BP increases with age, but medication helps

A positive association exists between blood pressure (BP) and age, with nearly threefold variation across subgroups, indicating differences in biology, behaviour, or exposures, reports a study. However, use of antihypertensive medication strongly attenuates this association and weakens the variation.

“BP was positively associated with age in the overall population, and the association varied … across more than 25,000 subgroups in China, with sociodemographic characteristics determining the strength of such an association and antihypertensive treatment being of unique value in curbing the increasing burden accompanied with the ageing of population,” the researchers said.

Data from approximately 3.3 million individuals aged 35–75 years from all 31 provinces in mainland China were collected from September 2014 through August 2019 and analysed in this cross-sectional study. The researchers then created subgroups of at least 10,000 individuals based on possible combinations of eight characteristics and antihypertensive status. The age–blood relationship was determined for each group.

Overall, 3,291,058 participants (mean age 55.8±9.8 years, 59.6 percent women) were included, with a hypertension prevalence of 47.6 percent, of which 30.0 percent were taking antihypertensive medications. [J Hypertens 2021;39:1143-1154]

The mean systolic (S)BP was 135.9±20.2 mm Hg. SBP rose at a mean unadjusted rate of 0.639±0.001 mm Hg per year. Specifically, SBP increased by 0.28–0.85 mm Hg per year for 95 percent of the 25,145 subgroups. The following characteristics were common in subgroups showing the steepest association: female sex, rural area, low education, low-income family, farmer occupation, and Tibet region.

Additionally, SBP increased from 0.13 to 0.41 mm Hg per year for 95 percent of the treated subgroups and from 0.33 to 0.82 mm Hg per year for 95 percent of the untreated subgroups, indicating that antihypertensive treatment eased the association between BP and age.

“Females were among the subgroups with the greater association of age and SBP, which may be explained by the fact that young women have a lower SBP compared with age-matched men, but have a greater increase after menopause and eventually reach higher SBP than men of the same age when older,” the researchers said. [Hypertension 2012;60:1393-1399; Maturitas 2015;80:282-287; Lancet Global health 2018;6:e641-e649]

These findings have robust public health and clinical implications, as the total size of the elderly aged >65 years is estimated to increase to 331 million in China in 2050. Assuming that the prevalence of hypertension in older adults remain the same, hypertension due to ageing could possibly lead to more than 170,000 cases of stroke and 250,000 cases of ischaemic heart disease per year by 2050 if no further intervention is performed, according to the researchers.

“Although antihypertensive treatment is the most important measure to mitigate the increased burden with ageing population, China has marked deficiencies in the access, cost, and prescription of these medications, and only one in four individuals with hypertension was receiving treatment,” the researchers said. [Lancet 2017;390:2559-2568]

“Such low treatment rates exemplify the vast action field currently available in China for interventions. In particular, increasing awareness can be achieved through increased population screening, initiating strategies to improve the patient education, and reducing barriers to healthcare utilization, including medications,” they added.

Moreover, delivery of primary healthcare needs to be intensified to sustain high treatment rates through optimal stocking of medication and increasing workforce. [Lancet 2020;395:1802-1812]