Contribution of preterm delivery to perinatal mortality.

A detailed retrospective analysis was made of the records of 486 preterm infants, who accounted for 5-1% of all births during 1973 and 1974. Whereas preterm delivery did not contribute to perinatal mortality in terms of stillbirth, it outweighed all other causes in terms of early neonatal deaths. Preterm birth was responsible for 85% of the early neonatal deaths not due to lethal congenital deformities. Early neonatal mortality rates were closely linked both to gestational age and birth weight and to the reason for preterm birth. Early neonatal mortality was high (97 per 1000) when preterm labour was spontaneous, whether or not associated with material or fetal disease or with multiple pregnancy, but low (27 per 1000) when preterm delivery was elective. Preventing spontaneous preterm labour would considerably reduce neonatal mortality in our community.     

Cardiovascular risk factors in British children from towns with widely differing adult cardiovascular mortality.

OBJECTIVE--To examine whether cardiovascular risk factors differ in children from towns in England and Wales with widely differing adult cardiovascular death rates. DESIGN--School based survey conducted during 1994 in 10 towns, five with exceptionally high adult cardiovascular mortality (standardised mortality ratio 131-143) and five with exceptionally low adult cardiovascular mortality (64-75). Towns were surveyed in high-low pairs. SUBJECTS--3415 white children aged 8-11 years with physical measurements (response rate 75%), including 1287 with blood samples (response rate 64%), of whom 515 had blood samples taken 30 minutes after a glucose load. RESULTS--Children in towns with high cardiovascular mortality were on average shorter than those in towns with low mortality (mean difference 1.2 cm; 95% confidence interval 0.3 to 2.1 cm; P = 0.02) and had a higher ponderal index (0.34 kg/m3; 0.16 to 0.52 kg/m3; P = 0.006). Mean systolic pressure was higher in high mortality towns, particularly after adjustment for height (2.0 mm Hg; 0.8 to 3.2 mm Hg; P = 0.009). Mean waist:hip ratio, total cholesterol concentration, and 30 minute post-load glucose measurements were similar in high and low mortality towns. The differences in height and blood pressure between high and low mortality towns were unaffected by standardisation for birth weight. CONCLUSIONS--The differences in height, ponderal index, and blood pressure between towns with high and low cardiovascular mortality, if persistent, may have important future public health implications. Their independence of birth weight suggests that the childhood environment rather than the intrauterine environment is involved in their development.     

The relation of small head circumference and thinness at birth to death from cardiovascular disease in adult life.

OBJECTIVE--To determine how fetal growth is related to death from cardiovascular disease in adult life. DESIGN--A follow up study of men born during 1907-24 whose birth weights, head circumferences, and other body measurements were recorded at birth. SETTING--Sheffield, England. SUBJECTS--1586 Men born in the Jessop Hospital. MAIN OUTCOME MEASURE--Death from cardiovascular disease. RESULTS--Standardised mortality ratios for cardiovascular disease fell from 119 in men who weighed 5.5 pounds (2495 g) or less at birth to 74 in men who weighed more than 8.5 pounds (3856 g). The fall was significant for premature cardiovascular deaths up to 65 years of age (chi 2 = 5.0, p = 0.02). Standardised mortality ratios also fell with increasing head circumference (chi 2 = 4.6, p = 0.03) and increasing ponderal index (weight/length3) (chi 2 = 3.8, p = 0.05; for premature deaths chi 2 = 6.0, p = 0.01). They were not related to the duration of gestation. Among men for whom the ratio of placental weight to birth weight was in the highest fifths the standardised mortality ratio was 137. CONCLUSION--These findings show that reduced fetal growth is followed by increased mortality from cardiovascular disease. They suggest that reduction in growth begins early in gestation. They are further evidence that cardiovascular disease originates through programming of the body''s structure, physiology, and metabolism by the environment during fetal life. Maternal nutrition may have an important influence on programming.     

Perinatal characteristics in relation to incidence of and mortality from prostate cancer.

OBJECTIVE--To test the hypothesis that factors causing morbidity and mortality from prostate cancer may operate in utero. DESIGN--Matched case-control study of singleton men born between 1874 and 1946 at one hospital. SETTING--Uppsala University Hospital. SUBJECTS--250 patients with prostate cancer and 691 controls, including 80 patients who died from prostate cancer and their 196 matched controls. MAIN OUTCOME MEASURES--Mother''s age at menarche, parity, pre-eclampsia or eclampsia before delivery, age at delivery and socioeconomic status; case or control''s birth length and weight, placental weight, prematurity derived from gestational age, and presence of jaundice. RESULTS--Both pre-eclampsia (odds ratio 0, 95% confidence interval 0 to 0.71) and prematurity (0.31, 0.09 to 1.04) were inversely associated with incidence of prostate cancer. Among subjects born full term, placental weight, birth weight, and ponderal index (weight/height 3) showed non-significant positive associations with prostate cancer incidence, and stronger associations with mortality. CONCLUSION--Prenatal exposures that are likely correlates of pregnancy hormones and other growth factors are important in prostate carcinogenesis and influence the natural course as well as the occurrence of this cancer.     

Growth in utero,blood pressure in childhood and adult life,and mortality from cardiovascular disease.

In national samples of 9921 10 year olds and 3259 adults in Britain systolic blood pressure was inversely related to birth weight. The association was independent of gestational age and may therefore be attributed to reduced fetal growth. This suggests that the intrauterine environment influences blood pressure during adult life. It is further evidence that the geographical differences in average blood pressure and mortality from cardiovascular disease in Britain partly reflect past differences in the intrauterine environment. Within England and Wales 10 year olds living in areas with high cardiovascular mortality were shorter and had higher resting pulse rates than those living in other areas. Their mothers were also shorter and had higher diastolic blood pressures. This suggests that there are persisting geographical differences in the childhood environment that predispose to differences in cardiovascular mortality.     

Contribution of twin pregnancy to perinatal mortality and fetal growth retardation; reversal of growth retardation after birth.

A survey of factors associated with perinatal mortality in 511 twins and fetal growth retardation and its reversal in 262 twins is presented. The incidence of stillbirth was almost 50% higher in twins than in singletons and the neonatal mortality was six times as high. Eighty percent of the neonatal deaths occurred in infants born prior to or at 30 weeks of gestation; 93% of the deaths were in infants weighing less than 1500 g and 75% occurred within 48 hours of birth. Fetal malnutrition was the main cause of stillbirth, and respiratory distress syndrome and asphyxia neonatorum were the main causes of neonatal death. One quarter of the twins had fetal growth retardation, a prevalence 10 times that in singletons. In almost all, the growth retardation was reversed by high-energy feedings. Although twins represented only 1% of all pregnancies and 2% of live births, they composed 12% of infants with early neonatal death and 17% of growth-retarded infants. A program is suggested for reduction of twin mortality and morbidity.     

Changes in cognition and mortality in relation to exercise in late life: a population based study

Background

On average, cognition declines with age but this average hides considerable variability, including the chance of improvement. Here, we investigate how exercise is associated with cognitive change and mortality in older people and, particularly, whether exercise might paradoxically increase the risk of dementia by allowing people to live longer.

Methods and Principal Findings

In the Canadian Study of Health and Aging (CSHA), of 8403 people who had baseline cognition measured and exercise reported at CSHA-1, 2219 had died and 5376 were re-examined at CSHA-2. We used a parametric Markov chain model to estimate the probabilities of cognitive improvement, decline, and death, adjusted for age and education, from any cognitive state as measured by the Modified Mini-Mental State Examination. High exercisers (at least three times per week, at least as intense as walking, n = 3264) had more frequent stable or improved cognition (42.3%, 95% confidence interval: 40.6–44.0) over 5 years than did low/no exercisers (all other exercisers and non exercisers, n = 4331) (27.8% (95% CI 26.4–29.2)). The difference widened as baseline cognition worsened. The proportion whose cognition declined was higher amongst the high exercisers but was more similar between exercise groups (39.4% (95% CI 37.7–41.1) for high exercisers versus 34.8% (95% CI 33.4–36.2) otherwise). People who did not exercise were also more likely to die (37.5% (95% CI 36.0–39.0) versus 18.3% (95% CI 16.9–19.7)). Even so, exercise conferred its greatest mortality benefit to people with the highest baseline cognition.

Conclusions

Exercise is strongly associated with improving cognition. As the majority of mortality benefit of exercise is at the highest level of cognition, and declines as cognition declines, the net effect of exercise should be to improve cognition at the population level, even with more people living longer.     

Using sparse survey data to investigate the declining abundance of British harbour seals

This study presents an analysis of changes in the regional abundance of harbour seals Phoca vitulina based on repeated aerial surveys of haulouts, and demonstrates the use of sparse data to deliver advice about population status and management. Generalized linear models with negative binomial errors were used to represent these overdispersed data. The shape parameter of the negative binomial distribution was directly estimated from the data where this was possible. Information from time-series of counts where there were few gaps in the data was used to improve the estimation of this parameter in areas where fewer surveys had been carried out. The results show that the number of harbour seals in eastern England has not increased since the end of the 2002 phocine distemper epidemic. There is also evidence of a general decline in most of the large harbour seal colonies around Britain. The populations in the Inner Hebrides were an exception, with numbers appearing to be stable or increasing. Between 2001 and 2006, the population in Orkney and Shetland declined by 40% (95% confidence interval: 30–50%), indicating harbour seals in these areas experienced substantially increased mortality or very low recruitment over this period. The widespread declines, ranging from Shetland to The Wash, suggest that the causes may have been present over a large part of the North Sea.     

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.     

Evaluating perinatal mortality rates: effects of referral and case mix.

OBJECTIVE--To evaluate perinatal mortality rates as a method of auditing obstetric and neonatal care after account had been taken of transfer between hospitals during pregnancy and case mix. DESIGN--Case-control study of perinatal deaths. SETTING--Leicestershire health district. SUBJECTS--1179 singleton perinatal deaths and their selected live born controls among 114,362 singleton births to women whose place of residence was Leicestershire during 1978-87. MAIN OUTCOME MEASURE--Crude perinatal mortality rates and rates adjusted for case mix. RESULTS--An estimated 11,701 of the 28,750 women booked for delivery in general practitioner maternity units were transferred to consultant units during their pregnancy. These 11,701 women had a high perinatal mortality rate (16.8/1000 deliveries). Perinatal mortality rates by place of booking showed little difference between general practitioner units (8.8/1000) and consultant units (9.3-11.7/1000). Perinatal mortality rates by place of delivery, however, showed substantial differences between general practitioner units (3.3/1000) and consultant units (9.4-12.6/1000) because of the selective referral of high risk women from general practitioner units to consultant units. Adjustment for risk factors made little difference to the rates except when the subset of deaths due to immaturity was adjusted for birth weight. CONCLUSION--Perinatal mortality rates should be adjusted for case mix and referral patterns to get a meaningful result. Even when this is done it is difficult to compare the effectiveness of hospital units with perinatal mortality rates because of the increasingly small subset of perinatal deaths that are amenable to medical intervention.     

Malaria prophylaxis: survey of the response of British travellers to prophylactic advice.

A cohort study was conducted to determine the compliance of travellers with chemoprophylactic advice given over the telephone by the malaria reference advisory service. Travellers who visited their general practitioner first for advice about malaria prophylaxis were often advised to consult a specialist service themselves. Compliance fell in travellers who were given complicated information and those who received conflicting advice when they contacted other advisory services. After returning to Britain 48% of the travellers reported that they were fully compliant with prophylactic advice; over a third of the travellers studied did not maintain prophylaxis on their return.     

Childhood energy intake and adult mortality from cancer: the Boyd Orr Cohort Study.

OBJECTIVE: To examine the relation between energy intake in childhood and adult mortality from cancer. STUDY DESIGN: Cohort study. SETTING: 16 rural and urban centres in England and Scotland. SUBJECTS: 3834 people who took part in Lord Boyd Orr''s Carnegie survey of family diet and health in prewar Britain between 1937 and 1939 who were followed up with the NHS, central register. Standardised methods were used to measure household dietary intake during a one week period. MAIN OUTCOME MEASURES: Cancer mortality. RESULTS: Significant associations between childhood energy intake and cancer mortality were seen when the confounding effects of social variables were taken into account in proportional hazards models (relative hazard for all cancer mortality 1.15 (95% confidence interval 1.06 to 1.24), P = 0.001, for every MJ increase in adult equivalent daily intake in fully adjusted models). This effect was essentially limited to cancers not related to smoking (relative hazard 1.20; 1.07 to 1.34; P = 0.001), with similar effects seen in men and women. CONCLUSION: This positive association between childhood energy intake and later cancer is consistent with animal evidence linking energy restriction with reduced incidence of cancer and the association between height and human cancer, implying that higher levels of energy intake in childhood increase the risk of later development of cancer. This evidence for long term effects of early diet confirm the importance of optimal nutrition in childhood and suggest that the unfavourable trends seen in the incidence of some cancers may have their origins in early life.     

Lumbar epidural analgesia in labour: relation to fetal malposition and instrumental delivery.

The incidence of instrumental delivery and malposition immediately before delivery was compared in patients who were given lumbar epidural analgesia and those who were not. Instrumental delivery was five times more common and a malposition of the fetal head was more than three times as common in the epidural group as in women who did not receive regional analgesia. Similar incidences were found even when the epidural was electively chosen before labour in the absence of medical indications. The instrumental delivery rate was affected by parity, the length of the second stage of labour, and the return of sensation by the second stage but not by other factors studied. The high incidence (20%) of malposition associated with epidural analgesia was not affected by any of the factors studied. The psychological and physical disadvantages of malposition and instrumental delivery have yet to be assessed. In the meantime, when there are no medical indications for epidural analgesia, the advantages of pain relief should be weighed against those of a normal spontaneous delivery.