SEX DIFFERENCES IN BLOOD PRESSURE BY AGE AND MENOPAUSAL STATUS: RESULTS FROM THE UK BIOBANK

Objective: Cardiovascular disease (CVD) risk associated with higher blood pressure (BP) starts at lower levels in women than men, leading to a suggestion that sex-based BP thresholds are required. However, sex differences in BP as people age remain under-studied. Therefore, we aimed to investigate sex differences in BP and whether these vary by age and menopause in women.Design and method: 456,672 UK Biobank participants (54.4% women) with systolic BP (SBP) and/or diastolic BP (DBP) measured at baseline (2006-2010) were included in this cross-sectional study. Hypertension was defined as SBP >=130 mmHg or DBP >=80 mmHg, self-reported hypertension or self-reported antihypertensive medication use. We examined sex differences, by age and menopausal status, in SBP and DBP, as well as the prevalence and treatment of hypertension and control of BP. We also considered change in BP over time among a sub-sample of 20,328 participants with BP re-measured at follow-up (2012-2013). Results: Mean SBP and DBP were lower in women than men (women-to-men differences: -5.6 and -3.4 mmHg, respectively). Sex differences in SBP and DBP were smaller among older (-2.8 and -2.7 mmHg, respectively, >=60 years) versus younger adults (-9.9 and -4.4 mmHg, <50 years). Moreover, sex differences in SBP and DBP were also smaller among post-menopausal women (-4.4 and -3.1 mmHg, respectively) than pre-menopausal women (-9.9 and -4.8 mmHg) when compared with similarly aged men. The prevalence of hypertension was lower among women (70.4%) than men (84.2%), and sex differences were smaller at older ages and in post-menopausal women. Treatment of hypertension and BP control were 26.9% and 4.6%, respectively, among women and 31.0% and 4.8%, respectively, among men. Among participants with repeat BP measurements, women-to-men differences in BP were smaller at the follow-up (women-to-men differences: -3.1 and -2.5 mmHg, respectively) compared with baseline (-5.8 and -3.7 mmHg). Conclusions: Hypertension prevalence, treatment and control were low in both sexes in UK Biobank. While men had overall higher BP than women, sex differences in BP varied by age and menopausal status, with differences becoming smaller at older ages and in post-menopausal women.