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Blood pressure in prospective population based cohort of newborn and infant twins
R S Levine1, C H Hennekens, M J Jesse
1Department of Family and Preventive Medicine, Meharry Medical College, Nashville, TN 37208.
Insights
Blood pressure in twins correlates with body weight throughout infancy. Lower birth weight twins showed a faster rise in blood pressure, with intrauterine factors influencing infant blood pressure.
Area of Science:
- Pediatrics
- Cardiovascular Health
- Twin Studies
Background:
- Infant blood pressure tracking is crucial for long-term cardiovascular health.
- Understanding factors influencing blood pressure in early life is essential for identifying potential health risks.
- Twin studies offer a unique model to disentangle genetic and environmental influences on physiological parameters.
Purpose of the Study:
- To describe the developmental trajectory of blood pressure in twins during infancy.
- To investigate the relationship between body weight and blood pressure in infants.
- To explore the impact of birth weight and intrauterine factors on infant blood pressure.
Main Methods:
- Prospective cohort study of 166 twin pairs.
- Blood pressure and body weight measurements taken at birth, 14 days, and at 1, 3, 6, 9, and 12 months.
- Analysis included correlations between blood pressure and body weight, and comparisons between different birth weight groups and within monozygotic twin pairs.
Main Results:
- Both systolic and diastolic blood pressure positively correlated with body weight throughout infancy.
- Infants with lower birth weights (<1500g) exhibited a more rapid increase in blood pressure from birth to 1 year compared to higher birth weight infants (>3000g).
- Differences in birth weight within monozygotic twin pairs were negatively correlated with differences in systolic blood pressure at 1 year.
Conclusions:
- Blood pressure and body weight in twins show a strong positive correlation that declines over infancy.
- Lower birth weight is associated with a faster rise in blood pressure during infancy, with blood pressure catch-up exceeding body weight catch-up by 1 year.
- Intrauterine environmental factors, as suggested by birth weight differences in monozygotic twins, play a significant role in determining infant blood pressure.
Objective:
To describe blood pressure in twins during infancy.
Design:
Prospective study of cohort of twins.
Setting:
Teaching hospital in Florida.
Subjects:
166 viable twin pairs born between July 1976 and December 1989.
Main Outcome Measures:
Blood pressure and body weight at birth, at 14 days, and at 1, 3, 6, 9, and 12 months.
Results:
Both systolic and diastolic pressure correlated with body weight throughout infancy (at birth r = 0.41, P < 0.001 and r = 0.42, P < 0.001 respectively; at 1 year r = 0.23, P < 0.001 and r = 0.26, P < 0.001 respectively). In infants weighing < 1500 g at birth mean blood pressure rose from about 45/25 mm Hg to 101/55 mm Hg from birth to the age of 1 year, while in infants weighing > 3000 g at birth it rose from 63/39 mm Hg to 100/61 mm Hg; corresponding mean body weights at 1 year were 7.86 kg and 9.88 kg. Differences in birth weight within pairs of monozygotic twins were negatively correlated with such differences in systolic blood pressure at 1 year (r = -0.37, P < 0.01).
Conclusions:
Blood pressure and body weights in twins showed strongly positive but generally declining correlations throughout infancy. Twins of lower birth weight showed a more rapid rate of rise in blood pressure during infancy. At 1 year the catch up in blood pressure exceeded that in body weight. Greater differences in birth weights between monozygotic twins were associated with smaller differences in systolic blood pressure at 1 year, suggesting that intrauterine environmental factors related to birth weight are important in determining blood pressure in infancy.