title: Changes in lifestyle and plasma total homocysteine: the Hordaland Homocysteine Study.
abstract: BACKGROUND
  Elevated plasma concentrations of total homocysteine (tHcy) are a risk factor for cardiovascular disease. tHcy is a marker of folate and cobalamin deficiencies and is also related to several lifestyle factors.
  
  
  OBJECTIVE
  We examined whether changes in lifestyle influence tHcy over time.
  
  
  METHODS
  A population-based, prospective study was conducted in 7031 subjects from western Norway who constituted 2 age groups (41-42 and 65-67 y) at baseline (1992-1993). The subjects were reinvestigated in 1997-1999 ( follow-up: 6 y).
  
  
  RESULTS
  During follow-up, median tHcy concentrations decreased 0.10 (25th and 75th percentiles: -1.24, 1.00) micromol/L in the younger subjects and increased 0.39 (25th and 75th percentiles: -0.99, 1.79) micromol/L in the older subjects. Changes in plasma vitamin status and vitamin supplement use were the strongest determinants of changes in tHcy over time. Each unit increase in plasma folate (nmol/L) and vitamin B-12 (pmol/L) was associated with reductions in tHcy concentrations of 0.2 and 0.1 micromol/L, respectively. Among the younger and older age groups, those who started to take vitamin supplements during follow-up had significant reductions in tHcy concentrations of 0.42 (95% CI: -0.65, -0.20) and 0.41 (-0.78, -0.03) micromol/L, respectively. In the younger subjects who quit smoking, tHcy concentrations decreased 0.54 (-0.91, -0.16) micromol/L. Weight changes were inversely related to tHcy. Both baseline history of cardiovascular disease or hypertension and cardiovascular events during follow-up were significantly associated with changes in tHcy.
  
  
  CONCLUSIONS
  Changes in lifestyle factors over time influence tHcy concentrations. These changes are modest when compared with the strong associations between tHcy and lifestyle factors in cross-sectional studies.
authors.affiliation: Department of Public Health and Primary Health Care, University of Bergen, Norway. eha.nurk@linacre.oxford.ac.uk
authors.forename: Eha
authors.initials: E
authors.lastname: Nurk
authors.forename: Grethe S
authors.initials: GS
authors.lastname: Tell
authors.forename: Stein E
authors.initials: SE
authors.lastname: Vollset
authors.forename: Ottar
authors.initials: O
authors.lastname: Nygård
authors.forename: Helga
authors.initials: H
authors.lastname: Refsum
authors.forename: Roy M
authors.initials: RM
authors.lastname: Nilsen
authors.forename: Per M
authors.initials: PM
authors.lastname: Ueland
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology*; D003069:Coffee / Q000009:adverse effects; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008019:Life Style; D008297:Male; D009664:Norway / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000097:blood; D014803:Vitamin B Complex / Q000008:administration & dosage* / Q000097:blood; D014815:Vitamins / Q000008:administration & dosage* / Q000097:blood
chemical_list: D003069:Coffee; D014815:Vitamins; D006710:Homocysteine; D014803:Vitamin B Complex