Lifetime and 10-year risks of cardiovascular mortality in relation to risk factors in middle and old age: 50-year follow-up of the Whitehall study of London Civil Servants.

BACKGROUND: Cardiovascular disease (CVD)-related mortality has declined substantially in the United Kingdom (UK) in recent decades, but the continued relevance of conventional risk factors for prediction of CVD mortality throughout the life-course is uncertain. We compared the 10-year risks and lifetime risks of CVD mortality associated with conventional risk factors recorded in middle and old age. METHODS: The Whitehall study was a prospective study of 19,019 male London civil servants (mean age 52 years) when enrolled in 1967-1970 and followed-up for 50 years for cause-specific mortality. In 1997, 7044 (83%) survivors (mean age 77 years) were re-surveyed. The 10-year and lifetime risks of CVD mortality were estimated by levels of CVD risk factors recorded in middle-age and old-age, respectively. RESULTS: By July 2020, 97% had died (22%, 51% and 80% before age 70, 80 and 90 years, respectively) and 7944 of 17,673 deaths (45%) were from CVD. The 10-year and lifetime risks of CVD death increased linearly with higher levels of CVD risk factors recorded in middle-age and in old-age. Individuals in the top versus bottom 5% of CVD risk scores in middle age had a 10.3% (95% CI:7.2-13.4) vs 0.6% (0.1-1.2) 10-year risk of CVD mortality, a 61.4% (59.4-65.3) vs 31.3% (24.1-34.5) lifetime risk of CVD mortality and a 12-year difference in life expectancy from age 50 years. The corresponding differences using a CVD risk score in old-age were 11.0% (4.4-17.5) vs 0.8% (0.0-2.2) for 10-year risk and 42.1% (28.2-50.0) vs 30.3% (6.0-38.0) for lifetime risk of CVD mortality and a 6-year difference in life expectancy from age 70 years. CONCLUSIONS: Conventional risk factors remained highly predictive of CVD mortality and life expectancy through the life-course. The findings highlight the relevance of estimation of both lifetime risks of CVD and 10-year risks of CVD for primary prevention of CVD.

Tissue sodium content in patients with systemic lupus erythematosus: association with disease activity and markers of inflammation.

OBJECTIVES: Sodium (Na+) is stored in the skin and muscle and plays an important role in immune regulation. In animal models, increased tissue Na+ is associated with activation of the immune system, and high salt intake exacerbates autoimmune disease and worsens hypertension. However, there is no information about tissue Na+ and human autoimmune disease. We hypothesized that muscle and skin Na+ content is (a) higher in patients with systemic lupus erythematosus (SLE) than in control subjects, and (b) associated with blood pressure, disease activity, and inflammation markers (interleukin (IL)-6, IL-10 and IL-17 A) in SLE. METHODS: Lower-leg skin and muscle Na+ content was measured in 23 patients with SLE and in 28 control subjects using 23Na+ magnetic resonance imaging. Demographic and clinical information was collected from interviews and chart review, and blood pressure was measured. Disease activity was assessed using the SLE Disease Activity Index (SLEDAI). Plasma inflammation markers were measured by multiplex immunoassay. RESULTS: Muscle Na+ content was higher in patients with SLE (18.8 (16.7-18.3) mmol/L) than in control subjects (15.8 (14.7-18.3) mmol/L; p < 0.001). Skin Na+ content was also higher in SLE patients than in controls, but this difference was not statistically significant. Among patients with SLE, muscle Na+ was associated with SLEDAI and higher concentrations of IL-10 after adjusting for age, race, and sex. Skin Na+ was significantly associated with systolic blood pressure, but this was attenuated after covariate adjustment. CONCLUSION: Patients with SLE had higher muscle Na+ content than control subjects. In patients with SLE, higher muscle Na+ content was associated with higher disease activity and IL-10 concentrations.

Induction of ß-defensins by l-isoleucine as novel immunotherapy in experimental murine tuberculosis.

Tuberculosis is a worldwide health problem, and multidrug-resistant (MDR) and extensively multidrug-resistant (XMDR) strains are rapidly emerging and threatening the control of this disease. These problems motivate the search for new treatment strategies. One potential strategy is immunotherapy using cationic anti-microbial peptides. The capacity of l-isoleucine to induce beta-defensin expression and its potential therapeutic efficiency were studied in a mouse model of progressive pulmonary tuberculosis. BALB/c mice were infected with Mycobacterium tuberculosis strain H37Rv or with a MDR clinical isolate by the intratracheal route. After 60 days of infection, when disease was in its progressive phase, mice were treated with 250 µg of intratracheal l-isoleucine every 48 h. Bacillary loads were determined by colony-forming units, protein and cytokine gene expression were determined by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), respectively, and tissue damage was quantified by automated morphometry. Administration of l-isoleucine induced a significant increase of beta-defensins 3 and 4 which was associated with decreased bacillary loads and tissue damage. This was seen in animals infected with the antibiotic-sensitive strain H37Rv and with the MDR clinical isolate. Thus, induction of beta-defensins might be a potential therapy that can aid in the control of this significant infectious disease.

BMI peak in infancy as a predictor for later BMI in the Uppsala Family Study.

BACKGROUND: The development of obesity through childhood, often characterized by using body mass index (BMI), has received much recent interest because of the rapidly increasing levels of obesity worldwide. However, the extent to which the BMI trajectory in the first year of life (the BMI 'peak' in particular) is associated with BMI in later childhood has received little attention. SUBJECTS: The Uppsala Family Study includes 602 families, comprising mother, father and two consecutive singleton offspring, both of whom were delivered at the Uppsala Academic Hospital, Sweden, between 1987 and 1995. The children's postnatal growth data, including serial measurements of height and weight (from which BMI was calculated), were obtained from health records. All children had a physical examination when they were aged between 5 and 13 years, at which height and weight were again recorded and used to calculate age- and sex-adjusted BMI z-scores. METHODS: Subject-specific growth curves were fitted to the infant BMI data using penalized splines with random coefficients, and from these the location of the BMI peak for each participant was estimated. A multilevel modelling approach was used to assess the relationships between the BMI peak and BMI z-score in later childhood. RESULTS: The BMI peak occurred, on average, slightly later in female children, with a higher BMI peak in male children. Considered separately, both age and BMI at BMI peak were positively associated with later BMI z-score. Considered jointly, both dimensions of BMI peak retained their positive associations. CONCLUSIONS: The growth trajectory associated with higher childhood BMI appears to include a later and/or higher BMI peak in infancy.

Lifetime reproductive output over two generations in patients with psychosis and their unaffected siblings: the Uppsala 1915-1929 Birth Cohort Multigenerational Study.

BACKGROUND: Schizophrenic patients have fewer offspring than the general population but it is unclear whether (i) this persists for more than one generation, (ii) the reduced fertility is compensated by increased fertility in unaffected relatives, (iii) sociodemographic factors confound or interact with the association, and (iv) patients with affective psychosis have a similar fertility disadvantage. This study measured biological fitness over two generations in patients with schizophrenia or affective psychosis, and their unaffected siblings. METHOD: We conducted a historical cohort study using a Swedish birth cohort of 12 168 individuals born 1915-1929 and followed up until 2002. We compared biological fitness over two generations in patients with schizophrenia (n=58) or affective psychosis (n=153), and their unaffected siblings, with the population, adjusting for a range of sociodemographic variables from throughout the lifespan. RESULTS: Patients with schizophrenia had fewer children [fertility ratio (FR) 0.42, 95% confidence interval (CI) 0.29-0.61] and grandchildren (FR 0.51, 95% CI 0.33-0.80) than the population. Some of this reduction was related to lower marriage rates in schizophrenic patients. The unaffected siblings of schizophrenic patients showed no evidence of any compensatory increase in fitness, but there was a trend towards enhanced fertility among the offspring of schizophrenia patients. Patients with affective psychosis and their relatives did not differ from the general population on any fertility measure. CONCLUSIONS: Schizophrenia, but not affective psychosis, is associated with reduced biological fertility; this disadvantage is partly explained by marital status and persists into the second generation.

Breast-feeding influences on later life--cardiovascular disease.

Current evidence, almost exclusively from observational studies, provides a rather mixed picture. From the few studies that have been able to look at fatal or non-fatal cardiovascular events, there is little indication that breast-feeding is associated with either an increased or decreased risk. With respect to blood pressure, the meta-analyses suggest a small but statistically significant lowering of around 1 mmHg SBP associated with having been breast-fed in infancy. However, there is a strong indication from the meta-analyses that even this small effect may partly be accounted for by publication bias. The strongest evidence for an effect of breast-feeding reviewed in this chapter is for serum lipids, where there is good evidence that being breast-fed is associated with an increase in serum total cholesterol in infancy. In childhood there appears to be no association, while in adults there is some indication of breast-feeding being associated with a small decline in total cholesterol levels. As already outlined at the start of the chapter, this whole area of research is made particularly difficult by the fact that breast-feeding can be defined in many different ways. Some studies use definitions that are equivalent to exclusive breast-feeding prior to weaning, while others define it as having ever been breast-fed. This problem of classification is likely to dilute any real associations that may exist. The other major problem is one of interpretation. A result implying that breast-feeding is a "good thing" for cardiovascular health could equally be construed as evidence for a "bad" effect of bottle-feeding. From these data alone, we cannot convincingly determine which conclusion is correct. This is not simply a philosophical debating point. As discussed above in relation to the interpretation of results from the randomised trial of infant feeding, the issue has implications for all research on this topic. Some progress in this area will be made if studies are conducted which define breast-feeding in a more precise and comparable way, and take account of the composition of alternative infant feeds. This will be most easily done by following up more recent study populations that were originally recruited to look at shorter-term effects of infant feeding on outcomes such as growth. With respect to randomised trial evidence, looking at the cardiovascular disease risk profiles of children (and later adults) who were part of the PROBIT trial in Belarus (see Chapters 5 and 10) is likely to prove fruitful.

Obesity in urban civil servants in Ghana: association with pre-adult wealth and adult socio-economic status.

OBJECTIVE: To investigate the distribution of obesity and its association with pre-adult wealth and adult socio-economic factors in urban Ghanaian civil servants. STUDY DESIGN: Cross-sectional study of urban civil servants. METHODS: A total of 1015 (615 men and 400 women) civil servants aged 25 years and above employed in seven central government ministries and departments in Accra, Ghana were studied (participation rate 82.7%). RESULTS: The prevalence of obesity [body mass index (BMI) > or =30.0 kg/m(2)] was 10% in men and 36% in women. Men of higher pre-adult or current socio-economic position generally had higher mean BMI and waist circumference. In women, however, the mean waist circumference was higher in those of lower socio-economic position (lower education, less pre-adult wealth), but mean BMI did not differ significantly between socio-economic groups. There was a positive graded association between pre-adult and adult levels of wealth (determined by the availability of selected household amenities) and the risk of obesity in men (P-trend=0.003), but weak suggestions of an inverse association between adult level of wealth and obesity in women under 45 years of age. CONCLUSIONS: The high prevalence of obesity in this population indicates the need for appropriate interventions for its prevention and treatment. Programmes and interventions to control obesity need to address different needs of men and women in the various social strata, and must not be limited to adults.

Prevalence and socio-economic distribution of hazardous patterns of alcohol drinking: study of alcohol consumption in men aged 25-54 years in Izhevsk, Russia.

AIM: To estimate the prevalence of hazardous drinking and its socio-economic distribution among Russian men. DESIGN: Participants were an age-stratified, population-based random sample of men aged 25-54 years living in Izhevsk, a city in the Urals, Russia. Interviewers administered questionnaires to cohabiting proxy respondents about behavioural indicators of hazardous drinking derived from frequency of hangover, frequency of drinking beverage spirits, episodes in the last year of extended periods of drunkenness during which the participant withdraws from normal life (zapoi), consumption of alcoholic substances not intended to be drunk (surrogates) and socio-economic position. Logistic regression was used to examine associations between socio-economic position and indicators of hazardous drinking in the past year. FINDINGS: Of 1750 men, 79% drank spirits and 8% drank surrogates at least sometimes in the past year; 25% drank spirits and 4% drank surrogates at least weekly and 10% had had an episode of zapoi in the past year. After adjustment for other socio-economic factors, education was strongly associated with indicators of hazardous drinking. Men with the lowest level of education compared to the highest level of education had an odds ratio of surrogate drinking of 7.7 (95% CI 3.2-18.5), of zapoi of 5.2 (2.3-11.8) and of frequent hangover of 3.7 (1.8-7.4). These indicators of hazardous drinking were also independently strongly associated with being unemployed (versus employed) and with levels of household wealth/amenities. Associations of all these variables with daily consumption of beverage spirits were weaker. CONCLUSION: Using a novel range of indicator variables of hazardous drinking, this paper shows that the prevalence of these behaviours is high among working-age men in this Russian city. Moreover, these hazardous behaviours show very clear socio-economic patterns, with particularly high prevalence among those who have had the least education and are not in employment. In contrast, more conventional measures of heavy drinking, based on frequency of consumption of beverage spirits, are less prevalent and show much weaker associations with socio-economic position.

Birth weight, hypertension and "white coat" hypertension: size at birth in relation to office and 24-h ambulatory blood pressure.

We investigated the association of size at birth with hypertensive status defined by office blood pressure (BP) and 24-h ambulatory BP monitoring in a historical cohort study of 736 men born 1920-1924 and examined at age 70 years. Office BP was measured after 10-min supine rest with a sphygmomanometer, ambulatory BP was recorded with Accutracker 2, and anthropometric and other measurements were taken at a clinic. Birth weight and gestational age were abstracted from the men's birth records. A total of 24% of the men were treated for hypertension at the time of the study. Among not treated subjects, there was a weak positive association of birth weight with daytime and 24-h diastolic ambulatory BP. In subjects treated for hypertension, both office and ambulatory BP were inversely related to birth weight, although these associations were not statistically significant. Birth weight did not show significant association with sustained hypertension (elevated office and daytime ambulatory BPs) but showed a strong and statistically significant inverse association with "white coat" hypertension (elevated office BP and normal daytime ambulatory BP) when adjusted for concurrent body mass index (odds ratios 1.91, 1.59, 1 and 1.21 from lowest to highest quartile of birth weight, P-value for trend 0.035). We conclude that BP measured by 24-h-ambulatory monitoring is not related to birth weight in a pattern previously reported for office BP and that factors related to growth in utero are particularly related to higher risk of "white coat" hypertension.

Is the effect of low birth weight on cardiovascular mortality mediated through high blood pressure?

OBJECTIVE: To explore whether the inverse association between birth weight and mortality from circulatory diseases is mediated through blood pressure in men aged 50-75 years. DESIGN: Cohort study with retrospectively collected data on size at birth. SUBJECTS AND SETTING: The study included 1334 men born during 1920-1924, living in Uppsala, Sweden, who were examined at the ages of 50 and 60 years, and followed-up to the end of 1995. MAIN OUTCOME MEASURES: Mortality from circulatory diseases based on routine death registration. RESULTS: Birth weight showed a specific, inverse association with mortality from circulatory diseases: the rate ratio was 0.67 (95% confidence interval 0.50 to 0.89) per 1000 g increase in birth weight. This association was not appreciably affected by adjustment for sociodemographic characteristics or smoking, but was strengthened slightly by adjustment for body mass index at the ages of 50 and 60 years. Adjustment for systolic blood pressure at the age of 50 years only slightly reduced the strength of the inverse association between birth weight and mortality from ischaemic heart disease, and did not affect the inverse association between birth weight and mortality from stroke. Adjustments for systolic and diastolic blood pressure and hypertension treatment at the ages of 50 and 60 years did not reduce the strength of the association between birth weight and mortality from circulatory diseases at the age of 60-75 years. CONCLUSIONS: The inverse association between birth weight and mortality from circulatory diseases in men aged 50-75 years is independent of adult sociodemographic characteristics, smoking and adult obesity and does not seem to be mediated through an increased blood pressure in those with low birth weight.

Self-perceived health status and inequalities in use of health services in Spain.

BACKGROUND: Socioeconomic differences have been described among the Spanish population. The purpose of this study was to investigate whether these variations are associated with differences in the use of health services between socioeconomic groups in Spain, taking into account self-perceived health as a measure of need. METHODS: Data were obtained from the 1987 Spanish National Health Survey. Socioeconomic position was measured by educational level and household income. Health care use was measured in two ways: prevalence of having consulted a doctor and of hospitalization over a defined period of time. Logistic regression models were used to analyse the relationship of interest. RESULTS: After adjustment for age, an inverse association was seen between education and both consultation with a doctor and hospitalization. A very different picture emerged when the association between socioeconomic position and probability of health service use was examined according to level of self-perceived health. Among those with poor or very poor health, people in higher educational groups showed the greatest probability of consulting a doctor (odds ratio [OR] = 1.41, 95% confidence interval [CI] : 0.89-2.23) or of being hospitalized (OR = 1.79, 95% CI : 1.09-2.93) compared to those in the lower educational groups. The corresponding OR for household income were 1.02 (95% CI : 0.74-1.42) for consultation with a doctor and 1.67 (95% CI : 1.15-2.44) for hospitalization. These finding were broadly similar for men and women. CONCLUSIONS: There is a socioeconomic variation in the pattern of use of health services in Spain in the sense that among those with poor self-perceived health, the more privileged have higher levels of health services use than others.

Social determinants of birthweight and length of gestation in Estonia during the transition to democracy.

BACKGROUND: To investigate social variation in birthweight and length of gestation in Estonia in the period of transition to a democracy and market economy. METHODS: All live births resulting from singleton pregnancies reported to the Estonian Medical Birth Registry in 1992-1997 (n = 84, 629) were studied with respect to social variation in birthweight and preterm delivery (<37 weeks gestation). The results were adjusted for maternal age, parity, education, nationality, marital status, smoking in pregnancy, sex of the infant (and gestational age). RESULTS: Between 1992 and 1997, mean birthweight increased from 3,465g to 3,497g (P < 0.001) and the preterm rate fell from 5.8% to 5.1% (P = 0.001). Maternal education, marital status and nationality were all independently related to the mean birthweight and the risk of preterm birth. The mean difference in birthweight between children of mothers with basic and university education was 87 g (95% CI : 74-100). Children born to mothers of non-Estonian compared to Estonian nationality were on average 77 g lighter (95% CI: 70-84). While the effect of nationality and marital status on birthweight was relatively stable during the study period, differences in birth outcome by maternal education became stronger. CONCLUSIONS: The mean birthweight increased and the preterm rate decreased in Estonia as a whole during the transition. However, the improvements were not shared equally by all social groups. An increase in variation in birthweight by maternal education was particularly notable.

Can confounding by sociodemographic and behavioural factors explain the association between size at birth and blood pressure at age 50 in Sweden?

STUDY OBJECTIVE: To evaluate whether socioeconomic confounding explains the relationship between size at birth and blood pressure at age 50. DESIGN: Cross sectional study with retrospectively collected data on size at birth. SETTING: Uppsala, Sweden. PARTICIPANTS: 1333 men born in 1920-24, and a subset of 615 men for analyses including early social circumstances. MAIN OUTCOME MEASURES: Blood pressure measured after 10 minutes rest in supine position. Crude and adjusted effect measures were compared. MAIN RESULTS: Controlling for sociodemographic characteristics at age 50, such as socioeconomic position, highest education achieved and marital status did not reduce the strength of the association between birth weight and systolic blood pressure at 50 years. In the total population, the slope of the body mass index adjusted relationship changed from -3.4 mmHg/kg to -3.5 mmHg/kg on additional adjustment for sociodemographic characteristics at age 50 (both p values < 0.01). Controlling for behavioural characteristics at age 50, such as smoking and recent alcohol drinking, did not affect the relationship between birth weight and blood pressure at 50. In the 615 men for whom information on sociodemographic circumstances in early life was available, adjustment for factors such as social class of the family, mother's marital status or area of residence, led to a slight reduction of the effect of birth weight on systolic blood pressure at age 50. The slope of the body mass index adjusted relationship changed from -2.8 mmHg/kg to -2.6 mmHg/kg after additional adjustment for early life circumstances in the sample as a whole (p values 0.09 and 0.12). Simultaneous adjustment for sociodemographic characteristics at birth together with sociodemographic and behavioural characteristics at age 50 led to only a slight reduction of the effect of birth weight on systolic blood pressure at 50 years. CONCLUSION: The strong inverse associations between birth weight and blood pressure among 50 year old Swedish men are highly unlikely to be explained by confounding with socioeconomic circumstances at birth or in adult life.

Adult height and mortality in London: early life, socioeconomic confounding, or shrinkage?

STUDY OBJECTIVE: To examine in detail the cause specific associations between height and mortality. DESIGN: A prospective cohort study with an 18 year mortality follow up. SETTING AND PARTICIPANTS: The Whitehall study of 18,403 men in the civil service in London examined between 1967 and 1969 aged 40-64 and followed up for mortality until the end of January 1987. MAIN RESULTS: There was considerable variation in the strength of height-mortality association by cause. Respiratory disease showed the strongest inverse association, cardiovascular disease a moderate effect, and all neoplasms virtually no effect. Adjustment for age and civil service grade reduced the strength of these associations slightly, but had no impact on the heterogeneous pattern by cause (chi 2 3df p < 0.001). The height-mortality association declined with the length of follow up. By 15+ years, the only appreciable height affect was for respiratory disease mortality. CONCLUSIONS: The attenuation of the height-mortality association with length of follow up might be explained by differential height reduction before entry that was greatest for people who were already ill, and hence at greatest risk of dying. The cause specific variation in the height-mortality association lends little support to the contention that impaired growth in childhood is a marker of general susceptibility to disease in adulthood.

Educational level and adult mortality in Russia: an analysis of routine data 1979 to 1994.

The investigation of socio-economic differences in mortality in Russia was effectively prohibited in the Soviet period. The extent and nature of any such differences is of considerable interest given the very different principles upon which Russian society has been organised for most of this century compared to the West where socio-economic differences in health have been extensively documented. Using cross-sectional data on mortality in Russia around the 1979 and 1989 Censuses, we have analysed mortality gradients according to length of education. Our results show that educational differences in mortality are at least as big as seen in Western countries, and are most similar to the recently reported differences observed for other former communist countries such as the Czech Republic, Estonia and Hungary. As observed in many other countries the strength of association of mortality with education declines with age, varies by cause of death and is generally stronger among men than women. Differentials are particularly large for accidents and violence, where for men and women the mortality rate among those with primary or basic secondary education is over twice that of people with higher education. Even larger effects are seen for causes directly related to alcohol (including alcoholic cirrhosis and accidental poisoning by alcohol), and for infectious and parasitic diseases and respiratory diseases. These educational differences may in part be related to educational differences in alcohol consumption. Of particular significance is the fact that there are indications that socio-economic differences in mortality have widened considerably in the 1990s, a period during which there was a huge increase in the national burden of alcohol-related deaths. This widening of socio-economic differences at this time suggest that these increases in consumption were especially acute among those with less education. At a more general level the fact that large educational differences in mortality were seen in Russia in 1979 and 1989, prior to the collapse of the Soviet Union, is very striking and informative. In this period there was a far weaker association between income and education than is seen in the West, suggesting that the education effects are unlikely to be driven by underlying differences in financial resources. The protective effect of education, in the Russian context at least, has been driven by more subtle and mechanisms. The apparent widening of socio-economic mortality differences since the collapse of the Soviet Union suggests that the transformation underway in Russian society requires a strengthening of the public health function.

Fetal growth and adult disease.

Current knowledge on associations between variations in fetal growth on the one hand and blood pressure, noninsulin dependent diabetes, coronary heart disease and cancer in adulthood on the other is reviewed and related to more conventional preoccupations of perinatal epidemiology. Commonly used definitions and indicators of impaired fetal growth, possible explanations and mechanisms of the association between fetal growth impairment and later disease, and the concept and operational definitions of programming are discussed. Implications and research priorities that can be derived from this information are presented.

Influence of birth weight on differences in infant mortality by social class and legitimacy.

OBJECTIVE: To investigate the influence of birth weight on the pronounced social class differences in infant mortality in Britain. DESIGN: Analysis of routine data on births and infant deaths. SETTING: England and Wales. SUBJECTS: All live births and infant deaths, 1983-5. MAIN OUTCOME MEASURE: Mortality in infants by social class, birth weight, and legitimacy according to birth and death certificates. RESULTS: Neonatal and postneonatal mortality (deaths/1000 births) increased with social class. Neonatal and postneonatal mortality was 4.2/1000 and 2.3/1000 respectively for social class I and 6.8/1000 and 5.6/1000 respectively for social class V. Mortality was lower among births registered within marriage (postneonatal 3.5/1000; neonatal 5.2/1000) than among those jointly registered outside marriage (5.1/1000; 6.4/1000); mortality was highest in those solely registered outside marriage (7.2/1000; 7.0/1000). For neonatal mortality the effect of social class varied with birth weight. Social class had little effect on neonatal mortality in low birthweight babies and increasing effect in heavier babies. For postneonatal mortality the effect of social class was similar for all birth weights and was almost as steep as for all birth weights combined. CONCLUSION: Birth weight mediates little of the effect of social class on postneonatal mortality.

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.

Social class differences in infant mortality in Sweden: comparison with England and Wales.

OBJECTIVES: To investigate social class differences in infant mortality in Sweden in the mid-1980s and to compare their magnitude with that of those found in England and Wales. DESIGN: Analysis of risk of infant death by social class in aggregated routine data for the mid-1980s, which included the linkage of Swedish births to the 1985 census. SETTING: Sweden and England and Wales. SUBJECTS: All live births in Sweden (1985-6) and England and Wales (1983-5) and corresponding infant deaths were analysed. The Swedish data were coded to the British registrar general's social class schema. MAIN OUTCOME MEASURES: Risk of death in the neonatal and postneonatal period. RESULTS: Taking the non-manual classes as the reference group, in the neonatal period in Sweden the manual social classes had a relative risk for mortality of 1.20 (95% confidence interval 1.02 to 1.43) and those not classified into a social class a relative risk of 1.08 (0.88 to 1.33). In the postneonatal period the equivalent relative risks were 1.38 (1.08 to 1.77) for manual classes and 2.14 (1.65 to 2.79) for the residual; these are similar to those for England and Wales (1.43 (1.36 to 1.51) for manual classes, 2.62 (2.45 to 2.81) for the residual). CONCLUSIONS: The existence of an equitable health care system and a strong social welfare policy in Sweden has not eliminated inequalities in post-neonatal mortality. Furthermore, the very low risk of infant death in the Swedish non-manual group (4.8/1000 live births) represents a target towards which public health interventions should aim. If this rate prevailed in England and Wales, 63% of postneonatal deaths would be avoided.