Women who develop hypertension in their 40s are up to 73 percent more likely to suffer from dementia later in life than normotensive counterparts, recent research published in Neurology states, while men with high blood pressure don’t see an increased risk at all.
Hypertension, which is a known risk factor for dementia in middle-aged patients and is associated with cognitive impairment, stroke and brain atrophy, is more common in men than in women, senior author Rachel A. Whitmer, PhD, and colleagues wrote in the new study. Still, risk of target organ damage and development of cardiovascular disease linked to high blood pressure is consistently higher in women, and few studies have explored the relationship between dementia risk and hypertension between the sexes at different life stages.
Whitmer and her team pulled data from 5,646 members of the Kaiser Permanente Northern California (KPNC) integrated healthcare system and analyzed those patients’ hypertensive status and how it related to their risk of developing dementia. Patients received routine checkups between the 1960s and 1980s, allowing the researchers to pinpoint medical data from certain phases in the individuals’ lives. Patients were an average of 33 years old in the “early-adulthood” stage and 44 years old in the “mid-adulthood” phase of the study.
Whitmer and co-authors examined the distribution of blood pressure, demographics, mid-adulthood health behaviors and late-life conditions overall and by sex, they wrote, before adding the presence of hypertension in early- and mid-adulthood to the equation. To evaluate dementia risk in the population, the team compared dementia risk among people with stable, normotensive blood pressure to those with onset hypertension, remitted hypertension and persistent hypertension.
The researchers tallied a total of 532 dementia cases over the course of their 15-year follow-up period—298 in women and 234 in men. Fifteen percent of the original population died without a dementia diagnosis, and 22 percent of patients were censored due to a lapse in KPNC membership. Still, more than half of the original sample were alive, members of KPNC and dementia-free by the end of the study, Whitmer and colleagues reported.
In both men and women, neither hypotension, pre-hypertension or hypertension were associated with an increased dementia risk in early adulthood. In midlife, an elevated dementia risk was connected only to hypertension.
Mid-adulthood saw a 65 percent increased risk in hypertensive women, Whitmer and co-authors wrote, and those women were 73 percent more likely to develop dementia than women with normotensive blood pressure. The estimated effect of early adulthood hypertension status on dementia risk was higher in women, as well, but men with hypertension didn’t see those same increased risk factors in either phase of life.
“Despite the fact that the men in our study were more likely to have high blood pressure at all ages, developing high blood pressure in mid-adulthood was a risk factor for dementia only in women,” Whitmer said in a release from Kaiser Permanente.
Early-adulthood hypertension wasn’t associated with dementia risk in women. Although hypertensive women in their 30s did see a 31 percent increased risk of dementia, those numbers don’t differ largely from counterparts with normotensive blood pressure.
“Our results show the importance of delineating the timing of risk factors in both sexes,” lead author Paola Gilsanz, ScD, said in the release. “In future studies, we’ll be looking at how risk factors may have different impacts at different times in life for women compared to men.”