Sodium intake in infancy and blood pressure at 7 years: findings from the Avon Longitudinal Study of Parents and Children.
BACKGROUND
Infancy may be a sensitive period regarding effects of sodium intake on future blood pressure (BP). This has only been demonstrated in one randomized trial of low sodium formulae with follow-up in adolescence in one-third of participants.


OBJECTIVE
To prospectively assess associations between sodium intake in infancy and BP at 7 years in the Avon Longitudinal Study of Parents and Children (ALSPAC).


METHODS
A total of 533 children with sodium data at 4 months and 710 children with sodium at 8 months.


RESULTS
0.4% of participants at 4 months and 73.0% at 8 months exceeded recommended levels for infant sodium intake. After minimal adjustment (child age, sex, energy), sodium intake at 4 months was positively associated with systolic blood pressure (SBP) at 7 years (beta=0.54 mm Hg/mmol; 95% CI: 0.09, 0.98 mm Hg; P=0.02). This changed little following adjustment for confounders but attenuated after adjusting for breastfeeding. This association was not mediated by sodium intake at 7 years. Due to high sodium-potassium correlations, effects of sodium independent of potassium could not be estimated with reasonable precision. Sodium intake neither at 8 months nor at 7 years was associated with SBP at 7 years.


CONCLUSIONS
The association between sodium intake at 4 months and future SBP requires replication in studies that can control for effects of potassium before we can conclude that early infancy is a sensitive period with respect to effects of sodium on future BP. The majority of infants exceeded recommended levels of sodium intake at 8 months, and interventions to reduce sodium in infants' diets should be considered.
Brion
M-J
MJ
Department of Social Medicine, University of Bristol, Whiteladies Road, Bristol, Avon, UK. Marie-Jo.Brion@bristol.ac.uk
Ness
A R
AR
Davey Smith
G
G
Emmett
P
P
Rogers
I
I
Whincup
P
P
Lawlor
D A
DA
D000375:Aging / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002648:Child; D015331:Cohort Studies; D003971:Diastole; D004739:England; D005260:Female; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena / Q000502:physiology*; D008297:Male; D018673:Nutrition Policy; D017419:Potassium, Dietary / Q000008:administration & dosage / Q000009:adverse effects; D011446:Prospective Studies; D012982:Sodium, Dietary / Q000008:administration & dosage* / Q000009:adverse effects; D013599:Systole; D013997:Time Factors
D017419:Potassium, Dietary; D012982:Sodium, Dietary