Citation:
Karjalainen, J., Tikkanen, H., Hernelahti, M. & Kujala, U. (2006). Muscle fiber-type distribution predicts weight gain and unfavourable left ventricular geometry: a 19 year follow-up study. BMC Cardiovascular Disorders, 6 (2). Retrieved from http://www.biomedcentral.com/1471-2261/6/2
Title: | Muscle fiber-type distribution predicts weight gain and unfavourable left ventricular geometry: a 19 year follow-up study |
Author: | Karjalainen, Jouko; Tikkanen, Heikki; Hernelahti, Miika; Kujala, Urho |
Abstract: | BACKGROUND:
Skeletal muscle consists of type-I (slow-twitch) and type-II (fast-twitch) fibers, with proportions highly variable between individuals and mostly determined by genetic factors. Cross-sectional studies have associated low percentage of type-I fibers (type-I%) with many cardiovascular risk factors.
METHODS:
We investigated whether baseline type-I% predicts left ventricular (LV) structure and function at 19-year follow-up, and if so, which are the strongest mediating factors. At baseline in 1984 muscle fiber-type distribution (by actomyosin ATPase staining) was studied in 63 healthy men (aged 32–58 years). The follow-up in 2003 included echocardiography, measurement of obesity related variables, physical activity and blood pressure.
RESULTS:
In the 40 men not using cardiovascular drugs at follow-up, low type-I% predicted higher heart rate, blood pressure, and LV fractional shortening suggesting increased sympathetic tone. Low type-I% predicted smaller LV chamber diameters (P ≤ 0.009) and greater relative wall thickness (P = 0.034) without increase in LV mass (concentric remodeling). This was explained by the association of type-I% with obesity related variables. Type-I% was an independent predictor of follow-up body fat percentage, waist/hip ratio, weight gain in adulthood, and physical activity (in all P ≤ 0.001). After including these risk factors in the regression models, weight gain was the strongest predictor of LV geometry explaining 64% of the variation in LV end-diastolic diameter, 72% in end-systolic diameter, and 53% in relative wall thickness.
CONCLUSION:
Low type-I% predicts obesity and weight gain especially in the mid-abdomen, and consequently unfavourable LV geometry indicating increased cardiovascular risk.
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Publisher: | BioMed Central |
Date: | 2006 |
Belongs to series: | BMC Cardiovascular Disorders |
ISSN: | 1471-2261 Search the Publication Forum |
Subjects: | lihassolu lihavuus sydän liikunta muscle fiber-type obesity heart physical activity |
Rights: | © 2006 Karjalainen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Rights: | http://creativecommons.org/licenses/by/2 |
DOI: | doi:10.1186/1471-2261-6-2 |
Permanent link to this item: http://urn.fi/URN:NBN:fi:jyu-2011051310797