TABLE 1.
Sample Characteristics and Association of Muscular Strength (MusS) with Risk of Sudden Cardiac Death
| Tertiles of Muscular Strength | |||||
|---|---|---|---|---|---|
| Overall | Lower | Middle | Upper | P-value | |
| N | 8,116 | 2,696 | 2,723 | 2,697 | |
| Age, mean (SD), years | 42.0 (9.7) | 42.5 (9.6) | 42.1 (9.7) | 41.4 (9.8) | <0.0001 |
| Body Mass Index, mean (SD), kg/m2 | 26.1 (3.7) | 27.3 (4.4) | 25.8 (3.2) | 25.2 (2.9) | <0.0001 |
| Meeting Aerobic Guidelines, No. (%)* | 3056 (38) | 840 (31) | 992 (36) | 1224 (45) | <0.0001 |
| Current Smoking, No. (%)† | 1315 (16) | 493 (18) | 464 (17) | 358 (13) | <0.0001 |
| Heavy Alcohol Drinking, No. (%)‡ | 1991 (25) | 695 (26) | 705 (26) | 591 (22) | 0.0006 |
| Parental CVD, No. (%)§ | 2359 (29) | 804 (30) | 802 (29) | 753 (28) | 0.2641 |
| Abnormal ECG, No. (%)‖ | 459 (6) | 170 (6) | 153 (6) | 136 (5) | 0.1326 |
| Hypertension, No. (%)# | 2177 (27) | 848 (31) | 685 (26) | 644 (24) | <0.0001 |
| Diabetes, No. (%)** | 226 (3) | 106 (4) | 64 (2) | 56 (2) | <0.0001 |
| CRF, mean (SD), METs†† | 12.4 (2.5) | 11.3 (2.3) | 12.4 (2.4) | 13.4 (2.5) | <0.0001 |
| Upper Body Strength: | |||||
| kg | 72.0 (17.7) | 62.0 (12.7) | 70.3 (12.9) | 83.7 (19.3) | <0.0001 |
| kg/kg of body weight | 0.9 (0.2) | 0.7 (0.1) | 0.9 (0.1) | 1.1 (0.2) | <0.0001 |
| Lower Body Strength: | |||||
| kg | 138.1(27.6) | 126.2(26.1) | 136.8(23.7) | 151.2(26.8) | <0.0001 |
| kg/kg of body weight | 1.7 (0.3) | 1.4 (0.2) | 1.7 (0.2) | 1.9 (0.3) | <0.0001 |
| Composite Strength Score | 8.6x10−6 (0.91) | −0.81 (0.48) | −0.05 (0.44) | 0.87 (0.79) | <0.0001 |
| MusS and Risk of SCD | |||||
| Tertiles of Muscular Strength | Per 1-SD increase## | ||||
| Lower | Middle | Upper | |||
| No. of Participants | 2696 | 2723 | 2697 | 8116 | |
| No. of SCD | 13 | 4 | 6 | 23 | |
| Hazard Ratio (95% CI) Model 1‡‡ | 1.00 [ref] | 0.28 (0.09- 0.87) | 0.43 (0.16-1.14) | 0.57 (0.33-0.96) | |
| Hazard Ratio (95% CI) Model 2§§ | 1.00 [ref] | 0.31 (0.10-0.97) | 0.48 (0.17-1.32) | 0.61 (0.35-1.05) | |
| Hazard Ratio (95% CI) Model 3‖‖ | 1.00 [ref] | 0.31 (0.10-0.96) | 0.52 (0.19- 1.44) | 0.63 (0.36-1.11) | |
Data are presented as means (standard deviations) unless indicated otherwise. Data were analyzed with chi-square tests (categorical variables) or F-tests (continuous variables).
≥500 MET-minutes per week;
current smoking (yes or no);
>14 drinks per week;
Parental history of cardiovascular disease (yes or no);
abnormal electrocardiogram (yes or no from resting or exercise ECG);
hypertension (yes or no from self-report or measured Blood Pressure ≥140/90 mm Hg);
diabetes (yes or no from self-report, taking insulin, or measured glucose ≥126 mg/dL);
only in the subsample with CRF data (n=7,669).
Adjusted for age;
Adjusted for Model 1 plus body mass index (kg/m2), meeting aerobic physical activity guidelines (≥500 MET-minutes per week), current smoking, and heavy alcohol drinking (>14 drinks per week).
Adjusted for Model 2 plus parental history of cardiovascular disease, abnormal electrocardiogram, hypertension, and diabetes (all yes or no).
CI, confidence interval.CRF, cardiorespiratory fitness. CVD, cardiovascular disease.
Total muscular strength scores were standardized into z-scores using the sample’s mean and standard deviation of their standardized total strength (combined bodyweight-adjusted leg and chest press) scores. Total muscular strength z-scores had a mean of 0 and a standard deviation of 1.