Changes in lifestyle and plasma total homocysteine: the Hordaland Homocysteine Study.
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.
Nurk
Eha
E
Department of Public Health and Primary Health Care, University of Bergen, Norway. eha.nurk@linacre.oxford.ac.uk
Tell
Grethe S
GS
Vollset
Stein E
SE
Nygård
Ottar
O
Refsum
Helga
H
Nilsen
Roy M
RM
Ueland
Per M
PM
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
D003069:Coffee; D014815:Vitamins; D006710:Homocysteine; D014803:Vitamin B Complex