Association of cumulative blood pressure with progression of depressive symptoms and functional impairment among adults aged 50 years or older: 10-year follow-up of two longitudinal cohorts

Background
The association of cumulative blood pressure (BP) with progression rate of depressive symptoms and functional impairment remained largely unknown, and this study aims to explore whether higher cumulative BP is associated with a faster rate of aggravation of depressive symptoms and functional impairment.

Methods
This longitudinal cohort study adopted data from the English Longitudinal Study of Ageing (ELSA) and the Health and Retirement Study (HRS). Cumulative BP was calculated as area under the curve using BP measurements from 3 visits (wave 0, 2 and 4) in ELSA and 2 visits (wave 8 and 10) in HRS. Depressive symptoms were evaluated in a biennial frequency via Center for Epidemiological Studies Depression (CES-D) scale, while functional status was measured every two years using adapted versions of Katz Activities of Daily Living (ADL) scale and Lawton Instrumental Activities of Daily Living (IADL) scale.

Results
A total of 3500 and 6036 participants from ELSA and HRS were included. Elevated cumulative pulse pressure (PP) was significantly associated with accelerated aggravation of depressive symptoms (P < 0.001 for both). Elevated cumulative systolic BP and PP were significantly associated with accelerated decline of ADL function (P < 0.001 for both) and IADL function (P < 0.001 for both). However, elevated cumulative diastolic BP was associated with decelerated decline of IADL function (P = 0.031 in ELSA and P < 0.001 in HRS).

Conclusions
Elevated cumulative BP was associated with accelerated aggravation of depressive symptoms and functional impairment, suggesting that controlling systolic BP and PP while maintaining adequate diastolic BP is of paramount importance for adults to achieve health longevity.