Salt Restriction Lowers Resting Blood Pressure but not 24-H Ambulatory Blood Pressure

Moore, Thomas J.; Malarick, Charlene; Olmedo, Angelo; Klein, Russell C.

doi:10.1093/ajh/4.5.410

Cited by 23 publications

(11 citation statements)

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“…Their findings would tend to support taking BP measurements over several days, rather than simply taking the same total number of Although three small studies of nonpharmacological therapy reported that the BP change measured by ABPM tended to be smaller than that detected by standard measurements, [20][21][22] we found no evidence of this in the DASH trial. Thus, we conclude that the standard deviation of BP change appears to be the key factor in determining relative sample size requirements and computing statistical power.…”

Section: Discussioncontrasting

confidence: 56%

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Comparing office-based and ambulatory blood pressure monitoring in clinical trials

et al. 2004

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Ambulatory blood pressure monitoring (ABPM) is commonly used in clinical trials. Yet, its ability to detect blood pressure (BP) change in comparison to multiple officebased measurements has received limited attention. We recorded ambulatory and five daily pairs of random zero (RZ) BPs pre-and post-intervention on 321 adult participants in the multicentre Dietary Approaches to Stop Hypertension trial. Treatment effect estimates measured by ambulatory monitoring were similar to those measured by RZ and did not differ significantly for waking vs 24-h ambulatory measurements. For systolic BP, the standard deviations of change in mean 24-h ambulatory BP (8.0 mmHg among hypertensives and 6.0 mmHg among nonhypertensives) were comparable to or lower than the corresponding standard deviations of change in RZ-BP based on five daily readings (8.9 and 5.9 mmHg). The standard deviations of change for mean waking ambulatory BP (8.7 and 6.7 mmHg) were comparable to those obtained using three to four daily RZ readings. Results for diastolic BP were qualitatively similar. Ambulatory monitoring was more efficient (ie, a smaller sample size could detect a given BP change) than three to four sets of daily RZ readings and required fewer clinic visits. The average of 33 ambulatory BP readings during the waking hours had an efficiency comparable to that from the mean of four daily pairs of RZ-BPs. Participants readily accepted the ABPM devices, and their use requires less staff training. ABPM provides a useful alternative to RZ-BP measurements in clinical trials.

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Section: Discussioncontrasting

confidence: 56%

“…In three small studies of nonpharmacologic therapy, the effect size (BP change) measured by ABPM tended to be smaller than that detected by standard measurements. [20][21][22] In clinical trials, the ratio of BP change to its standard deviation is key in determining sample size requirements and computing statistical power.…”

Section: Introductionmentioning

confidence: 99%

Comparing office-based and ambulatory blood pressure monitoring in clinical trials

et al. 2004

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“…Previous studies of lifestyle changes have not consistently shown round-the-clock BP lowering. For example, Moore et al 14 reported that sodium restriction lowered pressure more during the night than day in 15 hypertensives, and Straznicky et al 15 found that a low fat diet reduced SBP during the day but not night. Exercise training also lowered BP more during the day than night in several trials.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies of nonpharmacological treatments have often shown either different BP effect sizes by standard methods versus ABP 20,21 or significant responses with one measurement but not the other. 15,22 Two studies of salt restriction did show significant correlation between the changes in resting versus ambulatory pressure, 14,23 but both of these studies determined resting pressure by averaging 20 to 60 separate BP measurements. Most other studies used fewer measurements and thus may not have captured as representative an estimate of BP.…”

Section: Discussionmentioning

confidence: 99%

Effect of Dietary Patterns on Ambulatory Blood Pressure

et al. 1999

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Abstract-We measured ambulatory blood pressure (ABP) in 354 participants in the Dietary Approaches to StopHypertension (DASH) Trial to determine the effect of dietary treatment on ABP (24-hour, day and night) and to assess participants' acceptance of and compliance with the ABP monitoring (ABPM) technique. After a 3-week run-in period on a control "typical" American diet, subjects (diastolic blood pressure [BP], 80 to 95 mm Hg; systolic BP, Ͻ160 mm Hg; mean age, 45 years) were randomly assigned to 1 of 3 diets for an 8-week intervention period: a continuation of the control diet; a diet rich in fruits and vegetables; and a "combination" diet that emphasized fruits, vegetables, and low-fat dairy products. We measured ABP at the end of the run-in and intervention periods. Both the fruit/vegetable and combination diets lowered 24-hour ABP significantly compared with the control diet (PϽ0. 0001 for systolic and diastolic pressures on both diets: control diet, Ϫ0.2/ϩ0.1 mm Hg; fruit/vegetable diet, Ϫ3.2/Ϫ1.9 mm Hg; combination diet, Ϫ4.6/Ϫ2.6 mm Hg). The combination diet lowered pressure during both day and night. Hypertensive subjects had a significantly greater response than normotensives to the combination diet (24-hour ABP, Ϫ10.1/Ϫ5.5 versus Ϫ2.3/Ϫ1.6 mm Hg, respectively). After correction for the control diet responses, the magnitude of BP lowering was not significantly different whether measured by ABPM or random-zero sphygmomanometry. Participant acceptance of ABPM was excellent: only 1 participant refused to wear the ABP monitor, and 7 subjects (2%) provided incomplete recordings. These results demonstrate that the DASH combination diet provides significant round-the-clock reduction in BP, especially in hypertensive participants. (Hypertension. 1999;34:472-477.)Key Words: blood pressure monitoring, ambulatory Ⅲ nutrition Ⅲ diet Ⅲ blood pressure T wenty-four-hour ambulatory blood pressure monitoring (ABPM) provides valuable information otherwise unattainable when casual, office-based measurements are used. ABPM has aided our understanding of blood pressure (BP) circadian rhythm and has identified differences in BP rhythms in several population subgroups (eg, less than the expected BP fall occurred during sleep-also called "nondipping"-in blacks and in people with Cushing's syndrome, congestive heart failure, and type II diabetes 1-4 ). Furthermore, in cross-sectional studies, ambulatory blood pressure (ABP) also shows a better correlation with risk of stroke and left ventricular hypertrophy than does casual office measurement, 5-7 although prospective data examining ABP and cardiovascular risk are lacking.ABPM is often used in testing antihypertensive drugs. Compared with standard BP measurements, it simplifies the determination of the time of a drug's peak and trough effects, 8 shows minimal placebo effect, 8,9 and offers less withinsubject test-retest variability than casual office readings. 9,10 There is less experience with ABP in trials of nonpharmacological therapy. The Dietary Approaches to Stop Hyperte...

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“…Moore et al observed a significant fall in resting BP but not in 24-h BP after low sodium intake in hypertensive subjects (17). Fotherby and Potter were also unable to find a fall in 24-h BP by moderate sodium restriction in elderly hypertensive subjects (36).…”

Section: Discussionmentioning

confidence: 95%

Different Effects of Alcohol and Salt on 24-Hour Blood Pressure and Heart Rate in Hypertensive Patients.

et al. 1996

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To compare the influences of alcohol and salt intake on 24-h blood pressure (BP), we studied short-term effects of repeated alcohol ingestion and dietary salt intake in hypertensive patients. Thirty-two Japanese men with mild to moderate essential hypertension (54± 1 years old, mean±SE)were examined. Sixteen patients were given alcohol (1 ml/kg) with dinner for 7 d after a 7-d control period with an isocaloric beverage. Another group consisting of 16 age-and weight-matched patients consumed a low-sodium diet (25 mmol/d) for 7 d, followed by a high-sodium diet (250 mmol/d) for 7 d. Twenty-four-hour BP was measured at the end of each period. Average 24-h BP in the alcohol period (137±4 l 83±2 mmHg) was similar to that in the control period (138±4184±2 mmHg). However, BP in the alcohol period was significantly lower in the evening, but significantly higher in the morning than that in the control period. Heart rate increased for several hours after alcohol ingestion, resulting in a significant increase in 24-h heart rate (67±2 vs. 64±2 beats/min). Average 24-h BP was higher in the high salt period (144+4 189+ 4 mmHg) than in the low salt period (135±3 / 85±3 mmHg, p<0.05).The pressor effect of high salt intake was sustained throughout the day and was associated with a decrease in 24-h heart rate (60±2 vs. 66 ± 2 beats/min). In conclusion, short-term repeated intake of alcohol may have little effect on average 24-h BP while it causes an evening fall and a morning rise in BP, and high salt intake raises BP throughout the day. Alcohol consumption increases and salt loading decreases 24-h heart rate. (Hypertens Res 1996;19: 255-261) Key Words: hypertension, alcohol, sodium, ambulatory blood pressure, heart rate Both salt and alcohol have been recognized as important environmental factors in the pathogenesis of human hypertension. A number of epidemiological studies have documented a positive relationship between the level of blood pressure (BP) and the amount of dietary salt intake (1-3) or alcohol consumption (4-6). It also has been shown that BP rises after repeated intake of a high salt diet or alcohol, and falls with reductions in their intake (5, 7-10). Restrictions of salt and alcohol , intake are widely recommended in the management of hypertension (11, 12). However, the results of earlier studies were derived from casual BP measurements. Twenty-four-hour ambulatory BP monitoring is accepted as a useful method because it provides multiple BP recordings throughout the whole day, has good reproducibility, and eliminates observer bias (13,14). The pressor effect of high salt intake was seen for 24 h in several studies (15, 16), although its effect may be less than that assessed on the basis of casual BP readings (I7). The measurement of 24-h BP may be particularly important in evaluating BP of drinkers, since people drink alcohol mainly in the evening and at night. Alcohol has both vasoconstrictive and vasodilative actions (18). Our previous studies suggest that the effects of alcohol on BP depends on the duratio...

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Salt Restriction Lowers Resting Blood Pressure but not 24-H Ambulatory Blood Pressure

Cited by 23 publications

References 0 publications

Comparing office-based and ambulatory blood pressure monitoring in clinical trials

Comparing office-based and ambulatory blood pressure monitoring in clinical trials

Effect of Dietary Patterns on Ambulatory Blood Pressure

Different Effects of Alcohol and Salt on 24-Hour Blood Pressure and Heart Rate in Hypertensive Patients.

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