High-normal systolic blood pressure in early midlife is a stronger risk factor for incident hypertension later in life for women than men

Abstract

Abstract Background We have previously found that having high-normal blood pressure (BP) in early midlife is a stronger risk factor for incident hypertension later in life for women than for men. Whether this risk is related both to high-normal systolic and diastolic BP is not known. Purpose To explore whether there is a sex difference in risk of incident hypertension related to high-normal systolic and diastolic BP in early midlife. Methods In the community-based Hordaland Health Study, 1025 women and 703 men were examined at age 42 years (baseline) and re-examined after 26 years. Patients with hypertension at baseline were excluded. Attended BP was measured in triplets, and clinic BP taken as the average of the two last measurements. High-normal systolic BP was identified as systolic BP of 130-139 mmHg and high normal diastolic BP as diastolic BP 85-89 mmHg. Incident hypertension was identified as BP ≥140/90 mmHg or patient reported use of antihypertensive drugs on the follow-up visit. The associations of systolic and diastolic BP at baseline with incident hypertension at follow-up were explored in sex specific multivariable logistic regression analyses. Multivariable analysis looking at high-normal diastolic BP was adjusted for baseline BMI, systolic BP, high-normal diastolic BP , heart rate, physical activity, daily smoker, cholesterol, triglycerides. Multivariable analysis looking at high-normal systolic BP was adjusted for baseline BMI, diastolic BP, high normal systolic BP , heart rate, physical activity, daily smoker, cholesterol, triglyceride. Results are presented as odds ratios (OR), 95% confidence intervals (CI) and p-values. Results At baseline, average BP was 119/73 mmHg in women and 126/76 mmHg in men (p<0.001). A high-normal systolic BP was found in 16% of women and 35% of men (p< 0.001). A high-normal diastolic BP was found in 7% of women and 11% of men(p=0.008). After 26 years of follow-up, 39% of women and 45% of men had developed hypertension (p<0.05). In multivariable logistic regression analyses, high-normal systolic and diastolic BP at baseline predicted incident hypertension at follow up in both sexes (Table 1). High-normal systolic BP was a significantly stronger predictor for incident hypertension in women (OR 2.32, CI 1.5-3.5) with p<0.01 for sex interaction (Table 1). In men, high-normal diastolic BP at baseline, was the strongest predictor of incident hypertension (OR 2.1, 95% CI 1.2-3.7), but no sex-interaction was found for high-normal diastolic BP, possibly due to low numbers. Conclusions Having a high-normal systolic BP in early midlife is a greater risk for developing hypertension later in life for women than men.Table 1