The Non-linear Relationship Between Normal Range Systolic Blood Pressure and Cardiovascular or All-Cause Mortality...

Area of Science:

• Gerontology
• Cardiovascular Medicine
• Epidemiology

Background:

• Hypertension is a major risk factor for cardiovascular disease and mortality in older adults.
• The optimal systolic blood pressure (SBP) range for cardiovascular health and longevity in non-hypertensive older adults remains unclear.
• Previous research has primarily focused on elevated blood pressure, leaving a gap in understanding the implications of normal SBP ranges.

Purpose of the Study:

• To investigate the association between normal systolic blood pressure (SBP) levels and all-cause and cardiovascular mortality in adults aged 65 and older without a diagnosis of hypertension.
• To determine if there is a J-shaped or U-shaped curve relationship between SBP and mortality in this specific demographic.
• To provide evidence-based insights for clinical guidelines regarding blood pressure management in non-hypertensive elderly individuals.

Main Methods:

• Utilized data from the National Health and Nutrition Examination Survey (NHANES) from 1999-2014.
• Included participants aged 65 years and older with no history of hypertension and SBP readings between 90 and 129 mmHg.
• Employed multivariate Cox regression analysis to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality across different SBP categories (90-99, 100-109, 110-119, 120-129 mmHg), adjusting for potential confounders.

Main Results:

• Analysis included 1,074 participants (54.38% male).
• Compared to the 110-119 mmHg SBP group, the 90-99 mmHg group had a significantly higher risk of all-cause mortality (HR: 1.83, 95% CI: 1.04-3.23).
• No significant associations were found for other SBP categories with all-cause mortality, nor for any category with cardiovascular mortality, though trends suggested nonlinearity (P for trend = 0.448 for all-cause, P=0.349 for cardiovascular).

Conclusions:

• A nonlinear association exists between normal range SBP and both all-cause and cardiovascular mortality in older adults without hypertension.
• The lowest SBP category (90-99 mmHg) was associated with an increased risk of all-cause mortality, suggesting that very low normal SBP may not be benign.
• Further research is warranted to elucidate the mechanisms behind this association and to refine optimal SBP targets in elderly populations without diagnosed hypertension.