High-normal blood pressure in midlife is a stronger risk factor for incident hypertension 26 years later in women than men: the Hordaland Health Study

Purpose To identify modifiable risk factors in early midlife associated with incident hypertension 26 years later in women and men. Materials and methods We used data from 1025 women and 703 men in the community-based Hordaland Health Study examined at the mean age of 42 years (baseline) and after a 26-year follow-up. Patients with hypertension at baseline were excluded. Blood pressure (BP) was classified according to European guidelines. Factors associated with incident hypertension were identified in logistic regression analyses. Results At baseline, women had a lower average BP and a lower prevalence of high-normal BP (19% vs 37%, p < .05). Overall, 39% of women and 45% of men developed hypertension during follow-up (p < .05). Among those with high-normal BP at baseline, 72% of women and 58% of men developed hypertension (p < .01). In multivariable logistic regression analyses, high-normal BP at baseline was a stronger predictor of incident hypertension in women (odds ratio, OR 4.8, [95% confidence interval, CI 3.4-6.9]) than in men (OR 2.1, [95% CI 1.5-2.8]), p < .01 for sex interaction. A higher baseline body mass index (BMI) was associated with incident hypertension in both sexes. Conclusions High-normal BP in midlife is a stronger risk factor for developing hypertension 26 years later in women than in men, independent of BMI. Plain language summary There is a knowledge gap regarding the understanding of sex differences in hypertension and cardiovascular disease. The World Health Organisation has identified hypertension as the leading cause of morbidity and mortality in women. This manuscript focuses on sex differences in risk factors in early midlife associated with the development of hypertension 26 years later. We studied 1025 women and 703 men who participated in the community-based Hordaland Health Study at the age of 42 years, and after 26 years. Factors associated with hypertension were identified in statistical analyses. Our main findings were that having a high-normal blood pressure (systolic blood pressure 130-139 mmHg or a diastolic blood pressure 85-89 mmHg) in midlife was a significantly stronger risk factor for the development of hypertension in women than in men during follow-up. Having a higher body mass index in midlife was associated with the development of hypertension in both sexes. This study contributes to the understanding of sex differences in hypertension development and adds further knowledge regarding high-normal blood pressure as a particularly important risk factor for hypertension and cardiovascular disease in women.

Automated summary

This study aimed to identify modifiable risk factors in early midlife associated with incident hypertension 26 years later in women and men. The results showed that high-normal blood pressure in midlife was a significantly stronger risk factor for the development of hypertension in women than in men during follow-up, independent of body mass index.