|High blood pressure in young adults associated with increased risks of cardiovascular disease in middle age|
|The American College of Cardiology (ACC)/American Heart Association (AHA) decreased the level of normal blood pressure of less than 120/80 mmHg in 2017, based on evidence where higher incidences of cardiovascular disease were observed in those with blood pressure greater than 120/80 mmHg. Therefore, in the new criteria, elevated blood pressure is defined systolic blood pressure between 120-129 mmHg and diastolic blood pressure less than 80 mmHg, in addition to two degrees of hypertension (blood pressure>=130/80 mmHg) -- Stage 1 hypertension (systolic blood pressure between 130-139 mmHg or diastolic blood pressure between 80 and 89 mmHg) and Stage 2 hypertension (>=140/90 mmHg). According to these criteria, approximately 2- to 3-fold more young adults would be diagnosed with hypertension. However, it remains unknown if those of blood pressure greater than 120/80 who are younger than 40 years would harbor a higher risk of cardiovascular disease events in the middle age compared to those of normal blood pressure.
In order to describe the association between increased blood pressure during the young adulthood and the risk of cardiovascular disease events during the middle age, the team led by Dr. Yuichiro Yano at Duke University published their data in the 2018 November 6th issue of the Journal of American Medical Association (JAMA, here). The study, named CARDIA, enrolled 4851 African American and white individuals from 4 American cities in 1985 and 1986, who were followed twice a year for up to 30 years. Two or more blood pressure readings before age 40 years were documented, which were used to categorize participants into four groups—the normal blood pressure group (2574 individuals), the elevated blood pressure group (445 individuals), the stage 1 hypertension group (1194 individuals), and the stage 2 hypertension group (638 individuals).
During the follow-up period, 228 cardiovascular disease events and 319 deaths occurred in the middle age of participants (40-60 years old). The rates for cardiovascular disease per 1000 person-years were highest in the stage 2 hypertension group (8.04), followed by the stage 2 hypertension group (3.15), and the elevated blood pressure group (2.74). Moreover, the normal blood pressure group had the lowest rate (1.37). By comparison, the stage 2 hypertension group had approximately a cardiovascular event rate of 6 times higher than that of the normal blood pressure group. More importantly, the stage 2 hypertension group harbored the highest death rate per 1000 person-years (7.96) among the four groups, which was approximately 2.8 times of that of the normal blood pressure group. However, the groups of elevated blood pressure and stage 1 hypertension did not have a higher death rate compared to the normal blood pressure group. No evidence supported the association between blood pressure and race or sex. Similar results were also observed in a South Korean population that is published in the same issue of the JAMA (here), indicating increased blood pressure in young adults predicts higher risks of cardiovascular disease in the middle age regardless races or geographic locations.
This study highlights that those with blood pressure greater than 120/80 mmHg before the age of 40 years have a higher risk for cardiovascular disease and all-cause death in their middle ages. Therefore, it is imperative to recognize hypertension and intervene in this situation early. Easy access to blood pressure measurements is the key. Nowadays, not only pharmacies but also many homes have a sphygmometer that can be easily used for blood pressure checkups. It is also foreseeable that wearable sphygmometers will be available in the near future thanks to this technology era. Anyone who has a record blood pressure higher than 120/80 mmHg should see their doctors soon.