Blood pressure and interactions between the angiotensin polymorphism AGT M235T and sodium intake: a cross-sectional population study.
BACKGROUND
Intervention studies have indicated an interaction between the blood pressure response to a low-sodium or a low-fat and high-fruit and -vegetable diet and the angiotensinogen gene (AGT) polymorphisms G-6A and M235T.


OBJECTIVE
We investigated whether this interaction is also present in a large free-living population.


METHODS
Urinary sodium, potassium as biomarkers of intake, and blood pressure were measured in 11 384 men and women aged 45-79 y participating in the Norfolk arm of the European Prospective Investigation of Nutrition and Cancer (EPIC). The M235T polymorphism was assessed by pyrosequencing.


RESULTS
Highly significant associations between sodium and blood pressure were shown for all genotypes (P < 0.001), but the regression coefficient for systolic blood pressure associated with each unit of sodium for each of the MT and TT genotypes was approximately double that for the MM homozygotes (P < 0.001 for heterogeneity between genotypes). Differences were evident at high exposures to sodium but not at low exposures. There were no significant associations between blood pressure and dietary or urinary potassium.


CONCLUSIONS
This large cross-sectional study supports public health recommendations to reduce salt consumption in the population as a whole, and it confirms intervention trial data showing the greatest response to intervention in persons with the AA and TT genotype in the AGT G-6A and M235T polymorphisms. Genotype effects in populations at low exposure to sodium are not likely to be seen.
Norat
Teresa
T
MRC Dunn Human Nutrition Unit, Cambridge, United Kingdom.
Bowman
Richard
R
Luben
Robert
R
Welch
Ailsa
A
Khaw
Kay Tee
KT
Wareham
Nick
N
Bingham
Sheila
S
D000368:Aged; D000809:Angiotensins / Q000235:genetics*; D015415:Biomarkers / Q000652:urine; D001794:Blood Pressure / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004039:Diet, Sodium-Restricted; D004041:Dietary Fats / Q000008:administration & dosage; D005260:Female; D005638:Fruit; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000178:diet therapy* / Q000453:epidemiology / Q000235:genetics; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011188:Potassium / Q000652:urine; D011446:Prospective Studies; D012964:Sodium / Q000652:urine; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*; D016896:Treatment Outcome; D014675:Vegetables
D000809:Angiotensins; D015415:Biomarkers; D004041:Dietary Fats; D017673:Sodium Chloride, Dietary; D012964:Sodium; D011188:Potassium