ODP146 Exploring Systemic Inflammation in the Relationships Between Poor Sleep Health or Shift-Work and Blood Pressure Across BMI, Sex and Age Groups
Authors: Young Morag , Kanki Miss Monica , Nath Artika , Cãnovas Rodrigo , Fuller Peter , Cole Timothy 
Published: November 2022

Abstract
Circadian challenges such as social and travel jetlag, poor sleep health or undertaking shift-work is becoming increasingly linked to incidences of cardiovascular disease, metabolic syndrome and hypertension due to the impact of circadian disruption. Currently, studies that address how such challenges can become specific risk factors for the development of hypertension show inconsistent findings and the underlying pathophysiology is not well understood. Using a cross-sectional study approach, we investigate the associations between markers of circadian strain, including sleep length, sleep quality and shift-work, and blood pressure. Furthermore, we explore whether systemic inflammation could be a potential driving mechanism in these associations. Systolic and diastolic blood pressure (SBP and DBP, respectively) measurements collected from European White participants recruited under the UK Biobank cohort were compared between those who reported a short (≤5 hours and 6), normal (7 hours) or long (8 and ≥ 9 hours) sleep duration or a healthy (4-5), moderate (2-3) or poor (0-1) sleep quality score. Using logistic regression models, we tested the effect of adjusting for body mass index (BMI) and then further stratifying by key covariates, including BMI, sex and age. Similarly, these analyses were repeated to compare SBP and DBP between individuals who undertake different types of shift-work (day, mixed, night, permanent-night or no shift-work) at the time of recruitment. Participants who reported 7 hours of sleep or a healthy sleep quality score had the lowest mean blood pressure, ∼139/83 mmHg. A U-shape relationship was observed when plotting the beta-estimates (β) of the associations between each sleep length group and SBP or DBP. However, this U-shape is blunted following further adjusting for BMI and respective stratification revealed this relationship is driven by female participants with a BMI greater than 25 kg/m 2 . Moderate and poor sleep quality scores were positively associated with only DBP when BMI is adjusted for and across all BMI groups (≤25, 25-&lt;30 and ≥30 kg/m 2, p&lt;0. 05 is all instances) compared to healthy sleep quality scores. Shift-work was reported in 15.3% of this sample and of which, more males reported undertaking day-shift, mixed-shift, night-shift or permanent night-shift work than female participants. Mean SBP and DBP reported in all these shift-work types were higher than in non-shift workers. Exploratory data also suggests that some associations may be partly driven by inflammatory markers, such as C-reactive protein (CRP) levels and immune cell count. Taken together our data suggest that both inadequate or compromised sleep health or undertaking shift-work are associated with heightened blood pressure, which could be potentially driven by an inflammatory component. Establishing the adverse consequences of these circadian challenges on blood pressure can help understand how re-aligning our behaviour reduces blood pressure and thus, minimises the risk of developing hypertension.
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