Oral exposure of male and female mice to formulations of organophosphorous pesticides: congenital malformations.

Birth outcome was studied in pre-partum litters of mice exposed to oral doses of organophosphorous pesticides at low and high concentrations before mating. Exposed and unexposed pregnant dams were delivered by Caesarean section 1 day before partum, the fetuses were collected, counted and weighed, and the numbers of resorptions were recorded. Live litter sizes were non-significantly higher in all the exposed groups compared with the control group. The numbers of resorptions were significantly higher in all the exposed groups than in the comparison groups. The incidence of intra-uterine growth retardation was significantly higher in all the exposed groups than in the comparison groups. The incidences of congenital malformations were significantly higher in the exposed groups than in one or more of the comparison groups for the defects of the ears, eyes, jaws, brain, and tongue in all the exposed groups. Low set microtia, cataract or open eyelids, microcephaly or anencephaly, maxillary or mandibular hypoplasia, and protruding tongue were observed in all groups, but the numbers were significantly higher in the exposed groups compared with one or more of the comparison groups. Curled or missing tail and intra-auricular septal or intra-ventricular septal defects were observed in higher numbers in the groups in which both the males and the females were exposed than in the comparison groups. Male:female sex ratios were significantly higher in the groups in which males only and females only were exposed.

Respiratory illnesses and ventilatory function among workers at a cement factory in a rapidly developing country.

Chronic exposure to Portland cement dust has been reported to lead to a greater prevalence of chronic respiratory symptoms and a reduction of ventilatory capacity. The seriousness of pulmonary function impairment and respiratory disease has not been consistently associated with the degree of exposure. Regular use of appropriate personal protective equipment, if available at the worksite, could protect cement workers from adverse respiratory health effects. For a variety of reasons, industrial workers in rapidly developing countries do not adequately protect themselves through personal protective equipment. This study explores the prevalence of chronic respiratory symptoms and ventilatory function among cement workers and the practice of use of personal protective equipment at work. An interviewer-administered questionnaire was used to collect information on sociodemographic characteristics, smoking profile and history of respiratory health among workers at a Portland cement plant (exposed) and workers occupationally unexposed to dust, fumes and gases (unexposed). Pulmonary function was assessed and pulmonary function impairment was calculated for the exposed and the unexposed workers. A higher percentage of the exposed workers reported recurrent and prolonged cough (30%), phlegm (25%), wheeze (8%), dyspnoea (21%), bronchitis (13%), sinusitis (27%), shortness of breath (8%) and bronchial asthma (6%). Among the unexposed, prevalences of these symptoms were 10, 5, 3, 5, 4, 11, 4 and 3%, respectively. Ventilatory function (VC, FVC, FEV(1), FEV(1)/VC, FEV(1)/FVC and PEF) was significantly lower in the exposed workers compared with unexposed workers. These differences could not be explained by age, body mass index (BMI) or pack-years smoked. Ventilatory function impairment, as measured by FEV(1)/FVC, showed that 36% of the exposed workers had some ventilatory function impairment compared with 10% of those unexposed. Certain jobs with greater exposure to cement dust had lower ventilatory function compared with others among the exposed workers. It was concluded that adverse respiratory health effects (increased frequency of respiratory symptoms and decreased ventilatory function) observed among cement workers could not be explained by age, BMI and smoking, and were probably caused by exposure to cement dust.

Dust exposure and impairment of lung function at a small iron foundry in a rapidly developing country.

OBJECTIVES: A cross sectional prospective study was carried out among iron foundry workers (exposed) and soft drink bottling and supply company workers (unexposed) to assess their occupational exposure to ambient respiratory dust in their work environment and its effect on their lung function profile. PARTICIPANTS: Lung function was measured in 81 exposed and 113 unexposed workers. Personal respirable dust concentrations were measured for all the exposed and the unexposed workers. Information on respiratory signs and symptoms was also collected from the participants. RESULTS: Among the exposed workers, midexpiratory flow (FEF25-75), forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), FEV1/FVC, and FEV1/VC ratios were significantly lower whereas the vital capacity (VC) and forced vital capacity (FVC) were non-significantly higher. Job at the iron foundry was a significant predictor of lung function. Exposure to high concentration of respirable dust at the iron foundry was also a significant predictor. Workers working in high exposure areas (general works, furnace, continuous casting areas, and fabrication workshop) had lower lung function values than workers in medium and low exposure areas. Smoking did not enhance the effects of exposure to dust on lung function. CONCLUSIONS: Exposure to respirable dust was higher among the iron foundry workers; and among these, general, furnace, rolling mill, and fabrication workers had higher exposures to dust than did workers in continuous casting, the mechanical workshop, and the bottling plant. Job type and exposure to dust were significant predictors of lung function. Implementation of industrial hygiene and proper and efficient use of personal protection equipment while at work could help to protect the respiratory health of industrial workers.

The influence of personal protection, environmental hygiene and exposure to pesticides on the health of immigrant farm workers in a desert country.

OBJECTIVES: Farm workers in developing countries tend not to use protective measures while handling pesticides. This study investigates the use of personal protection equipment and the practice of safety and hygiene procedures in the handling of pesticides in agriculture. METHODS: Through a multi-stage sampling technique, one-fifth of the farms in a region were selected and all the farm workers at these farms were included in the study. A comparison population matching in age, socio-economic status and stay in the region was selected. A specifically designed questionnaire was used to collect information on the use of protective measures and the practice of safety and hygiene during work and on the disposal of empty pesticide containers. Blood pressure and erythrocyte acetylcholinesterase (AChE) activity were measured in the exposed and the unexposed populations. RESULTS: Protective equipment was worn by a minority of farm workers - gloves, by 35%; work coveralls, by 36%; a scarf to cover the nose and mouth, by 39%; and shoes at work, by 79%. With regard to personal hygiene measures, 83% of the workers changed clothes after work and the same proportion took a shower after work; 63% and 46% drank and ate while at work respectively; and 11% used articles of domestic use in the preparation of pesticides on the farm. Most of the farm workers (96%) were asked to prepare pesticides for spraying by the foreman and 61% were asked to spray the pesticides on the crops. AChE activity was highly significantly depleted in the exposed population as compared with the unexposed population. CONCLUSIONS: AChE depletion was found to be negatively associated with the use of gloves, of work coveralls, and of a scarf to cover the nose and mouth and with the implementation of safety and hygiene procedures on the farm. AChE depletion was positively associated with the frequency of pesticide spraying.

Socioeconomic correlates of infant mortality in Hong Kong, 1979-93.

Although Hong Kong's infant mortality is among the lowest in the world, there may still be subgroups in the population with unusually high and possibly avoidable mortality rates. We conducted an ecological study on the relationship between socioeconomic deprivation and infant mortality in Hong Kong by using government data from three periods: 1979-83, 1984-88 and 1989-93. The study population comprised all infant births in 65 modified districts in Hong Kong in the period 1979-93. Infant, neonatal and post-neonatal mortality rates (IMRs, NMRs and PNMRs) were used as the health indicators. An F score was derived from highly correlated socioeconomic variables by factor analysis and used as a summary index of socioeconomic status. In 1979-83, socioeconomic deprivation was found to be significantly associated with high IMRs and high NMRs in both sexes, while in 1984-88 this association was observed only in baby girls. None of the observed associations were significant in 1989-93. Overall, the territory's infant mortality rates fell from 10.2 per thousand live births in 1979-83 to 5.6 per thousand live births in 1989-93. Individual-based studies are needed to ascertain whether this apparent disappearance of the socioeconomic relationship with infant and neonatal mortality is real.

PIP: This study determined the relationship between socioeconomic deprivation and infant mortality in Hong Kong by using government data from three periods: 1979-83; 1984-88; 1989-93. The study population comprised all infant births in 65 modified districts in Hong Kong. Infant mortality rates (IMR), neonatal mortality rates (NMR) and postneonatal mortality rates were used as the health indicators. A factor score for each modified district was calculated using factor analysis to provide a summary indicator of the socioeconomic variables. Findings demonstrated that in 1979-83 socioeconomic deprivation was significantly associated with high IMR and high NMR in both sexes, while in 1984-88 this association was observed only for baby girls. None of the observed associations were significant in 1989-93. Overall, the territory's infant mortality rates fell from 10.2/1000 live births in 1979-83 to 5.6/1000 live births in 1989-93. Further studies based on individuals are needed to confirm that the link between socioeconomic factors and infant mortality no longer exists, since a group-based study such as this is potentially vulnerable to the usual problems of confounding and ecologic fallacies.

Trends of infant mortality in Hong Kong (1956-90) and evaluation of preventable infant deaths.

OBJECTIVE: This study describes the time trends for infant mortality in Hong Kong and aims to develop statistical models that can be used to predict changes of infant mortality in places already having low levels of infant mortality. METHODOLOGY: Data on births and deaths of infants in Hong Kong during the years 1956-90 were analysed annually as well as by aggregating the data into seven consecutive quinquennia. To assess the contribution of preventable infant deaths, causes for infant deaths were classified into two broad categories: (i) congenital anomalies; and (ii) preventable diseases. A simple linear regression model was used to analyse the time trend of the mortality rate of the preventable diseases (PIMR) over the seven quinquennia. RESULTS: During the period 1956-90, the infant mortality rate fell from 60.9 in 1956-5.9 per 1000 in 1990 and the neonatal mortality rate fell from 24.2-3.8 per 1000. There was no clear time trend observed for infant mortality of congenital anomalies. However, the time trend for PIMR (log scale) was very close to a straight line and simple linear regression modelling showed a R2 of 0.9970. CONCLUSION: As the infant mortality rate (IMR) falls to below 30 per 1000, the further rate of decrease becomes less predictable from the regression model of the IMR. By removing the portion of deaths attributable to congenital anomalies, the further decrease in infant mortality became more predictable down to very low levels of IMR.

PIP: This study determines the pattern of reliability of infant mortality reports in Hong Kong. Data are obtained from annual reports of the director of Medical and Health Services during 1956-88 and the director of Health during 1989-90. Deaths were grouped in 5-year age periods during 1956-90. Infant deaths were registered according to cause based on 3 different versions of the International Classification of Disease into 4 major groups: congenital anomalies, conditions originating in the perinatal period, pneumonia, and all other causes. Preventable infant deaths were grouped into 2 categories based on Bourgeois-Pichat's classification: congenital causes and preventable ones. These 2 causes were plotted on a line chart by quinquennial period. Infant mortality rates (IMR) declined from 60.9/1000 in 1956 to 5.9/1000 in 1990. The neonatal mortality rate declined from 24.2 to 3.8/1000 in the same period. Postneonatal mortality rates declined the most from 36.7 to 2.2/1000. The 3 mortality trends were mostly linear. All 3 rates were highly correlated with each other. Major decreases occurred for pneumonia and other. The other group of infectious diseases that included tuberculosis, tetanus, gastroenteritis, and other diarrheal diseases declined the most rapidly by as much as 66 times. Mortality rates by congenital causes increased during the early period and declined slowly during the 1980s, while proportional mortality continued to increase. 84.6% of all infant deaths during 1986-90 were congenital deaths and deaths occurring in the perinatal period. The authors suggest reducing congenital deaths by imposing public health measures, raising the medical knowledge of the public, and improving the use of modern technology. Conditions originating in the perinatal period could be reduced by addressing intrauterine hypoxia, birth asphyxia, and other respiratory conditions.

Health care needs in the Tai Po district of Hong Kong initial indications from a population-based study.

The objective of this study was to obtain a representative profile of residents in Tai Po district, Hong Kong, with regard to their health status, health service use and socio- demographic characteristics. From October 1992 to February 1993, a cross-sectional telephone survey of 7573 Tai Po residents was undertaken. Acute illness episodes in the past month, chronic illness history, and treatment choices for acute and chronic illnesses were used as outcomes. Socio-demographic data were also obtained. Seventeen per cent of respondents reported having acute illness in the previous month, 66% of whom attended private clinics; 5.2% reported having chronic illness, 58.5% of whom attended public clinics. Most (88.5%) acute illness sufferers who used Western medical services for acute illness did so within Tai Po, while 52.7% of chronic illness sufferers used services outside of the district. Older, female, and lower income respondents were more likely to use public clinics. These preliminary findings help to reflect the health needs of residents in Tai Po.

Factors associated with the utilization of traditional Chinese medicine in a small town in Hong Kong.

The practice of Traditional Chinese Medicine (TCM) is largely unregulated in Hong Kong. Yet, as previous studies have shown, a sizable segment of the population consults TCM practitioners for health problems. This paper uses health care utilization data from a telephone health survey of 847 adult subjects in Tai Po District who had suffered from acute illness in the past month, to examine the profile of TCM users in the District. Women, older residents, unemployed workers, low skill laborers, current smokers and subjects dissatisfied with the quality of private sector clinics were significantly more likely to consult TCM practitioners.

Telematics in undergraduate teaching.

The use of telematics in the practice of medicine has received much recent attention but little has been written about the use of these techniques in medical education. This is a report of a pilot study in which an interactive video-conference took place between medical students at the UAE University and their opposite numbers at Aberdeen University. In Aberdeen, the Dean of the Medical Faculty simultaneously taught Aberdeen and UAE students on a clinical case. He was able to confine his activities largely to the correction of misconceptions, the emphasis of important points and the addition of missing information, while the students themselves conducted most of the presentation. The UAE students presented their Community Health projects and had a spirited discussion on them with the Aberdeen students. Recent technological advances have so improved the quality of transmission of both visual and auditory images and at reasonable cost, using the ISDN telephone system, that the feasibility of using this medium as an aid to teaching has suddenly materialized. The experiment showed that the technology was adequate for easy, fully interactive teaching among students from different continents and with different cultural backgrounds. It is particularly suitable for the Arab world where it is the custom to teach males and females separately. The pilot study has pointed out the existence of a medium of communication and teaching which, if proved to be effective, could have far-reaching consequences in the undergraduate and postgraduate teaching of medicine.

Sex ratios of births, mortality, and air pollution: can measuring the sex ratios of births help to identify health hazards from air pollution in industrial environments?

OBJECTIVES: To compare the sex ratios of births and mortality in 12 Scottish localities with residential exposure to pollution from a variety of industrial sources with those in 12 nearby and comparable localities without such exposure. METHODS: 24 localities were defined by postcode sectors. SMRs for lung cancer and for all causes of death and sex ratios of births were calculated for each locality for the years 1979-83. Log linear regression was used to assess the relation between exposure, sex ratios, and mortality. RESULTS: Mortalities from all causes were consistently and significantly higher in the residential areas exposed to air pollution than in the non-exposed areas. A similar, but less consistently significant, excess of mortality from lung cancer in the exposed areas was also found. The associations between exposure to the general air pollution and abnormal sex ratios, and between abnormal sex ratios and mortality, were negligible. CONCLUSIONS: Sex ratios were not consistently affected when the concentrations or components of the air pollution were insufficiently toxic to cause substantially increased death rates. Monitoring of the sex ratio does not provide a reliable screening measure for detecting cryptic health hazards from industrial air pollution in the general residential environment.

Ischaemic heart disease: trends in mortality in Hong Kong, 1970-89.

STUDY OBJECTIVE: To describe the time trends for ischaemic heart disease (IHD) mortality in Hong Kong between 1970 and 1989, and to examine these trends in relation to the risk factors for IHD. DESIGN: A descriptive epidemiological study of time trends using mortality and population data from the Hong Kong Census and Statistics Department. Direct standardisation using the world population was made to adjust for the changing age structure. Log-linear analyses for trends were performed for the whole period and separately for 1970-79 and 1980-89. The cohort effect was studied by regrouping the data into five year groups according to the year of birth. The influences of risk factors, including hypertension, diet, and smoking, on the time trends of IHD were explored. The role of improved hospital treatment of myocardial infarction on the trends of mortality from categories of IHD was also examined. SETTING: The total Hong Kong population, 1970-89. MAIN RESULTS: The substantial and steady decline of IHD mortality seen in most western countries in the past two decades was not observed in Hong Kong, which showed a plateau or slowly decreasing trend only in the past decade for both women and men. The decreasing trends were more apparent in the younger age groups, especially for women. Cohort analysis showed no significant cohort effect in men, but women born more recently had a lower mortality. Trends of risk factors did not show any close relationship with the mortality trends of IHD, except that a decrease in cigarette smoking might have contributed to the slight decrease in IHD mortality in recent years. Better detection and wider availability of treatment for hypertension might also have contributed to the decrease in IHD mortality. CONCLUSIONS: Hong Kong started to show a slow decline in IHD mortality during the 1980s, about one to two decades later than in other western countries and with the decreasing trend less pronounced. The reasons for this decline are not clear. More detailed information from systematic, population based surveys on life style and risk factors for IHD among the general population are needed.

Mortality mapping in Hong Kong, 1979-83 and 1984-88: feasibility study and the patterns of cancers.

To examine the practicability and value of mapping cancers in Hong Kong, selected data from consecutive censuses were used to assess the demographic stability and socioeconomic characteristics of the 27 districts. Mortality data in two quinquennia (1979-1988) were used to calculate the districts' standardized mortality ratios (SMRs) for various cancers and their ranks were presented in maps. Correlations were calculated between the SMRs for the cancers, and between the SMRs and the socioeconomic characteristics. Population sizes and socioeconomic characteristics of the districts were fairly stable in most districts. The SMRs of many cancers differed widely between districts. Affluent districts tended to have high SMRs for colorectal and breast cancers, but low SMRs for nasopharyngeal cancer (NPC) as well as liver and lung cancers. The directions of the SMR ranking correlations between the two quinquennia were generally consistent. Statistically significant correlations between some cancers were replicated, particularly for males, and between some cancers and socioeconomic characteristics.

Mortality mapping in Hong Kong, 1979-83 and 1984-88: the patterns of major non-malignant diseases.

We examined the spatial patterns of mortality from various non-malignant diseases in Hong Kong during the two quinquennia, 1979-83 and 1984-88. Population data and parameters reflecting socioeconomic factors, including ethnic backgrounds, were selected from census data. Mortality data were obtained from death registration files. The standardized mortality ratios (SMRs) for major diseases were calculated for 27 census districts. The rankings of the districts' SMRs were shown in map form. Correlations were calculated between the districts' SMRs for the diseases, between them and the SMRs for cancers, and between them and socioeconomic and ethnic parameters. Many spatial patterns and correlations showed consistency and were biologically plausible. These results showed that mapping for a rapidly growing city such as Hong Kong could be a valuable exercise for detecting "at risk" populations where causal factors for non-malignant diseases can be investigated and identified for possible elimination.

Spatial and temporal patterns of airborne metal pollution: the value of low technology sampling to an environmental epidemiology study.

To investigate an epidemic of respiratory cancer in Armadale, central Scotland, its air pollution was studied. During a period of 18 months, low technology samplers were exposed at 47 sites in the town to monitor the local variations in contamination by atmospheric metals. The samplers were two types of lichen and two types of moss, one of each type being a transplant and the other an in situ sampler. Following each exposure, the comparability of the samplers' uptake and retention of the metals was assessed. The sources of the metals and the effects of environmental variables on the pollution patterns were investigated through statistical analyses of spatial and temporal trends in the data. The spatial patterns of the metals indicated the steel foundry in the town as the major source of most of the pollutants. The temporal patterns, although less statistically significant, suggested the pollution might have been affected by some meteorological factors and by the foundry's output, but not by the output of the other main industry in the town, i.e. a brickworks. The types of sampler showed a general similarity of pollution pattern, but with some differences which indicated that some types of sampler were more suitable than others for particular forms of survey. Low technology sampling can provide information about short-distance and short-term changes in the patterns of airborne pollution by metals, thereby assisting the interpretation of epidemiological patterns of respiratory disease.

Low sex ratios of births in areas at risk from air pollution from incinerators, as shown by geographical analysis and 3-dimensional mapping.

Previous research in environmental and occupational health has suggested that fluctuations in the sex ratios of births might provide a useful early warning to the possible health effects of toxins or other stresses in the environment. To examine further this hypothesis, we investigated the sex ratios of births in an area in central Scotland which contained two incineration plants. Analyses of the sex ratios, at various levels of geographical detail and using 3-dimensional mapping techniques, in the residential areas at risk from airborne pollution from these incinerators showed locations with statistically significant excesses of female births.

PIP: Researchers calculated sex ratios of births for the 3 control areas and 4 comparison areas of Falkirk District in central Scotland based on 1975-1983 birth records to determine if abnormal sex ratios of births occurred in areas at risk from airborne pollution from 2 incinerators in the Larbert area. These incinerators had stopped operating before the study began in the early 1990s. A significant excess of female births occurred in 1 of the most at risk areas in both 1975-1979 and 1980-1983 (p.05). Further another at risk area also had excess female births, but the excess was not significant. The other at risk area had an excess of male births, again not a significant excess. Yet there were no significant differences between the total at risk areas and the comparison areas. Computer mapping analysis revealed a definite northeast-southwest axial pattern of excess female births. A possible explanation for the lack of complete uniformity in excess female births may be that the incinerators' plumes contained several pollutants and different toxins change the sex ratios in different ways. Besides wind direction, particulate size, and weather conditions influenced fall out of particulates differently. Other researchers have shown that some pollutants affect metabolism of rapidly dividing cells of gonadal and fetal tissues. For example, a study of workers' exposure to the nematocide DBCP suggested damage to the spermatozoa bearing the Y chromosome. This study's researchers have found similar associations between airborne pollution and abnormal sex ratios. If indeed airborne pollution exposure influences sex ratios, the presence of abnormal sex ratios can be used as a screening procedure to forewarn medical and environmental health authorities of health hazards.