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.

Obesity prevalence and associations with socio-economic and behavioral factors in population-based studies in Russia and Norway, 2015–2017

Background

Obesity is an epidemic of XXI century, as its prevalence doubled during the last forty years. As Russia and Norway are countries with different life expectancy there could be differences in obesity and its correlates.

Purpose

To investigate and compare prevalence and socio-economic and behavioral factors associated with obesity in Russia and Norway with data from population-based studies.

Methods

We used multivariable logistic regression to examine associations of obesity (body mass index>30 kg/m2) with socio-economic factors (age, education, marital status, and poor financial situation defined as difficulty to afford clothes) and behavioral characteristics (smoking, alcohol use) in participants aged 40–69 years from the Know Your Heart study (Russia, 2015–2017, N=4 106) and the seventh Study (Norway, 2015–16, N=17 604). All results for covariates are mutually adjusted. Between-study comparisons of the associations of obesity with the same covariates were performed through investigation of their interactions with the “study” variable.

Results

The age-standardized prevalence of obesity was higher in Russia among women (36.8 vs 22.0%, p<0.001) and did not differ among men (26.7 vs 25.7%, p=0.224). In Russian women, obesity was positively associated with age of 50–69 years relative to 40–49 years (OR=2.5, 95% CI 2.0–3.1), no university education (OR=1.5, 95% CI 1.2–1.8), and poor financial situation (OR=1.5, 95% CI 1.2–1.9). In Norwegian women, obesity was negatively associated with the age of 50–69 years (OR=0.8, 95% CI 0.8–1.0), current smoking (OR=0.8, 95% CI 0.7–1.0) and drinking alcohol ≥2 times per week (OR=0.6, 95% CI 0.5–0.6), and positively associated with no university education (OR=1.5, 95% CI 1.3–1.7), previous smoking (OR=1.3, 95% CI 1.1–1.4), and drinking ≥5 alcohol drinks per occasion (OR=1.7, 95% CI 1.3–2.2). In Russian men, obesity was positively associated with living with spouse/partner (OR=1.5, 95% CI 1.1–2.2), drinking alcohol ≥2 times per week (OR=1.4, 95% CI 1.1–1.8), and negatively associated with current smoking (OR=0.6, 95% CI 0.4–0.8). In Norwegian men, obesity was positively associated with no university education (OR=1.4, 95% CI 1.2–1.6), previous smoking (OR=1.3, 95% CI 1.2–1.5), and drinking ≥5 alcohol drinks per occasion (OR=1.7, 95% CI 1.5–1.9), and negatively associated with current smoking (OR=0.8, 95% CI 0.7–1.0) and drinking alcohol ≥2 times per week (OR=0.7, 95% CI 0.6–0.7). Interactions with the “study” variable in women were significant for age, financial situation, frequency of alcohol use; in men - for living with spouse/partner, frequency of alcohol use, number of alcohol drinks taken per occasion.

Conclusion

The prevalence of obesity was higher in Russian compared to Norwegian women, but there was no difference between Russian and Norwegian men. There were different between-country patterns of the associations of obesity with the socio-economic and behavioral characteristics.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The Know Your Heart study was a component of International Project on Cardiovascular Disease in Russia and funded by Wellcome Trust Strategic Award [100217], UiT The Arctic University of Norway, Norwegian Institute of Public Health, and Norwegian Ministry of Health and Care Services. The Tromsø Study was funded by UiT The Arctic University of Norway, Northern Norway Regional Health Authority, Norwegian Ministry of Health and Care Services, Norwegian Research Council, and various public and charity research funds in Norway. PhD scholarship and operational funds of the first author were provided by Northern State Medical University, Arkhangelsk, Russia and by UiT The Arctic University of Norway

Availability and Affordability of Medicines for the Treatment of Cardiovascular Diseases in Pharmacies in Six Regions of the Russian Federation

Aim. To evaluate the availability and affordability of medicines used to treat of cardiovascular diseases (CVD) in several regions of the Russian Federation with different climatic, geographic, economic and demographic characteristics. Material and methods. The study was conducted in 6 regional capitals, chosen to differ in geographically, economically, and demographically. In each city, 5 pharmacies providing free medicines to certain categories of citizens (beneficiaries) and 5 private pharmacies serving anyone were selected at random. Medicine availability was assessed in all pharmacies, along with price only in the private pharmacies. Data were obtained for both original drug and appropriate generics. A list of 25 of the most frequently prescribed medicines for cardiovascular diseases was compiled. Results. Some general findings emerged. With the existence of a generic drug, the original drug was not available in the pharmacy supplying beneficiaries. Diuretics, as well as some ACE inhibitors, are not available in a number of pharmacies for beneficiaries. Enalapril in most licensed pharmacies is represented by generics, lisinopril in a number of cities is represented by both the original drug and generics. The presence of sartans was much lower than ACE inhibitors. Bisoprolol was most common beta-blocker. Calcium antagonists: if amlodipine was present in all licensed pharmacies, at list as generic, then nifedipine was not available in many licensed pharmacies. Among antiplatelet agents, aspirin was available in most pharmacies, and clopidogrel was mostly represented by generics. As for statins, only simvastatin could be found in almost all pharmacies. When analyzing the cost of drugs in licensed pharmacies, it was found that drugs containing furosemide are the cheapest among generics – about 17 rubles. The most expensive treatment with generics of rosuvastatin – about 4,374 rubles a month. The most expensive original medicine was also rosuvastatin – about 4,500 rubles for 30 tablets, the cheapest – the original drug of furosemide – about 35 rubles. On average, the cost of CVD treatment with major classes of drugs, including ACE inhibitor, beta-blocker, antiplatelet drug and statin, is 1,921.9 rubles per month. Conclusion. The basic cardiovascular medicines were characterized by a relatively high availability in 6 regions of the Russian Federation included in the analysis both by the criterion of the availability of drugs and by the criterion of the minimum price.

Sex-specific relevance of diabetes to occlusive vascular and other mortality: a collaborative meta-analysis of individual data from 980 793 adults from 68 prospective studies

BACKGROUND

Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women than among men, but whether this increased relative risk in women exists across age groups and within defined levels of other risk factors is uncertain. We aimed to determine whether differences in established risk factors, such as blood pressure, BMI, smoking, and cholesterol, explain the higher relative risks of vascular mortality among women than among men.

METHODS

In our meta-analysis, we obtained individual participant-level data from studies included in the Prospective Studies Collaboration and the Asia Pacific Cohort Studies Collaboration that had obtained baseline information on age, sex, diabetes, total cholesterol, blood pressure, tobacco use, height, and weight. Data on causes of death were obtained from medical death certificates. We used Cox regression models to assess the relevance of diabetes (any type) to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke, or other atherosclerotic deaths) by age, sex, and other major vascular risk factors, and to assess whether the associations of blood pressure, total cholesterol, and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes.

RESULTS

Individual participant-level data were analysed from 980 793 adults. During 9·8 million person-years of follow-up, among participants aged between 35 and 89 years, 19 686 (25·6%) of 76 965 deaths were attributed to occlusive vascular disease. After controlling for major vascular risk factors, diabetes roughly doubled occlusive vascular mortality risk among men (death rate ratio [RR] 2·10, 95% CI 1·97-2·24) and tripled risk among women (3·00, 2·71-3·33; χ2 test for heterogeneity p<0·0001). For both sexes combined, the occlusive vascular death RRs were higher in younger individuals (aged 35-59 years: 2·60, 2·30-2·94) than in older individuals (aged 70-89 years: 2·01, 1·85-2·19; p=0·0001 for trend across age groups), and, across age groups, the death RRs were higher among women than among men. Therefore, women aged 35-59 years had the highest death RR across all age and sex groups (5·55, 4·15-7·44). However, since underlying confounder-adjusted occlusive vascular mortality rates at any age were higher in men than in women, the adjusted absolute excess occlusive vascular mortality associated with diabetes was similar for men and women. At ages 35-59 years, the excess absolute risk was 0·05% (95% CI 0·03-0·07) per year in women compared with 0·08% (0·05-0·10) per year in men; the corresponding excess at ages 70-89 years was 1·08% (0·84-1·32) per year in women and 0·91% (0·77-1·05) per year in men. Total cholesterol, blood pressure, and BMI each showed continuous log-linear associations with occlusive vascular mortality that were similar among individuals with and without diabetes across both sexes.

INTERPRETATION

Independent of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes to reduce smoking and obesity and use of cost-effective drugs that target major vascular risks (eg, statins and antihypertensive drugs) are important in both men and women with diabetes, but might not reduce the relative excess risk of occlusive vascular disease in women with diabetes, which remains unexplained.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union BIOMED programme, and National Institute on Aging (US National Institutes of Health).

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.

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.

Socioeconomic position and hypertension: a study of urban civil servants in Ghana

BACKGROUND

The association of socioeconomic position and cardiovascular disease risk factors in low- and middle-income countries has not been as consistent as that reported from high-income countries.

METHODS

A cross-sectional study of 1015 participants from seven civil service departments in Accra, Ghana, was conducted in 2006. Hypertension was diagnosed when the mean of a second and third blood pressure reading on each of two visits 3 weeks apart was > or =140/90 mmHg or where participants were already diagnosed and on antihypertensive drugs. Socioeconomic measures considered were education, early life and adult wealth and civil service employment grade.

RESULTS

The age-adjusted prevalence of hypertension was lowest in participants of lower socioeconomic position (OR 21.9%; 95% CI 16.3 to 27.5) and highest in those of highest socioeconomic position (OR 31.8%; 95% CI 23.4 to 40.2) with inconsistent patterns among participants in the intermediate socioeconomic groups. Participants in the highest employment grade category were more likely to have hypertension than those in the lowest category (OR 1.91; 95% CI 1.14 to 3.20). There was a positive graded association between adult wealth and hypertension, with more assets associated with a greater risk (p trend 0.008). This trend was partly explained by body mass index differences. Blood pressure control among those with diagnosed hypertension was generally poor across the socioeconomic strata.

CONCLUSIONS

In low-income countries such as Ghana, there is a need to promote primary prevention of hypertension across the socioeconomic strata, with a focus on weight control among civil servants of higher socioeconomic position, and better hypertension control in those with hypertension.

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.

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.

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.

The associations of birthweight, gestational age and childhood BMI with type 2 diabetes: findings from the Aberdeen Children of the 1950s cohort

AIMS/HYPOTHESIS

The aim of this study was to examine the associations of birthweight, gestational age and childhood BMI (assessed at a mean age of 5 years) with a self-report of a doctor diagnosis of diabetes in middle age.

METHODS

We studied a birth cohort of 5,793 individuals who were born between 1950 and 1956 in Aberdeen, Scotland, and who responded to a questionnaire administered in 2000.

RESULTS

Birthweight and gestational age were inversely associated with diabetes. These associations remained with additional adjustment for indicators of childhood and adult socioeconomic position, maternal complications of pregnancy, adult smoking, adult BMI and simultaneous adjustment for each other: the adjusted odds ratio per unit increase in birthweight z score was 0.73 (95% CI 0.60-0.88), the odds ratio per week increase in gestational age was 0.91 (95% CI 0.82-1.00) and odds ratio for preterm birth was 2.04 (94% CI 1.18-3.53). The positive association of childhood BMI with diabetes was attenuated on adjustment for adult BMI.

CONCLUSIONS/INTERPRETATION

In this population, who were born in the 1950s, poor intrauterine growth and preterm birth are associated with an increased risk of diabetes.

Childhood intelligence, educational attainment and adult body mass index: findings from a prospective cohort and within sibling-pairs analysis

BACKGROUND

The mechanisms underlying the observed association of childhood intelligence with body mass index (BMI) are unclear and few studies of this association have been prospective in design.

METHODS

Prospective study in a birth cohort of 5467 individuals who were born in Aberdeen, Scotland between 1950 and 1956 and who responded to a follow-up survey in 2001. Comparison of associations within sibling pairs of the same family to associations between different families in 643 sibling pairs (1286 individuals) who are participants in the main cohort.

RESULTS

Childhood intelligence (age 7 years) and educational attainment were both inversely associated with adult BMI (mean age 48 years): the sex- and age-adjusted mean change in adult BMI per s.d. of intelligence was -0.35 kg/m(2) (95% CI: -0.49, -0.21 kg/m(2)) and per unit increase in educational category (seven categories) was -0.28 kg/m(2) (95% CI: -0.34, -0.22). On adjustment for education the association between childhood intelligence and adult BMI attenuated to the null (-0.03 kg/m(2) (-0.19, 0.13 kg/m(2))); other potential confounding or mediating factors had little or only modest effects on this association. The association between education and adult BMI was not affected by adjustment for childhood intelligence or other potential covariates. The within sibling-pair effect of education on adult BMI (-0.06 kg/m(2) (95% CI: -0.26, 0.14)) was weaker than the effect between different families (-0.37 kg/m(2) (95%CI: -0.58, -0.17)), P-value for difference of within sibling and between family effect=0.03.

CONCLUSIONS

The association of childhood intelligence with adult BMI is attenuated to the null on adjustment for educational attainment, whereas the association of educational attainment with adult BMI appears to be independent of childhood intelligence and other measured covariates. However, our family analyses suggest that fixed family and neighbourhood factors, which are closely matched in siblings of a similar age, explain much of the association between greater educational attainment and lower adult BMI.

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.

Fetal growth and subsequent risk of breast cancer: results from long term follow up of Swedish cohort

OBJECTIVE

To investigate whether size at birth and rate of fetal growth influence the risk of breast cancer in adulthood.

DESIGN

Cohort identified from detailed birth records, with 97% follow up.

SETTING

Uppsala Academic Hospital, Sweden.

PARTICIPANTS

5358 singleton females born during 1915-29, alive and traced to the 1960 census.

MAIN OUTCOME MEASURES

Incidence of breast cancer before (at age <50 years) and after (> or = 50 years) the menopause.

RESULTS

Size at birth was positively associated with rates of breast cancer in premenopausal women. In women who weighed > or =4000 g at birth rates of breast cancer were 3.5 times (95% confidence interval 1.3 to 9.3) those in women of similar gestational age who weighed <3000 g at birth. Rates in women in the top fifths of the distributions of birth length and head circumference were 3.4 (1.5 to 7.9) and 4.0 (1.6 to 10.0) times those in the lowest fifths (adjusted for gestational age). The effect of birth weight disappeared after adjustment for birth length or head circumference, whereas the effects of birth length and head circumference remained significant after adjustment for birth weight. For a given size at birth, gestational age was inversely associated with risk (P=0.03 for linear trend). Adjustment for markers of adult risk factors did not affect these findings. Birth size was not associated with rates of breast cancer in postmenopausal women.

CONCLUSIONS

Size at birth, particularly length and head circumference, is associated with risk of breast cancer in women aged <50 years. Fetal growth rate, as measured by birth size adjusted for gestational age, rather than size at birth may be the aetiologically relevant factor in premenopausal breast cancer.

The foetal origins of adult disease: interpreting the evidence from twin studies

Twin studies have a contribution to make to the debate concerning the foetal origins of adult disease. Twins are growth retarded compared to singletons and experience post-natal catch-up growth. However, there is no evidence that twins are at increased risk of cardiovascular disease. Studying whether discordance in size at birth within monozygotic twin pairs is predictive of discordance in later life disease should help resolve whether the association between size at birth and later disease is due to common genetic factors. Results from studies of blood pressure in childhood and adult life looking at these within twin effects are far from conclusive. There are, however, methodological problems in the interpretation of these results, not least of which is the relatively small numbers of twin pairs studied. Studies exploring the effect of zygosity and chorion type on later disease provide may provide a useful extension of the research agenda. In summary, twin studies to date have raised more questions about the foetal origins hypothesis than they have resolved.

Changes in life expectancy in Russia in the mid-1990s

BACKGROUND

Between 1987 and 1994, life expectancy in Russia declined substantially. Between 1994 and 1998, this trend reversed, and mortality rates returned to those of the early 1980s. Although the decline in life expectancy has been examined previously, much less is known about the subsequent improvement in mortality rates. We used recently published cause-specific mortality data up to 1998 to clarify this issue.

METHODS

Changes in cause-specific death rates at ages 15-74 years were examined. Rates for 1998 were compared with those for 1994 (the year of lowest life expectancy) and for 1991 (the year the Soviet Union broke up).

FINDINGS

Death rates among children fell steadily throughout the 1990s, and those in elderly people changed little. The reduction in mortality since 1994 was mainly due to a decrease in the death rate among middle-aged adults, which had increased until 1994. Deaths among those aged 15-30 years, which rose during 1991-94, remained high. Some causes of death, such as stomach cancer and road-traffic accidents, declined throughout the 1990s, whereas others, such as breast and prostate cancers and tuberculosis, increased. The decline in mortality since 1994 was, however, mainly due to a reduction in the rate of deaths from a group of causes associated with alcohol consumption.

INTERPRETATION

The changing life expectancy in Russia is a consequence of a complex pattern of trends in different causes of death, some of which have their origins long in the past, and others that result from contemporary circumstances. This study provides further support for the view that alcohol has played an important part in the fluctuations in life expectancy in Russia in the 1990s, although there remains a need for a much better understanding of the factors underlying these continuing changes.

Do socioeconomic disadvantages persist into old age? Self-reported morbidity in a 29-year follow-up of the Whitehall Study

OBJECTIVES

This study examined (1) the relation of employment grade in middle age to self-reported poor health and functional limitations in old age and (2) whether socioeconomic status at approximately the time of retirement modifies health differentials in old age.

METHODS

Survivors of the Whitehall Study cohort of men were resurveyed. Respondents were aged 40 to 69 years when they were originally screened in 1967 to 1970.

RESULTS

Compared with senior administrators, men in clerical or manual (low-grade) jobs in middle age had quadruple the odds of poor physical performance in old age, triple the odds of poor general health, and double the odds of poor mental health and disability. At most, 20% of these differences were explained by baseline health or risk factors. Men who moved from low to middle grades before retirement were less likely than those who remained in low grades to have poor mental health.

CONCLUSIONS

Socioeconomic status in middle age and at approximately retirement age is associated with morbidity in old age.

Consequences of cAMP-binding site mutations on the structural stability of the type I regulatory subunit of cAMP-dependent protein kinase

The regulatory (R) subunit of cAMP-dependent protein kinase (cAPK) is a multidomain protein with two tandem cAMP-binding domains, A and B. The importance of cAMP binding on the stability of the R subunit was probed by intrinsic fluorescence and circular dichroism (CD) in the presence and absence of urea. Several mutants were characterized. The site-specific mutants R(R209K) and R(R333K) had defects in cAMP-binding sites A and B, respectively. R(M329W) had an additional tryptophan in domain B. Delta(260-379)R lacked Trp260 and domain B. The most destabilizing mutation was R209K. Both CD and fluorescence experiments carried out in the presence of urea showed a decrease in cooperativity of the unfolding, which also occurred at lower urea concentrations. Unlike native R, R(R209K) was not stabilized by excess cAMP. Additionally, CD revealed significant alterations in the secondary structure of the R209K mutant. Therefore, Arg209 is important not only as a contact site for cAMP binding but also for the intrinsic structural stability of the full-length protein. Introducing the comparable mutation into domain B, R333K, had a smaller effect on the integrity and stability of domain A. Unfolding was still cooperative; the protein was stabilized by excess cAMP, but the unfolding curve was biphasic. The R(M329W) mutant behaved functionally like the native protein. The Delta(260-379)R deletion mutant was not significantly different from wild-type RIalpha in its stability. Consequently, domain B and the interaction between Trp260 and cAMP bound to site A are not critical requirements for the structural stability of the cAPK regulatory subunit.

Gestational age and growth rate of fetal mass are inversely associated with systolic blood pressure in young adults: an epidemiologic study of 165,136 Swedish men aged 18 years

The objective of this study was to identify specific components of fetal growth that may underlie the observed association between birth weight and later blood pressure. A record linkage was made between the Swedish Medical Birth Registry, the Military Conscription Register, and censuses. For 165,136 men born in Sweden between 1973 and 1976 and conscripted from 1990 to 1996, systolic blood pressure was measured at age 18 years. Systolic pressure was independently inversely associated with birth weight for gestational age and with gestational age itself but not with birth length for gestational age. The difference in systolic pressure between the top and the bottom quintiles of birth weight for gestational age was -1.61 mmHg (95% confidence interval: -1.82 to -1.40) after adjustment for birth length for gestational age, height, and weight. The change in systolic pressure was -0.25 mmHg (-0.29 to -0.22) for a 1-week increase in gestational age. How far the inverse association of systolic pressure with length of gestation represents an independent effect of maturation is unclear. These findings help to refine the fetal origins hypothesis and provide further criteria against which potential biological mechanisms that link circumstances in utero to later blood pressure can be assessed.

Probing the multidomain structure of the type I regulatory subunit of cAMP-dependent protein kinase using mutational analysis: role and environment of endogenous tryptophans

The regulatory R-subunit of cAMP-dependent protein kinase (cAPK) is a thermostable multidomain protein. It contains a dimerization domain at the N-terminus followed by an inhibitor site that binds the catalytic C-subunit and two tandem cAMP-binding domains (A and B). Two of the three tryptophans in the RIalpha subunit, Trp188 and Trp222, lie in cAMP-binding domain A while Trp260 lies at the junction between domains A and B. The unfolding of wild-type RIalpha (wt-RI), monitored by intrinsic fluorescence, was described previously [Leon, D. A., Dostmann, W. R. G., and Taylor, S. S. (1991) Biochemistry 30, 3035 (1)]. To determine the environment of each tryptophan and the role of the adjacent domain in folding and stabilization of domain A, three point mutations, W188Y, W222Y, and W260Y, were introduced. The secondary structure of wt-RI and the point mutants has been studied by far-UV circular dichroism spectropolarimetry (CD). The CD spectra of wt-RI and the three point mutants are practically identical, and the thermal unfolding behavior is very similar. Intrinsic fluorescence and iodide quenching in the presence of increasing urea established that: (a) Trp222 is the most buried, whereas Trp188 is the most exposed to solvent; (b) Trp260 accounts for the quenching of fluorescence when cAMP is bound; and (c) Trp222 contributes most to the intrinsic fluorescence of the wt-RI-subunit, while Trp188 contributes least. For wt-RI, rR(W188Y), and rR(W260Y), removal of cAMP causes a destabilization, while excess cAMP stabilizes these three proteins. In contrast, rR(W222Y) was not stabilized by excess cAMP.

Wood dust exposure and cancer incidence: a retrospective cohort study of furniture workers in Estonia

BACKGROUND

Occupational wood dust exposure is associated with increased risk of sinonasal cancer in men. However, little is known whether it is associated with sinonasal cancer in women or with malignancies of other sites.

METHODS

In a retrospective cohort study of furniture workers, cancer incidence in 3723 men and 3063 women between 1968 and 1995 was compared to the incidence in the general population of Estonia. Cancer risks were analyzed by employment duration and occupation.

RESULTS

The standardized incidence ratio (SIR) for all cancers did not differ significantly from one. Two men and one woman had sinonasal cancer (expected 1.07 and 0.53, respectively). Significantly increased risk of colon cancer was seen in the cohort (SIR 1.65, 95% confidence interval (CI) 1.22-2.17). Subjects employed for 10 years and over had significant excess of colon cancer (SIR 2.29, 95% CI 1.28-3.77) and rectal cancer (SIR 2.10, 95% CI 1.05-3.76) in the analysis by employment duration using exposure with a latency of 20 years. The nonsignificant excess of pharyngeal cancer in men (SIR 1.82) and lung cancer in women (SIR 1.43) was restricted to short-term workers.

CONCLUSIONS

This study found an excess of colon and rectal cancer in furniture workers. There was no increase in total cancer risk.

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.

The effect of air pollution on infant mortality appears specific for respiratory causes in the postneonatal period

To examine the association between individual lifetime measures of mean exposure to air pollution and postneonatal respiratory deaths, we have conducted a matched population-based case-control study covering all births registered in the Czech Republic from 1989 to 1991 that were linked to death records. For each case of infant death, we have randomly selected 20 controls from infants of the same sex born on the same day and alive when the case died. Exposure was assigned as the arithmetic mean of all 24-hour air pollution measurements in the district of residence of each case and control for the period between the birth and death of the index case. We used conditional logistic regression to estimate the effects of suspended particles, sulfur dioxide, and nitrogen oxides on risk of death in the neonatal and postneonatal period, controlling for maternal socioeconomic status and birth weight, birth length, and gestational age. There were 2,494 infant deaths with exposure data on at least one pollutant, 133 of them from respiratory causes. The effects of all pollutants were strongest in the postneonatal period and were specific for respiratory causes. For these, rate ratios for a 50 microg/m3 increase in particles, sulfur dioxide, and nitrogen oxides were 1.95 [95% confidence interval (CI) = 1.09-3.50], 1.74 (95% CI = 1.01-2.98), and 1.66 (95% CI = 0.98-2.81), respectively, after controlling for all covariates. Only particles showed a consistent association when all pollutants were entered in one model. We found no evidence of a relation between any pollutant and mortality from other causes. These results indicate that the effects of air pollution on infant mortality are specific for respiratory causes in the postneonatal period, are independent of socioeconomic factors, and are not mediated by birth weight or gestational age.

Pregnancy outcomes and outdoor air pollution: an ecological study in districts of the Czech Republic 1986-8

OBJECTIVES

Outdoor air pollution has consistently been shown to predict mortality. The finding that this association is stronger in infants than in children or adults raises the question whether air pollution could also be related to pregnancy outcomes--such as birthweight and stillbirth. The association between outdoor air pollution and stillbirths and low birthweight in the Czech Republic, where air pollution was high, was examined.

METHODS

An ecological study was conducted, with routinely collected data on stillbirths and low birthweight (< 2500 g), air pollution (total suspended particulates, sulphur dioxide (SO2), and nitrogen oxides (NOx)), and socioeconomic factors (mean income, car ownership, divorce rate, etc). The analyses were restricted to 45 districts on which data on air pollution were available for the period 1986-8. The effects of exposure variables on frequency of pregnancy outcomes were estimated by logistic regression with district-years as the units of analysis.

RESULTS

Stillbirth rate (4.2/1000 births in monitored districts) was not significantly associated with any indicator of air pollution, and was weakly related to mean income and proportion of births outside marriage. Crude prevalence of low birthweight (prevalence 5.5%) showed highly significant associations with several socioeconomic factors; after controlling for these, odds ratios (ORs)/50 micrograms/m3 increase in pollutant were: 1.04 (95% confidence interval (95% CI) 0.96 to 1.12) for total suspended particles, 1.10 (1.02 to 1.17) for SO2, and 1.07 (0.98 to 1.16) for NOx. When all pollutants were included in one model, SO2 remained related to low birthweight (OR 1.10 (1.01 to 1.20), p = 0.033).

CONCLUSION

These results are consistent with a recent study in China where birthweight was also associated with total suspended particles and SO2 but ecological studies must be interpreted cautiously. Residual confounding by socioeconomic factors cannot be ruled out. The association between air pollution and birthweight requires further investigation.

Social determinants of birthweight, ponderal index and gestational age in Sweden in the 1920s and the 1980s

This study compared the effect of social class and marital status on birth outcomes in Sweden, using (i) data on all births at the Akademiska Hospital in Uppsala from 1920 to 1924 with socioeconomic information from records at birth; and (ii) a linkage of the Medical Births Registry for all births in Sweden in November/December 1985 to the 1985 Census. Preterm births (<37 weeks) have become less common during the 20th century. Between 1920-24 and 1985, mean and median birthweight increased, as did mean ponderal index, indicating a shift to the right of the birthweight and ponderal index distributions. In 1920-24, birthweight and ponderal index were associated with the social class of the household and with the marital status of the mother. Babies of single mothers were lighter and thinner, and had a much greater probability of being born preterm. In contrast, in 1985, maternal marital status (and cohabitation status) had a weaker effect on birthweight and ponderal index. The importance of household social class for ponderal index and preterm birth changed similarly, but its importance for birthweight remained. The mediating mechanism may have changed. Mothers from farming households now gave birth to the heaviest babies (nearly 200 g heavier than those of unskilled workers). Adjustment for a number of factors, including smoking, had a limited effect on these social class differences. In conclusion, biological processes during the foetal period are systematically linked to the social circumstances of the mother, but in a different way in the 1920s and in 1985.

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.

Glucose tolerance and resistance to insulin-stimulated glucose uptake in men aged 70 years in relation to size at birth

Although several studies have shown that reduced size at birth predicts glucose intolerance and insulin resistance in adult life, the relation has been inconsistent and usually stronger for ponderal index than for birthweight. We examined glucose tolerance and insulin sensitivity (by the euglycaemic clamp method) in relation to size at birth in 709 men aged 69-73 years in Uppsala, Sweden. After adjusting for adult body mass index, prevalence of glucose intolerance (defined as diabetes or impaired glucose tolerance) was inversely related to birthweight. In men born at term, there was a positive monotonic relation of insulin sensitivity with birthweight, strongest in those who were overweight at age 70. This relation was reversed in men born before term (p = 0.005 for interaction between pre-term birth and birthweight effect). Glucose intolerance and insulin resistance showed inverted U-shaped relations with ponderal index, in contrast with the monotonic inverse relation seen in this cohort at earlier ages. This change in form of the relations was partly accounted for by selective loss to follow-up between ages 60 and 70 years. These results confirm that the association between reduced fetal growth and glucose intolerance is mediated through insulin resistance and depends upon an interaction with obesity in adult life. This relation is obscured when pre-term births are included. Failure to stratify by gestational age in previous studies could account for inconsistencies in the relations of insulin resistance and glucose intolerance to size at birth and for the detection of stronger associations with ponderal index than with birthweight.

Increasing social variation in birth outcomes in the Czech Republic after 1989

OBJECTIVES

This study investigated social variation in birth outcome in the Czech Republic after the political changes of 1989.

METHODS

Routinely collected records on singleton live births in 1989, 1990, and 1991 (n = 380,633) and 1994, 1995, and 1996 (n = 286,907) were individually linked to death records.

RESULTS

Mean birthweight fell from 3,323 g to 3,292 g (P < .001) between 1989 and 1991 and then increased to 3,353 g by 1996. The gap in mean birthweight between mothers with a primary education and those with a university education, adjusted for age, parity, and sex of infants, widened from 182 g (95% confidence interval [CI] = 169, 19) in 1989 to 256 g (95% CI = 240, 272) in 1996. Similar trends were found for preterm births. Postneonatal mortality declined most among the better educated and the married. The odds ratio for postneonatal death for infants of mothers with a primary (vs university) education, adjusted for birthweight, increased from 1.99 (95% CI = 1.52, 2.60) in 1989 through 1991 to 2.39 (95% CI = 1.55, 3.70) in 1994 through 1995.

CONCLUSIONS

Despite general improvement in the indices of fetal growth and infant survival in the most recent years, social variation in birth outcome in the Czech Republic has increased.

Economic change, crime, and mortality crisis in Russia: regional analysis

OBJECTIVE

To identify which aspects of socioeconomic change were associated with the steep decline in life expectancy in Russia between 1990 and 1994.

DESIGN

Regression analysis of regional data, with percentage fall in male life expectancy as dependent variable and a range of socioeconomic measures reflecting transition, change in income, inequity, and social cohesion as independent variables. Determination of contribution of deaths from major causes and in each age group to changes in both male and female life expectancy at birth in regions with the smallest and largest declines.

SETTING

Regions (oblasts) of European Russia (excluding Siberia and those in the Caucasus affected by the Chechen war).

SUBJECTS

The population of European Russia.

RESULTS

The fall in life expectancy at birth varied widely between regions, with declines for men and women highly correlated. The regions with the largest falls were predominantly urban, with high rates of labour turnover, large increases in recorded crime, and a higher average but unequal distribution of household income. For both men and women increasing rates of death between the ages of 30 and 60 years accounted for most of the fall in life expectancy, with the greatest contributions being from conditions directly or indirectly associated with heavy alcohol consumption.

CONCLUSIONS

The decline in life expectancy in Russia in the 1990s cannot be attributed simply to impoverishment. Instead, the impact of social and economic transition, exacerbated by a lack of social cohesion, seems to have played a major part. The evidence that alcohol is an important proximate cause of premature death in Russia is strengthened.