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Chicago, IL - A new report from the Framingham Heart Study shows the residual lifetime risk for developing hypertension among middle-aged men and women is an astonishing 90%. The new report appears in the February 27, 2002 issue of JAMA.1
Many women know their lifetime risk of breast cancer is one in eight or nine, and men their lifetime risk of prostate cancer about one in 10, lead author Dr Ramachandran S Vasan (Boston University) told heartwire in an interview. The residual lifetime risk of hypertension has not been clear until now, but the new results suggest 9 in 10 of middle-aged individuals will develop high blood pressure.
"It is an astounding statistic," Vasan said. "If I had to guess, I would have guessed something like 70-75%."
Previous studies have suggested though, that the development of hypertension is not an inevitable feature of aging, and can be prevented by adopting lifestyle related measures including increased physical activity, lower weight, reduced consumption of dietary sodium and increased intake of fruits and vegetables.
"It is possible to age successfully without having an increase in blood pressure," Vasan said. "We're hoping that this statistic is the motivation people need to adopt a healthier lifestyle."
Cause for concern
"Ninety percent is a staggering statistic and cause for concern," Health and Human Services Secretary Tommy G Thompson said in a statement from the National Heart Lung and Blood Institute (NHLBI) that supports the Framingham Heart Study. "This finding should energize Americans to take steps to protect themselves against high blood pressure."
In the same statement, NHLBI director Dr Claude Lenfant said, "Americans have to better understand their risk of developing high blood pressure. They cannot adopt a wait and see approach," he added. "If they do, chances are they will find themselves with high blood pressure, and that puts them at increased risk for heart disease and stroke."
Dr Jerome D Cohen (St Louis University Medical Center, St Louis, MO), a member of the National High Blood Pressure Education Program, was also taken aback by the high risk shown in this study. "That number was a surprise to me," he told heartwire. "This group has shown that [hypertension] is quite a burden, and most people will develop it over time if they live long enough."
The high numbers mean strategies to prevent, detect, and treat this condition become even more critical, Cohen said.
Threshold of risk
In the current study, Vasan and colleagues used a cohort from the Framingham data, 1298 participants who were free of hypertension in 1975, and aged either 55 or 65 at baseline. They calculated the lifetime risk for hypertension for these subjects, defined as blood pressure > 140/90 mm Hg or the use of antihypertensive medications, based on data gathered between 1976 and 1998. In addition, they compared lifetime risk from this time period to a previous period from the Framingham study, 1952 to 1975, to see whether the risk had changed over time.
The residual lifetime risk for stage 1 hypertension (> 140/90 mm Hg regardless of treatment) was about 90% for both age groups, and was similar for both women and men. The lifetime probability of receiving antihypertensive medication was 60%.
Several trends emerged from the comparison of the two time periods. While the risk for women remained unchanged, the risk for men of developing hypertension was 60% higher in the contemporary time period compared to the earlier 1952-1975 period.
In their report, the researchers speculate this finding may be related to trends in BMI, which remained more or less unchanged for women between these time periods, but increased significantly among men in the later period.
Residual lifetime risk of hypertension for men and women, aged 55 and 65 at baseline, comparing two Framingham time periods|
Patient group |
1952-1975 |
1976-1998 |
p value |
|
Men - baseline 55 years | 82% | 93% | <0.001 |
|
Men - baseline 65 years | 65% | 83% | <0.001 |
|
Women - baseline 55 years | 92% | 91% | 0.68 |
|
Women - baseline 65 years | 93% | 89% | 0.51 |
The comparison also showed that the risk of stage 2 hypertension (160 mm Hg or higher regardless of treatment) decreased for both sexes between the time periods, probably due to an increased use of antihypertensive medications.
"We also asked a parallel question, dividing the lifetime risk into short-term risks over 10 years following the attainment of age 55 or 65, and the long-term risk over 20 to 25 years - the average life expectancy of 55- and 65-year-olds," Vasan said.
The researchers found that a substantial proportion of the increase in lifetime risk was realized within the first 10 years after age 55 and 65. More than half of those aged 55 and about two thirds of those aged 65 went on to develop hypertension within 10 years of the baseline measure.
"It's not that people are developing high blood pressure toward the end of their life span; it's occurring within 10 years of reaching age 55 or 65," Vasan said.
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