title: Habitual intake of flavonoid subclasses and incident hypertension in adults.
abstract: BACKGROUND
  Dietary flavonoids have beneficial effects on blood pressure in intervention settings, but there is limited information on habitual intake and risk of hypertension in population-based studies.
  
  
  OBJECTIVE
  We examined the association between habitual flavonoid intake and incident hypertension in a prospective study in men and women.
  
  
  METHODS
  A total of 87,242 women from the Nurses' Health Study (NHS) II, 46,672 women from the NHS I, and 23,043 men from the Health Professionals Follow-Up Study (HPFS) participated in the study. Total flavonoid and subclass intakes were calculated from semiquantitative food-frequency questionnaires collected every 4 y by using an updated and extended US Department of Agriculture database.
  
  
  RESULTS
  During 14 y of follow-up, 29,018 cases of hypertension in women and 5629 cases of hypertension in men were reported. In pooled multivariate-adjusted analyses, participants in the highest quintile of anthocyanin intake (predominantly from blueberries and strawberries) had an 8% reduction in risk of hypertension [relative risk (RR): 0.92; 95% CI: 0.86, 0.98; P < 0.03] compared with that for participants in the lowest quintile of anthocyanin intake; the risk reduction was 12% (RR: 0.88; 95% CI: 0.84, 0.93; P < 0.001) in participants ≤60 y of age and 0.96 (0.91, 1.02) in participants >60 y of age (P for age interaction = 0.02). Although intakes of other subclasses were not associated with hypertension, pooled analyses for individual compounds suggested a 5% (95% CI: 0.91, 0.99; P = 0.005) reduction in risk for the highest compared with the lowest quintiles of intake of the flavone apigenin. In participants ≤60 y of age, a 6% (95% CI: 0.88, 0.97; P = 0.002) reduction in risk was observed for the flavan-3-ol catechin when the highest and the lowest quintiles were compared.
  
  
  CONCLUSIONS
  Anthocyanins and some flavone and flavan-3-ol compounds may contribute to the prevention of hypertension. These vasodilatory properties may result from specific structural similarities (including the B-ring hydroxylation and methyoxylation pattern).
authors.affiliation: School of Medicine, University of East Anglia, Norwich, United Kingdom.
authors.forename: Aedín
authors.initials: A
authors.lastname: Cassidy
authors.forename: Éilis J
authors.initials: ÉJ
authors.lastname: O'Reilly
authors.forename: Colin
authors.initials: C
authors.lastname: Kay
authors.forename: Laura
authors.initials: L
authors.lastname: Sampson
authors.forename: Mary
authors.initials: M
authors.lastname: Franz
authors.forename: J P
authors.initials: JP
authors.lastname: Forman
authors.forename: Gary
authors.initials: G
authors.lastname: Curhan
authors.forename: Eric B
authors.initials: EB
authors.lastname: Rimm
mesh_terms: D000328:Adult; D000872:Anthocyanins / Q000008:administration & dosage / Q000627:therapeutic use; D047310:Apigenin / Q000008:administration & dosage / Q000627:therapeutic use; D002392:Catechin / Q000008:administration & dosage / Q000627:therapeutic use; D004032:Diet; D004034:Diet Surveys; D005260:Female; D005419:Flavonoids / Q000008:administration & dosage / Q000627:therapeutic use*; D005500:Follow-Up Studies; D031985:Fragaria / Q000737:chemistry; D005638:Fruit; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000517:prevention & control*; D015994:Incidence; D008297:Male; D015999:Multivariate Analysis; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000627:therapeutic use*; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013995:Time; D029796:Vaccinium / Q000737:chemistry; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D010936:Plant Extracts; D014665:Vasodilator Agents; D047310:Apigenin; D002392:Catechin