Wilson W.S. Tam

Air pollution and hospital admissions for respiratory and cardiovascular diseases in Hong Kong

OBJECTIVE: To investigate short term effects of concentrations of pollutants in ambient air on hospital admissions for cardiovascular and respiratory diseases in Hong Kong. METHODS: Retrospective ecological study. A Poisson regression was performed of concentrations of daily air pollutant on daily counts of emergency hospital admissions in 12 major hospitals. The effects of time trend, season, and other cyclical factors, temperature, and humidity were accounted for. Autocorrelation and overdispersion were corrected. Daily concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), and particulate matter < 10 microns in aerodynamic diameter (PM10) were obtained from seven air monitoring stations in Hong Kong in 1994 and 1995. Relative risks (RR) of respiratory and cardiovascular disease admissions (for an increase of 10 micrograms/m3 in concentration of air pollutant) were calculated. RESULTS: Significant associations were found between hospital admissions for all respiratory diseases, all cardiovascular diseases, chronic obstructive pulmonary diseases, and heart failure and the concentrations of all four pollutants. Admissions for asthma, pneumonia, and influenza were significantly associated with NO2, O3, and PM10. Relative risk (RR) for admissions for respiratory disease for the four pollutants ranged from 1.013 (for SO2) to 1.022 (for O3), and for admissions for cardiovascular disease, from 1.006 (for PM10) to 1.016 (for SO2). Those aged > or = 65 years were at higher risk. Significant positive interactions were detected between NO2, O3, and PM10, and between O3 and winter months. CONCLUSIONS: Adverse health effects are evident at current ambient concentrations of air pollutants. Further reduction in air pollution is necessary to protect the health of the community, especially that of the high risk group.

Temporal relationship between air pollutants and hospital admissions for chronic obstructive pulmonary disease in Hong Kong

Aims: To assess any relationship between the levels of ambient air pollutants and hospital admissions for chronic obstructive pulmonary disease (COPD) in Hong Kong. Methods: A retrospective ecological study was undertaken. Data of daily emergency hospital admissions to 15 major hospitals in Hong Kong for COPD and indices of air pollutants (sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), particulates with an aerodynamic diameter of <10 μm (PM10) and 2.5 μm (PM2.5)) and meteorological variables from January 2000 to December 2004 were obtained from several government departments. Analysis was performed using generalised additive models with Poisson distribution, adjusted for the effects of time trend, season, other cyclical factors, temperature and humidity. Autocorrelation and overdispersion were corrected. Results: Significant associations were found between hospital admissions for COPD with all five air pollutants. Relative risks for admission for every 10 μg/m3 increase in SO2, NO2, O3, PM10 and PM2.5 were 1.007, 1.026, 1.034, 1.024 and 1.031, respectively, at a lag day ranging from lag 0 to cumulative lag 0–5. In a multipollutant model, O3, SO2 and PM2.5 were significantly associated with increased admissions for COPD. SO2, NO2 and O3 had a greater effect on COPD admissions in the cold season (December to March) than during the warm season. Conclusion: Ambient concentrations of air pollutants have an adverse effect on hospital admissions for COPD in Hong Kong, especially during the winter season. This might be due to indoor exposure to outdoor pollution through open windows as central heating is not required in the mild winter. Measures to improve air quality are urgently needed.

Cluster of SARS among Medical Students Exposed to Single Patient, Hong Kong

We studied transmission patterns of severe acute respiratory syndrome (SARS) among medical students exposed exclusively to the first SARS patient in the Prince of Wales Hospital in Hong Kong, before his illness was recognized. We conducted a retrospective cohort study of 66 medical students who visited the index patient’s ward, including 16 students with SARS and 50 healthy students. The risk of contracting SARS was sevenfold greater among students who definitely visited the index case’s cubicle than in those who did not (10/27 [41%] versus 1/20 [5%], relative risk [RR] 7.4; 95% confidence interval [CI] 1.0 to 53.3). Illness rates increased directly with proximity of exposure to the index case. However, four of eight students who were in the same cubicle, but were not within 1 m of the index case-patient, contracted SARS. Proximity to the index case-patient was associated with transmission, which is consistent with droplet spread. Transmission through fomites or small aerosols cannot be ruled out.

Effects of air pollution on asthma hospitalization rates in different age groups in Hong Kong

Aims To assess the relationship between levels of ambient air pollutants and hospitalization rates for asthma in Hong Kong (HK).

Evaluation of a psychoeducation program for Chinese clients with schizophrenia and their family caregivers

OBJECTIVES To evaluate the effectiveness of a psychoeducation program for Chinese clients with schizophrenia and their family caregivers. METHODS A randomized controlled trial was conducted. Seventy-three clients with a diagnosis of schizophrenia and their caregivers (n=73) were recruited and randomized into a study (n=36) and control group (n=37). Ten psychoeducation sessions were provided to the study group. The outcomes were measured at the baseline, immediately after (post-1), six months (post-2), and 12 months after the intervention (post-3). RESULTS There were significant treatment effects across time for all client outcomes: adherence to medication (p<0.01), mental status (p<0.01), and insight into illness (p<0.01). However, no significant differences were found between groups at the post-3 measures for all client outcomes. For the caregivers, significant group differences were only detected in self-efficacy at the post-1 (p=0.007) and post-2 (p<0.001) measures, the level of satisfaction at the post-1 (p=0.033) and post-2 (p<0.021) measures, and the perception of family burden at the post-2 measures (p=0.043). CONCLUSION A psychoeducation intervention had positive effects on Chinese clients and their caregivers. However, these effects might not be sustained 12 months after the intervention. PRACTICE IMPLICATIONS To substantiate its effects, psychoeducation should be an ongoing intervention, with its outcomes constantly evaluated.

Effects of Coarse Particulate Matter on Emergency Hospital Admissions for Respiratory Diseases: A Time-Series Analysis in Hong Kong

Background: Many epidemiological studies have linked daily counts of hospital admissions to particulate matter (PM) with an aerodynamic diameter ≤ 10 μm (PM10) and ≤ 2.5 μm (PM2.5), but relatively few have investigated the relationship of hospital admissions with coarse PM (PMc; 2.5–10 μm aerodynamic diameter). Objectives: We conducted this study to estimate the health effects of PMc on emergency hospital admissions for respiratory diseases in Hong Kong after controlling for PM2.5 and gaseous pollutants. Methods: We conducted a time-series analysis of associations between daily emergency hospital admissions for respiratory diseases in Hong Kong from January 2000 to December 2005 and daily PM2.5 and PMc concentrations. We estimated PMc concentrations by subtracting PM2.5 from PM10 measurements. We used generalized additive models to examine the relationship between PMc (single- and multiday lagged exposures) and hospital admissions adjusted for time trends, weather conditions, influenza outbreaks, PM2.5, and gaseous pollutants (nitrogen dioxide, sulfur dioxide, and ozone). Results: A 10.9-μg/m3 (interquartile range) increase in the 4-day moving average concentration of PMc was associated with a 1.94% (95% confidence interval: 1.24%, 2.64%) increase in emergency hospital admissions for respiratory diseases that was attenuated but still significant after controlling for PM2.5. Adjusting for gaseous pollutants and altering models assumptions had little influence on PMc effect estimates. Conclusion: PMc was associated with emergency hospital admissions for respiratory diseases in Hong Kong independent of PM2.5 and gaseous pollutants. Further research is needed to evaluate health effects of different components of PMc.

The Patient Health Questionnaire-9 for measuring depressive symptoms among the general population in Hong Kong

OBJECTIVES The Patient Health Questionnaire-9 (PHQ-9) assesses depressive symptoms by self-report, is brief, and was developed to correspond to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for major depression. This article presents information regarding its reliability and validity and the distribution of scores in a Chinese community sample in Hong Kong. METHODS A total of 6028 participants 15 years or older were recruited using random household sampling. They completed the Chinese version of the PHQ-9, the Happiness Scale, the Chinese Health Questionnaire, and the Short-Form 12-Item Health Survey (SF-12). Information was also gathered on health and health service use. RESULTS Exploratory factor analysis and confirmatory factor analysis supported a single factor with strong loadings for all 9 items. Multiple-group analyses demonstrated that the structure can be generalized across sex and age groups (ie, adolescents, adults, and individuals 65 years or older). The internal consistency of the PHQ-9 was 0.82. The test-retest reliability over a 2-week interval was 0.76. As expected, the total score of the PHQ-9 was significantly associated with the Chinese Health Questionnaire (r = 0.49) and the Happiness Scale (r = -0.41). In addition, as expected, the relationship with the physical component subscale of the SF-12 was significantly weaker (r = -0.27) than for the mental component subscale of the SF-12 (r = -0.60). Participants with higher scores on the PHQ-9 were more likely to report having been diagnosed with depression by a physician, having chronic illness, using medicine, and using inpatient and outpatient health services. Almost 40% of participants did not report any depressive symptoms (score, 0). Self-reported symptoms at a level that would qualify for a diagnosis of major depressive disorder were provided by 1.7% of the participants. CONCLUSIONS Our data support the reliability and validity of the PHQ-9 in assessing depressive symptoms among the general population in Hong Kong. Its validity against diagnostic interview for major depressive disorder and its sensitivity and specificity should be determined in future studies.

The efficacy of thymosin in the treatment of chronic hepatitis B virus infection: a meta-analysis

Trials of thymosin treatment in chronic hepatitis B virus infection have been small and the results have been inconsistent.

Hypertension prevalence, awareness, treatment, control, and associated factors in adults in southern China.

BACKGROUND Hypertension is the most important risk factor for cardiovascular diseases. Little information exists on the status of hypertension among southern Chinese. We therefore investigated the hypertension prevalence, awareness, treatment, control, and associated factors in a southern Chinese population with 85 million residents. METHODS Stratified multistage cluster sampling with probability proportional to size method was used in this survey. A representative sample of 13,889 residents aged 20 years or above with completed questionnaire and blood pressure (BP) measurement was obtained. BP was measured in accordance with the 1999 World Health Organization/International Society of Hypertension Guidelines. Information related to history of diagnosis and treatment of hypertension was collected through questionnaire. RESULTS The prevalence of hypertension in this population was 20.5% (16.5%, 24.4%), which translated to 9.8 million adults suffering from hypertension in Guangdong province. The urban population had higher prevalence of hypertension than the rural population (25.1 vs. 16.1%). The prevalence of awareness, treatment, and control of hypertension in hypertensive patients living in urban regions were 42.8, 37.9, and 13.5%, respectively, which were higher than those in rural regions (the corresponding figures were 17.6, 10.4, and 3.4%, respectively). Nearly 50% urban adults and 80% rural adults did not measure their BP in the last 12 months. Frequency of BP measurement was associated with both awareness and treatment. CONCLUSIONS Hypertension was prevalent in southern China. The prevalence of awareness, treatment, and control of hypertension is low. Urgent strategies are needed to improve prevention, detection, and treatment of hypertension in this large Chinese population.

Association between Sleep Behavior and Sleep‐Related Factors among University Students in Hong Kong

Sleep problems among university students are common; however, the association between many sleep‐related factors and sleep behaviors is still unclear. The purpose of this study is to examine different sleep behaviors and sleep‐related factors influencing such behaviors in university students. A descriptive survey was conducted on 400 university students in Hong Kong. The instruments for data collection consisted of the Pittsburgh Sleep Quality Index (PSQI), a sleep hygiene practice questionnaire, demographic data, and other sleep‐related factors. The results reveal that 57.5% of the 400 university students are poor sleepers. Sex, year of study, sleep hygiene practice, and perceived adequate sleep in the past month all demonstrate significant associations with poor sleepers. A high prevalence of sleep‐related problems among college students is confirmed and associated factors are identified. Students should be encouraged to follow sleep hygiene practice, adequate time management for academic and social activities, and suitable stress‐relieving measures.