Stress, Salt Excretion, and Nighttime Blood Pressure

Not Applicable

Completed

Conditions: Psychological Stress
Blood Pressure

Interventions: Behavioral: Psychological Stress Intervention

Registration Number: NCT03636490

Lead Sponsor: Columbia University

Brief Summary: The study will examine urinary sodium excretion induced by psychological stress and its diurnal pattern as a novel biological mechanism that may underlie an abnormal diurnal pattern of blood pressure. The study will test the hypotheses that lower stress-induced sodium excretion is associated with an abnormal diurnal pattern of sodium excretion, and that an abnormal diurnal pattern of sodium excretion is associated with an abnormal diurnal pattern of blood pressure.

Primary Aim 1: To examine the association between urinary sodium excretion after provoked psychological stress and the diurnal pattern of sodium excretion.

Primary Aim 2: To examine the association between the diurnal pattern of sodium excretion and the diurnal pattern of BP.

Secondary Aim: To examine whether the association between urinary sodium excretion after provoked stress and the diurnal pattern of sodium excretion is modified by ecological momentary levels of perceived stress, experienced during the daytime period.

Exploratory Aim: To determine the socio-demographic, behavioral, and psychological traits, chronic stress, and biological stress-related factors that are associated with lower stress-induced sodium excretion. Identification of these factors will help determine who is at risk for having a differential sodium excretion response to psychological stress.

Detailed Description: Blood pressure (BP) has a diurnal rhythm; it is normally highest during the daytime period and lowest during the nighttime period (BP dipping). The diurnal pattern of BP over a 24-hour period can be assessed using ambulatory BP monitoring (ABPM). Evidence indicates that an abnormal diurnal pattern of BP on ABPM, defined by reduced BP dipping or elevated nighttime BP, is associated with an increased risk of cardiovascular disease (CVD) events.

Psychological stress occurs when an individual perceives that the environmental demands exceed his/her adaptive capacity. An individual's response to events that are representative of this overload, such as perceived stress and negative affect including anger, hostility, depression, vital exhaustion, and symptoms of posttraumatic stress disorder, are associated with reduced BP dipping and/or higher nighttime BP. Exposure to environmental factors which tax an individual's ability to cope, including lower socioeconomic status, job strain, and perceived racism, are also associated with reduced BP dipping and/or higher nighttime BP. This study will examine the disruption of the normal diurnal pattern of sodium excretion by psychological stress as a novel biological mechanism underlying an abnormal diurnal pattern of BP.

The study will be conducted both in the laboratory and in the naturalistic environment with a multi-ethnic sample of 211 adult community participants from upper Manhattan who do not have a history of CVD, diabetes, chronic kidney disease, or another major medical condition and are not taking antihypertensive medication. During a laboratory visit, urinary sodium excretion in response to mental stress tasks will be examined.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 323

Inclusion Criteria

Age 21 years or older
Screening mean blood pressure less than or equal to 160/105 mm Hg

Exclusion Criteria

History of overt cardiovascular disease (coronary heart disease, stroke, peripheral arterial disease, heart failure, permanent or recurring arrhythmia)
History of secondary hypertension
History of other major medical condition (cancer, rheumatologic diseases, immunologic diseases, etc.)
Taking anti-hypertensive medications or other medications that are known to substantially affect blood pressure (e.g. steroids, chronic anti-inflammatory medications, etc.)
Non-English speaking

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Psychological Stress	Psychological Stress Intervention	All participants will undergo stress-inducing tasks (psychological stress intervention) using cognitive research tools.

Primary Outcome Measures

Name	Time	Method
Ratio of Awake-to-asleep Urinary Sodium Excretion Rate (Aim 1)	Over 24-hour ambulatory period
Systolic Blood Pressure Dipping (Aim 2)	Over 24-hour ambulatory period	Systolic blood pressure (SBP) dipping refers to the normal physiological decline in SBP during nighttime sleep. SBP dipping (%) was calculated as 100 \* (mean awake SBP - mean asleep SBP) / (mean awake SBP).

Secondary Outcome Measures

Name	Time	Method
24-hour Potassium Excretion	Over 24-hour ambulatory period	Rate of potassium excretion, measured from urine collected from participants during the ambulatory period.
24-hour Creatinine Clearance	Over 24-hour ambulatory period	Rate of creatine clearance, measured from urine collected from participants during the ambulatory period.
Mean Perceived Stress Level	Over 24-hour ambulatory period	This is to measure the ecological stress level for the awake period during which the participants' sodium excretion is monitored. A 10-point Visual Analog Scale (VAS) (0=Not at all, 5=Moderately, and 10=Extremely) was used to assess stress.
24-hour Sodium Excretion	Over 24-hour ambulatory period	Rate of sodium excretion, measured from urine collected from participants during the ambulatory period.
Fractional Excretion of Sodium	Over 24-hour ambulatory period	Fractional excretion of sodium is the amount of sodium that leaves the body through urine compared to the amount filtered and reabsorbed by the kidney.
EMA Stress	Over 24-hour ambulatory period	10-point Ecological Momentary Assessment (EMA) measures self-reported stress through a questionnaire (0=Not at all, 5=Moderately, and 10=Extremely). Higher score indicates worse stress. The average EMA score over 5 time points in a 24-hour ambulatory period are reported.
EMA Anger	Over 24-hour ambulatory period	10-point Ecological Momentary Assessment (EMA) measures self-reported anger through a questionnaire (0=Not at all, 5=Moderately, and 10=Extremely). Higher score indicates worse anger. The average EMA score over 5 time points in a 24-hour ambulatory period are reported.
EMA Aggravation	Over 24-hour ambulatory period	10-point Ecological Momentary Assessment (EMA) measures self-reported aggravation/irritation through a questionnaire (0=Not at all, 5=Moderately, and 10=Extremely). Higher score indicates worse aggravation. The average EMA score over 5 time points in a 24-hour ambulatory period are reported.
EMA Anxiety	Over 24-hour ambulatory period	10-point Ecological Momentary Assessment (EMA) measures self-reported anxiety through a questionnaire (0=Not at all, 5=Moderately, and 10=Extremely). Higher score indicates worse anxiety. The average EMA score over 5 time points in a 24-hour ambulatory period are reported.
EMA Depressed	Over 24-hour ambulatory period	10-point Ecological Momentary Assessment (EMA) measures self-reported sadness/depression through a questionnaire (0=Not at all, 5=Moderately, and 10=Extremely). Higher score indicates worse depression. The average EMA score over 5 time points in a 24-hour ambulatory period are reported.