Predictors of dietary change and maintenance in the Women's Health Initiative Dietary Modification Trial.
OBJECTIVE
To identify predictors of dietary change to and maintenance of a low-fat eating pattern (<20% energy from fat, > or = 5 servings fruits/vegetables daily, and > or = 6 servings grains daily) among a cohort of postmenopausal women. Candidate predictors included intrapersonal, interpersonal, intervention program characteristics, and clinical center.


METHODS
Longitudinal study within the Women's Health Initiative Dietary Modification Trial. Dietary change was evaluated after 1 year of participation in the Women's Health Initiative Dietary Modification Trial, and dietary maintenance after 3 years.


METHODS
Postmenopausal women aged 50 to 79 years at baseline who were randomized to the intervention arm of the Women's Health Initiative Dietary Modification Trial (n=19,541).


METHODS
Univariate and multivariate linear regression analysis was performed and associations evaluated between candidate predictors and each of the three dietary goals: percent energy from fat, fruit/vegetable servings, and grain servings.


RESULTS
Year 1 (change) predictors of percent energy from fat (P<0.005) included being younger (beta=2.12; 70 to 79 years vs 50 to 59 years), more educated (beta=-.69; college vs high school), more optimistic (beta=-.07), attending more sessions (beta=-.69), and submitting more self-monitoring records (beta=-.74). At year 3 (maintenance), the predictors of percent energy from fat (P<0.005) included attending more sessions (beta=-.65) and submitting more self-monitoring scores (beta=-.71). The analytic model predicted 22% of the variance in fat intake at year 1 and 27% at year 3 (P<0.01).


CONCLUSIONS
The strongest predictors of dietary change and maintenance were attending intervention sessions and self-monitoring dietary intake. Novel was the finding that optimism predicted dietary change.
Tinker
Lesley F
LF
Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. ltinker@whi.org
Rosal
Milagros C
MC
Young
Anne F
AF
Perri
Michael G
MG
Patterson
Ruth E
RE
Van Horn
Linda
L
Assaf
Annlouise R
AR
Bowen
Deborah J
DJ
Ockene
Judith
J
Hays
Jennifer
J
Wu
Lieling
L
D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D018752:Diet, Fat-Restricted / Q000379:methods / Q000523:psychology*; D004041:Dietary Fats / Q000008:administration & dosage*; D002523:Edible Grain; D004522:Educational Status; D002149:Energy Intake; D005260:Female; D005638:Fruit; D006285:Health Planning; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D052756:Nutritional Sciences / Q000193:education*; D010349:Patient Compliance / Q000523:psychology*; D017698:Postmenopause; D014675:Vegetables; D016387:Women's Health
D004041:Dietary Fats