Household cleaning products and the risk of allergic dermatitis: a prospective cohort study with primary-school children.

BACKGROUND: Household cleaning products are widely used by the public, but limited data have been obtained on whether their use induces allergic dermatitis in children. OBJECTIVE: This study investigated the association between exposure to household cleaning products and allergic dermatitis in primary-school children. METHODS: A prospective cohort study of Hong Kong primary-school children was conducted between 2012 and 2014. A baseline survey was administered to 1812 students who did not have allergic dermatitis. Information on respiratory symptoms, exposure to household chemical cleaning products and other topics was collected using a self-administered questionnaire. A cumulative chemical burden (CCB) score was calculated for each student by summing the duration of exposure to 14 chemical cleaning products. Principal component analysis was used to identify patterns in the use of these cleaning products. Logistic regression was performed to calculate relative risk (RR) with 95% confidence intervals (CIs) after adjusting for potential confounders. RESULTS: Eighty-nine (4.9%) of the students surveyed had dermatitis during the follow-up. However, exposure to individual chemical cleaning products was not found to be associated with the children's allergic dermatitis (all P > 0.05). In contrast to those in the lowest tertile, neither CCB scores in the middle tertile (RR: 1.16, 95% CI: 0.67 to 2.00) nor those in the highest tertile (RR: 1.24, 95% CI: 0.73 to 2.14) were significantly associated with the risk of allergic dermatitis. The adjusted RR for every 5-unit increment in CCB score was 1.01 (95% CI: 0.98 to 1.03). Four patterns of cleaning-product use were derived, but none were found to be associated with the risk of dermatitis (all P > 0.05). CONCLUSION: The use of household chemical cleaning products is not associated with the risk of dermatitis in primary-school children.

Effects of acrylonitrile on the pathological morphology and apoptosis of neurons in rats.

This study aimed to evaluate the effects of acrylonitrile (ACN) on neuronal morphology and apoptosis in rats. An ACN solution was administered to Wistar rats by gavage at doses of 0, 5, 10, or 20 mg/kg, 5 days a week for 13 weeks. The morphology of neurons and the presence of apoptosis was examined by light and electron microscope, DNA electrophoresis, immunohistochemistry, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. Significant vacuolation and the widening of the interspaces around blood vessels were observed in the groups that received the highest dose. Disordered myelin sheaths, malformed neuronal nuclei, and chromatin condensation at the periphery of the nucleus that formed crescents were also observed in the treated rats. The number of apoptotic neurons was significantly decreased (P < 0.05) in the treated groups (5 mg/kg group: 1.5 ± 1.22 apoptotic neurons/slide; 10 mg/kg group: 2.5 ± 1.05 apoptotic neurons/slide; 20 mg/kg group: 2.34 ± 1.21 apoptotic neurons/slide) compared to the control group (4.5 ± 1.52 apoptotic neurons/slide). The number of Bcl-2-positive neurons and the levels of staining were increased in the treated rats compared to those of the control group. These results suggested that ACN may induce serious morphological changes in rat neurons and inhibit neuronal apoptosis in rats.

Meta-analysis on night shift work and risk of metabolic syndrome.

This study aims to quantitatively summarize the association between night shift work and the risk of metabolic syndrome (MetS), with special reference to the dose-response relationship with years of night shift work. We systematically searched all observational studies published in English on PubMed and Embase from 1971 to 2013. We extracted effect measures (relative risk, RR; or odd ratio, OR) with 95% confidence interval (CI) from individual studies to generate pooled results using meta-analysis approach. Pooled RR was calculated using random- or fixed-effect model. Downs and Black scale was applied to assess the methodological quality of included studies. A total of 13 studies were included. The pooled RR for the association between 'ever exposed to night shift work' and MetS risk was 1.57 (95% CI = 1.24-1.98, pheterogeneity = 0.001), while a higher risk was indicated in workers with longer exposure to night shifts (RR = 1.77, 95% CI = 1.32-2.36, pheterogeneity = 0.936). Further stratification analysis demonstrated a higher pooled effect of 1.84 (95% CI = 1.45-2.34) for studies using the NCEP-ATPIII criteria, among female workers (RR = 1.61, 95% CI = 1.10-2.34) and the countries other than Asia (RR = 1.65, 95% CI = 1.39-1.95). Sensitivity analysis confirmed the robustness of the results. No evidence of publication bias was detected. The present meta-analysis suggested that night shift work is significantly associated with the risk of MetS, and a positive dose-response relationship with duration of exposure was indicated.

Dietary patterns and oesophageal squamous cell carcinoma: a systematic review and meta-analysis.

BACKGROUND/OBJECTIVE: Dietary patterns, which represent a complex integration of food and nutrients, have been used to explore the association between dietary factors and the risk of oesophageal cancer. However, the association remains unclear. This systematic review was performed to evaluate the relationship between dietary patterns and oesophageal squamous cell carcinoma (ESCC) by pooling available data from existing studies. METHODS: Pertinent articles published up to the end of 2013 were systematically searched and retrieved. The most common dietary patterns with high loadings of foods/nutrients were selected. Adjusted odds ratios (ORs) were derived by comparing the highest with the lowest categories of dietary pattern scores and by using a random-effect model. Heterogeneity was tested using I(2) statistic. RESULTS: From nine available case-control studies, in which smoking and other confounding factors were considered, three most common dietary patterns were selected: western pattern, healthy pattern, and drinker/alcohol pattern. Healthy pattern was significantly associated with a decreased risk of ESCC (OR=0.36, 95% confidence interval (CI): 0.23, 0.49); drinker/alcohol pattern was related to a significantly increased risk (OR=2.34, 95% CI: 1.22, 3.45), while no significant association with western pattern was observed (OR=1.29, 95% CI: 0.83, 1.75). CONCLUSIONS: Based on available studies, though limited in number, this meta-analysis suggests that some dietary patterns may be associated with the risk of ESCC.

A meta-analysis on dose-response relationship between night shift work and the risk of breast cancer.

This study aimed to conduct a systematic review to sum up evidence of the associations between different aspects of night shift work and female breast cancer using a dose-response meta-analysis approach. We systematicly searched all cohort and case-control studies published in English on MEDLINE, Embase, PSYCInfo, APC Journal Club and Global Health, from January 1971 to May 2013. We extracted effect measures (relative risk, RR; odd ratio, OR; or hazard ratio, HR) from individual studies to generate pooled results using meta-analysis approaches. A log-linear dose-response regression model was used to evaluate the relationship between various indicators of exposure to night shift work and breast cancer risk. Downs and Black scale was applied to assess the methodological quality of included studies. Ten studies were included in the meta-analysis. A pooled adjusted relative risk for the association between 'ever exposed to night shift work' and breast cancer was 1.19 [95% confidence interval (CI) 1.05-1.35]. Further meta-analyses on dose-response relationship showed that every 5-year increase of exposure to night shift work would correspondingly enhance the risk of breast cancer of the female by 3% (pooled RR = 1.03, 95% CI 1.01-1.05; Pheterogeneity < 0.001). Our meta-analysis also suggested that an increase in 500-night shifts would result in a 13% (RR = 1.13, 95% CI 1.07-1.21; Pheterogeneity = 0.06) increase in breast cancer risk. This systematic review updated the evidence that a positive dose-response relationship is likely to present for breast cancer with increasing years of employment and cumulative shifts involved in the work.

Pulmonary tuberculosis and lung cancer mortality in a historical cohort of workers with asbestosis.

OBJECTIVES: To examine pulmonary tuberculosis (PTB) infection and lung cancer mortality among workers with asbestosis in Hong Kong. STUDY DESIGN: Historical cohort study. METHODS: All 124 male incident cases of asbestosis registered at the Pneumoconiosis Clinic of the Tuberculosis and Chest Service of the Department of Health between 1981 and 2008 were recruited and followed-up until 2008 to ascertain vital status and underlying causes of death. Standardized mortality ratios (SMRs) were calculated using the person-year method. Axelson's indirect method was used to adjust for the potential confounding effect of cigarette smoking. RESULTS: Forty-five patients (36.29%) had a history of PTB at the time of asbestosis diagnosis. The SMR of lung cancer was 5.22 [95% confidence interval (CI) 1.08-15.25] for subjects with a history of PTB, and this was reduced to 2.35 (95% CI 0.49-6.85) after indirect adjustment for smoking. Among asbestosis workers without a history of PTB, the SMR after indirect adjustment for smoking was 4.25 (95% CI 1.55-9.25) and 5.92 (95% CI 1.92-13.79) for those with comorbidities and those without comorbidities, respectively. Compared with other workers, those with a history of PTB had the highest all-cause SMR (6.73, 95% CI 4.55-9.63) and very high mortality due to heart diseases. CONCLUSIONS: This historical cohort study revealed that the prevalence of PTB infection was high among workers with asbestosis in Hong Kong. An excess risk of lung cancer mortality was observed among workers with a history of PTB, but the risk was lower than that seen among workers without a history of PTB. These interesting findings need to be confirmed by future studies.

Incidence of ischaemic and haemorrhagic stroke and the association with smoking and smoking cessation: a 10-year multicentre prospective study in China.

OBJECTIVES: To examine the effects of cigarette smoking and smoking cessation on the incidence of ischaemic and haemorrhagic stroke in a multicentre prospective cohort study among Chinese. STUDY DESIGN: A multicentre population-based prospective cohort study. METHODS: The incidence of, and deaths from, stroke were monitored among 26,607 participants (12,560 men and 14,047 women) who were enrolled in 1986 and free from stroke until 2000. Cox's proportional hazard model was performed to obtain the hazard ratio (HR) of cigarette smoking for stroke risk after adjustment for major confounders. RESULTS: After an average of 9.5 years of follow-up, 1108 subjects developed stroke. The excess risk of all types of stroke (total stroke) among male current smokers [HR 1.39, 95% confidence interval (CI) 1.15-1.67] was mainly due to a significantly elevated risk of ischaemic stroke (HR 1.49, 95% CI 1.17-1.90). A significantly increased risk for total stroke and ischaemic stroke was observed among men who smoked >15 cigarettes/day and men who had smoked for >25 years. The rate of smoking cessation was very low among Chinese men (7.2%) and women (1.5%). Smoking cessation did not appear to reduce the risk of haemorrhagic stroke, but may reduce the risk of ischaemic stroke; however, the possibility that this result was due to chance cannot be excluded (HR 0.74, 95% CI 0.26-2.08). CONCLUSION: This study confirmed that cigarette smoking is a major determinant for the incidence of ischaemic and haemorrhagic stroke in Chinese men, and emphasizes the need for improved strategies to help people quit smoking.

Cancer mortality among Chinese chrysotile asbestos textile workers.

To determine mortality associated with exposure to chrysotile asbestos, a cohort of asbestos workers from an asbestos textile factory in China was followed prospectively from 1972 to 2008. A total 577 workers were successfully followed, achieving a follow-up rate of 98.5% over 37 years. Employment data and smoking information were obtained from factory and individual workers. Vital status was ascertained from factory personnel records and the municipal death registry. Workers were categorized into high, medium and low exposure groups in terms of their job titles and workshops. Follow-up generated 17,508 person-years, with 259 deaths from all causes, 96 all cancers and 53 lung cancers and 2 mesotheliomas. The highest cancer mortality was observed in the high exposure group, with 1.5-fold age-adjusted mortality from all cancers and 2-fold from lung cancer compared to the low exposure group. Age and smoking adjusted hazard ratio in the high exposure group was 2.99 (95%CI, 1.30, 6.91) for lung cancer and 2.04 (1.12, 3.71) for all cancers. Both smokers and nonsmokers at the high exposure level had a high death risk of lung cancer, with a clearer exposure-response trend seen in smokers. This study confirmed increased mortality from lung cancer and all cancers in asbestos workers, and the cancer mortality was associated with exposure level.

The roles of smoking and cooking emissions in lung cancer risk among Chinese women in Hong Kong.

BACKGROUND: We conducted this case-control study to evaluate smoking effect on lung cancer conditional on the level of exposure to cooking emissions and to explore whether there is a joint effect of these two risk factors. SUBJECTS AND METHODS: We selected 279 newly diagnosed primary lung cancer cases and 322 community controls from Hong Kong females, frequency matched by age group, and collected relevant data. We applied logistic regression to estimate lung cancer risk related to smoking and cooking fume exposure, expressed as total cooking dish-years, while adjusting for various potential confounding factors. RESULTS: Current smoking was associated with four-fold increased risk, and ex-smoking with two-fold risk, which was not much influenced by cooking dish-years. No increased risk was observed in environmental tobacco smoking. Increasing intakes of yellow/orange vegetables and multivitamins were significant protective factors in all models. In the analysis of joint effect, the combination of smoking and cooking dish-years tended to have a greater risk than exposure to cooking fumes alone. There was a dose-response gradient with total dish-years in nonsmokers, but not in smokers. Smoking was more strongly associated with nonadenocarcinoma, whereas exposure to cooking fumes appeared to be related to both adenocarcinoma and nonadenocarcinoma. CONCLUSION: We confirmed the important roles of smoking and cooking emissions in lung cancer risk among the women. These two major risk factors appeared to act independently.

Lung cancer mortality among silicotic workers in Hong Kong--no evidence for a link.

BACKGROUND: The link between silica dust/silicosis and lung cancer is still very controversial. We examined the relationship between silica dust exposure and/or silicosis and lung cancer in a large cohort of silicotic workers in Hong Kong. PATIENTS AND METHODS: All workers with silicosis in Hong Kong diagnosed during the period 1981-1998 were followed up till the end of 1999 to ascertain their vital status and causes of death. Standardized mortality ratio (SMR) for lung cancer and other major causes of death were calculated. Axelson's indirect method was used to adjust for smoking effect. Multiple Cox regression models were carried out to examine the exposure-response relationship between silica dust and lung cancer. RESULTS: About 10% (86) of all 853 deaths were from lung cancer, giving a SMR of 1.69 [95% confidence interval (CI) 1.35-2.09]. Lung cancer SMR for caisson and surface construction workers were 2.39 (95% CI 1.50-3.62) and 1.61 (95% CI 1.21-2.10), respectively, which became 1.56 (95% CI 0.98-2.36) and 1.09 (95% CI 0.82-1.42) after adjusting for smoking. No consistent exposure-response relationship was detected between silica dust or severity of silicosis and lung cancer death. CONCLUSION: Our cohort study did not offer positive support to a link between silica or silicosis and lung cancer.

Transient risk factors for acute traumatic hand injuries: a case-crossover study in Hong Kong.

OBJECTIVES: To identify the remediable transient risk factors of occupational hand injuries in Hong Kong in order to guide the development of prevention strategies. METHODS: The case-crossover study design was adopted. Study subjects were workers with acute hand injuries presenting to the government Occupational Medicine Unit for compensation claims within 90 days from the date of injury. Detailed information on exposures to specific transient factors during the 60 minutes prior to the occurrence of the injury, during the same time interval on the day prior to the injury, as well as the usual exposure during the past work-month was obtained through telephone interviews. Both matched-pair interval approach and usual frequency approach were adopted to assess the associations between transient exposures in the workplace and the short-term risk of sustaining a hand injury. RESULTS: A total of 196 injured workers were interviewed. The results of the matched-pair interval analysis matched well with the results obtained using the usual frequency analysis. Seven significant transient risk factors were identified: using malfunctioning equipment/materials, using a different work method, performing an unusual work task, working overtime, feeling ill, being distracted and rushing, with odds ratios ranging from 10.5 to 26.0 in the matched-pair interval analysis and relative risks ranging between 8.0 and 28.3 with the usual frequency analysis. Wearing gloves was found to have an insignificant protective effect on the occurrence of hand injury in both analyses. CONCLUSIONS: Using the case-crossover study design for acute occupational hand injuries, seven transient risk factors that were mostly modifiable were identified. It is suggested that workers and their employers should increase their awareness of these risk factors, and efforts should be made to avoid exposures to these factors by means of engineering and administrative controls supplemented by safety education and training.

Mortality from non-malignant respiratory diseases among people with silicosis in Hong Kong: exposure-response analyses for exposure to silica dust.

OBJECTIVES: To examine the exposure-response relationships between various indices of exposure to silica dust and the mortality from non-malignant respiratory diseases (NMRDs) or chronic obstructive pulmonary diseases (COPDs) among a cohort of workers with silicosis in Hong Kong. METHODS: The concentrations of respirable silica dust were assigned to each industry and job task according to historical industrial hygiene measurements documented previously in Hong Kong. Exposure indices included cumulative dust exposure (CDE) and mean dust concentration (MDC). Penalised smoothing spline models were used as a preliminary step to detect outliers and guide further analyses. Multiple Cox's proportional hazard models were used to estimate the dust effects on the risk of mortality from NMRDs or COPDs after truncating the highest exposures. RESULTS: 371 of the 853 (43.49%) deaths occurring among 2789 workers with silicosis during 1981-99 were from NMRDs, and 101 (27.22%) NMRDs were COPDs. Multiple Cox's proportional hazard models showed that CDE (p = 0.009) and MDC (p<0.001) were significantly associated only with NMRD mortality. Subgroup analysis showed that deaths from NMRDs (p<0.01) and COPDs (p<0.05) were significantly associated with both CDE and MDC among underground caisson workers and among those ever employed in other occupations with high exposure to silica dust. No exposure-response relationship was observed for surface construction workers with low exposures. A clear upward trend for both NMRDs and COPDs mortality was found with increasing severity of radiological silicosis. CONCLUSION: This study documented an exposure-response relationship between exposure to silica dust and the risk of death from NMRDs or COPDs among workers with silicosis, except for surface construction workers with low exposures. The risk of mortality from NMRDs increased significantly with the progression of International Labor Organization categories, independent of dust effects.

Incidence rate trends of histological subtypes of nasopharyngeal carcinoma in Hong Kong.

The overall decline in incidence rate of nasopharyngeal carcinoma in Hong Kong during 1988-2002 was limited primarily to a decrease in keratinising carcinoma, which could be explained by the decline in cigarette smoking. Genetic and Epstein-Barr virus interactions may explain the relatively stable incidence rate of non-keratinising carcinoma.

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.

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

UNLABELLED: 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.

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

UNLABELLED: 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.

A registry of tuberculous meningitis in Hong Kong.

BACKGROUND: A prospective observational study of the presentation, diagnosis, treatment and outcome of tuberculous meningitis (TBM). METHODS: Demographic characteristics, clinical information, treatment and progress of TBM patients were followed. Their outcomes were ascertained every 6 months for 3 years after diagnosis. Prognostic factors associated with death or full recovery were examined using multivariate Cox's and logistic regression models, respectively. RESULTS: Between 1993 and 2000, 166 TBM patients were recruited. Their mean age was 42.9, 153 were Chinese and 81 were males; 92% received HRZS (H = isoniazid; R = rifampicin; Z = pyrazinamide; S = streptomycin), HRZE (E = ethambutol) or HRZES. Steroids were given to 105 patients, with no significant effect on outcome. After 3 years of follow-up, 110 patients had completely recovered, 20 survived with disability and 26 died. Death was significantly associated with older age, lower cerebrospinal fluid (CSF) lymphocyte and poorer consciousness levels at the time of presentation, while full recovery was associated with younger age, being female and absence of complications. CONCLUSIONS: Relatively good outcomes of TBM cases were documented in this Hong Kong study with a case-fatality ratio of 15.7% (26/166) up to 3 years. Early recognition, diagnosis and administration of effective treatment regimens were probably the most important factors in reducing mortality and morbidity.