Association Between Occupational Sitting With High Sensitivity C-Reactive Protein: The Jackson Heart Study

Abstract

Modifiable, behavioral risk factors like occupational sitting may contribute to inflammation, an important cardiovascular risk factor. This study evaluated the association of self-reported occupational sitting with changes in c-reactive protein (CRP) and the role of sex. We examined occupational sitting and baseline CRP levels for 2889 African American participants in the Jackson Heart Study. Four multivariable linear regression models were estimated to determine the association of occupational sitting and CRP. Analyses were conducted in 2020. The mean age was 50.8 years and 61% were female. Participants who reported occupational sitting as "often/always" had CRP levels of 4.9±6.8 mg/L, "sometimes" had levels of 4.8±8.1 mg/L, and "never/seldom" had levels of 4.3±6.8 mg/L. In the unadjusted model, "often/always" engaging in occupational sitting was significantly associated with higher levels of CRP when compared to "never/seldom" (P < .05). This differed by sex with female participants who reported "often/always" occupational sitting had CRP levels of 6.0±7.6 mg/L compared to only 5.1±6.9 mg/L for "never/seldom." Neither the overall association nor the female-specific association remained statistically significant in the adjusted models. We found an association between occupational sitting and inflammation, measured by CRP. This association varied by sex but did not remain significant after fully adjusting for covariates.

Keywords: inflammation; minority health; sedentary behavior; workplace.

Figure 1.

Directed acyclic graph (DAG) for the causal relationship between occupational sitting and CRP. Factors in boxes are covariates to adjust for per the DAG rules. Sociodemographics included age, sex, education, and income. Cardiovascular disease risk factors included diabetes, hypertension, cholesterol (total, HDL), and self-report myocardial infarction and stroke. Lifestyle behaviors referred cigarette smoking, leisure-time moderate-to-vigorous physical activity, occupational standing, and occupational walking. Note: CRP: c-reactive protein, DAG: directed acyclic graph.