Background: Preterm birth is associated with hypertension and increased fat contents in later life. Salt sensitivity (SS) could be a mechanism underlying this relationship. In adults SS has been recognised as a cause of hypertension that is related to low birth weight and obesity.
Objective and hypotheses: We studied the prevalence of SS in 78-year old children born <32 weeks of gestation and/or with a birth weight <1500 g as well as its relation with birth weight, infant growth and body composition.
Method: Subjects were recruited from a cohort (n=152) that participated in a nutritional randomized controlled trial during the first 6 months of life. Birth weight, gestational age and height at 0, 3, 6, 12 and 24 months were available. Of the original cohort, 79 children (40 males) aged 7.9 (IQR 7.68.3) years were enrolled. After an overnight fast, anthropometry, venipuncture and dual-energy X-ray absorptiometry (DEXA) were performed. Blood pressure (BP) was measured at baseline and after a 7-day high-salt diet (0.12 g/kg per day salt supplements in addition to regular diet). SS was defined as delta mean arterial BP ≧5%. HOMA-IR was calculated; (glucose (mmol/l)*insulin (mIU/l))/22.5.
Results: Sixty-three children completed the study and were included in the analyses. The prevalence of SS was 15.9% (n=10). SS subjects had lower BMI (13.8 vs 15.5 kg/m2), fat mass (at ages 0 and 6 months and 78 years) and systolic (95.0 vs 105.5 mmHg) and diastolic (51.1 vs 61.7 mmHg) BP at baseline compared with the non-SS subjects (all P<0.05). Birth characteristics, height and HOMA-IR were similar in both groups.
Conclusion: Children with SS had lower fat mass from infancy onwards, lower baseline BP and showed no signs of the metabolic syndrome. Associations between SS and cardiometabolic parameters as found in adults, may only become manifest after fat accretion and increased salt intake later in life.
01 Oct 2015 - 03 Oct 2015