Objective: To assess the role of blood pressure in the association between cigarette smoking and left ventricular mass in male and female subjects with essential hypertension.
Design: A case-control study with matching ratio of 1:4.
Patients and methods: We studied 115 heavy smokers (> or = 20 cigarettes/day; 91 men) and 460 non-smokers (364 men) with essential hypertension. Subjects were matched by sex, age (within 5 years) and clinic systolic and diastolic blood pressures (within 5 mmHg). All the subjects underwent 24 h off-therapy non-invasive ambulatory blood pressure monitoring and echocardiography.
Results: By matching, clinic blood pressure was nearly identical in smokers and non-smokers (158/99 versus 158/98 mmHg). Daytime ambulatory blood pressure was significantly higher in the smokers than in the non-smokers (150/97 versus 143/93 mmHg), whereas night-time blood pressure did not differ between the two groups (129/79 versus 126/78 mmHg). Smokers had a higher 24 h but not clinic heart rate. Variability of systolic and diastolic blood pressure was slightly greater in smokers when expressed in terms of the standard deviation of the 24 h average (15.9/13.0 versus 14.6/12.2 mmHg), but not after correction for average blood pressure. Left ventricular mass was greater in the smokers than in the non-smokers (119 versus 110 g/m2), and this difference remained after adjustment for clinic blood pressure and other related covariates. However, when clinic blood pressure was replaced by daytime ambulatory blood pressure in the equation, adjusted values of left ventricular mass did not differ between the smokers and the non-smokers (113 versus 112 g/m2).
Conclusion: In patients with essential hypertension, heavy cigarette smoking (> or = 20 cigarettes/day) is associated with a definite increase in left ventricular mass through a rise in whole-day blood pressure. A pressor mechanism of that type may not be detected by the standard measurement of blood pressure in the clinic, which would make ambulatory blood pressure monitoring a valuable diagnostic tool in this setting.