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Table 1 Characteristics of study participants

From: Association between protoporphyrin IX and sarcopenia: a cross sectional study

Characteristics of study participants Non-sarcopenic group Sarcopenic group Total P value
(n = 998) (n = 174) (n = 1172)
Continuous variables a
Age at screening 64.00 (14.00) 70.00 (18.00) 65.00 (14.00) < 0.001
Body mass index
(kg/m2)
28.68 (5.94) 22.52 (3.32) 27.81 (6.46) < 0.001
Protoporphyrin
(μg/dL RBC)
47.00 (18.00) 50.00 (22.00) 48.00 (19.00) < 0.001
Hemoglobin
(g/dL)
14.75 (1.70) 14.35 (1.60) 14.50 (1.70) < 0.001
Comorbidity 0.00 (1.00) 0.00 (1.00) 0.00 (1.00) < 0.001
Average peak force (Newtons) 281.30 (134.33) 207.50 (112.90) 270.10 (132.00) < 0.001
Skeletal muscle index (kg/m2) 7.60 (1.81) 5.61 (1.52) 7.31 (1.98) < 0.001
Gait speed (m/s) 1.00 (0.29) 0.96 (0.33) 0.99 (0.29) < 0.001
Categorical variables b (%)
Race/ethnicity 234 (23.4) 34 (19.5) 268 (22.9) 0.259
Gender 535 (53.6) 91 (52.2) 626 (53.4) 0.750
Smoking 548 (54.9) 108 (62.1) 656 (56.0) 0.072
Education level past high school 578 (57.9) 97 (56.1) 675 (57.6) 0.650
Arthritis 391 (39.2) 60 (34.5) 451 (38.5) 0.240
Congestive heart failure 39 (3.9) 12 (6.9) 51 (4.4) 0.075
Coronary heart disease 61 (6.1) 15 (8.6) 76 (6.5) 0.215
Angina 61 (6.1) 14 (8.0) 75 (6.4) 0.337
Heart attack 62 (6.2) 19 (10.9) 81 (6.9) 0.024
Stroke 6 (0.6) 2 (1.1) 8 (0.7) 0.418
Emphysema 23 (2.3) 13 (7.5) 36 (3.1) < 0.001
  1. BMI body mass index; RBC red blood cell
  2. a Values were expressed as median (interquartile range)
  3. b Values in the categorical variables were expressed as number (%)
  4. The percentages of race/ethnicity, gender, and smoking represent Mexican American, men, and smokers respectively