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

OBJECTIVE

To determine whether restricted growth in utero is associated with an increased risk of coronary heart disease are among men in Finland, where rates of the disease are among the highest in the world.

DESIGN

Follow up study.

SETTING

Helsinki, Finland.

SUBJECTS

3302 men born in Helsinki University Central Hospital during 1924-33 who went to school in the city of Helsinki and were resident in Finalnd in 1971.

MAIN OUTCOME MEASURES

Standardised mortality ratios for coronary heart disease.

RESULTS

Men who were thin at birth, with low placental weight, had high death rates from coronary heart disease. Men whose mothers had a high body mass index in pregnancy also had high death rates. In a multivariate analysis the hazard ratio for coronary heart disease was 1.37 (95% confidence interval 1.20 to 1.57) (P < 0.0001) for every standard deviation decrease in ponderal index at birth and 1.24 (1.10 to 1.39) (P = 0.0004) for every standard deviation increase in mother's body mass index. The effect of mother's body mass index was restricted to mothers of below average stature.

CONCLUSION

These findings suggest a new explanation for the epidemics of coronary heart disease that accompany Westernisation. Chronically malnourished women are short and light and their babies tend to be thin. The immediate effect of improved nutrition is that women become fat, which seems to increase the risk of coronary heart disease in the next generation. With continued improvements in nutrition, women become taller and heavier; their babies are adequately nourished; and maternal fatness no longer increases the risk of coronary heart disease, which therefore declines.

Relation of fetal growth to adult lung function in south India

BACKGROUND

Follow up studies in Britain have shown that low rates of fetal growth are followed by reduced lung function in adult life, independent of smoking and social class. It is suggested that fetal adaptations to undernutrition in utero result in permanent changes in lung structure, which in turn lead to chronic airflow obstruction. India has high rates of intrauterine growth retardation, but no study has examined the association between fetal growth and adult lung function in Indian people. We have related size at birth to lung function in an urban Indian population aged 38-59 years.

METHODS

Two hundred and eighty six men and women born in one hospital in Mysore City, South India, during 1934-1953 were traced by a house-to-house survey of the city. Their mean forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were measured using a turbine spirometer. These measurements were linked to their size at birth, recorded at the time.

RESULTS

In both men and women mean FEV1 fell with decreasing birthweight. Adjusted for age and height, it fell by 0.09 litres with each pound (454 g) decrease in birthweight in men (95% confidence interval (CI) 0.01 to 0.16) and by 0.06 (95% CI -0.01 to 0.13) in women. Likewise, mean FVC fell by 0.11 litres (95% CI 0.02 to 0.19) with each pound decrease in birthweight in men, and by 0.08 litres (95% CI 0.002 to 0.16) in women. FEV1 and FVC were lower in men who smoked, but the associations with size at birth were independent of smoking. Small head circumference at birth was associated with a low FEV1/FVC ratio in men which may reflect restriction in airway growth in early gestation.

CONCLUSION

This is further evidence that adult lung function is "programmed" in fetal life. Smoking may be particularly detrimental to the lung function of populations already disadvantaged by poor rates of fetal growth.

Is the age of menopause determined in-utero?

OBJECTIVE

To determine whether age at menopause is related to size at birth.

DESIGN

A follow-up study of two groups of women whose size at birth was recorded.

SETTING

Hertfordshire and Sheffield, England.

POPULATION

755 women aged 60-71 years born in Hertfordshire; 235 women aged 40-42 years born in the Jessop Hospital, Sheffield.

MAIN OUTCOME MEASURES

Age at natural menopause or serum follicle stimulating hormone concentration greater than 25 IU/ml.

RESULTS

Age at menopause was unrelated to birth weight. However, it occurred at a younger age in women who had low weight at 1 year. This was independent of their body weight and smoking habits. In the population of younger women those who had had an early menopause tended to have been short at birth, with a high ponderal index (birth weight/length3).

CONCLUSION

Growth retardation in late gestation, leading to shortness at birth and low weight gain in infancy, may be associated with a reduced number of primordial follicles in the ovary leading in turn to an earlier menopause.

Maternal nutrition, fetal nutrition, and disease in later life

Recent findings suggest that many human fetuses have to adapt to a limited supply of nutrients and in doing so they permanently change their physiology and metabolism. These "programmed" changes may be the origins of a number of diseases in later life, including coronary heart disease and the related disorders stroke, diabetes, and hypertension.

Association between low birthweight and high resting pulse in adult life: is the sympathetic nervous system involved in programming the insulin resistance syndrome?

To test the hypothesis that elevated sympathetic nervous system (SNS) activity could be determined in utero and be one of the processes mediating the link between size at birth and insulin resistance and raised blood pressure in adult life, we have studied the resting pulse rate of 449 men and women aged 46 to 54 (mean 50) years born in Preston, Lancashire, England whose birth size was recorded in detail. The subjects were visited at home by trained fieldworkers who measured resting pulse rate and blood pressure using an automated recorder. The resting pulse rate ranged from 44 to 108 (mean 73) beats min(-1). It rose with increasing body mass index (r = 0.14, p = 0.003) and waist to hip ratio (adjusted for sex r = 0.10, p = 0.003) and correlated significantly with systolic and diastolic blood pressures (p = 0.001), fasting glucose (p = 0.02), split proinsulin (p = 0.001), and triglyceride concentrations (p = 0.02). The pulse rate fell progressively from 76 beats min(-1) among subjects who weighed 5.5 lb (2.5 kg) or less at birth to 71 beats min(-1) among those who weighed 7.5 lb (3.3 kg) or more (decline in pulse rate per kg increase in birthweight = 2.7, 95 % CI 0.6 to 4.8 beats min(-1). The association was independent of current body mass index, waist to hip ratio and of potential confounding variables including smoking, alcohol consumption, and social class. Although the resting pulse rate is an imperfect index of SNS activity, these findings are consistent with the hypothesis that elevated SNS activity established in utero is one mechanism linking small size at birth with the insulin resistance syndrome in adult life.

The fetal origins of coronary heart disease

Animal studies have shown that undernutrition before birth programmes persisting changes in a range of metabolic, physiological and structural parameters. Studies in humans have shown that men and women whose birthweights were at the lower end of the normal range, who were thin or short at birth or small in relation to placental size have increased rates of coronary heart disease. We are beginning to understand something of the mechanisms underlying these associations.

The effects of genotype and infant weight on adult plasma levels of fibrinogen, factor VII, and LDL cholesterol are additive

High circulating levels of cholesterol, particularly low density lipoprotein (LDL) cholesterol and the clotting factors fibrinogen and factor VII, are associated with increased risk of myocardial infarction. Variations in the plasma levels of these factors are determined in part by polymorphisms in the genes concerned and also by weight at 1 year (infant weight). We have looked at the possibility of interactions between these genetic factors and infant weight in a sample of 290 men and 192 women from Hertfordshire using the beta-fibrinogen G/A-455, factor VII R353Q, and ApoE polymorphisms. The rare allele frequencies of the three polymorphisms were 0.19 for beta-fibrinogen, 0.10 for factor VII, and 0.07 and 0.13 for the 2 and 4 alleles of ApoE, and these frequencies were not different in subjects of different infant weight. In this sample, the polymorphisms showed the expected effects on plasma levels of fibrinogen, factor VII, and LDL cholesterol. The A-455 allele was associated with higher fibrinogen levels but the effect was only statistically significant in women (p = 0.003). The R353 allele was associated with higher factor VII activity in both men and women (p < 0.0001 for both). The ApoE2 allele was associated with lower levels of LDL cholesterol (p = 0.03 in men, p = 0.006 in women), while the ApoE4 allele was associated with higher levels (p < 0.001 in men, not significant in women). In this sample of men and women the effect of low infant weight was only associated with significant effects on fibrinogen and LDL cholesterol in the group of men (p = 0.005 and p = 0.008 respectively). Compared with the E3E3 subjects, the LDL lowering effect of the E2 allele and the raising effect of the E4 allele was greater in those with low infant weight compared with those with high infant weight (low v high infant weight for E2: 12.7% v 9.4%; for E4 12.7% v 8.5%). Although in this sample the interactive effect did not reach statistical significance, the additive effect of ApoE genotype and low infant weight on determining plasma LDL cholesterol levels, if confirmed, may be of relevance in determining a person's future risk of atherosclerosis.

Maternal birthweight and diet in pregnancy in relation to the infant's thinness at birth

OBJECTIVE

To examine how maternal diet in pregnancy and parental body size and birthweight influence an infant's thinness at birth measured by a low ponderal index.

DESIGN

An observational study of newborn infants and their parents.

SETTING

Southampton, England.

POPULATION

Five hundred and thirty-eight infants born at term.

MAIN OUTCOME MEASURE

Ponderal index at birth.

RESULTS

Women who had a high intake of carbohydrate in early pregnancy and a low intake of dairy protein in late pregnancy tended to have infants that were thin at birth (P = 0.01 and P = 0.03, respectively, in a simultaneous analysis). Women who themselves had a low birthweight also tended to have thin infants, ponderal index falling from 28.3 kg/m3 to 26.2 kg/m3 as the women's birthweights decreased from more than 4.0 kg to 2.5 kg or less (P < 0.0001). Tall fathers had thin infants, but ponderal index was not related to the women's heights or the fathers' birthweights.

CONCLUSION

These associations may reflect constraints on placental development imposed by a woman's nutrition in pregnancy and during her own intrauterine life. Effects of the father's height may be mediated through genetic influences on skeletal growth.

Fetal undernutrition and disease in later life

Recent findings suggest that coronary heart disease and stroke, and the associated conditions, hypertension and non-insulin dependent diabetes, originate through impaired growth and development during fetal life and infancy. These diseases may be consequences of 'programming', whereby a stimulus or insult at a critical, sensitive period of early life results in long-term changes in physiology or metabolism. Animal studies provide many examples of programming, which occurs because the systems and organs of the body mature during periods of rapid growth in fetal life and infancy. There are critical windows of time during which maturation must be achieved; and failure of maturation is largely irrecoverable.

Intra-uterine programming of the adult cardiovascular system

We have become accustomed to the idea that the major disorders of adult life, including coronary heart disease, stroke and diabetes, arise through an interaction between influences in our adult lifestyle and a genetically determined susceptibility. Recent research, however, suggests that growth in utero may also play an important role.

Fetal nutrition and cardiovascular disease in later life

Recent finding suggest that many fetuses have to adapt to a limited supply of nutrients and in doing so they permanently change their physiology and metabolism. These 'programmed' changes may be the origins of a number of diseases in life, including coronary heart disease and the related disorders stroke, diabetes and hypertension.

Size at birth and adrenocortical function in childhood

OBJECTIVE

The mechanisms underlying the association between reduced size at birth and cardiovascular disease and non-insulin-dependent diabetes mellitus in adult life are not known. One possibility is that the intra-uterine environment has permanent effects on the function or activity of the hypothalamo-pituitary-adrenal axis. We tested this by relating size at birth to the urinary excretion of adrenal androgen and glucocorticoid metabolites in a population sample of 9-year-old children.

SUBJECTS AND METHODS

One hundred and ninety children (89 boys and 101 girls) of known present height, weight and size at birth collected a 24-hour urine sample. The urinary breakdown products of dehydroepiandrosterone sulphate and of cortisol and cortisone were measured by gas chromatography and their respective breakdown products summed ('adrenal androgen metabolites' and 'glucocorticoid metabolites'). Excretion was expressed in microgram/day.

RESULTS

Urinary adrenal androgen metabolite excretion was higher in children who had been light at birth. A 1-kg decrease in birthweight was associated with a 40% (95% CI 9-79%) increase in metabolite excretion. Excretion was positively associated with current weight and age, but the relation with birth weight was independent of weight, age or sex. Urinary glucocorticoid metabolite excretion was positively associated with current weight, but not independently with age. The urinary excretion of total glucocorticoid metabolites was higher in children who had been light at birth, but the relation was best described as U-shaped, with the highest average urinary glucocorticoid metabolite excretion being found in children who had been either light or heavy at birth. The U-shaped (quadratic) relation persisted after adjustment for sex and current weight (P for quadratic term 0.006).

CONCLUSION

These findings suggests that the intra-uterine environment, as measured by fetal size at birth, has long-lasting effects on the function of the hypothalamo-pituitary-adrenal axis.

The fetal origins of hypertension

RESULTS OF UNDERNUTRITION BEFORE BIRTH: Animal studies have shown that undernutrition before birth leads to persisting changes in blood pressure and in a range of other physiological, metabolic and structural parameters. Studies in humans have shown that men and women whose birthweights were at the lower end of the normal range, who were thin or short at birth, or small in relation to placental size, have increased rates of hypertension and coronary heart disease.

CONCLUSIONS

We are beginning to understand something of the mechanisms underlying these associations. Elevation of blood pressure may be a fetal response to undernutrition and may initiate hypertension in adult life.

Fetal growth and coronary heart disease in south India

BACKGROUND

Coronary heart disease is predicted to become the commonest cause of death in india within 15 years People from India living overseas already have high rates of the disease that are not explained by known coronary risk factors. Small size at birth is a newly described risk factor for coronary heart disease, but associations between size at birth and the disease have not been examined in India.

METHODS

We studied 517 men and women who were born between 1934 and 1954 in a mission hospital in Mysore, South India, and who still lived near to the hospital. We related the prevalence of coronary heart disease, defined by standard criteria, to their birth size.

FINDINGS

25 (9%) men and 27 (11%) women had coronary heart disease. Low birthweight, short birth length, and small head circumference at birth were associated with a raised prevalence of the disease. Prevalence fell from 11% in people whose birthweights were 5.5 lb (2.5 kg) or less to 3% in those whose birthweights were more than 7 lb (3.1 kg), p for trend = 0.09. The trends were stronger and statistically significant among people aged 45 years and over (p = 0.03 for birthweight, 0.04 for length, and 0.02 for head circumference). High rates of disease were also found in those whose mothers had a low body weight during pregnancy. The highest prevalence of the disease (20%) was in people who weighted 5.5 lb (2.5 kg) or less at birth and whose mothers weighted less than 100 lb (45 kg) in pregnancy. These associations were largely independent of known coronary risk factors.

INTERPRETATION

In India, as in the UK, coronary heart disease is associated with small size at birth, suggesting that its pathogenesis is influenced by events in utero. The association with low maternal bodyweight is further evidence that the disease originates through fetal undernutrition. Prevention of the rising epidemic of the disease in India may require improvements in the nutrition and health of young women.

Mothers' pelvic size, fetal growth, and death from stroke and coronary heart disease in men in the UK

BACKGROUND

People who have a low birthweight show increased death rates from coronary heart disease and a higher prevalence for its risk factors. These findings have led to the hypothesis that the disease is programmed in fetal life. The aim of this study was to explore whether risk of stroke in adult life was linked to impaired fetal growth.

METHODS

We ascertained deaths from stroke and coronary heart disease in 13 249 men in two cohorts from Hertfordshire and Sheffield, UK. We related death rates from these disease to body size at birth, weight at 1 year, and to measurements of the mothers' pelvises.

FINDINGS

Death rates from both stroke and coronary heart disease tended to be highest in men whose birthweight had been low. Standardised mortality ratios (SMRs) for stroke fell by 12% (95% Cl 1-22) and for coronary heart disease by 10% (6-14) between each of five groupings of increasing birthweight (< or = 5.5 lb, 5.6-6.5 lb, 6.6-7.5 lb, 7.6-8.5 lb, and > 8.5 lb). Mortality from stroke was most strongly associated with low birthweight in relation to head size, and low placental weight in relation to head size. These patterns of growth occurred in offspring of mothers with flat bony pelvises. The SMR in sons of these women was 184 (67-396) compared with 104 (78-138) in the remainder of the cohort. In contrast, mortality from coronary heart disease was associated with small head circumference, thinness or shortness at birth and an altered ratio of placental weight to birthweight.

INTERPRETATION

Stroke may originate in poor nutrition during the mother's childhood, which deforms the bony pelvis and subsequently impairs her ability to sustain the growth of the placenta and fetus in late pregnancy. Coronary heart disease, on the other hand, seems to originate in adaptations made by the fetus to inadequate delivery of nutrients when it occurs for reasons other than failure of placental growth.

Cell mediated immunity after measles in Guinea-Bissau: historical cohort study

OBJECTIVE

To investigate whether children who have had measles have reduced general cell mediated immunity three years later compared with vaccinated children who have not had measles.

DESIGN

Historical cohort study.

SETTING

Bissau, Guinea-Bissau.

SUBJECTS

391 children aged 3-13 years who were living in Bissau during a measles epidemic in 1991 and still lived there. These included 131 primary cases and 139 secondary cases from the epidemic and 121 vaccinated controls with no history of measles.

MAIN OUTCOME MEASURES

General cell mediated immunity assessed by measurement of delayed type hypersensitivity skin responses to seven recall antigens. Anergy was defined as a lack of response to all antigens.

RESULTS

82 out of 268 cases of measles (31%) were anergic compared with 20 of the 121 vaccinated controls (17%) (odds ratio adjusted for potential confounding variables 2.2 (95% confidence interval 1.2 to 4.0); P 0.009). The prevalence of anergy was higher in secondary cases (33% (46/138)) than in primary cases (28% (36/130)), although this difference was not significant. Anergy was more common in the rainy season (unadjusted prevalence 31% (91/291) than in the dry season (11% (11/98)) (adjusted odds ratio 4.8 (2.2 to 10.3)). This seasonal increase occurred predominantly in the case of measles.

CONCLUSION

Reduced general cell mediated immunity may contribute to the higher long term mortality in children who have had measles compared with recipients of standard measles vaccine and to the higher child mortality in the rainy season in west Africa.

Nutrition in pregnancy and the concentrations of proinsulin, 32-33 split proinsulin, insulin, and C-peptide in cord plasma

As insulin is a major fetal growth hormone, we have related the mother's nutrient intakes (assessed by a food frequency questionnaire) and other influences associated with fetal growth to the baby's concentrations of insulin and its propeptides in umbilical cord plasma. Among 391 term babies studied, those whose mothers had high energy intakes in early pregnancy and low protein intakes in late pregnancy had lower cord plasma concentrations of 32-33 split proinsulin, insulin, and C-peptide. Concentrations of split proinsulin fell by 0.66 (95% Cl 0.29 to 1.03, p = 0.0006) log pmol l-1 for each log kcal increase in the mother's energy intake in early pregnancy and by 0.005 (95% Cl 0.000 to 0.010, p = 0.04) log pmol l-1 for each g decrease in protein intake in late pregnancy. Insulin and propeptide concentrations were however unrelated to the mother's height and body mass index, and to smoking during pregnancy. These observations parallel recent studies relating the same pattern of dietary intakes to impaired fetal and placental growth. Although dietary intakes assessed by food frequency questionnaires allow only cautious conclusions, our findings could have implications for the offspring's risk of Type 2 diabetes mellitus in adult life.

Relation of cord plasma concentrations of proinsulin, 32-33 split proinsulin, insulin and C-peptide to placental weight and the baby's size and proportions at birth

Small and disproportionate size at birth are associated with type 2 diabetes and coronary heart disease in adult life. Insulin has an important role in controlling growth in utero and we hypothesised that reduced fetal insulin secretion could be one factor underlying these associations. We therefore measured cord plasma concentrations of proinsulin, 32-33 split proinsulin, insulin and C-peptide in 391 babies born at term and related them to the weight of the placenta and to the babies' size and proportions at birth. Babies with a small placental weight and a lower birth weight had lower cord plasma concentrations of split proinsulin and insulin. Babies who were disproportionate, either having a high ratio of head to abdominal circumference or being thin, had lower concentrations of split proinsulin, split proinsulin and insulin. The relations with split proinsulin were especially strong, the geometric mean concentration (pmol/l) falling from 14.2 in babies with a head to abdominal circumference ratio of 101.6% or less to 7.2 in those with a ratio above 107.3% (P < 0.0001), and from 17.4 in babies with a ponderal index above 28.5 kg/m3 to 7.4 in those with a ponderal index of 25.5 kg/m3 or less (P < 0.0001). These findings support the hypothesis that reduced fetal insulin secretion may be one factor underlying the associations between reduced growth in utero and type 2 diabetes and coronary heart disease in adult life.

Measles and atopy in Guinea-Bissau

BACKGROUND

Epidemiological studies have led to speculation that infections in early childhood may prevent allergic sensitisation but evidence to support this hypothesis is lacking. We investigated whether measles infection protects against the development of atopy in children of Guinea-Bissau, West Africa.

METHODS

We conducted a historical cohort study in Bandim, a semi-rural district of Bissau, the capital of Guinea-Bissau. 395 young adults, first surveyed in 1978-80 aged 0-6 years, were followed up in 1994. Our analyses were restricted to 262 individuals still living in Bandim for whom a measles history, documented in childhood, was judged to be reliable. We defined atopy as skin-prick test positivity (> or = 3 mm weal) to one or more of seven allergens.

FINDINGS

17 (12.8 percent) of 133 participants who had had measles infection were atopic compared with 33 (25.6 percent) of 129 of those who had been vaccinated and not had measles (odds ratio, adjusted for potential confounding variables 0.36 [95 percent CI 0.17-0.78], p=O.O1). Participants who had been breastfed for more than a year were less likely to have a positive skin test to housedust mite. After adjustment for breastfeeding and other variables, measles infection was associated with a large reduction in the risk of skin-prick test positivity to housedust mite (odds ratio for Dermatophagoides pteronyssinus 0.20 [0.05-0.81], p=0.02; D farinae 0.20 [0.06-0.71], p=0.01).

INTERPRETATION

Measles infection may prevent the development of atopy in African children.

Diet in pregnancy and the offspring's blood pressure 40 years later

OBJECTIVE

To determine how diet of the mother in pregnancy influences the blood pressure of the offspring in adult life.

DESIGN

A follow up study of men and women born during 1948-1954 whose mothers had taken part in a survey of diet in late pregnancy.

SETTING

Aberdeen, Scotland.

POPULATION

Two hundred and fifty-three men and women born in Aberdeen Maternity Hospital.

MAIN OUTCOME MEASURE

Systolic and diastolic blood pressure.

RESULTS

The relations between the diet of mothers and their offsprings' blood pressure were complex. When the mothers' intake of animal protein was less than 50 g daily, a higher carbohydrate intake was associated with a higher blood pressure in the offspring (a 100 g increase in carbohydrate being associated with a 3 mmHg increase in systolic pressure (P = 0.02)). At daily animal protein intakes above 50 g, lower carbohydrate intake was associated with higher blood pressure (a 100 g decrease in carbohydrate being associated with an 11 mmHg rise in systolic blood pressure (P = 0.004)). These increases in blood pressure were associated with decreased placental size.

CONCLUSION

Mothers' intakes of animal protein and carbohydrate in late pregnancy may influence their offsprings' adult blood pressure. This may be mediated through effects on placental growth.

Maternal nutrition in early and late pregnancy in relation to placental and fetal growth

OBJECTIVE

To assess how nutrient intakes of mothers in early and late pregnancy influence placental and fetal growth.

DESIGN

Prospective observational study.

SETTING

Princess Anne Maternity Hospital, Southampton.

SUBJECTS

538 mothers who delivered at term.

MAIN OUTCOME MEASURES

Placental and birth weights adjusted for the infant's sex and duration of gestation.

RESULTS

Mothers who had high carbohydrate intakes in early pregnancy had babies with lower placental and birth weights. Low maternal intakes of dairy and meat protein in late pregnancy were also associated with lower placental and birth weights. Placental weight fell by 49 g(95% confidence interval 16 g to 81 g; P=0.002) for each log g increase in intake of carbohydrate in early pregnancy and by 1.4 g (0.4 g to 2.4 g; P=0.005) for each g decrease in intake of dairy protein in late pregnancy. Birth weight fell by 165 g (49 g to 282 g; P=0.005) for each log g increase in carbohydrate intake in early pregnancy and by 3.1 g (0.3 g to 6.0 g; P=0.03) for each g decrease in meat protein intake in late pregnancy. These associations were independent of the mother's height and body mass index and of strong relations between the mother's birth weight and the placental and birth weights of her offspring.

CONCLUSION

These findings suggest that a high carbohydrate intake in early pregnancy suppresses placental growth, especially if combined with a low dairy protein intake in late pregnancy. Such an effect could have long term consequences for the offspring's risk of cardiovascular disease.