Masked hypertension: different blood pressure measurement methodology and risk factors in a working population.

OBJECTIVES

To estimate the prevalence of masked hypertension when the same ambulatory device is used for both manual and ambulatory blood pressure measurements and to measure associations with lifestyle risk factors in a working population.

METHODS

White-collar workers were recruited from three public organizations. Blood pressure was measured at the workplace using Spacelabs 90207 for manual measurements (mean of the first three readings taken by a trained assistant) followed by ambulatory measurements (mean of every other reading obtained during the working day). Masked hypertension was defined as manual blood pressure measurement of less than 140/90 mmHg and ambulatory blood pressure measurement of at least 135/85 mmHg. Smoking, alcohol intake, BMI and leisure physical activity were also assessed.

RESULTS

Blood pressure measurements were obtained from 2370 workers (80% participation, 61% women; mean age = 44 years). Masked hypertension was diagnosed in 15.02% of the participants. The prevalence was higher in men [adjusted odds ratio (OR) = 2.38, 95% confidence interval (CI) = 1.86-3.05]. The prevalence in men increased with age (adjusted OR = 2.08 for 40-49 years, 95% CI = 1.33-3.26 and adjusted OR = 1.91 for > or =50 years, 95% CI = 1.20-3.04) and BMI (adjusted OR = 1.78 for BMI > or = 27, 95% CI = 1.21-2.64). The prevalence in women increased with BMI (adjusted OR = 1.65 for BMI > or =27, 95% CI = 1.14-2.39) and alcohol intake (adjusted OR = 2.12 for at least six drinks per week, 95% CI = 1.34-3.35).

CONCLUSION

Masked hypertension is frequent and still present when blood pressure is measured out of the office, using the same device for manual and ambulatory measurements. Sex, age, BMI and alcohol intake are associated with masked hypertension.