Twins and fetal programming of blood pressure. Questioning the role of genes and maternal nutrition.
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Birth Weight↗
Biomedical subjects
D A Leon
Publications and source records attributed to D A Leon.
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.
Adult↗
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.
Aged↗
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.
Air Pollution↗
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.
Air Pollution↗
Height and mortality from cancer among men: prospective observational study.
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Adult↗
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.
Adolescent↗
Reduced fetal growth rate and increased risk of death from ischaemic heart disease: cohort study of 15 000 Swedish men and women born 1915-29.
OBJECTIVE: To establish whether fetal growth rate (as distinct from size at birth) is associated with mortality from ischaemic heart disease. DESIGN: Cohort study based on uniquely detailed obstetric records with 97% follow up over the entire life course and linkage to census data in adult life. SUBJECTS: All 14 611 babies delivered at the Uppsala Academic Hospital, Sweden, during 1915-29 followed up to end of 1995. MAIN OUTCOME MEASURES: Mortality from ischaemic heart disease and other causes. RESULTS: Cardiovascular disease showed an inverse association with birth weight for both men and women, although this was significant only for men. In men a 1000 g increase in birth weight was associated with a proportional reduction in the rate of ischaemic heart disease of 0.77 (95% confidence interval 0.67 to 0.90). Adjustment for socioeconomic circumstances at birth and in adult life led to slight attenuation of this effect. Relative to the lowest fourth of birth weight for gestational age, mortality from ischaemic heart disease in men in the second, third, and fourth fourths was 0.81 (0.66 to 0.98), 0.63 (0.50 to 0.78), and 0.67 (0.54 to 0.82), respectively. The inclusion of birth weight per se and birth weight for gestational age in the same model strengthened the association with birth weight for gestational age but removed the association with birth weight. CONCLUSION: This study provides by far the most persuasive evidence of a real association between size at birth and mortality from ischaemic heart disease in men, which cannot be explained by methodological artefact or socioeconomic confounding. It strongly suggests that it is variation in fetal growth rate rather than size at birth that is aetiologically important.
Adolescent↗
Social stress and the Russian mortality crisis.
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Humans↗
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.
Aged↗
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.
Adult↗
Social variation in size at birth and preterm delivery in the Czech Republic and Sweden, 1989-91.
All livebirths resulting from singleton pregnancies reported to the Czech (n = 380,633) and Swedish (n = 351,775) birth registries in 1989-91 were studied with respect to social variation in birthweight, ponderal index (weight/length at birth3) and preterm delivery. The mean birthweight was significantly lower in the Czech population (3310 g vs. 3522 g, P < 0.001). The mean difference in birthweight between children of mothers with primary and university education was 197 g [95% CI 190, 205] in the Czech and 136 g [95% CI 128, 144] in the Swedish population, adjusted for maternal age, parity and sex of the infant. Mean birthweight was significantly higher in mothers who were married or lived with partners in both countries; the difference was 167 g [95% CI 161, 173] in the Czech Republic (CR) and 86 g [95% CI 78, 94] in Sweden, adjusted for age, parity and sex. The extent of social variation in ponderal index and frequency of preterm birth was also greater in the CR. Between 1989 and 1991, mean birthweight in the CR fell from 3323 g to 3292 g (P < 0.001) and the social differences increased, largely as a result of more rapid worsening in the lower socio-economic groups. There did not appear to be such a decline in birthweight in Sweden. We suggest that the fall in mean birthweight and the increasing social variation in birth outcome in the CR is related to decline and divergence in living standards in 1989-91.
Adolescent↗
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.
Adult↗
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.
Adult↗
Huge variation in Russian mortality rates 1984-94: artefact, alcohol, or what?
BACKGROUND: According to published data, between 1984 and 1994 mortality rates in Russia initially underwent a rapid decline followed by an even steeper increase. In 1994, male life expectancy at birth was 57.6 years, having fallen by 6.2 years since 1990. There has been concern that such striking fluctuations in mortality are an artefact, although, among other factors, alcohol consumption has been implicated. METHODS: We analysed the age-specific and cause-specific patterns of mortality decrease and increase by use of data from a newly reconstructed mortality series for Russia so that we could examine the plausibility of various explanations for the mortality trends. FINDINGS: All major causes of death, with the exception of neoplasms, showed declines in mortality between 1984 and 1987 and increases between 1987 and 1994. In relative terms, these tended to be largest for the age-group 40-50 years; surprisingly, they were of the same magnitude among women and men. The largest declines and subsequent increases in proportional terms were observed for alcohol-related deaths and accidents and violence. However, pronounced effects were also seen for deaths from infections, circulatory disease, and respiratory disease. No substantial variations were seen for neoplasms. INTERPRETATION: The stability of mortality from neoplasms in contrast to other causes over the period 1984-94 largely precludes the possibility that the changes in life expectancy are mainly an artefact, particularly one due to underestimation of the population. Although factors such as nutrition and health services may be involved, the evidence is that substantial changes in alcohol consumption over the period could plausibly explain the main features of the mortality fluctuations observed. These results provide a major challenge to public health in Russia and to our understanding of the determinants of alcohol consumption and its role in explaining mortality patterns within and between many other countries.
Adolescent↗
Current status of injectable hormonal contraception, with special reference to the monthly method.
Injectable contraceptives are a valid option in every family planning program. Contraceptives which are administered every 2 or 3 months, containing only progestogen agents (DepoProvera, Noristerat) have proven efficacious and do not show long-term safety problems. They differ from other contraceptives in their long lasting action and by not presenting the contraindications of the estrogens. Their most prominent side-effect is the irregularity of cyclic bleeding. Although bleeding irregularities are not life threatening, many users stop the treatment for that reason. Monthly contraceptives comprising progestogens and estrogens, maintain or improve the high efficacy of the earlier forms and have the added benefit of allowing bleeding to resemble the physiologic one. This increases acceptability and the continuation rate. There is no long-term inconvenience. At this point, the greatest experience is with the formulation known as Topasel or Perlutal. Other formulations (Cyclofem, Mesigyna) are beginning to be commercialized and their characteristics must still be confirmed through daily use. Indications, contraindications, precautions and warnings for the use of monthly injectable contraceptives are basically identical to those of the combined oral contraceptives, as are the side-effects. Efficacy, though, proves to be superior, which can be correlated to a simpler method of use and less risk of error when using it. Main motivation factors are: efficacy, simplicity in usage, reversibility and confidentiality.
Contraceptive Agents, Female↗
Breast cancer risk in mothers of twins.
The risk of breast cancer associated with delivering a twin birth was examined in a population-based nested case-control study of nearly 4800 Swedish women with breast cancer and 47000 age-matched control subjects. All were aged less than 50 years and parous. After adjustment for age at first birth and parity, a 29% reduction in breast cancer risk was observed in mothers of twins relative to those who were not (odds ratio = 0.71, 95% confidence interval 0.55-0.91). These results provide evidence that women who bear twins are at reduced risk of breast cancer, one explanation for which may be their unusual levels of hormonal exposure.
Breast Neoplasms↗
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.
Adolescent↗