ArticlesBirthweight, childhood social class, and change in adult blood pressure in the 1946 British birth cohort
Introduction
The negative effect of birthweight on systolic blood pressure has been suggested to be initiated in utero and amplified with age.1 Limited assessment of this hypothesis has come from comparison of separate cross-sectional analyses of cohorts of varying ages.1, 2, 3, 4 In one systematic review, researchers estimated the change with age with a weighted regression,2 whereas in another study, workers suggested that although there was heterogeneity of effect, there was no clear trend across age.4 Trends noted in such reviews could be the result of cohort effects. Most studies with repeated records of blood pressure on one cohort of individuals over time use measures taken during childhood only,1, 5, 6, 7, 8, 9 or through to adolescence and early adulthood.10, 11, 12, 13 In studies that have addressed the amplification hypothesis, methods of analysis and conclusions have varied.1, 5, 6, 7, 9, 10, 12, 13 There are few longitudinal studies with repeated measures in adult samples.14, 15
Most estimates of the association between birthweight and blood pressure included in systematic reviews have been adjusted for present body-mass index, resulting in difficulties with interpretation16 and, possibly, upwardly biased relations between birthweight and outcome.4 Birthweight is a crude proxy measure for fetal growth and the underlying nutritional or other prenatal exposures that might have long-term effects on adult blood pressure. The birthweight-blood pressure association could also indicate postnatal growth and exposures, or genetic effects. Socioeconomic conditions during early life also affect blood pressure and other cardiovascular disease risk factors,17, 18, 19 and might act as a crude proxy of underlying measures of interest.
The medical research council (MRC) national survey of health and development—a birth cohort study originally of 5362 men and women born in Britain in 1946—has measured blood pressure at ages 36, 43, and 53 years, an age range not covered by any other study considering the effects of birthweight. Here, we tested whether the effect of birthweight as an indicator of fetal growth on blood pressure changes with increasing age. For comparison, we make a similar assessment of the effect of childhood social class on adult blood pressure.
Section snippets
Participants and procedures
The MRC national survey of health and development is a socially stratified birth cohort of 2547 women and 2815 men, in which there have been 20 follow-ups of the whole cohort between their birth in 1946 and age 53 years.20, 21 A total of 3035 (1472 men and 1563 women) were interviewed in their homes by trained research nurses with a standardised protocol at the age of 53 years. This sample consisted of 90% of cohort members alive and resident in Britain and for whom contact was attempted. 469
Results
The mean value of both systolic and diastolic blood pressure rose with age in men and women (table 1). In men, the lowest birthweight group had consistently higher mean systolic blood pressure than did the highest group. In women, a gradient with birthweight was not evident at age 36 years, but emerged at age 43 years. There was no pattern across birthweight categories for diastolic blood pressure. At all ages, people from a manual social class in childhood had higher blood pressure than did
Discussion
Our results showed that the negative effect of birth-weight on systolic blood pressure, but not diastolic blood pressure, is consistent throughout the middle years of life (age 36–53 years). However, there is little evidence of an increase in effect with age. Manual social class in childhood was associated with high diastolic and high systolic blood pressure. We reported stronger evidence of an increase in the effect of childhood social class with age, which seems to be largely accounted for by
References (29)
- et al.
Unravelling the fetal origins hypothesis: is there really an inverse association between birthweight and subsequent blood pressure
Lancet
(2002) - et al.
Influence of father's social class on cardiovascular disease in middle-aged men
Lancet
(1996) - et al.
Initiation of hypertension in utero and its amplification throughout life
BMJ
(1993) - et al.
Birth weight, blood pressure, and hypertension
- et al.
The role of size at birth and postnatal catch-up growth in determining systolic blood pressure: a systematic review of the literature
J Hypertens
(2000) - et al.
Relation between birth weight and blood pressure: longitudinal study of infants and children
BMJ
(1993) - et al.
Birth weight and blood pressure: cross sectional and longitudinal relations in childhood
BMJ
(1995) - et al.
Growth in childhood and blood pressure in Finnish children
J Hum Hypertens
(1998) - et al.
Insulin resistance syndrome in 8-year-old Indian children
Diabetes
(1999) - et al.
The relationship between birth weight and blood pressure from childhood to adulthood
J Hyertens
(1999)
Blood pressure is related to placental volume and birth weight
Hypertension
Prenatal and postnatal factors in predicting later blood pressure among children
Pediatr Res
Birth weight versus childhood growth as determinants of adult blood pressure
Hypertension
Birth size, growth, and blood pressure between the ages of 7 and 26 years: failure to support the fetal origins hypothesis
Am J Epidemiol
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2015, Journal of Clinical EpidemiologyCitation Excerpt :This effect was demonstrated in a large study among Swedish young men where it was shown that within narrowly defined BMI strata, there was a clear inverse relationship between birth weight and SBP [39]. The association between low maternal occupation and SBP is noteworthy and is consistent with work of Barker and others who have shown relationships between poor maternal social class and higher BP in later life [13,40,41]. The importance of social factors, including those in early life, to NCD epidemiology is now well established and has resulted in recommendations for the inclusion of action on the social determinants of health as key elements in the fight against NCDs [6,15,42].
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