Low birth weight as a marker of changes in ambulatory blood pressure monitoring.

BACKGROUND: Low birth weight (LBW) is associated with increased incidence of high blood pressure (BP) and cardiovascular diseases in adulthood.

OBJECTIVE: To evaluate possible changes in Ambulatory Blood Pressure Monitoring (ABPM) in LBW children.

METHODS: The birth weight (BW) of 1049 school children (ages 8 to 11) living in Goiânia was assessed. Children with low birth weight (BW or= 3.0 Kg). Information on birth weight was obtained from each child's health card. Casual BP and ABPM were measured. Height and weight measurements were obtained to calculate the body mass index (BMI), and sexual maturity was assessed according to Tanner's criteria (those at Tanner stage >or= 2 were excluded).

RESULTS: Thirty-four children had low birth weight (LBW) and 34 had normal birth weight (NBW). Both groups were similar regarding age, gender, race, body weight, height, BMI, and family history of hypertension. Low-birth-weight children had higher casual systolic blood pressure (SBP) (p = 0.007). ABPM recordings showed that these children had higher 24-hour diastolic blood pressure (DBP) (p = 0.009), daytime DBP (p = 0.002), night-time DBP and SBP (p = 0.005 and p = 0.001), and reduced nocturnal dip in SBP and DBP (p = 0.001) than those born with normal weight. Birth weight was positively correlated with nocturnal dip in SBP (p = 0.022) and negatively correlated with sleep SBP (p = 0.032).

CONCLUSION: Low-birth-weight children have higher BP and changes in circadian rhythm of blood pressure, with reduced nocturnal dipping. These findings may reflect increased risk of adult hypertension and cardiovascular diseases.