Dietary Salt in Rheumatoid Arthritis

The study is a random-order, 2 period crossover study with washout. Participants will be
randomly assigned to be on the high-sodium diet (200mmol/24hours x 8weeks) or low-sodium diet
(50mmol/24hours x 8 weeks ) with crossover separated by 4-week washout period. Investigators
will allow a 7-day window on the diet (i.e., to facilitate scheduling the diet can be between
7-9 weeks), and investigators will allow a 1-week window for the washout (i.e., washout can
be 3-5 weeks).

Investigators will measure changes in inflammation (as measured by DAS28 (using tender and
swollen joint count, disease activity and sedimentation rate)), blood pressure measured over
a 24 hour period, and tissue sodium (using Magnetic Resonance Imaging (MRI)).

If a relatively simple dietary modification has a clinically important effect on inflammation
and blood pressure regulation in vivo in patients with RA, this will have far-reaching
implications for the treatment of RA and prevention of Cardiovascular disease in this
population.

Inclusion Criteria:

1. Male and female patients older than 18 years who are willing to participate.

2. Satisfy the ACR criteria for the diagnosis of RA.

3. Have stable disease activity as evidenced by no clinically meaningful change in
immunomodulating or corticosteroid therapy in the past 1 month.

4. Have moderate disease activity as reflected by a minimum of 3 swollen and tender
joints.

Exclusion Criteria:

1. Pregnancy

2. Receiving dialysis

3. Organ or bone marrow transplant

4. Taking diuretics, uncontrolled hypertension (>160/100 mmHg), or cardiac failure
requiring treatment.

5. Severe edema (as judged by the investigator)

6. Diabetes mellitus treated with an insulin pump

7. Major surgery within the previous 3 months

8. Severe co-morbid conditions such as active cancer likely to compromise study
participation

9. Unwillingness, or other inability, to cooperate

10. Contraindication to MRI

11. Presence of a condition that could make 24-hour blood pressure monitoring difficult:
atrial fibrillation, inability to operate machine, receiving anticoagulants, presence
of a condition that in the opinion of the investigator may be exacerbated by blood
pressure cuff inflation (e.g., lymphedema).