Vitamin D and Omega-3 Hypertension Trial (VITAL Hypertension)

The human toll of hypertension is staggering, and effective preventive measures are needed.
Studies suggest that inadequate vitamin D and omega-3 fatty acid levels may be involved in
the development of hypertension through multiple pathways. Results from several small
clinical trials suggest that these agents may have blood pressure lowering effects, however,
larger trials using higher doses of both vitamin D and omega-3 fatty acids for the prevention
of hypertension among people with normal blood pressure levels are lacking. The VITamin D and
OmegA-3 TriaL (VITAL) provides a cost-effective setting to examine the effects of both study
agents on changes in blood pressure and new diagnoses of hypertension.

VITAL Hypertension will test the following hypotheses: (1) whether vitamin D and fish oil
supplementation lowers 24-hour blood ambulatory blood pressure (ABP) compared to placebo in a
subcohort of 1,000 participants; (2) whether vitamin D and fish oil supplementation reduces
the risk of incident hypertension compared to placebo among all randomized VITAL participants
without baseline hypertension; and (3) whether vitamin D and fish oil supplementation
favorably change hypertension-related biomarkers that are potential mechanisms linking
vitamin D and omega-3 fatty acids with hypertension compared to placebo.

A representative subcohort of 1,000 VITAL participants without hypertension from selected
major metropolitan areas throughout the US will be invited to participate in home-based study
visits at baseline and 2 years follow-up. During these visits, participants will be asked to
wear monitors to record 24-hour ABP measurements, provide fasting bloods, spot urine samples,
and other clinical measurements. The visits will be conducted by Examination Management
Services, Inc. (EMSI), a nationally based, clinical services provider. We will compare 2-year
changes in ABP among those randomized to vitamin D and omega-3 fatty acid supplements versus
those randomized to placebo. In addition, we will assess the 2-year changes in levels of
clinically and mechanistically relevant biomarkers of hypertension compared the 2 treatment
groups.

New diagnoses of hypertension among all VITAL participants will be ascertained on annual
follow-up questionnaires. To strengthen our classification of hypertension status, we will
supplement our questionnaire data with annual updates of hypertension information based upon
outpatient diagnostic codes and medication prescription usage from the Centers for Medicare &
Medicaid Services (CMS) database. Incidence of hypertension among those assigned to each
active agent versus placebo will be compared.

In addition, baseline blood samples from 1,000 participants with new diagnoses of
hypertension will be compared with those from 2,000 participants without hypertension to
determine whether the effect of vitamin D and/or omega-3 fatty acid supplements on the
incidence of hypertension is modified by baseline plasma levels of vitamin D or omega-3 fatty
acids.

Results from VITAL Hypertension will provide important evidence to support or refute the
potential preventive roles of vitamin D and omega-3 fatty acids on blood pressure and the
development of hypertension.

Participants eligible and willing to participate in the main VITAL trial (NCT 01169259) who
meet the following criteria are eligible to participate in the VITAL Hypertension ancillary
study: all participants with no baseline history of hypertension and, for home visits in
the subcohort of 1,000 participants, those living in selected cities throughout the U.S..