Centenarian white coat hypertension

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Hi All,

Previously presented for its abstract, a paper was discussed related to the

level of

hypertension in Polish centenarians, in:

http://lists.calorierestriction.org/cgi-bin/wa?A2=ind0409 & L=crsociety & P=R31185 & X\

=5639D403317A2F0CD7 & Y=old542000

It discussed:

Zyczkowska J, Klich-Raczka A, Mossakowska M, Gasowski J, Wieczorowska-Tobis K,

Grodzicki T.

Blood pressure in centenarians in Poland.

J Hum Hypertens. 2004 Oct;18(10):713-6.

PMID: 15085168

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve & db=pubmed & dopt=Abstra\

ct & list_uids=15085168 & query_hl=14

From the Medline abstract, is:

" ... Hypertension diagnosed based on the criterion > or = 160/95 mmHg was found

in

29% of subjects ... "

From the available pdf, are:

" ... hypertensive. In contrast, the data from other Polish studies in people

aged

80-93 years showed the prevalence of the disease to be 60.3%. ... "

and

" ... Another problem lies with the possible white-coat effect, as any stressing

factor including a visit of investigators, may have a pressor effect on the

bed-and-chair-ridden very old individual. This could have been overcome had the

24-h

ABP measurements been performed. ... "

A new paper on centenarian blood pressure has been published. It examines a

particularly longevous population for the level of blood pressure among its

centenarians, compared with much less elderly members of the same population.

It is

described in partial detail below from its similarly available full-text.

Am J Hypertens. 2005 Aug;18(8):1040-5.

White coat hypertension in centenarians.

Jumabay M, Ozawa Y, Kawamura H, Saito S, Izumi Y, Mitsubayashi H, Kasamaki Y,

Nakayama T, Cheng Z, Ma Y, Mahumut M.

BACKGROUND: To study white coat (WC) hypertension in centenarians, a

cross-sectional surveillance was carried out on Uygurs, a long-lived population

in

China. METHODS: Twenty-four-hour ambulatory blood pressure (BP) monitoring

(ABPM)

was performed in 33 centenarians (age range, 100 to 113 years) and compared with

100

elderly subjects (age range, 65 to 70 years). All subjects were clinically

healthy

and capable of self-care. Subjects had no history, signs, or symptoms of

cardiovascular disease and were receiving no medical treatments. Office BP, 24-h

mean, daytime and night-time BP, pulse pressure, heart rate, standard deviation

(SD), and coefficient of variation (CV) of the same variables were extracted

from

ABPM. The WC effect was defined as the difference between mean office and

daytime

BP. RESULTS: Centenarians demonstrated higher prevalence of WC hypertension,

compared to elderly group (15% vs. 5%). The WC effect was also greater in

centenarians than in elderly subjects, and was more marked for systolic BP than

for

diastolic BP and heart rate. The WC effect for systolic BP was positively

correlated

with both SD (r = 0.45, P < .01) and CV (r = 0.55, P < .01) for 24-h systolic BP

in

centenarians, but not in elderly subjects. CONCLUSIONS: Prevalence of WC

hypertension was greater in centenarians than in elderly subjects. The WC effect

and

BP variation may be increased in centenarians. Previously observed higher BPs

seen

in very elderly individuals might be explained by the greater impact of WC

hypertension. PMID: 16109317

.... Results

Physiologic Characteristics of Subjects

.... Table 1. Physiologic characteristics of subjects

......................................

Elderly (n = 100) Centenarian (n = 33)

......................................

------Men/women 66/34 25/8

Age (y)

Men 68±2.0 104±5

Women 67±2.0 104±3

Height (cm)

Men 160±5.7 154±12 †

Women 149±4.7 148±6.9

Weight (kg)

Men 55±5.8 53±6.6 †

Women 46±6.7 40±5.6 †

BMI (kg/m2)

Men 21±1.9 21±3.3

Women 21±2.8 18±1.9

....................................

BMI = body mass index.

Values are means±SD.

†P < .01, differences between the elderly and centenarian groups.

.... Table 2. White coat effect

....................................

----Elderly (n = 100) Centenarian (n = 33)

....................................

Office

SBP (mm Hg) 128±10.3 145±10.1 †

DBP (mm Hg) 74±5.8 85±6.9 †

HR (beats/min) 83±3.3 82±5.1

Daytime

SBP (mm Hg) 123±17 129±22 †

DBP (mm Hg) 72±7.2 74±11

HR (beats/min) 80±8.5 79±11

White coat effect

SBP (mm Hg) 15±11.9 19±8.8 †

DBP (mm Hg) 10±8.1 12±5.1

HR (beats/min) 10±5.7 11±6.0

......................................

SBP = systolic blood pressure; DBP = diastolic blood pressure; HR = heart rate.

Values are means±SD.

†P < .01, differences between the elderly and centenarian groups.

.... Table 3. Blood pressure and pulse rate on ambulatory monitoring

....................................

----Elderly (n = 100) Centenarian (n = 33)

....................................

Mean 24-h

SBP (mm Hg) 121±16 128±23 †

DBP (mm Hg) 72±6.8 71±12

PP (mm Hg) 45±21 60±15 †

HR (beats/min) 78±8.9 76±11

Daytime

SBP (mm Hg) 123±17 129±22 †

DBP (mm Hg) 72±7.2 74±11

HR (beats/min) 80±8.5 79±11

Night-time

SBP (mm Hg) 117±18 127±20 †

DBP (mm Hg) 68±7 70±14

HR (beats/min) 71±12 71±13

Daytime–night-time

SBP (mm Hg) 9.5±7.4 1.7±1.2 †

DBP (mm Hg) 2.8±1.5 2.6±1.1

HR (beats/min) 10.6±5.5 9.5±7.1

.......................................

Abbreviations as in Table 2; PP = pulse pressure.

Values are means±SD.

†P < .01, differences between the elderly and centenarian groups.

Circadian BP and HR profiles are shown in Fig. 1. Two peaks and one dip pattern

characterized circadian systolic BP in elderly subjects. Circadian variations in

systolic BP showed multiple peaks, and the overall pattern tended to be flatter

in

centenarians. However, circadian patterns for HR were similar between

centenarians

and elderly subjects.

The SD and CV for 30-min variations in 24-h measurements are shown in Fig. 2.

The SD

and CV for BP were higher in centenarians than in elderly subjects. However, no

significant differences in SD or CV of HR were observed between elderly subjects

and

centenarians.

FIG. 2. Blood pressure variations every 30 min for 24 h in elderly and

centennial

groups. SD = standard deviation; CV = coefficient of variation; other

abbreviations

as in Fig. 1.

The WC effect was associated with SD and CV for 24-h BP in centenarians. The WC

effect for systolic BP was positively correlated with both SD (r = 0.45, P <

..01)

and CV (r = 0.55, P < .01) of 24-h systolic BP in centenarians, but not in

elderly

subjects (Fig. 3). However, the WC effect for diastolic BP was unrelated to SD

or CV

of 24-h diastolic BP in both elderly subjects (SD: r = 0.09, P = .352; CV: r =

0.06,

P = .253) and centenarians (SD: r = 0.13, P = .113; CV: r = 0.15, P = .082).

Discussion

....Centenarians and WC Hypertension

In the Hotan region, an area densely populated by Uygurs, the proportion of

centenarians in the population is 18.9/100,000.4 The Uygurs in Xinjiang, China,

are

particularly long-lived. Extreme longevity in humans seems to be associated with

numerous factors. In the present study, incidence of hypertension was lower in

elderly Uygur subjects (65- to 70-year-old) than in the general Chinese elderly

population. Prevalence of hypertension differs according to ethnicity in China,

but

averages 13.58% in the general population and 32% to 49% in elderly subjects.13

and

14 Uygur elderly subjects, presenting as less hypertensive, may represent the

best

candidates for becoming centenarians.

Although aged individuals are typically thought to display reduced response to

stressors, WC hypertension in the present study was greater in centenarians than

in

elderly subjects. Supporting this finding, another study has shown that office

BP

was higher than mean 24-h BP values in centenarians (N = 11).5 However, the WC

effect and WC hypertension were not shown in centenarians in that study. A small

number of studies in older subjects have suggested that clinic BP is greater

than

ambulatory BP, and this difference between clinic and ambulatory BP increases

with

age,7 and 8 although subjects in those studies were <80 years old. A contrasting

report shows that BP variation increases with age, particularly after 60 years

old.15 However, no centenarians were investigated in that study. In our study,

WC

hypertension was more prevalent in centenarians than in elderly subjects,

indicating

that prevalence of hypertension in centenarians might differ from that in other

elderly populations.

The phenomenon of WC hypertension may reflect an abnormally vigorous sympathetic

nerve response to the measurement environment, particularly in the presence of

the

measuring nurse or physician. However, in the present study, ABPM was conducted

in

all subjects at the same period and in the same environment, and frequency and

time

of office visits were similar between elderly and centenarian subjects. However,

research has shown that BP reactions to measurements by clinical staff are

associated with enhanced BP responses to mental stress testing.16 In contrast,

Parati et al17 found that mental laboratory stressors did not correlate with

increases in BP accompanying a visit by a physician. Conflicting results exist

on

whether patients with WC hypertension are more susceptible to mental stress than

normal subjects.

In the present study, despite increases in both clinical and ambulatory BP in

centenarians, the WC effect was obviously greater for systolic than for

diastolic BP

or HR, indicating that arterial arteriosclerosis might be progressed and

responsive

to minimal stressors. Centenarians in the present study demonstrated a sharp

increase in PP and increased prevalence of isolated systolic hypertension,

revealing

that arterial vessels might be “reactive” for given stimuli. Therefore, high

responsiveness may be due to a higher level of adaptive morphologic changes in

thickened vascular walls.

BP Variation

In the present study, the same day–night definition was used for all subjects.

However, night-time systolic BP was higher in centenarians than in elderly

subjects.

One study has shown that reduced nocturnal BP declines in the very elderly,

particularly in women.18 Another study indicated the flatted circadian pattern

of BP

involves activity, sleeping quality, and arteriosclerosis.19 In the present

study,

centenarians also displayed high night-time systolic BP, and presented a

nondipper-type of circadian pattern. Decreased compliance of the large elastic

arteries in centenarians may lead to disturbance of baroreceptor reflex

function, in

turn resulting in increased variability of BP, for systolic BP in particular.

Centenarians in this study demonstrated higher SDs and CVs compared to elderly

subjects, and the WC effect correlated with BP variations. The BP variation may

represent one of the factors affecting the WC effect in centenarians, and might

involve reduced function of cardiac and vascular modulation systems that control

cardiovascular variation. An earlier study has shown that BP variability may

also

represent an increased risk factor, given an association with impaired arterial

distensibility.20 Centenarians might thus be at higher risk of cardiovascular

disease and mortality because of their advanced age. ...

....

Al Pater, PhD; email: old542000@...

____________________________________________________

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