Am J Cardiol. 2016 Dec 1;118(11):1769-1773. doi: 10.1016/j.amjcard.2016.08.058. Epub 2016 Aug 31.

Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters.

Korre M¹, Porto LG², Farioli A³, Yang J⁴, Christiani DC⁴, Christophi CA⁵, Lombardi DA⁶, Kovacs RJ⁷, Mastouri R⁷, Abbasi S⁸, Steigner M⁹, Moffatt S¹⁰, Smith D¹¹, Kales SN¹².

Author information

1: Department of Environmental Health, Environmental and Occupational Medicine and Epidemiology Program, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; Department of Occupational Medicine, Cambridge Health Alliance, Harvard Medical School, Cambridge, Massachusetts.
2: Department of Environmental Health, Environmental and Occupational Medicine and Epidemiology Program, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; Faculty of Physical Education, Cardiovascular Laboratory of the Faculty of Medicine, University of Brasilia, Brasilia, Brazil.
3: Department of Environmental Health, Environmental and Occupational Medicine and Epidemiology Program, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; Department of Occupational Medicine, Cambridge Health Alliance, Harvard Medical School, Cambridge, Massachusetts; Department of Medical and Surgical Sciences, University of Bologna, Italy.
4: Department of Environmental Health, Environmental and Occupational Medicine and Epidemiology Program, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
5: Department of Environmental Health, Environmental and Occupational Medicine and Epidemiology Program, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; Cyprus International Institute for Environmental and Public Health, Cyprus University of Technology, Limassol, Cyprus.
6: Department of Environmental Health, Environmental and Occupational Medicine and Epidemiology Program, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, Massachusetts.
7: Department of Medicine, Krannert Institute of Cardiology, Indiana University, Indianapolis, Indiana.
8: Department of Cardiology, Providence Veteran Affairs Medical Center, Cardiovascular Institute of the Alpert Medical School of Brown University, Providence, Rhode Island.
9: Heart & Vascular Center, Brigham and Women's Hospital, Boston, Massachusetts.
10: Public Safety Medical, Indianapolis, Indiana.
11: Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, New York, New York.
12: Department of Environmental Health, Environmental and Occupational Medicine and Epidemiology Program, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; Department of Occupational Medicine, Cambridge Health Alliance, Harvard Medical School, Cambridge, Massachusetts. Electronic address: skales@hsph.harvard.edu.

Abstract

Left ventricular (LV) mass is a strong predictor of cardiovascular disease (CVD) events; increased LV mass is common among US firefighters and plays a major role in firefighter sudden cardiac death. We aim to identify significant predictors of LV mass among firefighters. Cross-sectional study of 400 career male firefighters selected by an enriched randomization strategy. Weighted analyses were performed based on the total number of risk factors per subject with inverse probability weighting. LV mass was assessed by echocardiography (ECHO) and cardiac magnetic resonance, and normalized (indexed) for height. CVD risk parameters included vital signs at rest, body mass index (BMI)-defined obesity, obstructive sleep apnea risk, low cardiorespiratory fitness, and physical activity. Linear regression models were performed. In multivariate analyses, BMI was the only consistent significant independent predictor of LV mass indexes (all, p <0.001). A 1-unit decrease in BMI was associated with 1-unit (g/m^1.7) reduction of LV mass/height^1.7 after adjustment for age, obstructive sleep apnea risk, and cardiorespiratory fitness. In conclusion, after height-indexing ECHO-measured and cardiac magnetic resonance-measured LV mass, BMI was found to be a major driver of LV mass among firefighters. Our findings taken together with previous research suggest that reducing obesity will improve CVD risk profiles and decrease on-duty CVD and sudden cardiac death events in the fire service. Our results may also support targeted noninvasive screening for LV hypertrophy with ECHO among obese firefighters.