scholarly journals Joint modelling of individual trajectories, within-individual variability and a later outcome: systolic blood pressure through childhood and left ventricular mass in early adulthood

2019 ◽  
Author(s):  
Richard M.A. Parker ◽  
George Leckie ◽  
Harvey Goldstein ◽  
Laura D. Howe ◽  
Jon Heron ◽  
...  

ABSTRACTWithin-individual variability of repeatedly-measured exposures may predict later outcomes: e.g. blood pressure (BP) variability (BPV) is an independent cardiovascular risk factor above and beyond mean BP. Since two-stage methods, known to introduce bias, are typically used to investigate such associations, we introduce a joint modelling approach, examining associations of both mean BP and BPV across childhood to left ventricular mass (indexed to height; LVMI) in early adulthood with data from the UK’s Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Using multilevel models, we allow BPV to vary between individuals (a “random effect”) as well as to depend on covariates (allowing for heteroscedasticity). We further distinguish within-clinic variability (“measurement error”) from visit-to-visit BPV. BPV was predicted to be greater at older ages, at higher bodyweights, and in females, and was positively correlated with mean BP. BPV had a positive association with LVMI (10% increase in SD(BP) was predicted to increase LVMI by mean = 0.42% (95% credible interval: −0.47%, 1.38%)), but this association became negative (mean = −1.56%, 95% credible interval: −5.01%, 0.44%)) once the effect of mean BP on LVMI was adjusted for. This joint modelling approach offers a flexible method of relating repeatedly-measured exposures to later outcomes.

Author(s):  
Richard M A Parker ◽  
George Leckie ◽  
Harvey Goldstein ◽  
Laura D Howe ◽  
Jon Heron ◽  
...  

Abstract Within-individual variability of repeatedly-measured exposures may predict later outcomes: e.g. blood pressure (BP) variability (BPV) is an independent cardiovascular risk factor above and beyond mean BP. Since two-stage methods, known to introduce bias, are typically used to investigate such associations, we introduce a joint modelling approach, examining associations of mean BP and BPV across childhood to left ventricular mass (indexed to height; LVMI) in early adulthood with data (collected 1990-2011) from the UK’s Avon Longitudinal Study of Parents and Children cohort. Using multilevel models, we allow BPV to vary between individuals (a “random effect”) as well as to depend on covariates (allowing for heteroscedasticity). We further distinguish within-clinic variability (“measurement error”) from visit-to-visit BPV. BPV was predicted to be greater at older ages, at higher bodyweights, and in females, and was positively correlated with mean BP. BPV had a weak positive association with LVMI (10% increase in within-individual BP variance was predicted to increase LVMI by 0.21% (95% credible interval: -0.23%, 0.69%)), but this association became negative (-0.78%, 95% credible interval: -2.54%, 0.22%)) once the effect of mean BP on LVMI was adjusted for. This joint modelling approach offers a flexible method of relating repeatedly-measured exposures to later outcomes.


Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Gregory A Harshfield ◽  
Gregory A Harshfield ◽  
Jennifer Pollock ◽  
David Pollock

The overall goal of this study was to determine race/ethnic differences in the associations between renal ET-1 and indices of blood pressure-related target organ damage in healthy adolescents. The subjects ranged in age between 15-19 years, had no history of any disease, and were not on any prescription medications. The 92 subjects consisted of 48 Caucasians (CA) and 44 African-Americans (AA). The two groups were similar with respect to height, weight, body mass index, blood pressure, ET-1), albumin excretion rate (AER), and left ventricular mass). Results: The CA’s were slightly older 17±1 v 16±1 (p=.02). The protocol was preceded by a 3 day self-selected sodium controlled diet of 250 mEq/day day which the subject picked up each day. The test day began with an echocardiogram for the assessment of left ventricular mass. Next, the subjects were seated for 60 minutes of rest during which the subjects consumed 200 ml of water. This was followed by the collection of a urine sample for the measurement of ET-1 and AER. Overall, ET-1 excretion was correlated with AER (r=.278), LV mass/ht 2.7 (r=.341), and systolic blood pressure (SBP; r=.365; p=.01 for each). The significant overall correlations were the result of significant correlations in AAs for AER (r=.344; p=.05), LV mass/ht 2.7 (r=.520; p=.01), and SBP (r=.645; p=.01) which were not apparent in CA’s. These findings suggest urinary ET-1 contributes to the development of BP-related target organ damage in AA youths prior to the development of increases in blood pressure.


2011 ◽  
Vol 29 (4) ◽  
pp. 803-808 ◽  
Author(s):  
Raffaele Izzo ◽  
Giovanni de Simone ◽  
Richard B Devereux ◽  
Renata Giudice ◽  
Marina De Marco ◽  
...  

1996 ◽  
Vol 22 (2) ◽  
pp. 181-194 ◽  
Author(s):  
Angelo Scuteri ◽  
Mauro Cacciafesta ◽  
Maria Gabriella Di Bernardo ◽  
Anna Maria De Propris ◽  
Domenico Recchi ◽  
...  

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