A case-control study of physical activity patterns and risk of non-fatal myocardial infarction
1 Department of Community Health, Brown University, Providence, RI, 02912, USA
2 Department of Nutrition, Harvard School of Public Health, Boston, MA, 02115, USA
3 Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
4 Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA, 01655, USA
5 Deparment of Family Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
6 Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
BMC Public Health 2013, 13:122 doi:10.1186/1471-2458-13-122Published: 8 February 2013
The interactive effects of different types of physical activity on cardiovascular disease (CVD) risk have not been fully considered in previous studies. We aimed to identify physical activity patterns that take into account combinations of physical activities and examine the association between derived physical activity patterns and risk of acute myocardial infarction (AMI).
We examined the relationship between physical activity patterns, identified by principal component analysis (PCA), and AMI risk in a case-control study of myocardial infarction in Costa Rica (N=4172), 1994-2004. The component scores derived from PCA and total METS were used in natural cubic spline models to assess the association between physical activity and AMI risk.
Four physical activity patterns were retained from PCA that were characterized as the rest/sleep, agricultural job, light indoor activity, and manual labor job patterns. The light indoor activity and rest/sleep patterns showed an inverse linear relation (P for linearity=0.001) and a U-shaped association (P for non-linearity=0.03) with AMI risk, respectively. There was an inverse association between total activity-related energy expenditure and AMI risk but it reached a plateau at high levels of physical activity (P for non-linearity=0.01).
These data suggest that a light indoor activity pattern is associated with reduced AMI risk. PCA provides a new approach to investigate the relationship between physical activity and CVD risk.