Longitudinal effects of dietary sodium and potassium on blood pressure in adolescent girls.
OBJECTIVE
Identification of risk factors early in life for the development of high blood pressure is critical to the prevention of cardiovascular disease.


OBJECTIVE
To study prospectively the effect of dietary sodium, potassium, and the potassium to sodium ratio on adolescent blood pressure.


METHODS
The National Heart, Lung, and Blood Institute's Growth and Health Study is a prospective cohort study with sites in Richmond, California; Cincinnati, Ohio; and Washington, DC. Participants included 2185 black and white girls initially aged 9 to 10 years with complete data for early-adolescent to midadolescent diet and blood pressure who were followed up for 10 years. The first examination visits were from March 1987 through February 1988 and follow-up continued until February 1999. Longitudinal mixed models and analysis of covariance models were used to assess the effect of dietary sodium, potassium, and the potassium to sodium ratio on systolic and diastolic blood pressures throughout adolescence and after 10 years of follow-up, adjusting for race, height, activity, television/video time, energy intake, and other dietary factors.


METHODS
Mean dietary sodium and potassium intakes and the mean potassium to sodium ratio in individuals aged 9 to 17 years. To eliminate potential confounding by energy intake, energy-adjusted sodium and potassium residuals were estimated.


METHODS
Mean systolic and diastolic blood pressures throughout adolescence and at the end of follow-up (individuals aged 17-21 years).


RESULTS
Sodium intakes were classified as less than 2500 mg/d (19.4% of participants), 2500 mg/d to less than 3000 mg/d (29.5%), 3000 mg/d to less than 4000 mg/d (41.4%), and 4000 mg/d or more (9.7%). Potassium intakes ranged from less than 1800 mg/d (36.0% of participants) to 1800 mg/d to less than 2100 mg/d (26.2%), 2100 mg/d to less than 2400 mg/d (18.8%), and 2400 mg/d or more (19.0%). There was no evidence that higher sodium intakes (3000 to <4000 mg/d and ≥4000 mg/d vs <2500 mg/d) had an adverse effect on adolescent blood pressure and longitudinal mixed models showed that those consuming 3500 mg/d or more had generally lower diastolic blood pressures compared with individuals consuming less than 2500 mg/d (P = .18). However, higher potassium intakes were inversely associated with blood pressure change throughout adolescence (P < .001 for systolic and diastolic) and at the end of follow-up (P = .02 and P = .05 for systolic and diastolic, respectively). While the potassium to sodium ratio was also inversely associated with systolic blood pressure (P = .04), these effects were generally weaker compared with effects for potassium alone.


CONCLUSIONS
In this study of adolescent girls, consumption of 3500 mg/d of sodium or more had no adverse effect on blood pressure. The beneficial effects of dietary potassium on both systolic and diastolic blood pressures suggest that consuming more potassium-rich foods during childhood may help suppress the adolescent increase in blood pressure.
Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.
Justin R
JR
Buendia
Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.
M Loring
ML
Bradlee
Department of Pediatrics, University of Colorado School of Medicine, Aurora3The Children's Hospital, Aurora, Colorado.
Stephen R
SR
Daniels
Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.
Martha R
MR
Singer
Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.
Lynn L
LL
Moore
D000293:Adolescent; D001794:Blood Pressure / Q000187:drug effects*; D002648:Child; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000517:prevention & control*; D008137:Longitudinal Studies; D017419:Potassium, Dietary / Q000008:administration & dosage*; D012982:Sodium, Dietary / Q000008:administration & dosage*
D017419:Potassium, Dietary; D012982:Sodium, Dietary