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O L Lloyd

Publications and source records attributed to O L Lloyd.

At least 37 records · Page 2Linked to original sources
PubMed1992

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.

Air Pollution↗
PubMed1991

Toxicity from ragwort and fat cow syndrome, or from industrial chemicals: the value of epidemiological analysis for interpreting clinico-pathological findings.

When livestock in close proximity to industries develop signs of ill-defined disease, toxic effects from industrial pollution should be considered in the differential diagnosis. In establishing the final diagnosis, epidemiological methods should be applied to supplement the clinical and pathological techniques. This viewpoint is illustrated by two case-histories describing episodes of cattle disease in central Scotland. A long-established and successful dairy herd in central Scotland sustained severe morbidity and mortality amongst animals which had grazed on a field beside a recently established dump which contained wastes from a chemical waste incinerator. An official investigation concluded that the episode of disease was the result of ragwort poisoning; this diagnosis was reached on clinical and pathological grounds only. A similarly unexpected and severe epidemic occurred a few years later in another dairy herd, about 1 km further away from that incinerator (which was also within 100 m of a municipal incinerator). The official investigation, which again focused on clinical and pathological criteria, led to the diagnosis of fat cow syndrome. In the first episode, contaminated water drained from the chemical waste dump on to the cows' field; in the second episode, the relevant field was affected by airborne pollution from the two waste incinerators mentioned earlier. In both episodes, the epidemiological features, which were not examined systematically by the original investigators, were consistent with the hypothesis that these episodes resulted from exposures to toxic contaminants.

Animals↗
PubMed1991

The geography of the community sex ratios for young children in Newfoundland.

Abnormalities of the sex ratio of births may be linked with environmental factors, including diet and pollutants in the general or occupational environments, which in turn can cause ill-health. To examine this relationship in the Province of Newfoundland and Labrador, where a geographical imbalance of mortality has already been identified, we examined the geographical distribution of sex ratios (boys/girls x 100) of young children (0-4 years) in the communities of the Province during recent years. The individual communities of the 1976 and 1981 censuses were assigned to contiguous regions and their component districts. The numbers in the appropriate age-groups in the communities in these two census years were used to calculate a mean sex ratio for each community; each community was allocated, according to the value of its ratio, to one of four predefined categories of ratio. From the numbers of communities belonging to these various categories of sex ratio in the regions and districts, the community sex ratios of these areas (i.e. regions and districts) were derived. As a preliminary assessment of the relationship between sex ratios and mortality, a small group of communities with the highest sex ratios was selected, and the mean standardized mortality ratios (SMRs) for all deaths in those communities were calculated. The community sex ratios of regions and districts declined from east to west. The difference in the ratios between the Avalon region (in the most easterly part of the Province) and the southwest region was statistically significant. Districts with high ratios were frequent, particularly those on the Avalon peninsula in the south-east of the island, whereas low ratios were more frequent on the south-west coast of the island, and a low ratio was also found for the only inland district. Of the communities with statistically reliable numbers, the township of Makkovik in Labrador had the highest sex ratio (100 x 50/25 = 200). The SMR of that community during 1976-82 was statistically elevated at 218. In the small group of communities studied, however, high sex ratios from census data for individual communities were not reliable predictors of high SMRs. Further work is required to clarify the inter-relationships between the sex ratios of the census data, the sex ratios of births, the mortality rates and environmental factors.

Child, Preschool↗
PubMed1991

Deaths from road traffic accidents in Scotland: 1979-1988. Does it matter where you live?

The purpose of this study was to calculate and compare the geographical distributions of male and female deaths from road traffic accidents in Scotland. A retrospective, nationwide study of deaths from road traffic accidents was undertaken; all road traffic deaths between 1979 and 1988 were included. Deaths were abstracted from the Annual Reports of the Registrar General for Scotland. Standardized mortality ratios (SMRs) for males and for females were calculated for 1979-83 and 1984-88. Maps showing the distributions of high SMRs (SMR greater than 135 or P less than 0.05) and low SMRs (SMR less than 65 or P less than 0.05) were prepared for males and females separately. The geographical distributions of deaths from road traffic accidents in Scotland were dissimilar to those of England and Wales. For both sexes, high mortality was predominantly in the sparsely populated regions of the north and south of Scotland; whereas low mortality was found in the cities and the populous central belt. Possible reasons for this pattern are discussed: speed, response time (both of notification of the accident and of arrival of the ambulance), distance to nearest hospital with suitable emergency facilities, and road conditions.

Accidents, Traffic↗
PubMed1990

Mortality at early ages in Scottish communities, 1959-83: geographical distributions and associations with selected socioeconomic indices.

Mortality at early ages has long been known to reflect the general health of communities, and derived epidemiological parameters have been used to indicate those communities to which policies of environmental improvement and health promotion should be directed. The geographical distributions of stillbirths, and perinatal, neonatal, post-neonatal and infant mortalities in Scottish communities were analysed for the years 1959-63, 1969-73 and 1979-83. For all categories of mortality, urban-rural gradients were present in the earlier periods, but had disappeared by 1979-83. Several communities were identified which had high rates for at least two categories of mortality, and which may benefit, therefore, from intervention programmes. For 1979-83 only, bivariate correlation coefficients were calculated between the five categories of mortality and four socio-economic variables: social class, overcrowding (over 1.5 persons per room and persons per hectare), single parent households and housing tenure. For stillbirths and perinatal mortality, significant correlations were found with persons per room, housing tenure and social class. Neonatal and postneonatal mortalities were significantly correlated with council house tenure and persons per hectare respectively, whereas infant mortality was not significantly correlated with any variable. Multiple regression, using the five categories of mortality as dependent variables and social class, persons per room, persons per hectare, housing tenure and single parent families as the independent variables, showed that these socioeconomic characteristics explained between 10-32% of the variation in mortality.

Fetal Death↗
PubMed1990

Gastric and colorectal cancers in Scotland: a study of the geographical distributions and selected associations.

The geographical distributions of gastric and colorectal cancers in Scotland were investigated by analysing the data available for those diseases in the Annual Reports of the Registrar General for Scotland. For gastric cancer, the standardised mortality ratios (SMRs) for the 234 traditional communities in 1969-73 and for the 56 districts in 1979-83 were calculated. For colorectal cancer, only the data for the latter period were available, and SMRs for that period were calculated similarly. Possible determinants on the resulting pattern of high and low SMRs were investigated. Gastric cancer was generally associated with industrial and urban environments, particularly in west central Scotland, although mortality in Dundee was high in both periods; this cancer also showed significant negative correlations with social class II. By contrast, colorectal cancer showed no strong geographical pattern, no urban-rural gradient, and no social class associations. The cancers showed a weak association with each other.

Colonic Neoplasms↗
PubMed1989

Associations between data for male lung cancer and female breast cancer within five countries.

Mainly on the basis of associations noted between international rates of male lung cancer and female breast cancer, passive smoking has been suggested recently as a major risk factor for female breast cancer. In this report, the authors describe the associations between data for female breast cancer and male lung cancer within five countries. For one country (Scotland) the authors examined the mortality rates of these cancers over time, and their relationship to trends for tobacco consumption. The correlations between female breast cancer and male lung cancer were significantly positive in Italy, USSR, and West Germany, weakly positive in Canada, absent in Scotland, and significantly negative in England and Wales. In Scotland, the mortality rates of these cancers over time were significantly correlated. There was a clear relationship between male lung cancer and tobacco consumption, but only a weak relationship between female breast cancer and tobacco consumption.

Breast Neoplasms↗
PubMed1989

Cerebrovascular disease in Scotland during 1959 to 1983: its geographical distribution and associations.

A study of the geographical distribution of cerebrovascular disease in Scottish communities during three quinquennia between 1959 and 1983 showed a marked tendency for high SMRs to be present in the west of Scotland and low SMRs in the east. Cerebrovascular disease was significantly correlated with coronary heart disease, with bronchitis, emphysema and asthma, and to a lesser extent with other heart disease, with other circulatory disease and with indices of overcrowding. It was not associated with either urbanization or industrialization.

Cardiovascular Diseases↗
PubMed1988

Healthy cities.

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Health↗
PubMed1988

Twinning in human populations and in cattle exposed to air pollution from incinerators.

Human populations and animals are often exposed to the airborne pollutants in plumes from incinerators. The incineration of chemical and other waste may release polychlorinated hydrocarbons, some of which have oestrogenic properties. Increased numbers of twins had been reported anecdotally in cattle at risk from plumes from two incinerators near the town of Bonnybridge in central Scotland and also in cattle near a chemical factory in Eire. It was decided to follow up these reports in central Scotland and also to test the hypothesis that the frequency of human twinning might be increased there. Data on human twin and single births in hospitals in central Scotland were obtained for the years 1975-83. The twinning rates in areas exposed to airborne pollution from incinerators were compared with the background rates present in neighbouring areas. Farmers provided information on calving among the herds of two farms close to the incinerators. The frequency of human twinning was increased, particularly after 1979, in the areas most at risk from air pollution from the incinerators. Among the dairy cattle, there was a dramatic increase in twinning at about the same time.

Air Pollution↗
PubMed1987

Respiratory cancer and air pollution from iron foundries in a Scottish town: an epidemiological and environmental study.

A geographical association between respiratory cancer and air pollution from steel foundries has been shown previously in Scotland and elsewhere. In the present study the iron-founding town of Kirkintilloch was found to have standardised mortality ratios (SMRs) for respiratory cancer in 1959-63, 1964-8, and 1969-73 that were unexceptional in comparison with Scotland. Nevertheless, when SMRs were calculated for respiratory cancer for the period 1966-76 in five zones of the town arranged, a priori, according to probable exposure to fumes from two iron foundries, and in the individual enumeration districts of the 1971 census, higher SMRs were found in the residential areas most exposed to pollution from the foundries. The gradient of the zones' SMRs--high close to the foundries to low at some distance from them--persisted despite standardisation of the SMRs for social class. A survey of the concentrations of several metals in soil cores sampled at 51 sites throughout the town showed a pattern of pollution that probably illustrated the effects of prevailing winds and topography on the pollution plumes from the foundries. The value of sampling soil cores in investigations where historical sources of metallic air pollution are of epidemiological interest was emphasised by the detection of high concentrations of Ni in an area where a nickel refinery had been located many decades previously.

Aged↗
PubMed1987

Techniques of low technology sampling of air pollution by metals: a comparison of concentrations and map patterns.

During a 17 month survey of air pollution in the town of Armadale, central Scotland, the concentrations of some metals (iron, manganese, zinc, lead, copper, chrome, nickel, cadmium, and cobalt) were measured in seven types of low technology sampler--four indigenous and three transplanted--at 47 sites. The geographical patterns of the concentrations in the samplers were compared on two types of map. For most metals, sites with high concentrations were present close to the foundry and also in the north of the town. The differences between the patterns of pollution shown by the various types of sampler probably reflected differing mechanisms for collection and different affinities for various sizes and types of metal particle.

Air Pollutants↗