title: Habitual dietary sodium intake is inversely associated with coronary flow reserve in middle-aged male twins.
abstract: BACKGROUND
  Evidence links dietary sodium to hypertension and cardiovascular disease (CVD), but investigation of its influence on cardiovascular function is limited.
  
  
  OBJECTIVE
  We examined the relation between habitual dietary sodium and coronary flow reserve (CFR), which is a measure of overall coronary vasodilator capacity and microvascular function. We hypothesized that increased sodium consumption is associated with lower CFR.
  
  
  METHODS
  Habitual daily sodium intake for the previous 12 mo was measured in 286 male middle-aged twins (133 monozygotic and dizygotic pairs and 20 unpaired twins) by using the Willett food-frequency questionnaire. CFR was measured by positron emission tomography [N(13)]-ammonia, with quantitation of myocardial blood flow at rest and after adenosine stress. Mixed-effects regression analysis was used to assess the association between dietary sodium and CFR.
  
  
  RESULTS
  An increase in dietary sodium of 1000 mg/d was associated with a 10.0% lower CFR (95% CI: -17.0%, -2.5%) after adjustment for demographic, lifestyle, nutritional, and CVD risk factors (P = 0.01). Across quintiles of sodium consumption, dietary sodium was inversely associated with CFR (P-trend = 0.03), with the top quintile (>1456 mg/d) having a 20% lower CFR than the bottom quintile (<732 mg /d). This association also persisted within pairs: a 1000-mg/d difference in dietary sodium between brothers was associated with a 10.3% difference in CFR after adjustment for potential confounders (P = 0.02).
  
  
  CONCLUSIONS
  Habitual dietary sodium is inversely associated with CFR independent of CVD risk factors and shared familial and genetic factors. Our study suggests a potential novel mechanism for the adverse effects of dietary sodium on the cardiovascular system. This trial was registered at clinicaltrials.gov as NCT00017836.
authors.affiliation: Nutrition and Health Sciences Program, Emory University, Atlanta, GA 30322, USA.
authors.forename: Silvia C
authors.initials: SC
authors.lastname: Eufinger
authors.forename: John
authors.initials: J
authors.lastname: Votaw
authors.forename: Tracy
authors.initials: T
authors.lastname: Faber
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Ziegler
authors.forename: Jack
authors.initials: J
authors.lastname: Goldberg
authors.forename: J Douglas
authors.initials: JD
authors.lastname: Bremner
authors.forename: Viola
authors.initials: V
authors.lastname: Vaccarino
mesh_terms: D000241:Adenosine / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000503:physiopathology / Q000517:prevention & control; D005247:Feeding Behavior; D053805:Fractional Flow Reserve, Myocardial / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology / Q000517:prevention & control; D008019:Life Style; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D049268:Positron-Emission Tomography / Q000379:methods; D012307:Risk Factors; D012982:Sodium, Dietary / Q000008:administration & dosage* / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D014427:Twins
chemical_list: D012982:Sodium, Dietary; D000241:Adenosine