Hypertension stage 1 at early 40s in women associated with increased ACS risk during midlife
Stage 1 hypertension, sex and acute coronary syndromes during midlife: the Hordaland Health Study
Introduction and methods
Overall ACS incidence rates and ACS mortality rates in Western countries have lowered during the last decades, but this trend is not observed for younger women [1-4]. Hypertension may be an important risk factor for ACS in women as observed in two studies [5,6], but women in these studies were older and there was no focus on younger women.
Although women in their 40s have lower BP and lower prevalence of hypertension than men, women with MI have more often hypertension compared to men [1,7,8]. Women have a steeper increase in BP measures during their life, starting at their 30s, compared to men .
This study investigated whether mildly elevated BP in women in their early 40s is a stronger risk factor for ACS during midlife than in men.
Data of the population-base Hordaland Health Study (in Western Norway) were used. Residents born in 1950-52 were invited for the first survey in 1992-1993. For this analysis, those with a history of MI of treated for hypertension were excluded, leaving 6381 women and 5948 men with a mean baseline age of 41 years. BP was measured at baseline visit in triples with 1 min intervals by trained healthcare workers after the participant had been seated for >10 min and the average of the last 2 measurements was used for analysis. Normotension was defined as SBP <130 mmHg and DBP <80 mmHg, stage 1 hypertension as SBP 130-139 mmHg and/or DBP 80-89 mmHg and stage 2 hypertension as SBP ≥140 mmHg and/or DBP ≥90 mmHg. Outcome was incident ACS, defined as hospitalization or death with an acute MI or unstable angina pectoris diagnosis during follow-up of 16 years.
- Lower proportion of women than men had hypertension (25% vs. 35% for stage 1 and 14% vs. 31% for stage 2 hypertension, respectively, P<0.001).
- Women with stage 1 hypertension had 2-fold increased risk of ACS compared to normotensive women (HR 2.18, 95%CI: 1.32-3.60) and women with stage 2 hypertension had a 3-fold increased risk of ACS. Adjustment did not change the findings.
- Men with stage 1 and stage 2 hypertension had ~40% and 70% higher risk of ACS compared to normotensive men. After adjustment, only the association between stage 2 hypertension and risk of ACS remained significant.
- A significant interaction was found between BP category and sex for ACS in univariate and adjusted models, suggesting that hypertension stage 1 and 2 influenced the risk of ACS in a sex-specific manner.
- There was no significant sex-interaction between systolic BP categories and risk of ACS.
- There was a significant sex-interaction on the association of diastolic BP category and risk of ACS.
Women with stage 1 hypertension (BP 130-139/80-89 mmHg) in their early 40s had a 2-fold increased risk of ACS during midlife compared to normotensive women. This association between stage 1 hypertension and later ACS risk was not observed in men when corrected for CV risk factors. Diastolic hypertension was a stronger risk factor for ACS than systolic hypertension.