Oral contraceptive use and blood pressure in a German metropolitan population.

ABSTRACT

The relationship between blood pressure (BP) and oral contraceptive (OC) use in women has been examined with the data from the Munich Blood Pressure Study (MBS), a cross-sectional study with follow-up of a random sample of 3198 Munich citizens aged 30-69 (response rate 69.3%). Multiple linear and logistic regression analyses were run with BP as the dependent variable and age, OC use, obesity, alcohol consumption, and smoking habit as the independent variables. All second and third order interactions between the independent variables were tested during a backward stepping procedure. OC use appeared as a significant main effect in most of the analyses. The coefficient of the OC variable was about 3 in the linear regression analyses for both systolic BP and diastolic BP, indicating an increase of about 3 mmHg in the systolic and diastolic BP of the OC users. An analysis of the change in BP after one year in relation to change in OC user status has also been made. It was observed that women ceasing to use OC had a clear decrease in BP while those starting to use OC had on average an increase in BP.

ABSTRACT

PIP A random sample of 3198 persons aged 30-69, as part of the Munich Blood Pressure Study, revealed that oral contraceptive use raises blood pressure. Data were collected from December 1980 to May 1981, and from January to March 1982, on the same subjects. Each participant was interviewed about risk factors for about 30 minutes in a sitting position, and his pressure measured 3 times afterward with the Hawksley Random Zero sphygmomanometer. There were 113 women using pills, 32 different brands. Multiple linear and logistic regression analyses were run with blood pressure as the dependent variable, and age, pill use, obesity, alcohol consumption, and smoking habit as the independent variables. Pill use appeared as a significant main effect in most of the analyses. Based on the coefficient of the pill variable in the linear regression, an increase of about 3 mm Hg in both systolic and diastolic pressures was demonstrated. It was observed that women stopping oral contraception had a clear decrease of 7.2 mm Hg systolic, and 2.8 mm Hg diastolic pressure, and those beginning oral contraception appeared to have an increase in pressure, if the results were adjusted for regression toward the mean. Even a slight increase of 3 or 4 mm Hg in blood pressure, when added to other risk factors such as obesity, smoking, and age, may increase the overall risk for cardiovascular disease considerably.