Accelerometer-based assessment of occupational standing time and its association with venous disorders - results of a cross-sectional field study.

Pathophysiologically, prolonged standing is associated with varicose veins (VV) or pathological venous reflux. Prior work-related epidemiological studies are inconclusive due to crude and imprecise exposure assessments. This cross-sectional field study explored the association between work-related standing time and VV or pathological reflux, assessed using wearables. Daily standing time was tracked by accelerometer and categorized: ≤2 vs. >2 but ≤4 vs. >4 h. Long-term cumulative standing exposure were estimated by combining accelerometer and survey data. Employees underwent CEAP classification and duplex ultrasound to measure lower leg reflux. The associations between standing time and other predictors on VV or reflux were analyzed by multiple logistic regression. 198 employees working ≥30 h and ≥4 days per week for ≥2y in logistics, trade, retail, manufacturing, healthcare, research, and service sectors were included (n = 116♀, Ø-age = 40 ± 9y). 18% (n = 36) stood ≤2 h, 46% (n = 91) >2 but ≤4 h, 36% (n = 71) >4 h per day. Long-term cumulative standing exposure was 10,145.0 ± 8,396.0 h. 24% (n = 47) were described with VV, 38% (n = 74) with reflux. While neither daily nor long-term cumulative standing time were significantly associated with VV or reflux, age and family history were. Our findings partly contradict previous epidemiological studies, highlighting the value of objectively measured activity patterns for future research.