Preterm birth associated with cardiovascular risk factors in adolescence

1. Girls born before 34 weeks gestation were found to have higher blood pressures at age 16 than those born after 37 weeks. Boys born preterm had worse cholesterol levels in adolescence when compared to males born at term.

2. A dose-response relationship was observed with gestational age and health status such that the earlier an infant was born, the greater their cardiovascular risk in adolescence.

Evidence Rating Level: 1 (Excellent)      

Study Rundown: A substantial amount of infants are born preterm each year (<37 weeks gestational age), and previous research has shown that these children have greater cardiovascular risk and increased insulin resistance in adulthood. However, few studies have explored these factors in the context of the degree of prematurity and existing research has been inconclusive regarding gestational age and cholesterol levels. This study evaluated differences in blood pressure, glucose regulation, and cholesterol profile in preterm and term infants. Significant gender-related differences were observed. Girls born prior to 34 weeks gestation had higher blood pressure readings in their adolescent years than those born at term, and  among boys, a poor cholesterol profile was seen in adolescence among those born before 34 weeks when compared to those born at term. In addition, the earlier preterm infants were born, the greater amount of cardiovascular risk they had in adolescence. Results may be limited as adolescents who were born preterm were less likely to participate and subjects with health impairments related to preterm birth may be underrepresented. However, these findings should aid physicians in identifying those patients who are at a greater risk of developing high blood pressure and high cholesterol.

Click to read the study, published today in Pediatrics

Relevant Reading: Cardiovascular risk factors at age 30 following pre-term birth.

Study Author, Marika Sipola-Leppänen, MD, talks to 2 Minute Medicine: Department of Chronic Disease Prevention, National Institute for Health and Welfare.

“About 11% of all live-born infants worldwide are born preterm and nowadays increasing number of those infants survives in the adulthood. As adults, people born preterm have more pronounced cardiovascular risk factors compared with their term-born peers suggesting early life “programming” of adult disease. However, most previous studies of the adult outcomes have focused on smallest preterm infants.  In the population-based Northern Finland Birth Cohort study we show that preterm birth is associated with elevated blood pressure in adolescent girls and an atherogenic lipid profile in boys. Many of these risk factors are also present among the much larger group of those born less immature, consistent with a “dose-response” relationship with the degree of prematurity. Our findings suggest that former preterm infants are more vulnerable to disorders related to cardiovascular disease in later life, and lifestyle interventions and screening of risk factors is needed in children and adults born preterm.”

In-Depth [prospective cohort study]: Data from a total of 6642 infants from the (N = 79 early preterm [<34 week gestational age], N = 238 late preterm [34 to <37 weeks gestational age], N = 6325 term births [>37 weeks gestational age]) Northern Finland Birth Cohort 1986 were included for analysis. Participants were examined at 16 years of age and had blood pressures and lipid profiles checked (serum insulin, glucose, total cholesterol, HDL, LDL, triglycerides, and apolipoproteins A1 and B). Parents and participants completed a questionnaire pertaining to medical history, smoking, physical activity, and childhood socioeconomic status. Early preterm girls had a significantly greater mean difference in systolic and diastolic blood pressure, 6.8 mmHg (P < .001) and 3.5 mmHg (P< .01) respectively, when compared to adolescents born at term. Each additional week of gestation for girls was associated with a 0.5 mmHg decrease in systolic and 0.2 mmHg decrease in diastolic blood pressure. Early preterm boys had higher mean total cholesterol (6.7%, P < .05), LDL cholesterol (10.7%, P< .05), and apolipoprotein B (11.2%, P< .05) concentrations than adolescent boys born at term. Each additional week of gestation for boys was associated with a decrease in total cholesterol, LDL, and apolipoprotein B by 0.5%, 1.0%, and 1.0% respectively. Results were similar when adjusted for maternal smoking, birth weight, parental education, pubertal stage, BMI, and lifestyle.

More from this author: Parental conceptions of weight are becoming increasingly inaccurateVitamin K refusal for newborns linked to non-immunization; Amount of electronic gameplay associated with psychosocial adjustmentImpaired brain growth in preterm infants linked with delayed cognitive developmentDelayed umbilical cord clamping associated with potential antioxidant effect 

Image: PD

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