1.44 mm, 12.01 +/- 1.41 mm, 14.29 +/- 1.48 mm, respectively. CONCLUSIONS: There was a general increase in fetal limb biometry with gestation. Fetal limb length can be an early marker of early growth restriction as well as fetal skeletal dysplasia among women in the local population.