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Obesity modifies the relationship between ambulatory blood pressure and natriuresis in children
1Pediatric Nephrology Unit, Department of Pediatrics, General Hospital, University of Valencia, Valencia, Spain.
Insights
Childhood obesity impacts blood pressure regulation, with obese children showing higher systolic blood pressure and reduced sodium excretion capacity. Lowering sodium intake may benefit obese children with impaired sodium excretion.
Area of Science:
- Pediatric Endocrinology
- Cardiovascular Physiology
- Nutritional Science
Background:
- Childhood obesity is a growing concern with potential long-term health implications.
- Early-onset obesity may influence cardiovascular risk factors like blood pressure.
- The relationship between sodium balance and blood pressure in obese youth is not fully understood.
Purpose of the Study:
- To investigate how obesity starting in the first two decades of life affects the link between ambulatory blood pressure and urinary sodium excretion.
- To compare sodium excretion patterns in obese versus non-obese children.
Main Methods:
- Simultaneous 24-hour ambulatory blood pressure monitoring and complete urine collection were performed.
- Eighty-five obese and 88 non-obese children (aged 3-19 years) participated.
- Urinary excretion rates for sodium, potassium, and creatinine were analyzed for 24-hour, awake, and sleep periods.
Main Results:
- Weight and sodium excretion were directly associated with systolic blood pressure.
- Obese children exhibited higher ambulatory systolic blood pressure than non-obese children at similar sodium excretion levels.
- The interaction between sodium excretion and weight indicated a diminished blood pressure response to sodium in obese children.
Conclusions:
- Obesity in early life appears to impair sodium excretion, contributing to elevated blood pressure.
- Sodium excretion capacity varies, with the lowest capacity observed at the highest blood pressure levels.
- Reducing sodium intake could be a strategy to manage blood pressure in obese children with limited sodium excretion ability.
Background:
The objective in the present study was to evaluate if obesity beginning in the first two decades of life influences the relationship between ambulatory blood pressure and urinary sodium excretion.
Design And Methods:
Eighty-five obese and 88 non-obese children aged 3-19 years were included in the study. For each subject, a 24h ambulatory blood pressure monitoring and a complete urine collection were simultaneously performed according to the protocols designed. The averages of ambulatory blood pressure and of the urinary excretion rates for sodium, potassium and creatinine were calculated separately for 24-h, awake and sleep periods as defined by a mini-diary.
Results:
Weight and sodium excretion are directly associated with systolic blood pressure; however, the relationship between blood pressure and sodium excretion seems to be modified in obese children as compared to controls. The interaction between sodium excretion and weight was negative indicating that the rate of change of systolic blood pressure by sodium unit is smaller for the obese than for the non-obese, even though at the same urinary sodium excretion level the obese children had higher ambulatory systolic blood pressure.
Conclusions:
Obesity during the first two decades of life seems to restrict sodium excretion, leading to higher blood pressure values. The capacity to excrete sodium seems to be heterogeneous, the lowest capacity being at the highest blood pressure values. Subsets of the obese, those with the lowest ability to excrete sodium, may be further protected by low sodium intake in order to prevent a rise in blood pressure.