Long term effects of hysterectomy on mortality: nested cohort study

Objectives To investigate the long term risk (mean > 20 years) of death from all causes, cardiovascular disease, and cancer in women who had or had not had a hysterectomy.Design Nested cohort study.Setting Royal College of General Practitioners'' oral contraception study.Participants 7410 women (3705 flagged at the NHS central registries for cancer and death who had a hysterectomy during the oral contraception study and 3705 who were flagged but did not have the operation).Main outcome measures Mortality from all causes, cardiovascular disease, and cancer.Results 623 (8.4%) women had died by the end of follow-up (308 in the hysterectomy group and 315 in the non-hysterectomy group). Older women who had had a hysterectomy had a 6% reduced risk of death compared with women of a similar age who did not have the operation (adjusted hazard ratio 0.94, 95% confidence interval 0.75 to 1.18). Compared with young women who did not have a hysterectomy those who were younger at hysterectomy had an adjusted hazard ratio for all cause mortality of 0.82 (0.65 to 1.03). Hysterectomy was not associated with a significantly altered risk of mortality from cardiovascular disease or cancer regardless of age.Conclusion Hysterectomy did not increase the risk of death in the medium to long term.     

IAAT, catecholamines, and parity in African-American and European-American women

Objective: We have recently reported that parous European‐American (EA) women have disproportionately more intra‐abdominal adipose tissue (IAAT) than their nulliparous counterparts. Mediating mechanisms for IAAT accumulation remain unknown; however, some evidence suggests a possible catecholamine link. The objective of this study was to determine whether the IAAT‐parity relationship found in EA women exists in African‐American (AA) women and to determine whether catecholamines play a mediating role. Methods and Procedures: Subjects included 44 EA and 47 AA premenopausal women. Free‐living physical activity by doubly labeled water (activity‐related time equivalent (ARTE)), body composition (air plethysmography, computed tomography), and 24‐h fractionated urinary catecholamines were measured. Results: Repeated measures ANOVA revealed parous EA and AA women had significantly higher IAAT than their nulliparous counterparts (100.1 ± 28.5 and 76.2 ± 34.8 cm² vs. 75.9 ± 29.1 and 59.6 ± 15.0 cm²). In AA women and nulliparous women, 24‐h urinary dopamine was significantly higher (AA parous 260.8 ± 88; EA parous 197.2 ± 78.8; AA nulliparous 376.5 ± 81; EA nulliparous 289.6 ± 62). Multiple regression analysis for modeling IAAT indicated that race, parity, dopamine, ARTE, and VO_2max were all significant and independent contributors to the model (Unstandardized βs: race ?32.6 ± 7.4; parity (number of births) 10.0 ± 3.4; 24‐h urinary dopamine 0.08 ± 0.04; ARTE (min/day) ?0.09 ± 0.04; VO_2max (ml/kg/min) ?2.8 ± 1.0). Discussion: Independent of the potential confounders: age, race, percent body fat, IAAT, 24‐h fractionated urinary catecholamines, physical activity, and VO_2max, parous EA and AA women had more IAAT than their nulliparous counterparts. Of the catecholamines, dopamine was found to be significantly lower in parous women and higher in AA's. Dopamine, however, did not explain racial or parity differences in IAAT.     

Patterns of mortality in second generation Irish living in England and Wales: longitudinal study.

OBJECTIVE--To examine the mortality of second generation Irish living in England and Wales. DESIGN--Longitudinal study of 1% of the population of England and Wales (longitudinal study by the Office of Population Censuses and Surveys (now the Office for National Statistics)) followed up from 1971 to 1989. SUBJECTS--3075 men and 3233 women aged 15 and over in 1971. MAIN OUTCOME MEASURES--Age and sex specific standardised mortality ratios for all causes, cancers, coronary heart disease, cerebrovascular diseases, respiratory diseases, and injuries and poisonings. Deaths were also analysed by socioeconomic indicators. RESULTS--786 deaths were traced to men and 762 to women. At working ages (men, aged 15-64; women, 15-59) the mortality of men (standardised mortality ratio 126) and women (129) was significantly higher than that of all men and all women. At ages 15-44, relative disadvantages were even greater both for men (145) and for women (164). Mortality was raised for most major causes of death. Significant excess mortality from cancers was seen for men of working age (132) and for women aged 60 and over (122). At working ages mortality of the second generation Irish in every social class and in the categories of car access and housing tenure was higher than that of all men and all women in the corresponding categories. Adjusting for these socioeconomic indicators did not explain the excess mortality. CONCLUSION--Mortality of second generation Irish men and women was higher than that of all men and all women and for most major causes of death. While socioeconomic factors remain important, cultural and lifestyle factors are likely to contribute to this adverse mortality.     

Effectiveness of treatment with antihypertensive drugs and trends in mortality from stroke in the community.

A study was made of the changes in the treatment of hypertension, in the effectiveness of that treatment, and in mortality from cerebrovascular stroke in men and women in two counties in Finland. One of these counties was North Karelia, where a comprehensive cardiovascular programme based in the community had been launched in 1972. Cross sectional surveys in large representative samples of the middle aged populations were carried out in 1972, 1977, and 1982. Average annual mortality from stroke adjusted for age was calculated for the two year periods 1971-2, 1977-8, and 1980-1. The proportion of hypertensive men being effectively treated for their hypertension increased in both areas from 1972 to 1977 and further from 1977 to 1982. Mortality from stroke in middle aged men decreased in both areas during both observation periods. The proportion of hypertensive women being effectively treated greatly increased in both areas from 1972 to 1977. This was associated with a large decline in mortality from stroke. In North Karelia the proportion of women being effectively treated was remarkably high but decreased somewhat between 1977 and 1982; this decrease was associated with an increase in mortality from stroke in the women aged 35-64. These results support the idea that effective antihypertensive treatment in the community is a major determinant of mortality from stroke in both men and women.     

Mortality from cardiovascular disease among interregional migrants in England and Wales.

OBJECTIVE--To investigate the extent to which geographical variations in mortality from ischaemic heart disease and stroke in Britain are influenced by factors in early life or in adulthood. DESIGN--Longitudinal study of migrants. SUBJECTS--1% sample of residents in England and Wales born before October 1939 and enumerated at the 1971 census (the Office of Population Censuses and Surveys'' longitudinal study). MAIN OUTCOME MEASURE--18,221 deaths from ischaemic heart disease and 9899 deaths from stroke during 1971-88 were analysed by areas of residence in 1939 and 1971. These included 2928 deaths from ischaemic heart disease and 1608 deaths from stroke among individuals moving between 14 areas defined by the major conurbations and nine standard administrative regions of England and Wales. RESULTS--The southeast to northwest gradient in mortality from ischaemic heart disease was related significantly to both the 1939 area (chi 2 = 6.09, df = 1) and area in 1971 (chi 2 = 5.05, df = 1). Geographical variations in mortality from stroke were related significantly to the 1939 area (chi 2 = 4.09, df = 1) but the effect of area in 1971 was greater (chi 2 = 8.07, df = 1). The effect of 1971 area on mortality from stroke was largely due to a lower risk of death from stroke among individuals moving into Greater London compared with migrants to the rest of the South East region (chi 2 = 4.54, df = 1). CONCLUSIONS--Geographical variations in mortality from cardiovascular disease in Britain may be partly determined by genetic factors, environmental exposures, or lifestyle acquired early in life, but the risk of fatal ischaemic heart disease and stroke changes on migration between areas with differing mortality. The low risk of death from stroke associated with residence in Greater London is acquired by individuals who move there.     

Respiratory symptoms as predictors of 27 year mortality in a representative sample of British adults.

OBJECTIVE--To examine associations between reported respiratory symptoms (as elicited by questionnaire) and subsequent mortality. DESIGN--Prospective cohort study. SETTING--92 General practices in Great Britain. PARTICIPANTS--A nationally representative sample of 1532 British men and women aged between 40 and 64. MAIN OUTCOME MEASURES--Mortality from all causes, cardiovascular disease, lung cancer, and chronic bronchitis. RESULTS--Subjects were interviewed in 1958 regarding various respiratory symptoms (including cough, phlegm, breathlessness, and wheeze) by using a questionnaire which formed the basis of the Medical Research Council''s questionnaire on respiratory symptoms. By the end of 1985, 889 deaths had been reported, including 51 in men due to chronic bronchitis. After adjustment for differences in age and smoking habits death rates from chronic bronchitis in men who reported symptoms were greater than those in men who did not for each of the symptoms examined. The adjusted mortality ratios were 3.4 (95% confidence interval 1.8 to 6.5) for morning cough, 3.7 (2.0 to 6.9) for morning phlegm, 6.4 (3.0 to 13.8) for breathlessness when walking on the level, and 10.5 (4.4 to 24.6) for wheeze most days or nights. Mortality ratios were also significantly raised for four episodic symptoms not usually included in more recent respiratory symptom questionnaires--namely, occasional wheeze (mortality ratio 6.0; 95% confidence interval, 2.4 to 15.1), weather affects chest (5.7; 3.1 to 10.3), breathing different in summer (4.9; 2.8 to 8.6), and cold usually goes to chest (3.7; 2.0 to 6.8). The excess mortality associated with these symptoms remained significant after further adjustment for breathlessness or phlegm. Ratios for all cause mortality in men and women were also significantly raised for most respiratory symptoms, death rates being some 20-50% higher in people reporting symptoms after adjustment for age, sex, and smoking. Breathlessness was the only symptom significantly associated with excess mortality from cardiovascular disease (mortality ratio 1.4 (95% confidence interval 1.0 to 1.9) for breathlessness when walking on the level). Ratios were generally around unity and not significant for mortality due to lung cancer. CONCLUSIONS--The results suggest that episodic symptoms, which often do not appear in standard respiratory questionnaires, predict subsequent mortality from chronic obstructive airways disease. This supports the hypothesis that reversible airflow obstruction may be a precursor of progressive and irreversible decline in ventilatory function.     

Cancer mortality among immigrant populations in Ontario, 1969 through 1973.

Ontario is home to a sizeable, recently established immigrant population whose cancer mortality has until now remained unexamined. The province''s six largest immigrant groups (British, Italian, German, Dutch, Polish and Soviet) were investigated to compare their cancer mortality experience with that prevailing in Ontario and in their countries of birth for the period 1969 through 1973. Standardized mortality ratios (SMRs) were computed from data from Statistics Canada and the World Health Organization (for 1971) for five sites of cancer. The rates of death from stomach cancer were significantly higher for the immigrant groups (except the Germans) than for the Canadian-born (SMRs 158.6 to 256.1) and were significantly lower for the immigrants (except the Dutch) than for the populations of their countries of birth (SMRs 26.5 to 72.9). The rates of death from colorectal cancer and cancer of the breast tended to be lower among the immigrants. Most male immigrants had high rates of death from lung cancer relative to the Canadian-born, whereas their female counterparts had relatively low rates. For most of the immigrant groups the rates of death from prostate cancer closely resembled those prevailing in the country of birth. Displacement of cancer mortality experience towards that in Ontario was most evident for Polish immigrants. It may have been too soon to see trends among the more recent immigrants (Italian, German and Dutch), who, for the most part, had not yet reached the age of highest cancer risk. Ontario should provide a valuable resource for further studies of lifestyle and environmental determinants of cancer.     

Combined Impact of Lifestyle-Related Factors on Total and Cause-Specific Mortality among Chinese Women: Prospective Cohort Study

Background

Although cigarette smoking, excessive alcohol drinking, obesity, and several other well-studied unhealthy lifestyle-related factors each have been linked to the risk of multiple chronic diseases and premature death, little is known about the combined impact on mortality outcomes, in particular among Chinese and other non-Western populations. The objective of this study was to quantify the overall impact of lifestyle-related factors beyond that of active cigarette smoking and alcohol consumption on all-cause and cause-specific mortality in Chinese women.

Methods and Findings

We used data from the Shanghai Women''s Health Study, an ongoing population-based prospective cohort study in China. Participants included 71,243 women aged 40 to 70 years enrolled during 1996–2000 who never smoked or drank alcohol regularly. A healthy lifestyle score was created on the basis of five lifestyle-related factors shown to be independently associated with mortality outcomes (normal weight, lower waist-hip ratio, daily exercise, never exposed to spouse''s smoking, higher daily fruit and vegetable intake). The score ranged from zero (least healthy) to five (most healthy) points. During an average follow-up of 9 years, 2,860 deaths occurred, including 775 from cardiovascular disease (CVD) and 1,351 from cancer. Adjusted hazard ratios for mortality decreased progressively with an increasing number of healthy lifestyle factors. Compared to women with a score of zero, hazard ratios (95% confidence intervals) for women with four to five factors were 0.57 (0.44–0.74) for total mortality, 0.29 (0.16–0.54) for CVD mortality, and 0.76 (0.54–1.06) for cancer mortality. The inverse association between the healthy lifestyle score and mortality was seen consistently regardless of chronic disease status at baseline. The population attributable risks for not having 4–5 healthy lifestyle factors were 33% for total deaths, 59% for CVD deaths, and 19% for cancer deaths.

Conclusions

In this first study, to our knowledge, to quantify the combined impact of lifestyle-related factors on mortality outcomes in Chinese women, a healthier lifestyle pattern—including being of normal weight, lower central adiposity, participation in physical activity, nonexposure to spousal smoking, and higher fruit and vegetable intake—was associated with reductions in total and cause-specific mortality among lifetime nonsmoking and nondrinking women, supporting the importance of overall lifestyle modification in disease prevention. Please see later in the article for the Editors'' Summary     

Mortality and cancer incidence in women with extra X chromosomes: a cohort study in Britain

About one woman in 1,000 has an extra X chromosome, but such women have no recognised characteristic somatic features and little is known about their long-term health and cancer risks. We conducted a cohort study of mortality and cancer incidence in 542 women diagnosed with X polysomy at 25 cytogenetic centres in Britain since 1959. Fifty-nine deaths occurred during follow-up to mid-2004. Mortality was significantly raised (standardised mortality ratio (SMR) = 2.5 (95% confidence interval (CI) 1.9–3.2)), with excess deaths due particularly to cardiovascular disease (SMR = 2.5 (95% CI 1.5–3.8)) and respiratory disease (SMR = 4.0 (95% CI 1.7–7.9)). Risks of cancer incidence and cancer mortality overall were not raised, but there was significantly raised mortality from non-Hodgkin’s lymphoma (NHL) (SMR = 10.4 (95% CI 1.3–37.6); based on 2 cases). The data indicate that mortality in women diagnosed with X polysomy is considerably raised. The raised risk of NHL is seen also in males with more than one X chromosome, and hence although unexpected and based on small numbers, it might indicate the action of a gene on the X chromosome, possibly in the pseudoautosomal region, that escapes X-inactivation.On behalf of the UK clinical cytogenetics group     

Inequalities in health within the health sector.

Mortality among men employed in the health sector was examined using data surrounding the 1971 (1970-2) and 1981 (1979-83) censuses to assess the differences between social classes in the health service and to study changes over a decade. Relative to men in England and Wales, mortality in the 1980s was significantly lower among dentists (standardised mortality ratio 66), doctors (69), opticians (72), and physiotherapists (79) and significantly higher among hospital porters (151), male nurses (118), and ambulancemen (109). Mortality from lung cancer among hospital porters (185) was more than fivefold that seen in doctors (33) and dentists (37). Ischaemic heart disease varied twofold, being lowest in dentists (60) and doctors (70) and highest in hospital porters (138). Over the decade mortality from lung cancer and ischaemic heart disease declined in all groups except hospital porters, ambulancemen, and orderlies. Most groups showed excess deaths from suicides and cirrhosis of the liver. Differences in mortality between health workers in social class I and those in social class IV widened between the 1970s and 1980s and to a greater extent than among the general population. The high mortality of some groups within the NHS, and the fact that differentials between social classes have widened more than in the general population, suggest that the NHS needs to pay more attention to the health of its own staff.     

Parity and breast cancer.

Data from the 1961 and 1971 Censuses in England and Wales were used to estimate the age distribution of women of various parities in 1976. Applying the age-specific incidences of breast cancer for women in England and Wales in 1975 gave the expected number of cases of that disease in 1976 and permitted an estimate of the mean age at diagnosis of breast cancer at each parity. This showed that the highest average age for breast cancer occurred in nulliparous women (65.9 years) and that the lowest age for the disease occurred in women who had borne two children (60.4 years). The figures obtained were similar to those reported in a separate study of women treated in Birmingham. The results of that study, however, may have been due to the age distribution in the population of women by parity, rather than any direct influence of parity on the speed of growth of breast cancer.     

Immunoglobulin synthesis in the "resting" breast.

Nulliparous women have a greater risk of developing breast cancer than women who have borne children, but so far no functional differences in breast tissue have been reported between parous women and nulliparae. Macroscopically and histologically normal breast tissue was obtained from 74 women of reproductive age during biopsy of benign breast lesions and was examined for the presence of plasma cells by immunfluorescence. Immunoglobulin synthesis was detected by an in-vitro culture technique. Synthesis of IgA was detected in 81% of specimans of IgG in 45%, and of IgM in 3%. IgA synthesis much more intense than IgG or IgM synthesis. Plasma cells containing IgA were seen in 71% of the specimens examined, and 88% of specimens had deposits of IgA in the ductules. The findings were not significantly incluenced by the nature of the condition necessitating biopsy or by oral contraception. Nulliparous women showed no cyclical changes, but among parous women IgA synthesis was more intense during luteal phase of the menstrual cycle. This suggests that after the first pregnancy the breast is more sensitive to progesterone.     

Mother's weight in pregnancy and coronary heart disease in a cohort of Finnish men: follow up study.

OBJECTIVE: To determine whether restricted growth in utero is associated with an increased risk of coronary heart disease are among men in Finland, where rates of the disease are among the highest in the world. DESIGN: Follow up study. SETTING: Helsinki, Finland. SUBJECTS: 3302 men born in Helsinki University Central Hospital during 1924-33 who went to school in the city of Helsinki and were resident in Finalnd in 1971. MAIN OUTCOME MEASURES: Standardised mortality ratios for coronary heart disease. RESULTS: Men who were thin at birth, with low placental weight, had high death rates from coronary heart disease. Men whose mothers had a high body mass index in pregnancy also had high death rates. In a multivariate analysis the hazard ratio for coronary heart disease was 1.37 (95% confidence interval 1.20 to 1.57) (P < 0.0001) for every standard deviation decrease in ponderal index at birth and 1.24 (1.10 to 1.39) (P = 0.0004) for every standard deviation increase in mother''s body mass index. The effect of mother''s body mass index was restricted to mothers of below average stature. CONCLUSION: These findings suggest a new explanation for the epidemics of coronary heart disease that accompany Westernisation. Chronically malnourished women are short and light and their babies tend to be thin. The immediate effect of improved nutrition is that women become fat, which seems to increase the risk of coronary heart disease in the next generation. With continued improvements in nutrition, women become taller and heavier; their babies are adequately nourished; and maternal fatness no longer increases the risk of coronary heart disease, which therefore declines.     

Stressful life events,social support,and mortality in men born in 1933.

OBJECTIVE--To examine relations between stressful life events and mortality in middle aged men. DESIGN--Prospective population study. Data on stressful life events, social network, occupation, and other psychosocial factors derived from self administered questionnaires. Mortality data obtained from official registers. SETTING--City of Gothenburg, Sweden. SUBJECTS--752 men from a random population sample of 1016 men aged 50. MAIN OUTCOME MEASURE--Mortality from all causes during seven years'' follow up. RESULTS--Life events which had occurred in the year before the baseline examination were significantly associated with mortality from all causes during seven years'' follow up. Of the men who had experienced three or more events during the past year 10.9% had died compared with 3.3% among those with no life events (odds ratio 3.6; 95% confidence interval 1.5 to 8.5). The association between recent life events and mortality remained true after smoking, self perceived health, occupational class, and indices of social support were controlled for. Many of the deaths were alcohol related, but the number of deaths was too small to allow for analyses of specific causes of death. The association between life events and mortality was evident only in men with low emotional support. CONCLUSION--Stressful life events are associated with high mortality in middle aged men. Men with adequate emotional support seem to be protected.     

Climatic effects on sow fertility and piglet survival under influence of a moderate climate

Although the climate in Germany is moderate, heat stress conditions may occur during summer months. However, it is unknown to what extent sow fertility and piglet survival are affected under moderate climatic conditions in indoor systems. Therefore, this study estimated effects of temperature and temperature–humidity index (THI) on sow fertility and piglet survival under practical husbandry conditions. Temperature and relative humidity were recorded in six piglet-producing farms in Lower Saxony, Germany, from July 2011 to August 2012. Based on that, the THI was calculated. In one farrowing, waiting and servicing unit of each farm two data loggers were installed. Reproductive parameters of 8279 successful inseminations and 10 369 litters including total number of piglets born, liveborn, stillborn and weaned piglets as well as pre-weaning mortality were evaluated. The effects of temperature and THI on reproductive parameters were estimated for varying periods after breeding and before and after farrowing, respectively. Average daily temperature across all units ranged from 15.6°C to 29.0°C, and average THI from 62.4 to 75.1. Season and parity significantly affected total number of piglets born, number of liveborn, stillborn and weaned piglets (P<0.001). The number of piglets born increased with rising temperature and THI in the 1^st week post breeding. Higher temperatures and THI values before farrowing resulted in a reduced number of liveborn piglets. Elevated temperature and THI values after farrowing were associated with a greater number of weaned piglets. The pre-weaning mortality significantly decreased with increasing temperature and THI values after farrowing (P<0.05). In conclusion, temperature and THI affected the reproductive performance of the sows and the survival of the piglets in different ways. While increased climatic values at the time of breeding positively affected the total number of piglets born, increased values at the time of farrowing had negative impacts on the reproductive performance of the sows. Piglets benefited from higher temperature and THI values after farrowing.     

Retrospective study of maternal HIV-1 and HIV-2 infections and child survival in Abidjan,C?te d'Ivoire.

OBJECTIVES--To compare the effects of maternal HIV-1 and HIV-2 infections on outcome of pregnancy, infant mortality, and child survival, and to measure serological concordance between mothers and children. DESIGN--Retrospective cohort study with cross sectional study of concordance for HIV antibodies. SETTING--Hospital, tuberculosis clinic, and maternal and child health centre in Abidjan, Côte d''Ivoire, west Africa. SUBJECTS--986 women who had had a total of 2758 pregnancies since 1980. The last born children of 194 of these women. MAIN OUTCOME MEASURES--Pregnancy outcomes; mortality for all children born since 1980; and outcome for last born children. Serological concordance between mothers and last born children. RESULTS--Women with HIV-1 and HIV-2 infections had higher rates of spontaneous abortion and stillbirth than uninfected women (86/769 in HIV-1 positive women, 48/421 in HIV-2 positive, 31/234 in dually reactive, and 96/1131 in uninfected). Compared with children born to uninfected mothers (mortality 10.3%), greater proportions of children of HIV-1 positive (20.6%) and dually reactive (20.3%) mothers had died; mortality in children of HIV-2 infected women (13.1%) was not significantly increased. Infant mortalities for the last born children of HIV-1 positive, dually reactive, HIV-2 positive, and seronegative women were, respectively, 133, 82, 32, and 40 per 1000 live births. Nine of 77 last born children of HIV-1 positive mothers were concordantly seropositive compared with none of 21 children of HIV-2 infected mothers. CONCLUSIONS--Maternal HIV-2 infection has less influence on child survival than infection with HIV-1, probably because of a lower vertical transmission rate.     

Breast feeding and risk of breast cancer in young women. United Kingdom National Case-Control Study Group.

OBJECTIVE--To investigate whether breast feeding is related to subsequent risk of breast cancer. DESIGN--Population based case-control study designed primarily to investigate the relation between oral contraceptives and risk of breast cancer; data obtained from questionnaires administered by interviewers, general practitioner notes, and family planning clinic records. SETTING--11 health regions in Britain. SUBJECTS--Women diagnosed with breast cancer before age 36 living in the defined study areas. One control per case, matched for age, was selected from the list of the case''s general practitioner. 755 case-control pairs were interviewed. MAIN OUTCOME MEASURES--Duration of breast feeding each liveborn infant; timing of return of menses; hormone use; other risk factors for breast cancer. RESULTS--Risk of breast cancer fell with increasing duration of breast feeding (relative risk = 0.94 per three months'' breast feeding; test for trend p = 0.026) and with number of babies breast fed (relative risk = 0.86; test for trend, p = 0.017). Breast feeding each baby for longer than three months conferred no additional benefit. Breast feeding was more strongly negatively associated with risk of breast cancer than duration of postpartum amenorrhoea (chi 2 test for trend, p = 0.69). Hormonal suppression of lactation was unrelated to risk of breast cancer (relative risk = 0.96 per episode of suppressed lactation; test for trend, p = 0.72). CONCLUSIONS--These results suggest that breast feeding protects against the development of breast cancer in young women.     

Hodgkin's Disease in Patients with Previous Infectious Mononucleosis: 30 Years' Experience

Seventeen out of 17,073 people in Denmark who had had a positive reaction to a Paul-Bunnell test between the years 1940 and 1969 developed Hodgkin''s disease after an interval of at least 12 months. This number was significantly (P < 0·0002) greater than the expected number of two women and four men. Sixteen of those developing Hodgkin''s disease were men. Case records, which were available for 12 of them, confirmed that they had had infectious mononucleosis. The number of cases of leukaemia that developed in the sample population was no greater than expected.     

Causes and correlates of calf mortality in captive Asian elephants (Elephas maximus)

Juvenile mortality is a key factor influencing population growth rate in density-independent, predation-free, well-managed captive populations. Currently at least a quarter of all Asian elephants live in captivity, but both the wild and captive populations are unsustainable with the present fertility and calf mortality rates. Despite the need for detailed data on calf mortality to manage effectively populations and to minimize the need for capture from the wild, very little is known of the causes and correlates of calf mortality in Asian elephants. Here we use the world''s largest multigenerational demographic dataset on a semi-captive population of Asian elephants compiled from timber camps in Myanmar to investigate the survival of calves (n = 1020) to age five born to captive-born mothers (n = 391) between 1960 and 1999. Mortality risk varied significantly across different ages and was higher for males at any age. Maternal reproductive history was associated with large differences in both stillbirth and liveborn mortality risk: first-time mothers had a higher risk of calf loss as did mothers producing another calf soon (<3.7 years) after a previous birth, and when giving birth at older age. Stillbirth (4%) and pre-weaning mortality (25.6%) were considerably lower than those reported for zoo elephants and used in published population viability analyses. A large proportion of deaths were caused by accidents and lack of maternal milk/calf weakness which both might be partly preventable by supplementary feeding of mothers and calves and work reduction of high-risk mothers. Our results on Myanmar timber elephants with an extensive keeping system provide an important comparison to compromised survivorship reported in zoo elephants. They have implications for improving captive working elephant management systems in range countries and for refining population viability analyses with realistic parameter values in order to predict future population size of the Asian elephant.