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Randomized Controlled Trial
. 2016 Aug;29(8):959-68.
doi: 10.1093/ajh/hpv196. Epub 2015 Dec 26.

A Randomized Trial of a Low-Fat Diet Intervention on Blood Pressure and Hypertension: Tertiary Analysis of the WHI Dietary Modification Trial

Matthew A Allison  1 , Aaron K Aragaki  2 , Roberta M Ray  2 , Karen L Margolis  3 , Shirley A A Beresford  4 , Lewis Kuller  5 , Mary Jo O'Sullivan  6 , Sylvia Wassertheil-Smoller  7 , Linda Van Horn  8
Affiliations
Randomized Controlled Trial

A Randomized Trial of a Low-Fat Diet Intervention on Blood Pressure and Hypertension: Tertiary Analysis of the WHI Dietary Modification Trial

Matthew A Allison et al. Am J Hypertens. 2016 Aug.

Abstract

Background: This post hoc analysis determined if the Women's Health Initiative (WHI) Diet Modification intervention (DM-I) resulted in a significantly different rate of incident hypertension (HTN), as well as longitudinal changes in blood pressure.

Methods: Participants were 48,835 postmenopausal women aged 50-79 years who were randomly assigned to either the intervention or comparison group. HTN was defined as self-report of treated HTN collected semiannually or blood pressure ≥140/90mm Hg at one of the annual follow-up clinic visits.

Results: After a mean follow-up of 8.3 years, and among those who did not have HTN at baseline (n = 31,146), there were 16,174 (51.9%) HTN cases and those assigned to the intervention group had a 4% lower overall risk of developing incident HTN (hazard ratio (HR): 0.96, 95% confidence interval (CI): 0.93-0.99). Although the risk of HTN was lower in the DM-I group in the first few years, the HR became greater than 1 after year 5 (P-trend < 0.01). Similarly, randomization to the DM-I arm resulted in a small but significantly lower average systolic blood pressure (SBP) at 1 year of follow-up (-0.66mm Hg, 0.44-0.89) that increased over the following 8 years (0.16mm Hg/year, 0.11-0.21), such that any early benefit was eliminated by year 5 and a minimal deleterious effect emerged by year 7.

Conclusion: Randomization to an intensive behavioral dietary modification program aimed at a lower total fat intake is not associated with sustained reductions in blood pressure or risk of HTN in postmenopausal women.

Clinical trial registration: url http://www.clinicaltrials.gov, unique identifier nct00000611.

Trial registration: ClinicalTrials.gov NCT00000611.

Keywords: blood pressure; diet; hypertension; trial; women..

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Figures

Figure 1.
Figure 1.
Participant flow in the Dietary Modification Trial.
Figure 2.
Figure 2.
Mean longitudinal effect of randomization to the DM-I arm compared to DM-C on systolic blood pressure, diastolic blood pressure, and pulse pressure. Estimate (95% CI) is from a linear mixed effects (LME) regression model shown by a solid (dotted) lines. The LME model included the corresponding baseline BP measurement as a covariate, a cubic polynomial to model time since randomization, an indicator variable for randomization group, an interaction term for randomization group × time (linear), along with a random intercept and random slope for time (linear). To confirm the LME model was reasonable, estimates for mean BP (95% CI; bowties) were also computed from a classical repeated measures model, where annual visits were coded categorically, and therefore do not assume a cubic relationship with time, nor a linear intervention effect.
Figure 3.
Figure 3.
Kaplan–Meier estimates for incident hypertension during the intervention period by DMT arm. Solid black line, intervention group; dashed black line, control group.
See this image and copyright information in PMC

Comment in

References

    1. Ritenbaugh C, Patterson RE, Chlebowski RT, Caan B, Fels-Tinker L, Howard B, Ockene J. The Women’s Health Initiative Dietary Modification Trial: overview and baseline characteristics of participants. Ann Epidemiol 2003; 13:S87–S97. - PubMed
    1. Howard BV, Van Horn L, Hsia J, Manson JE, Stefanick ML, Wassertheil-Smoller S, Kuller LH, LaCroix AZ, Langer RD, Lasser NL, Lewis CE, Limacher MC, Margolis KL, Mysiw WJ, Ockene JK, Parker LM, Perri MG, Phillips L, Prentice RL, Robbins J, Rossouw JE, Sarto GE, Schatz IJ, Snetselaar LG, Stevens VJ, Tinker LF, Trevisan M, Vitolins MZ, Anderson GL, Assaf AR, Bassford T, Beresford SAA, Black HR, Brunner RL, Brzyski RG, Caan B, Chlebowski RT, Gass M, Granek I, Greenland P, Hays J, Heber D, Heiss G, Hendrix SL, Hubbell FA, Johnson KC, Kotchen JM. Low-fat dietary pattern and risk of cardiovascular disease: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA 2006; 295:655–666. - PubMed
    1. Howard BV, Curb JD, Eaton CB, Kooperberg C, Ockene J, Kostis JB, Pettinger M, Rajkovic A, Robinson JG, Rossouw J, Sarto G, Shikany JM, Van Horn L. Low-fat dietary pattern and lipoprotein risk factors: the Women’s Health Initiative Dietary Modification Trial. Am J Clin Nutr 2010; 91:860–874. - PMC - PubMed
    1. Allison MA, Aragaki A, Eaton C, Li W, Van Horn L, Daviglus ML, Berger JS. Effect of dietary modification on incident carotid artery disease in postmenopausal women: results from the Women’s Health Initiative Dietary Modification Trial. Stroke 2014; 45:1748–1756. - PMC - PubMed
    1. Stamler J, Stamler R, Neaton JD. Blood pressure, systolic and diastolic, and cardiovascular risks. US population data. Arch Intern Med 1993; 153:598–615. - PubMed

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