Background/Purpose:

The inactivity physiology hypothesis suggests that sedentarism is a cardiovascular risk factor independent of time spent in moderate-vigorous activity (MV). Previous research suggests that sedentary time may be associated with increased blood pressure. But research findings to date are mixed.

Methods:

The Osteoarthritis Initiative accelerometer ancillary study includes 1760 with objective measures of physical activity, sedentary time, and blood pressure at the 48 month exam. Participants were classified into four quartile groups according to accelerometer measures of the percentage of wear time that was sedentary (<100 activity counts per minute).  Systolic and diastolic blood pressures (SBP and DBP) were modeled as a function of sedentary quartiles, demographic factors (age, gender, race, income), health behaviors (average daily MV minutes, alcohol use) and general health (osteoarthritis status,  Charlson comorbidity score, BMI, NSAID and antihypertensive medication use during the month preceding the 48^–month visit).

Results:

Of 1,760 adults, 60% had knee OA, 42% used ≥1 antihypertensive medications within 30 days prior to the 48 month visit, and 24.4% had elevated BP (≥ 140/90 or 130/80 for diabetic or renal patients). BP values (see Table) show lowest SBP in the least sedentary group, while DBP is similar across all groups.  Adjusted analyses found the least sedentary group on average had SBP 1.82 mm Hg lower (95% CI, 0.04 – 3.59) than the other combined groups. Also, SBP was significantly elevated in adults with OA (2.3 mm Hg), blacks (5.7 mm Hg), and obesity (3.3 mm Hg).  But time spent in MV activity, NSAID use, and alcohol use were not associated with SBP.  The effect of sedentary time on SBP was primarily observed among adults not taking antihypertensive medications. Sedentary and MV activity were not associated with DBP in adjusted analyses. 

Conclusion:

Objectively measured sedentary time was significantly associated with increased SBP, while MV activity was not, in the model adjusted for all covariates. This finding supports the inactivity physiology hypothesis that, independent of MV physical activity, sedentary time is associated with deleterious effect on cardiovascular risk. This is the first study to test this hypothesis using objectively measured sedentary time and simultaneously controlling for antihypertensive medication use.

 

Relationship of Sedentary Behavior to Blood Pressure
Blood Pressure (mm Hg)	Quartile of Sedentary Behavior
	Quartile 1 (Least Sedentary)	Quartile 2	Quartile 3	Quartile 4 (Most Sedentary)
Unadjusted Analysis
Systolic, mean (SD)	122.0 (15.8)	124.9 (16.9)	124.2 (15.9)	126.4 (16.5)
Diastolic, mean (SD)	74.5 (10.1)	75.4 (9.8)	74.5 (9.8)	73.8 (10.7)
Multiple Regression Analysis
Systolic, Adjusted* Mean Difference (95% CI)	Reference	2.44 (0.37 – 4.51)	1.03 (-1.12 – 3.17)	1.83 (-0.48 – 4.14)	p = 0.045**
Diastolic, Adjusted* Mean Difference (95% CI)	Reference	1.23 (-0.05 – 2.50)	0.42 (-0.90 – 1.73)	0.29 (-1.12 – 1.71)	p = 0.187**
* Adjusted for demographic factors (age, gender, race,  income), health behaviors (average daily MV minutes, alcohol use) and general health (osteoarthritis status,  Charlson comorbidity score, BMI, NSAID and antihypertensive medication use during the month preceding the 48–month visit). ** Least sedentary Quartile 1 versus more sedentary Quartiles 2-4

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/sedentary-time-physical-activity-and-concurrent-blood-pressure-in-osteoarthritis-initiative-participants/