Is squatting a triggering factor for stroke in Indians?
Undocumented observations of ours suggested increased occurrence of strokes in the early hours of the morning and in the toilets where most Indians still squat. The present study has been designed to assess the validity of this observation and to identify the likely triggering factor in stroke onset in such situations. Part A of the study looked into stroke onset data of 100 consecutive CT-confirmed stroke patients specially in relation to time of day, place, posture and activity of the individual. Part B of the study included 67 healthy volunteers (age 24-49 years) whose supine and squatting blood pressure (BP) were measured and the differences noted. Part C of the study consisted of repeating the same procedure in 104 known hypertensives on treatment (age 28-60 years). Part A of the study revealed that most strokes (52%) occurred in the morning and at home (86%) and over a third (36%) while in toilets. Thirty-six per cent of the strokes occurred while the subjects squatted, mostly during the act of defecation. More than half of the haemorrhagic strokes occurred while the subjects were in squatting position. In normal healthy volunteers squatting produced a small (8.09 +/- 7.04 mmHg) but significant rise in systolic blood pressure (SBP) but not in diastolic blood pressure (DBP) (0.9 +/- 7.38 mmHg). In contrast, in treated hypertensives squatting produced a significantly higher rise in both SBP (14.49 +/- 11.63 mmHg) and DBP(9.10 +/- 9.19 mmHg). The relationship of the clinical observations regarding stroke onset with the BP changes noted on squatting in healthy as well as hypertensive subjects appears to be more than fortuitous. Squatting induced rise in BP appears to be an important triggering factor for stroke onset in subjects at risk in India.