Areas Of High Mortality Research Articles

Assessing the causes of under-five mortality in the Albert Schweitzer Hospital service area of rural Haiti

Limited information is available regarding the causes of under-five mortality in nearly all of the countries in which mortality is the highest. The purpose of this study was to use a standard computerized protocol for defining the leading causes of death among children in a high-mortality rural population of Haiti and to highlight the need for similar studies else-where in Haiti and throughout the high-mortality areas of Latin America and the Caribbean. In 2001 a standardized, closed-ended verbal autopsy questionnaire endorsed by the World Health Organization was administered to a representative, population-based sample of the mothers or other caregivers of 97 children who had died before reaching 5 years of age between 1995 and 1999 in the service area of the Albert Schweitzer Hospital, which is located in the rural Artibonite Valley of Haiti. With the data from the questionnaires we used a computerized algorithm to generate diagnoses of the cause of death; the algorithm made it possible to have more than one cause of death. Acute lower respiratory infection (ALRI) was the leading diagnosis, present in 45% of all under-five deaths, followed by enteric diseases, present in 21% of deaths. Neonatal tetanus, preterm birth, and other early neonatal causes unassociated with ALRI or diarrhea were present in 41% of the neonatal deaths. Among children 1-59 months of age, ALRI was present in 51% of the deaths, and enteric diseases in 30%. Deaths were concentrated during the first few months of life, with 35% occurring during the first month. Among the neonatal deaths, 27% occurred on the first day of life, and 80% occurred during the first 10 days of life. In the Albert Schweitzer Hospital program area--and presumably in other areas of Haiti as well--priority needs to be given to the prevention of and the early, effective treatment of ALRI, diarrhea, and early neonatal conditions. This study points to the need for more, similar standardized assessments to guide local, regional, and national programs.

Hepatitis B Vaccination Associated With Higher Female Than Male Mortality in Guinea-Bissau

Objective: Studies from high mortality areas have suggested that diphtheria-tetanus-pertussis may be associated with an increase in the mortality of girls relative to boys. We therefore examined whether hepatitis B vaccine (HBV) was associated with sex-specific differences in mortality. Design: As part of a randomized trial of measles vaccine, a subcohort of 876 children was offered HBV at 7½, 9 and 10½ months of age. We examined whether this cohort differed in mortality rate and female-male mortality ratio compared with previous and subsequent birth cohort enrolled in the same trial. Setting: Four districts in Bissau, the capital of Guinea-Bissau. Subjects: Six annual birth cohorts of 8906 children registered in the study area and followed from 1½ to 12 months of age between March 1995 and February 2001. Of these children, 6399 took part in a 2-dose measles vaccination trial; of those born between March 1996 and February 1997, 876 received HBV. Main Outcome Measures: (1) The mortality rate ratio (MR) between 7½ and 12 months and 1½ and 7½ months old children; (2) the female-male MR among trial children having received HBV plus measles vaccine or only measles vaccine. Results: In cohorts not receiving HBV, the MR for children 7½–12 and 1½-7½ months of age was 0.97 “95% confidence interval (95% CI), 0.79–1.24”, whereas the MR was 1.62 (95% CI 1.09–2.41) in the cohort receiving HBV at 7½ months (test of homogeneity, P = 0.030). Among children enrolled in the measles vaccination trial, HBV-vaccinated children 7½–12 months of age had higher mortality than both prior and subsequent cohorts who had not received HBV (MR = 1.81; 95% CI 1.19–2.75), the difference being particularly strong for girls (MR=2.27; 95% CI 1.31–3.94). In the cohort who had received both HBV and measles vaccine, the female-male MR between 9 and 24 months of age was 2.20 (95% CI 1.07–4.54) compared with 0.96 (95% CI 0.70–1.32) in trial participants who had received measles vaccine only (test for homogeneity, P = 0.040). With longer follow-up, these tendencies remained the same. Conclusions: These comparisons suggested changes in the mortality pattern after the introduction of HBV, particularly for girls. Hence in areas with high mortality, HBV may affect girls’ and boys’ susceptibility to infections differently.

Benefits of routine immunizations on childhood survival in Tari, Southern Highlands Province, Papua New Guinea

Non-specific beneficial as well as deleterious effects of childhood immunizations have been reported in areas of high mortality. This study aimed to determine the effects of diphtheria-tetanus-whole-cell-pertussis (DTP), BCG, hepatitis B, and measles vaccines on mortality in the highlands of Papua New Guinea (PNG). Demographic events for children born in 1989-1994 who were under monthly demographic surveillance in Tari were recorded from birth until age 2 years, out-migration, death, or the end of the study period. Data on BCG, hepatitis B, DTP, measles and pneumococcal polysaccharide vaccination were collected monthly from clinic records. To allow for different characteristics of immunized and non-immunized children, analysis included conditioning on a propensity score for vaccination, adjusting for differences in children's background characteristics. In all, 101/3502 children (3%) who had at least one vaccine died between ages 29 days and 24 months were compared to 112/546 (21%) who had none. BCG was associated with lower mortality in the 1-5 month age group (hazard ratio [HR] = 0.17, 95% CI: 0.09, 0.34), measles vaccine with lower mortality at age 6-11 months (HR = 0.42, 95% CI: 0.17, 1.01), and pneumococcal polysaccharide vaccine with lower mortality at age 12-23 months (HR = 0.42, 95% CI: 0.19, 0.93). One or more doses of DTP was associated with lower overall mortality (HR = 0.27, 95% CI: 0.16, 0.44), particularly in the 1-5 month age group (HR = 0.19, 95% CI: 0.10, 0.34), and also in those who had had prior BCG (HR = 0.45, 95% CI: 0.22, 0.91). Routine immunizations are effective in reducing overall mortality in young children in an area of high mortality. In particular, DTP, whether considered separately or in addition to BCG, was associated with a lowering of overall mortality, in contrast to findings reported from Guinea-Bissau.

The introduction of diphtheria-tetanus-pertussis vaccine and child mortality in rural Guinea-Bissau: an observational study.

and objective Previous studies from areas with high mortality in West Africa have not found diphtheria-tetanus-pertussis (DTP) vaccine to be associated with the expected reduction in mortality, a few studies suggesting increased mortality. We therefore examined mortality when DTP was first introduced in rural areas of Guinea-Bissau in 1984-1987. Setting Twenty villages in four regions have been followed with bi-annual examinations since 1979. In all, 1657 children aged 2-8 months. Design Children were weighed when attending the bi-annual examinations and they were vaccinated whenever vaccines were available. DTP was introduced in the beginning of 1984, oral polio vaccine later that year. We examined mortality for children aged 2-8 months who had received DTP and compared them with children who had not been vaccinated because they were absent, vaccines were not available, or they were sick. Mortality over the next 6 months from the day of examination for vaccinated and unvaccinated children. Prior to the introduction of vaccines, children who were absent at a village examination had the same mortality as children who were present. During 1984-1987, children receiving DTP at 2-8 months of age had higher mortality over the next 6 months, the mortality rate ratio (MR) being 1.92 (95% CI: 1.04, 3.52) compared with DTP-unvaccinated children, adjusting for age, sex, season, period, BCG, and region. The MR was 1.81 (95% CI: 0.95, 3.45) for the first dose of DTP and 4.36 (95% CI: 1.28, 14.9) for the second and third dose. BCG was associated with slightly lower mortality (MR = 0.63, 95% CI: 0.30, 1.33), the MR for DTP and BCG being significantly inversed. Following subsequent visits and further vaccinations with DTP and measles vaccine, there was no difference in vaccination coverage and subsequent mortality between the DTP-vaccinated group and the initially DTP-unvaccinated group (MR = 1.06, 95% CI: 0.78, 1.44). In low-income countries with high mortality, DTP as the last vaccine received may be associated with slightly increased mortality. Since the pattern was inversed for BCG, the effect is unlikely to be due to higher-risk children having received vaccination. The role of DTP in high mortality areas needs to be clarified.

The recent decline in gallbladder cancer mortality in Europe.

Mortality from gallbladder cancer has been traditionally high in Eastern Europe, and lower in northern countries. Trends in 18 European countries, including the European Union (EU) and selected Eastern European countries, have been updated using official death certification data abstracted from the WHO database over the period 1980-1999. In the EU, age-standardized rates declined by about 30% between the late 1980s and 1999 to reach 1.8/100 000 for women, and by about 10% to reach 1.4/100 000 for men. In the Czech Republic and Hungary, rates for women were over 6/100 000 until the early 1990s, and declined by about 25% thereafter. For males, gallbladder cancer mortality showed no consistent trend, with rates over 3/100 000. Thus, a high mortality area from gallbladder cancer is still evident for both sexes in Central and Eastern Europe. The trends in mortality from gallbladder cancer are probably influenced by changes in risk factor exposure, such as diet, nutrition or tobacco, but essentially reflect more widespread and earlier adoption of cholecystectomy in the EU, since gallstones are the major risk factor for gallbladder cancer. The data also indicate the scope for further improvement of the management of gallbladder disease in Eastern Europe.

Crossing the river: Khmer women’s perceptions of pregnancy and postpartum

In Cambodia, a setting of high maternal mortality, little is known about cultural perceptions of pregnancy. Often, cultural perceptions of what is considered normal or problematic guide a woman’s decision to seek care. In some settings, the difference between the emic, or cultural insider’s perception, and the biomedical perception of what is a serious obstetrical problem may delay lifesaving care. A qualitative study was undertaken to describe an emic perspective of what Khmer women view as normal and view as complications during pregnancy, birth, and postpartum. Focus group and key informant interviews were held to answer the questions: What do Khmer women and their birth attendants view as complications during pregnancy, birth, and postpartum? How are these complications defined? Eighty-eight rural and urban women of childbearing age participated in focus groups in three rural provinces and Phnom Penh. In-depth, semistructured interviews were held with 41 rural and urban women, traditional birth attendants, and trained midwives. Sixty-six hours of taped interviews were transcribed, translated, and analyzed, and descriptions of emic conditions during pregnancy and postpartum were developed. This report details emic categories of antepartum and postpartum conditions identified by these Khmer women. Specific emic categories of normal pregnancy and postpartum are described in detail as well as abnormal emic conditions occurring during the postpartum period. Recommendations are made for use of traditional emic taxonomies as a foundation for explaining biomedical complications and the need for similar studies to guide the development of safe motherhood programs in areas of high maternal mortality.

Evaluating the Relationships between Fire Induced Canopy Mortality and Pre‐fire Multispectral Patterns

Statistical tools were used to evaluate the relationships between observed fire effects and characteristics identifiable in pre‐fire multispectral and terrain data. Random points were placed within field delimited polygons representing areas of high and low canopy mortality. Each point was then used to extract Landsat TM based pre‐fire spectral characteristics and DEM derived terrain characteristics. The values for these random points were subjected to a multivariate discriminant analysis to ascertain whether specific spectral bands, indices, terrain characteristics, or specific combinations of these, could be effectively associated with the observed fire effects. Data values for high and low mortality points were found to be significantly different for all the pre‐fire data sets. The normalized difference vegetation index (NDVI) and tasseled cap greenness values provided the highest magnitude of direct differentiation between high and low mortality points. Discriminant analysis revealed that NDVI had the highest correspondence to degree of future canopy mortality, while the combined effect of the pre‐fire spectral response provided a prediction of observed fire effects with 87% accuracy, and the addition of terrain data improved accuracy to 90%.

Variation in vascular activity in the United Kingdom: an analysis of five regions

Background: The aim of this study was to define variations in vascular activity that may exist between different demographic regions of the UK. Methods: Five regions were studied. Data were obtained on OPCS codes for vascular surgery 1994–95 from the Department of Health or Welsh Office. Mortality and cause of death statistics were calculated for each region from OPCS data. Results: Ranges of vascular reconstruction, iliac and superficial femoral artery angioplasty and major amputation were 26.2–44, 10.5–23.0 and 11.5–15.7 per 100 000 population, respectively. The highest rates of amputation were seen in areas of high standard mortality and highest death rate from atheroma and ischaemic heart disease. Rates of amputation also rose in proportion to the number of men in the population aged >60 years. Conclusion: Variations exist in vascular activity between different regions. This may be caused by demographic differences in the population. It needs to be considered when calculating the number of vascular surgeons required in different areas of the country.

Where the poor die in a rich city: the case of Oxford

Research to date has established that there is a relationship between high mortality rates and area deprivation in Britain. However, the majority of this research has looked at the regional level and the few studies that have looked at a smaller area level have tended to focus on London or the North. At a national level a relationship between housing tenure and mortality has also been found. This paper considers the relationship between mortality and place and in particular housing, at ward level in a city in the South East of England. It is found that, in Oxford, there is no straightforward relationship between housing tenure and mortality rates. Rather, it is pockets of poverty within Oxford, expressed in different types of housing, that are associated with high mortality rates. Whilst the very poorest live in the worst quality and least preferred housing, the extent of this relationship is likely to differ in different areas, according to the historical and current patterns of housing provision. A method of identifying such areas nationally is needed, as a reliance on national studies, particular those on tenure, is likely to obscure the true picture and extent of geographical inequalities in health.

Alcohol, methylxanthine-containing beverages, and colorectal cancer in Córdoba, Argentina.

The relationship between social class indicators, body mass index (BMI), selected life-style habits (alcohol, coffee, maté and tea drinking) and colorectal cancer was investigated in a case-control study conducted between 1993 and 1997 in Córdoba, Argentina, a relatively high mortality area of colorectal cancer. Cases were 190 patients below age 80 years with incident, histologically confirmed colorectal adenocarcinomas, and controls were 393 patients admitted to hospital for a wide spectrum of acute, non-neoplastic disorders. Higher social class, based on occupation of the head of the household, was significantly associated with colorectal cancer risk: the odds ratios (OR) and 95% confidence intervals (95% CI) were 1.9 (1.2-2.9) for intermediate and 2.0 (1.2-3.4) for the highest as compared to the lowest social class individuals. When compared with subjects whose BMI was < 25 kg/m2, the OR was 1.1 (0.7-1.6) for those with BMI 25 to 29 kg/m2, and 1.3 (0.7-2.3) for those > or = 30. In comparison with alcohol abstainers, the OR was 2.8 (1.6-5.1) for drinkers, and there was a significant trend in risk with dose. The association was observed with wine (the most common alcoholic beverage in Argentina), as well as for beer and spirits. The consumption of coffee, maté and tea was not significantly related to colorectal cancer, but the ORs were below unity (0.9 (0.7-1.3) for coffee, 0.9 (0.6-1.2) for maté and 0.8 (0.6-1.2) for tea drinkers). The relationship between social class, alcohol drinking and colorectal cancer were consistent across strata of sex and age. This study confirms that colorectal cancer has positive social class correlates. The association with alcohol drinking is apparently stronger than previously reported, and may be due to the role of chance and/or peculiar correlates of alcohol drinking in this Argentinean population.

Modelling topoclimatic patterns of egg mortality of Epirrita autumnata (Lepidoptera: Geometridae) with a Geographical Information System: predictions for current climate and warmer climate scenarios

1. Our aim was to quantify the effects of a warmer winter climate on the egg mortality (and, consequently, the risk of an outbreak) of Epirrita autumnata, a serious defoliator of mountain birch. 2. The egg survival of E. autumnata was studied in northernmost Finland from 1993 to 1996, when minimum temperatures were also recorded. Utilizing a digital elevation map with a GIS (Geographical Information System), models were developed for egg survival and minimum temperature, taking into account altitude, local topography and temperatures at a meteorological station in the study area. 3. Areas of high egg mortality of E. autumnata can be modelled in the GIS with reasonable accuracy by the model describing areal distribution of minimum winter temperatures, taking account of the fact that the critical limit for egg survival of E. autumnata in midwinter is about −35·5°C. The approach can be applied in short‐term forecasting of outbreak areas when previous year population densities and minimum winter temperatures at meteorological stations are known. 4. In our study area, from 1961 to 1991 more than one‐third of the years were egg‐killing winters in the mixed birch‐pine forests zone, and 15% of years in the birch forest zone. In order for an outbreak to take place, at least three consecutive seasons with a high population growth rate are needed; in the mixed birch‐pine forests the possibilities of an E. autumnata outbreak during the period 1961–91 were very rare, while in the birch forest zone outbreak possibilities were also noticeably restricted by winter minimum temperatures. 5. If winter warming takes place according to the scenarios presented, by the middle of the next century the birch‐growing areas in our study area protected by low temperatures from outbreaks of E. autumnata will be only one‐third as great as those of today, and by the end of the next century only one‐tenth of those of today. 6. The models and methods described in this paper can be applied to other ecological processes. The modelling strategies and techniques described here serve as intermediate tools for linking large scale climate models (general circulation models, GCMs) and ecological processes happening at a smaller scale.

Outcome after coronary artery surgery in women and men in the north of England.

We prospectively studied, for 1 year initially, 353 consecutive patients (297 male 56 female, 57.2 +/- 7.32 years) with chronic stable angina admitted for coronary artery bypass graft (CABG) surgery in the North East of England. Patients generally had severe anginal symptoms (median 36 months duration) despite anti-anginal therapy (90% taking two or more anti-anginal drugs). Women were more severely symptomatic than men prior to surgery, despite a similar severity of angiographically-defined coronary artery disease, suggesting possible referral bias. Women were given fewer grafts than men in operations carrying similar risks. After surgery, clinical outcome was generally good but women had a higher mortality (12-month mortality 14% in women vs. 6% in men), and higher morbidity in terms of readmissions, angina symptoms, antianginal drug use and effort tolerance. This series describes clinical practice in an area of high coronary disease morbidity and mortality. It identifies the real risks for women with severe symptomatic disease undergoing coronary artery surgery. We believe it highlights the need for improved risk stratification in the treatment of women with angina, and a consideration of alternative treatment strategies for those women destined to have a poor outcome from CABG.

The spatial relationship between infant mortality and birth defect rates in a U.S. city.

The spatial patterns of infant mortality and birth defect rates in the Des Moines, Iowa, urban region are described as a contoured surface based on the punctual kriging of address-matched vital statistics records from The Iowa Department of Public Health. Areas defined as having high rates are shown to be sensitive to the size of the spatial filtering units. There is no correlation between infant mortality and birth defect rates in the region. The significance of areas with high rates is determined by a Monte Carlo simulation procedure. One area of high infant mortality is found in the region, which contrasts with many smaller areas with high birth defect rates in the region. The observed birth defect rate pattern is consistent with the hypothesis that each birth was equally likely to result in a birth defect, while the infant mortality pattern is unlikely to be the result of such an equal likelihood process.

People and places: contrasting perspectives on the association between social class and health.

While a substantial body of evidence demonstrates a strong association between socioeconomic variables and health outcomes, most analyses conceptualize socioeconomic status as an individual characteristic. This article argues for an expanded view that focuses on the relationship between social class and characteristics of the neighborhood and communities in which people live, and illustrates how these characteristics can provide some new directions for research relating class and health. Using the Alameda County Study, the author presents three analyses that support this view. They indicate that socioenvironmental characteristics of areas are importantly related to the mortality experience of individuals, independent of characteristics of the individuals, and that personal and socioenvironmental risk factors cluster together in areas of low income and high mortality. Studying the balance of demands and resources in areas may help to unravel some of the pathways that link social class and health.

Mapping and monitoring conifer mortality using remote sensing in the Lake Tahoe Basin

A prolonged drought in the western United States has resulted in alarming levels of mortality in conifer forests. Satellite remote sensing holds the potential for mapping and monitoring the effects of such environmental changes over large geographic areas in a timely manner. Results from the application of a forest canopy reflectance model using multitemporal Landsat TM imagery and field measurements, indicate conifer mortality can be effectively mapped and inventoried. The test area for this project is the Lake Tahoe Basin Management Unit in the Sierra Nevada of California. The Landsat TM images are from the summers of 1988 and 1991. The Li-Strahler canopy model estimates several forest stand parameters, including tree size and canopy cover for each conifer stand, from reflectance values in satellite imagery. The difference in cover estimates between the dates forms the basis for stratifying stands into mortality classes, which are used as both themes in a map and the basis of the field sampling design. Field measurements from 61 stands collected in the summer of 1992 indicate 15 % of the original timber volume in the true fir zone died between 1988 and 1992. The resulting low standard error of 11 % for this estimate indicates the utility of these mortality classes for detecting areas of high mortality. Also, the patterns in the estimated mean timber volume loss for each class follow the expected trends. The results of this project are immediately useful for fire hazard management, by providing both estimates of the degree of overall mortality and maps showing its location. They also indicate current remote sensing technology may be useful for monitoring the changes in vegetation that are expected to result from climate change.

Trends in pancreatic cancer mortality in Europe, 1955–1989

Trends in death certification rates from pancreatic cancer over the period 1955-1989 were analyzed for 25 European countries (excluding the former Soviet Union and a few smaller countries). In 1985-1989, rates for males ranged between 5.3/100,000 (age-standardized world population) in Spain and 10.3/100,000 in Hungary and Czechoslovakia. Other high-mortality areas were located in Northern Europe (Finland, Iceland, Ireland, Denmark) and Central Europe (Austria, Poland, Germany), whilst mortality was lower in Southern Europe (Portugal, Greece). Between 1955 and 1989, mortality rates increased in all the countries considered, the change ranging between 6% in Scotland and 279% in Spain; the rises were higher in the Mediterranean and Eastern European countries than in Northern Europe. Among females, Nordic countries such as Iceland, Sweden and Denmark had the highest mortality rates in 1985-1989 (over 6/100,000) and, as for males, Southern Europe (Spain, Portugal, Greece) appeared as a low-mortality area (around 3/100,000). During the 1955-1989 period, upward trends were observed in all the countries studied, with the highest increase in Greece, Italy, Bulgaria, Poland and Spain. A negative correlation was observed between the percent change in mortality rates between 1955-1959 and 1985-1989 and the rate in 1955-1959 among both males (r = -0.95, p < 0.001) and females (r = -0.81, p < 0.001). Thus, a systematic levelling of rates was observed in most countries, with the exception of the UK and some Nordic countries, whose rates were already high in the late 1950s. Tobacco smoking and dietary factors could account for some of the generalized upward trends. Improved diagnostic and death certification of the disease might also partially explain the observed figures.

Medical, economic and population factors in areas of high mortality: the case of Glasgow.

Medical, economic and population factors in areas of high mortality: the case of Glasgow.

Immunization against Echis ocellatus (carpet viper) venom using liposomes incorporating immunostimulants: role of lipopolysaccharide in conferring protection in a mouse model

G. D. Laing and R. D. G. Theakston. Immunization against Echis ocellatus (carpet viper) venom using liposomes incorporating immunostimulants: role of lipopolysaccharide in conferring protection in a mouse model. Toxicon 31, 615–626, 1993.—Varying doses of whole West African Echis ocellatus venom were incorporated, with or without immunostimulants, into membrane-stabilized reverse phase evaporation (REV) liposomes. Preparations were given either subcutaneously (s.c.) or intravenously (i.v.) to mice and the immune responses compared. Addition of lipopolysaccharide (LPS) significantly increased the venom antibody response. Lipid A produced a less pronounced and less sustained effect and the addition of muramyl dipeptide analogues made no significant contribution to the antibody response. The protective ability of circulating venom antibodies was assessed by challenging the immunized mice with a minimum lethal dose of whole venom after 175 days. A dose of 250 μg E. ocellatus venom + 300 μg LPS in REVs injected s.c. conferred the highest protection against lethal venom effects. Orally administered venom/liposomes incorporated with the mucosal adjuvant avridine primed the antibody response and produced a classic secondary response following a sublethal boost of whole venom. Single injections of venom or venom fraction/liposome preparations which produce a high and sustained immune response have potential in commercial antivenom production and in active immunization of man in areas of high snakebite incidence and mortality.

Descriptive epidemiology of gall-bladder cancer in Europe

Trends in mortality from cancer of the gall-bladder and bile ducts over the period 1965-1989 were analysed for 25 European countries on the basis of official death certifications from the World Health Organization databank. A high-mortality area--i.e. with overall death certification rates, world standard, around or over 2/100,000 men and 4/100,000 women in 1985-1989--was identified in Germany and the surrounding central European countries (Austria, Czechoslovakia, Hungary and Poland). The highest rates were in Hungary (3.9/100,000 men and 7.4/100,000 women). During the two decades considered, rates increased in Czechoslovakia and Hungary, remained stable in Poland and declined in Austria and Germany. Intermediate-mortality areas included Scandinavian countries (except Norway) and Switzerland: their rates in the late 1980s were between 1.5 and 2.5/100,000 men and between 2.2 and 4.2/100,000 women. Mortality increased in Finland and Sweden, declined in the Netherlands and Switzerland, and did not change consistently in Denmark. Low-mortality countries (i.e. with rates in 1985-1989 below 2.0/100,000 men and 2.5/100,000 women) included Belgium, France, Britain, Ireland, Norway, Bulgaria and Mediterranean countries. Over the last two decades, certification rates declined in Bulgaria and Great Britain, but increased in all other countries. The ratio between the countries with the highest and lowest gall-bladder cancer mortality rates declined from 21 to 12 in women, although they remained stable around 10 for men. The pattern was similar when analysis was restricted to truncated rates from patients aged between 35 and 64 years. These trends, and particularly the exceedingly high rates in central Europe, the low rates in Mediterranean countries and the low and declining rates in Britain and Ireland are discussed in terms of known (cholelithiasis) or potential (dietary) factors in gall-bladder cancer aetiology, and of trends in cholecystectomy rates.

Biological impact of eutrophication in the bay of somme and the induction and impact of anoxia

The first effects of eutrophication in the Bay of Somme became apparent in the years 1982–1985, when the cockle population collapsed. Areas of high mortality were mapped. Following exceptionally high summer temperatures, other effects were seen in 1982, 1983 and 1989, notably a mass mortality of the benthos. It appeared that the mortality of the benthos was a direct result of anoxia in the water promoted by phytoplankton blooms which were due to high nitrogen levels (nitrates from river and land runoff; ammonium from estuarine bivalve populations). Effects from the change in the benthic community (the disappearance of Cerastoderma edule and the proliferation of Pygospio elegans) were also apparent higher up in the food chain, viz. changes in the diet of the two main predators of the bivalve, the oystercatcher ( Haematopus ostralegus) and the common gull ( Larus canus). Following respirometry measurements of the water, sediment and the major macrobenthic species ( Cerastoderma edule, Macoma balthica, Nereis diversicolor, Hydrobia ulvae), a model for anoxia was constructed.