Demographic and lifestyle factors associated with dioxin-like activity (CALUX-TEQ) in human breast milk in Hong Kong

Maternal exposure to dioxins and related compounds before conception may affect the health of the fetus. To identify factors affecting dioxin body load in Hong Kong, in 2002, total dioxin-like activity was estimated in 250 individual milk samples at 2-6 weeks postpartum, from a representative group of primiparous mothers, aged 18-42 years (mean 29 +/- 5 years), by a chemically activated luciferase expression (CALUX) bioassay. Associations between the CALUX-TEQ and 20 socio-demographic and dietary variables were examined separately in mothers younger than 30 years (n = 114) and 30 years or older (n = 119), by multiple linear regression analysis. CALUX-TEQ (mean 14.5 +/- 5.8 pg/g fat) significantly increased by 0.4-0.5 pg/g fat for every year of the mother's age. Mothers born in Guangdong province of China had a significantly higher CALUX-TEQ. Higher seafood consumption (older mothers; p = 0.07) and having a female baby (younger mothers; p = 0.002) were associated with a higher maternal CALUX-TEQ level. Age was the strongest factor affecting human dioxin levels in Hong Kong. Birthplace and residence are important indicators of variations in exposure to environmental pollution in the Asia Pacific region. Temporal trends in body loads of dioxins remain to be established and continuous monitoring of dioxins in humans and foods is necessary as a precautionary approach to guide environmental control measures and prevent exposure to infants.

Non-invasive detection of significant coronary artery disease with multi-section computed tomography angiography in patients with suspected coronary artery disease

AIM

The objective of this prospective study was to compare the accuracy of multi-section computed tomography (MSCT) coronary angiography with invasive selective coronary angiography in the detection of significant coronary stenosis (> or =50% lumen diameter narrowing).

METHODS

Thirty consecutive patients (mean age 59+/-10 years) with suspected coronary artery disease underwent both invasive coronary angiography and MSCT using a 40-section multidetector row machine with temporal resolution of 53ms. Reconstruction images were performed in eight phases of the cardiac cycle. Images of MSCT and invasive coronary angiography were analysed using the 16-segment model of the American Heart Association.

RESULTS

A total of 480 segments from 30 patients were evaluated. Coronary segments distal to a vessel occlusion and segments with coronary stent were not considered for analysis (20 segments in total). Ninety-four (20.4%) segments showed significant (> or =50%) stenosis by invasive coronary angiogram. The accuracy of coronary MSCT was computed on a per segment basis. Average sensitivity, specificity, positive predictive value, and negative predictive value of MSCT were 99, 98, 94, and 99%, respectively.

CONCLUSION

This study demonstrated that MSCT is as reliable as coronary angiography at detecting significant obstructive coronary artery disease. In selected groups of patients, it may replace the more invasive and potentially more dangerous conventional coronary angiography.

Impact of occupational stress and other psychosocial factors on musculoskeletal pain among Chinese offshore oil installation workers

AIMS

To explore the relation between psychosocial factors and musculoskeletal pain in Chinese offshore oil installation workers.

METHODS

Half of all offshore workers (being a representative sample) in a Chinese oil company were invited to complete a self-administered questionnaire providing information on sociodemographic characteristics, occupational stressors, type A behaviour, social support, coping style, health related behaviour, past injuries, and musculoskeletal pain. Factor analysis was used to identify the sources of occupational stress and the domains of type A behaviour and coping style. Logistic regression analyses were used to study the relations between psychosocial factors and musculoskeletal pain in each body region.

RESULTS

The prevalence of musculoskeletal pain over the previous 12 months varied between 7.5% for elbow pain and 32% for low back pain; 56% workers had at least one complaint. Significant associations were found between various psychosocial factors and musculoskeletal pain in different body regions after adjusting for potential confounding factors. Occupational stressors, in particular stress from safety, physical environment, and ergonomics, were important predictors of musculoskeletal pain, as was coping by eating behaviour.

CONCLUSIONS

These observations supported the widely accepted biopsychosocial model of musculoskeletal disorders and suggested that in future studies of work related musculoskeletal disorders, psychosocial factors must be given due consideration.

Multi-zone modeling of probable SARS virus transmission by airflow between flats in Block E, Amoy Gardens

More than 300 residents of a private high-rise housing estate were infected with severe acute respiratory syndrome within a short period during the 2003 epidemic in Hong Kong. The outbreak occurred after the identified index patient visited a flat on a middle floor in Block E of the Amoy Gardens estate on two nights. Approximately 45% of the subsequently infected people resided in Block E, while the other 55% of infected cases mainly resided in six other blocks close to Block E. The distribution of the infected flats in Block E conformed to a non-uniform spatial pattern. Probable environmental causes for airborne transmission associated with the air movements between flats in Block E are identified. The well-established multi-zone airflow modeling method was used to analyze the virus-laden bio-aerosol dispersion between flats through door and window leakage areas in Block E under six different scenarios. The distribution of infection risk in Block E matched with the virus concentrations in flats predicted with the use of multi-zone modeling. Our study shows the importance of ventilation design in high-rise residential apartments.

PRACTICAL IMPLICATIONS

The present study on the Amoy Gardens outbreak presented a scenario in which crowded living spaces might lead to infection disasters. There is a need to improve the current sanitary drainage design and maintenance standards to avoid any leakage of foul gas into the indoor environments. Our study revealed the need for a review of indoor air quality and ventilation design in buildings including offices, homes and hotels. The study has implications to public health in, for example, the control of other airborne respiratory infectious diseases such as influenza, and in bio-terror safety in buildings.

Role of air distribution in SARS transmission during the largest nosocomial outbreak in Hong Kong

Severe acute respiratory syndrome (SARS) is primarily transmitted by bio-aerosol droplets or direct personal contacts. This paper presents a detailed study of environmental evidence of possible airborne transmission in a hospital ward during the largest nosocomial SARS outbreak in Hong Kong in March 2003. Retrospective on-site inspections and measurements of the ventilation design and air distribution system were carried out on July 17, 2003. Limited on-site measurements of bio-aerosol dispersion were also carried out on July 22. Computational fluid dynamics simulations were performed to analyze the bio-aerosol dispersion in the hospital ward. We attempted to predict the air distribution during the time of measurement in July 2003 and the time of exposure in March 2003. The predicted bio-aerosol concentration distribution in the ward seemed to agree fairly well with the spatial infection pattern of SARS cases. Possible improvement to air distribution in the hospital ward was also considered.

PRACTICAL IMPLICATIONS

Our study revealed the need for the development of improved ventilation and air-conditioning systems in an isolation ward or a general hospital ward for infectious respiratory diseases. The outbreak in Ward 8A, which was in a general hospital and could house nearly 40 patients, demonstrated the cross-infection risks of respiratory infectious diseases in hospitals if a potential highly infectious patient was not identified and isolated. Our example simulation, which extended the SARS Busters' design for an isolation room to Ward 8A, demonstrated that there was room for improvement to minimize cross-infection in large general hospital wards.

Role of air distribution in SARS transmission during the largest nosocomial outbreak in Hong Kong

Severe acute respiratory syndrome (SARS) is primarily transmitted by bio-aerosol droplets or direct personal contacts. This paper presents a detailed study of environmental evidence of possible airborne transmission in a hospital ward during the largest nosocomial SARS outbreak in Hong Kong in March 2003. Retrospective on-site inspections and measurements of the ventilation design and air distribution system were carried out on July 17, 2003. Limited on-site measurements of bio-aerosol dispersion were also carried out on July 22. Computational fluid dynamics simulations were performed to analyze the bio-aerosol dispersion in the hospital ward. We attempted to predict the air distribution during the time of measurement in July 2003 and the time of exposure in March 2003. The predicted bio-aerosol concentration distribution in the ward seemed to agree fairly well with the spatial infection pattern of SARS cases. Possible improvement to air distribution in the hospital ward was also considered.

PRACTICAL IMPLICATIONS

Our study revealed the need for the development of improved ventilation and air-conditioning systems in an isolation ward or a general hospital ward for infectious respiratory diseases. The outbreak in Ward 8A, which was in a general hospital and could house nearly 40 patients, demonstrated the cross-infection risks of respiratory infectious diseases in hospitals if a potential highly infectious patient was not identified and isolated. Our example simulation, which extended the SARS Busters' design for an isolation room to Ward 8A, demonstrated that there was room for improvement to minimize cross-infection in large general hospital wards.

Midazolam is more likely to cause hypotension than etomidate in emergency department rapid sequence intubation

OBJECTIVE

To compare the haemodynamic effect of low dose midazolam and etomidate as induction agent in emergency department rapid sequence intubation.

METHODS

A prospective observational study in two phases. In phase one, midazolam 2-4 mg was used as induction agent and in phase two, etomidate 0.2-0.3 mg/kg was used. The haemodynamic data were recorded before and after intubation for comparison. Changes in mean systolic blood pressure were analysed with SPSS software.

RESULTS

A 10% decrease in mean systolic blood pressure was observed in the midazolam group (p = 0.001) while there was no significant change in the etomidate group. Some 19.5% of patients had hypotension after being given midazolam while only 3.6% with etomidate (p = 0.002). Patients older than 70 tended to have more hypotension episodes but the difference was not statistically significant.

CONCLUSIONS

Midazolam, even in low dose, was more likely than etomidate to cause significant hypotension when used as an induction agent for rapid sequence intubation. Etomidate is a better alternative.

Household gas cooking: a risk factor for respiratory illnesses in preschool children

AIMS

To explore the association of household gas cooking and respiratory illnesses in preschool children and their relation to outdoor air pollution.

METHODS

Cross-sectional study among households that used gas stoves for cooking in two housing estates with contrasting air qualities in Hong Kong. A structured questionnaire was administered to parents of 426 children aged 0-6 years on their exposure to gas cooking and passive smoking, and the prevalence of respiratory illnesses.

RESULTS

A total of 111 children (26.1%) were reported to have one or more respiratory illnesses (allergic rhinitis, asthma, bronchitis, sinusitis, and pneumonia). Of these, 21 (18.9%), 41 (36.9%), and 49 (44.1%) children were from households that cooked once, twice, and three times a day with gas. Hierarchical logistic regression models adjusting for socioeconomic, demographic, and indoor risk factors including passive smoking showed that household gas cooking was positively associated with respiratory illnesses. There was a dose-response relation between the frequency of gas cooking and the prevalence of respiratory illnesses in the estate with lower outdoor air pollution (OR = 6.1 and 3.2 respectively, for cooking three and two meals a day, compared to one meal a day). This relation was not observed in the more polluted estate. The association between the presence of a cigarette smoker in the household and the prevalence of respiratory illnesses was not significant.

CONCLUSIONS

As gas cooking is common in urban households, the findings could have important public health implications.

Using child reported respiratory symptoms to diagnose asthma in the community

AIMS

To study how respiratory symptoms reported by children, with or without spirometry, could help to discriminate those with asthma from those without.

METHODS

Respiratory symptoms (frequent cough, frequent phlegm, and wheezing) reported by 1646 schoolchildren (aged 8-12 years) in a respiratory questionnaire and the FEV1:FVC ratio measured with spirometry (at three different cut-off values of 0.70, 0.75, and 0.80) were compared against the criterion standard of a physician diagnosis of asthma reported by the parents.

RESULTS

The overall prevalence of asthma was 6%; more boys had asthma. Wheezing had the best discriminating ability among the three symptoms and a cut-off point at 75% was best for the FEV1:FVC ratio. Combining wheezing with an FEV1:FVC ratio <75% gave the highest discriminating ability of 83%. If the tests were applied to hypothetical populations with higher prevalence ratios of asthma, the added value of the FEV1:FVC ratio became less apparent.

CONCLUSION

Respiratory symptoms, especially wheezing, reported by children had good discriminating ability for asthma and could be adopted for opportunistic screening in the primary care settings.

A survey on the involvement of accident and emergency doctors in medicolegal work in Hong Kong

This study reports the results from a questionnaire survey on the pattern of medico-legal work undertaken by doctors working in Accident & Emergency Departments (ED) and their self-evaluation of competency in forensic medicine. A total of 155 questionnaires were returned with a response rate of 46%. Only 30% (46) respondents were fellows of the Hong Kong College of Emergency Medicine but 46% (71) had more than 6 years of experience working in the ED. Most of the requests for medical report came from police and insurance companies. Fellows had more experience writing reports on homicide, sexual assault and child abuse than non-fellows did. Nearly all fellows and three quarters (74%) of non-fellows had given evidence in courts of law. Physical assault was the commonest and sexual assault the least common experience. Most respondents had experience of attending district court (83%), followed by coroner inquest (67%), magistracy (66%) and high court (45%). Respondents were asked to rate themselves on their competence in various subject areas. It can be seen that respondents were less comfortable in areas like homicide, child abuse and sexual assault. On the job coaching by a senior seems to be the major mode of training. Both fellows (61%) and non-fellows (36%) favored some form of courses with a hands-on workshop element in future.

Pertussis—a re-emerging infection?

Seven cases of pertussis in patients aged between 1 and 6 months detected over 3 months were reported. Paroxysmal cough (six cases), post-tussive vomiting (three cases) and poor feeding (three cases) were the most common presenting symptoms. Bordetella pertussis was isolated from six patients. The total leucocyte counts were mildly increased (10.8-15.6x10(9)/L). The lymphocyte counts were markly raised (59-73%) and appear to be useful indicators of pertussis. It appears that herd immunity does not offer adequate protection to the vulnerable group even in well-vaccinated populations. High vaccination coverage should be maintained, and vaccination should be given as early an age as possible. Aggressive efforts to identify cases and contacts are essential. Health care workers should have a high index of suspicion for pertussis, in particular for those with paroxysmal cough and high lymphocyte counts so as to give timely diagnosis and treatment.

Small area variations of cancer mortality in Hong Kong--the roles of health care and socio-economic status

Variations of cancer incidence and cancer mortality across small areas in Hong Kong were explored and attempt made to link them to socio-economic differences. The entire Hong Kong population during the period 1984-88 was divided into 65 small areas. The geographic distributions of incidence and mortality for ten most frequent sites of cancers (6 male and 4 female) were analyzed by separating the systematic variance from the random variance. A Poisson regression model was fitted for each cancer using the standardized incidence ratio (SIR) as a covariate for mortality. The geographic variations in SIR for the individual cancers were, in turn, analyzed similarly using a socio-economic score as the covariate. We found a statistically significant systematic variance in mortality for all six male cancers and three of the four female cancers studied. More than 50% of the systematic variance of mortality for nine cancers could be explained by the geographic variations in incidence, suggesting that other factors, like the provision and/or outcomes of health care services, played a minor role. There were statistically significant systematic variances in SIR for all male and female cancers. The socio-economic score accounted for over 50% of the systematic variance for three cancer sites. This study illustrated an approach to explore underlying explanations for the geographic variations of disease incidence and mortality. As more aggregate exposure data become available at the small area level, this type of ecological analysis would help in delineating the contributions of various factors and guide investigators in their search for the etiology background of diseases.

Agreement between hearing thresholds measured in non-soundproof work environments and a soundproof booth

AIMS

To study the agreement between audiometric test results measured in non-soundproof environments at the worksite, and in a soundproof booth.

METHODS

In a cross sectional prevalence study on noise induced hearing loss, 885 transport workers whose hearing thresholds were measured by a standard audiometric test method in non-soundproof environments at the worksite were identified to have some hearing loss (>25 dB), and were retested in a soundproof booth.

RESULTS

At 4-8 KHz, the mean of the absolute differences in hearing threshold obtained by these two methods was 2 dB or less. When the proportions of hearing loss (> or =30 dB for any frequencies at 3-8 KHz, or > or =90 dB for three low frequencies at 0.5-2 KHz, or > or =90 dB for three high frequencies at 3-6 KHz) were compared, considerable differences existed. A much better agreement was obtained when the criteria for hearing loss as measured in the field test under non-soundproof conditions were relaxed by 5 dB. At 4 KHz, the difference between the proportion of subjects with hearing loss as measured in the field and that as measured in the booth was the smallest. The kappa statistic was highest at 3 and 4 KHz.

CONCLUSIONS

Audiometric test results conducted in non-soundproof environments in the field are comparable to those obtained in a soundproof environment among transport workers with a hearing loss of >25 dB. The hearing threshold at 4 KHz appears suitable for the estimation of the prevalence of hearing loss when appropriate adjustments are made in the diagnostic criteria.

Unintentional residential child injury surveillance in Hong Kong

OBJECTIVES

To provide an overall pattern of morbidity in unintentional residential childhood injuries (URCI) in Hong Kong.

METHODOLOGY

A cross-sectional telephone survey of caregivers of children aged under 16-years and adolescents suffering from URCI and admitted to three selected local Accident and Emergency Departments.

RESULTS

Falls, cuts and scalds were the most common external causes of URCI observed, while boys predominated in the sample population. Most of the observed URCI were of moderate to mild severity. Children of new immigrant mothers were more likely to receive first aid immediately after the incidents. Parents were aware of potentially injurious behaviour and intervened on occasion, but most resorted to verbal warnings only.

CONCLUSIONS

Prevalence of falls among observed URCI offers evidence in support of the hypothesis that the high population density in Hong Kong plays an integral role in understanding mechanisms of morbidity. Parents show concern about URCI but often lack substantial action that modifies injury risk. Considering the local injury differentials, an active prevention effort such as behavioural intervention and education for parents may be useful.

Formation of alginate microspheres produced using emulsification technique

This study investigated the formative process of alginate microspheres produced using an emulsification technique. The alginate microspheres were produced by cross-linking alginate globules dispersed in a continuous organic phase using various calcium salts: calcium chloride, calcium acetate, calcium lactate and calcium gluconate. The size, shape, drug content and Ca2+ content of the microspheres were evaluated. The tack, viscosity and pH of the calcium salt solution and percentage of Ca2+ partitioned into the organic phase were determined. Microscopic examination of the test emulsion at various stages of the emulsification process was also carried out. The propensity of cross-linking reaction was found to be dependent on successful collision between alginate and calcium salt globules. Examination of the characteristics of microspheres indicated that the formed microsphere was a resultant product of alginate globule clustering. The growth propensity of microspheres was promoted by the higher rate and extent of cross-linkage which was governed by the pH, tack and/or Ca2+ content of the cross-linking solution, as well as the dissociation constant and diffusivity of the calcium salt. Overall, the amount of free Ca2+ cross-linked with alginate in the formed microspheres was in the following order: calcium acetate > calcium chloride + calcium acetate > calcium chloride + calcium gluconate; calcium chloride + calcium lactate > calcium chloride. In microencapsulation by emulsification, the mean size of the microspheres produced can be modified by varying the tack, pH and Ca2+ content of the cross-linking solution and through the use of a combination of calcium salts. The shape of the microspheres produced was, nonetheless, unaffected by the physicochemical properties of the cross-linking solution.

Is public access defibrillation needed in Hong Kong?

The survival rate for non-traumatic out-of-hospital cardiac arrest in Hong Kong is low (1.25%-1.6%). Despite the reduced time interval between call receipt and first defibrillatory shock to 11.12 minutes during the past decade, the time interval between collapse/recognition and first defibrillatory shock, at 14.25 minutes, is too long. Studies of out-of-hospital cardiac arrest performed in Hong Kong were reviewed to ascertain whether a public access defibrillation programme can improve survival in Hong Kong. Three delays were found in the traditional response by emergency medical service, namely in the collapse/recognise-to-call receipt, call receipt-to-vehicle stops, and vehicle stops-to-first defibrillatory shock time intervals. The first delay is related to public education, while the second and third delays are intrinsic to a dispatched response. A public access defibrillation programme employing responders at scenes of cardiac arrests can eliminate the collapse/recognise-to-call receipt and call receipt-to-vehicle stops time intervals before defibrillation. Possible sites of public access defibrillation could include the airport and other immigration points, which have a high volume of people passing through, with projected figures for out-of-hospital cardiac arrest at these sites supporting this consideration. For successful implementation of public access defibrillation, a comprehensive educational programme and coordination with the emergency medical service are required.

Before the paradigm shift: concepts and communication between doctors and nurses in a burns team

The evolution of care delivered by a multidisciplinary burns team is a function of the effectiveness of the professional communication between team members. In this exercise, we have explored concepts and communication between nurses and doctors in a burns team. Loosely structured weekly meetings were held over a 4-month period. The explicit objective was to determine and define the current model of burns care in a regional burn centre. The implicit objective, however, was to develop a mutual appreciation of actual and potential problems in communication. Consensus task identification was achieved at the end of each meeting with full compliance in completing the tasks before the next meeting. Although there was a unanimous commitment to the team concept, traditional, professional, paradigms persist. For nurses, the concept of holistic modelling predominated, whilst the disease centred paradigm remained the focus of medical modelling. Linguistic, cultural and professional barriers to effective communication were identified but did not readily conform to prior expectations. Experience in burns care can transcend these barriers more effectively than a common culture or profession. In conclusion, team work and team building is a complex process that can benefit from an ongoing process of re-evaluation. An obvious yet common error is to assume a level of mutual understanding that does not in fact exist. Stepping aside to re-explore fundamental principles on which team members base their personal and professional practice can help in elucidating and determining new paradigms of care, which can be evaluated and appropriately implemented. The consensus conclusion was that this approach was a very valuable investment in time in pursuing excellence in the field of burns care.

Assessing the provision of occupational health services in the construction industry in Hong Kong

A survey was conducted to review the provision of occupational health services (OHS) in the construction industry, the most hazardous industry in Hong Kong. A questionnaire was used to collect information on various aspects of OHS from a sample of construction companies. OHS provision was estimated by an overall score, with the various components weighted for their importance regarding prevention. Factors affecting the provision of services were explored by multiple linear regressions. Only 58 of the 183 establishments (32%) performed environmental assessment; 37 (20%) offered medical examinations to their workers and 70 (38%) provided health and safety talks. Scores for the provision of OHS were generally low, especially for the component of surveillance concerning workers' health. In general, larger establishment size and having safety and/or health policies were the important factors leading to high scores.

Release characteristics of pectin microspheres prepared by an emulsification technique

The potential application of pectin as a matrix polymer for making microspheres by an emulsification technique was explored, and the drug release property of these pectinate microspheres containing drug cores of varying aqueous solubilities: sulphanilamide, sulphaguanidine and sulphathiazole, was investigated using different dissolution media. The size and size distribution, specific surface area, drug content and drug release property of the pectinate microspheres were determined. The solubility and solution pH of drugs and their propensity to interact with pectin were characterized. Pectinate microspheres were successfully prepared by external gelation, using a modified emulsification technique. The kinetics of drug release from the microspheres best fitted Higuchi's model. Interestingly, the lowest percentage of drug released was produced by microspheres which were smallest in size and, therefore, largest in specific surface area, and containing sulphanilamide, the most aqueous soluble and the lowest molecular weight drug. Mathematical correlation study indicated that the drug release profile of pectinate microspheres was notably affected by the drug content and the extent of drug-pectin interaction in the microspheres. Generally, a higher percentage of drug was released from the microspheres with a higher drug content and/or lower extent of drug-pectin interaction. The extent of drug-pectin interaction was highest in microspheres containing sulphanilamide, followed by sulphaguanidine and sulphathiazole, opposite to that of drug content.

Attitude towards rape among doctors working in the emergency department

In this study, a 29-item questionnaire survey was conducted to explore the attitude and knowledge toward rape amongst doctors working in Hong Kong. The Likert scale was used for questions on attitude and knowledge. A composite score was computed for both attitude and knowledge. Comparisons of the attitude and knowledge scores were made between doctors of different genders and ranks. Existing practices in the handling of rape cases were also explored. The response rate was 58%; 175 questionnaires were completed by 147 (84%) male and 28 (16%) female doctors. There were 12 (6.3%) consultants, 44 (23%) senior medical officers and 119 (62%) medical officers. The average length of emergency department experience was 4.7 years. Most doctors held a favourable attitude towards rape victims, and there was no significant difference between senior and junior doctors (P=0.062) or between doctors of different genders (P=0.793). However, 36% of the doctors agreed that 'a women should be responsible for preventing her own rape', and more female doctors agreed that 'a woman can successfully resist rape if she tries hard enough' (P<0.042). Senior doctors had a higher knowledge score (P<0.0001). The correlation between knowledge and attitude scores was low (Spearman coefficient 0.258; P<0.05). In conclusion, doctors working in the emergency department generally held favourable attitudes towards rape victims. However, there is still room for improvements in attitude and knowledge. A one-stop service is suggested to avoid fragmentation and prevent 'revictimization'.

Associations between daily mortalities from respiratory and cardiovascular diseases and air pollution in Hong Kong, China

OBJECTIVE

To investigate the association between ambient concentrations of air pollutants and respiratory and cardiovascular mortalities in Hong Kong.

METHODS

Retrospective ecological study. A Poisson regression of concentrations of daily air pollutants on daily mortalities for respiratory and cardiovascular diseases in Hong Kong from 1995 to the end of 1998 was performed using the air pollution and health: the European approach (APHEA) protocol. The effects of time trend, seasonal variations, temperature, and humidity were adjusted. Autocorrelation and overdispersion were corrected. Daily concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), and particulate matter <10 microm in aerodynamic diameter (PM10) were averaged from eight monitoring stations in Hong Kong. Relative risks (RRs) of respiratory and cardiovascular mortalities (per 10 microg/m(3) increase in air pollutant concentration) were calculated.

RESULTS

Significant associations were found between mortalities for all respiratory diseases and ischaemic heart diseases (IHD) and the concentrations of all pollutants when analysed singly. The RRs for all respiratory mortalities (for a 10 microg/m(3) increase in the concentration of a pollutant) ranged from 1.008 (for PM10) to 1.015 (for SO2) and were higher for chronic obstructive pulmonary diseases (COPD) with all pollutants except SO2, ranging from 1.017 (for PM10) to 1.034 (for O3). RRs for IHD ranged from 1.009 (for O3) to 1.028 (for SO2). In a multipollutant model, O3 and SO2 were significantly associated with all respiratory mortalities, whereas NO2 was associated with mortality from IHD. No interactions were detected between any of the pollutants or with the winter season. A dose-response effect was evident for all air pollutants. Harvesting was not found in the short term.

CONCLUSIONS

Mortality risks were detected at current ambient concentrations of air pollutants. The associations with the particulates and some gaseous pollutants when analysed singly were consistent with many reported in temperate countries. PM10 was not associated with respiratory or cardiovascular mortalities in multipollutant analyses.

A prospective controlled clinical study of skin donor sites treated with a 1-4,2-acetamide-deoxy-B-D-glucan polymer: a preliminary report

The effect of Hyphecan (1-4,2-acetamide-deoxy-B-D-glucan) on skin donor site healing was compared with the standard skin donor site dressing Kaltostat (calcium sodium alginate) in 35 burn patients with 70 skin donor sites prospectively. The median time of wound healing for the Hyphecan group was 12 days with an average of 13.1+/-4.0 days (ranged from 9 to 28 days) while the Kaltostat group had a median healing time of 12 days (ranged from 8 to 28 days) with a mean of 13.0+/-4.1 days. The difference in healing time between these two groups was statistically insignificant with a P-value of 0.95. The infection rate was 2.9% for both Hyphecan and Kaltostat. These 35 patients had been followed up from 10 to 16 months and no difference in long-term donor site morbidity between Hyphecan and Kaltostat had been observed. This finding was encouraging because the cost of Hyphecan is less than 50% of Kaltostat and it may be worthwhile to explore the clinical application of Hyphecan in other area of burns treatment.