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Sir,—It is known that transient elevations in blood pressure are not solely attributable to internal factors; the person who takes the blood pressure measurement may also induce an increase in blood pressure.1 An example of this phenomenon is white coat hypertension.2 The present study compared the difference between blood pressure readings in male Japanese adolescents when measured by men and women.
We studied 373 consecutive male college freshmen (aged 18–20 years) during an annual check up programme. None of them had any evidence of clinically significant disease such as hypertension (⩾ 140 mm Hg), heart valve disease, arrhythmia, hypercholesterolaemia, renal impairment, or liver disease. In March 1997, blood pressures and pulse rates of these subjects were measured using a semiautomatic sphygmomanometer (Parama Co, Tokyo, Japan). All subjects were in a relaxed sitting position for a minimum of 15 minutes. After checking the pulsation of the brachial artery, the measurer placed the cuff over the subject’s bare right arm. A total of 231 subjects were monitored by men (M group) and 142 subjects were monitored by women (W group). There were six measurers, two women and four men, aged 22–24 years. All were fifth year medical students at the University of Tokyo. When the systolic blood pressure level was ⩾ 150 mm Hg, the same measurer repeated the measurements after engaging the subject in relaxed conversation for approximately five minutes and instructing him to take several deep breaths.
The distribution of the systolic and diastolic blood pressures in the W group was shifted to the right compared with that in the M group (fig1). There was a highly significant difference (two samplet test) in the systolic and diastolic blood pressures between the two groups (mean (SEM) systolic, 135.7 (0.9)v 130.7 (0.9) mm Hg, p = 0.0012; diastolic 74.4 (0.9) v 69.7 (0.8) mm Hg, p < 0.0001). In addition, 10.6% (15 of 142) of the readings obtained by the women showed a raised systolic blood pressure (⩾ 150 mm Hg)v 3.9% (9 of 231) of the M group (p = 0.0198, χ2). All of these subjects were shown to be normotensive (< 140 mm Hg) on repeated measurements. The pulse rate of the same subjects also showed a highly significant transient rise (13.5 (2.1) beats/min) above the repeat pulse measurements (paired two samplet test, p < 0.0001). The latter was weakly, but significantly, correlated with the increase in systolic blood pressure (r = 0.329, p = 0.0328). The subjects with transient hypertension had no demonstrable abnormalities on the electrocardiogram. Their total cholesterol concentrations and family history of hypertension did not differ from those of the consistently normotensive subjects.
The presence of a physician can cause an increase in blood pressure related to the patient’s nervousness (white coat hypertension).2 The rightward shift of blood pressure distributions presented in this study may be attributed to a different mechanism—that is, the men’s physical response to a woman taking the blood pressure. Interestingly, when blood pressure was assessed in the female freshman students (n = 113, aged 18–20 years), the sex of the six observers did not affect the distribution of blood pressures or pulse rates (data not shown).
We therefore propose the concept of “white skirt” hypertension to describe reactive hypertension in a young man whose blood pressure is measured by a woman. Follow up studies are needed to verify this phenomenon.
The authors reported this study on behalf of the colleagues who were in charge of the health screening programme: K Andoh, H Chang, Y Uehara, W S Shin, S Uwatoko, M Fujisawa, Z Honda, and T Okuda. This work was supported by a grant-in-aid for scientific research from the Ministry of Education, Science, Sports and Culture, Japan.