Standing, walking and climbing stairs at work associated with 11 year progression of atherosclerosis.
Krause-N; Dasinger-LK; Brand-RJ; Kaplan-GA; Salonen-JT
Conference Abstracts - 4th International Conference on Work Environment and Cardiovascular Diseases, March 9-11, 2005, Newport Beach, California. Irvine, CA: University of California, Irvine, 2005 Mar; :40
Recent epidemiological research has shown a strong association between prolonged standing at work and hospitalization due to varicose veins, four year progression of carotid atherosclerosis, and all cause mortality. This study investigates the progression of carotid atherosclerosis among 599 middle-aged Finnish men who participated in the prospective population-based Kuopio Ischemic Heart Disease Risk Factor Study and were gainfully employed at some point during the study's 11 year follow-up period. Ultrasound measurements of intima media thickness (IMT) of the common carotid artery were taken at baseline and at four and 11 year follow-up. Percent time spent in occupational physical activities requiring an upright body posture, i.e., standing, walking, and climbing stairs, was ascertained from an occupational physical activity interview administered at each assessment point. Averaged over the 11 year follow-up period, the percentage of time upright at work per year ranged from zero to 43%. The association of the percentage of time upright at work per year and average yearly change in ln(maximum IMT) between baseline and 11 years was studied in a multiple linear regression model controlling for 23 covariates, including technical, demographic, biomedical, psychosocial work, and behavioral factors, namely, leisure time physical activity, smoking, and alcohol consumption. Log transformed Maximum IMT was used because it gave substantially better fitting models compared to models with untransformed change in max IMT. Analysis of ln transformed change leads to estimates of relative change = RC = Final/Initial. Also %change = 100(RC -1). Maximum IMT increased an average of 2.4% per year among men who spent zero time in an upright body posture at work and who were in reference categories and had average values on continuous covariates. Otherwise similar men, who were in an upright work posture 43% of the year, had a corresponding increase of Maximum IMT of 3.3% per year (p=0.025). The increases in systolic blood pressure (p<0.001) and LDL (p=0.001) needed to get the same effect are 43.1 mmHg and 2.76 mmol/l, respectively. Also, the result for upright body posture was similar to the result for smokers who in contrast to the same reference group with 2.4% per year increased at 3.2% per year (p<0.001). Neither BMI nor leisure time physical activity had an effect on IMT change. These results suggest that an upright posture at work constitutes a major risk factor for the development of atherosclerosis, comparable to the risk found for traditional risk factors such as smoking, high blood pressure, and high cholesterol.
Age-groups; Biological-effects; Biological-monitoring; Cardiovascular-system; Cardiovascular-system-disorders; Demographic-characteristics; Epidemiology; Mathematical-models; Mortality-rates; Physical-stress; Physiological-effects; Physiological-response; Physiological-stress; Risk-analysis; Risk-factors; Statistical-analysis; Surveillance-programs; Veins; Work-analysis; Work-performance; Workplace-studies
Conference Abstracts - 4th International Conference on Work Environment and Cardiovascular Diseases, March 9-11, 2005, Newport Beach, California
University of California, San Francisco