Blood pressure recordings in epidemiological surveys are usually obtai
ned by non-ambulatory, multiple one-occasion, manual sphygmomanometric
measurements by trained observers in study participants subjected to
standardized examination conditions. High validity and reliability of
blood pressure measurements ensure the comparability of study results
obtained in different places and at different times, and have a major
impact on the detection of correlates and determinants of blood pressu
re and hypertension. A blood pressure measurement quality assessment w
as performed within the multi-center collaborative WHO-MONICA Project
investigating results of 47 surveys from various geographic regions of
the world. In an overall summary assessment, six out of these 47 surv
eys were found to have had major measurement problems which prohibited
their further inclusion in collaborative analyses. Most of the proble
ms were associated with observer-related factors. Therefore, it was co
ntended that automatic blood pressure measurement devices might be abl
e to reduce and abolish most of these ''nuisance'' factors. In 1995, w
e had the opportunity to simultaneously study two independent random s
amples of men and women, aged 45 to 64 years, from the city of Augsbur
g in Southern Germany. One sample was examined by 16 observers with a
random zero sphygmomanometer (MONICA Augsburg), the other sample (J.A.
P. Study) was examined by two observers with an invasively validated,
automatic oscillometric device (bose Oscillomat). In both surveys, blo
od pressure was measured three times under similarly standardized cond
itions. Comparing the blood pressure results of the two surveys, the i
ntra-individual measurement variation tended to be slightly higher wit
h the Oscillomat than with the random zero, and the population mean bl
ood pressures and hypertension prevalences were found to be significan
tly lower with the Oscillomat. We conclude that manual measurements of
blood pressure by sphygmomanometer should not be indiscriminately rep
laced by externally validated automatic devices. The imponderabilities
of automatic devices with varying technical principles have to be ass
essed in epidemiological settings and weighed against recognized disad
vantages of sphygmomanometry before any recommendations can be given a
s to changing the present epidemiological practice.