Table 1.
Baseline Characteristics of Older US Men and Women With Plasma TMAO Measurements in the CHS
| Characteristics | Participants free of prevalent cardiovascular disease (n=4131) | Participants with prevalent cardiovascular disease (n=1287) | P value* |
|---|---|---|---|
| TMAO, median (IQR), µmol/L | 4.72 (3.19–7.69) | 5.43 (3.57–8.74) | <0.001 |
| Demographics | |||
| Age, mean (SD), y | 72.2 (5.3) | 73.6 (5.8) | <0.001 |
| Female sex, n (%) | 2623 (64) | 603 (47) | <0.001 |
| Race, n (%) | |||
| White | 3470 (84) | 1055 (82) | 0.087 |
| Education, n (%) | |||
| <High school | 1121 (27) | 427 (33) | 0.001 |
| High school | 1189 (29) | 338 (26) | |
| Some college | 959 (23) | 277 (22) | |
| College graduate | 862 (21) | 245 (19) | |
| Income group, n (%) | |||
| <$11 999 | 996 (24) | 374 (29) | <0.001 |
| $12 000–$24 999 | 1486 (36) | 483 (38) | |
| $25 000–$49 999 | 1106 (27) | 302 (23) | |
| >$50 000 | 543 (13) | 128 (10) | |
| Lifestyle and risk factors | |||
| Self‐reported health status, n (%) | |||
| Excellent/very good | 1751 (42) | 281 (22) | <0.001 |
| Good | 1562 (38) | 475 (37) | |
| Fair/poor | 818 (20) | 531 (41) | |
| Smoking, n (%) | |||
| Never smoked | 1979 (48) | 559 (43) | <0.001 |
| Former smoker | 1639 (40) | 595 (46) | |
| Current smoker | 513 (12) | 133 (10) | |
| Physical activity, mean (SD), kcal | 1150 (1533) | 1143 (1603) | 0.405 |
| Alcohol, mean (SD), drinks/wk | 1.1 (1.6) | 1.0 (1.5) | 0.003 |
| BMI, mean (SD), kg/m2 | 26.7 (4.8) | 26.8 (4.7) | 0.481 |
| Waist circumference, mean (SD), cm | 94.0 (13.5) | 96.1 (12.8) | <0.001 |
| Systolic blood pressure, mean (SD), mm Hg | 136 (21) | 137 (23) | 0.124 |
| Diastolic blood pressure, mean (SD), mm Hg | 71 (11) | 70 (12) | <0.001 |
| Biochemical variables | |||
| HDL cholesterol, mean (SD), mg/dL | 56 (16) | 50 (15) | <0.001 |
| LDL cholesterol, mean (SD), mg/dL | 130 (35) | 131 (36) | 0.163 |
| Triglycerides, mean (SD), mg/dL | 136 (72) | 148 (79) | <0.001 |
| CRP, median (IQR), mg/L | 2.4 (1.2–4.4) | 3.0 (1.5–5.6) | <0.001 |
| Estimated glomerular filtration rate, mean (SD), mL/min per 1.73 m2 † | 70.1 (16.2) | 63.8 (17.9) | <0.001 |
| Medical history, n (%) | |||
| Prevalent diabetes mellitus | 439 (11) | 167 (13) | 0.02 |
| Lipid‐lowering medication | 196 (5) | 115 (9) | <0.001 |
| Hypertension medication | 1649 (40) | 902 (70) | <0.001 |
| Antibiotics in past 2 wk | 116 (3) | 46 (4) | 0.12 |
| Dietary habits, mean (SD) | |||
| Fruits, servings/d | 2.1 (1.1) | 2.2 (1.0) | 0.216 |
| Vegetables, servings/d | 2.6 (1.4) | 2.4 (1.3) | 0.018 |
| Fiber, g/d | 29.3 (11.8) | 29.8 (12.4) | 0.683 |
| Total animal product, servings/wk ‡ | 1.7 (1.0) | 1.7 (1.0) | 0.503 |
Values represent mean (SD) for continuous variables and frequency (percentage) for categorical variables, unless otherwise stated. For analyses of incident cardiovascular disease, 3877 participants entered the study at baseline (1989–1990 for main cohort; 1992–1993 for minority cohort) and 254 participants entered in 1996 to 1997, the time of their first TMAO measure. BMI indicates body mass index; CHS, Cardiovascular Health Study; CRP, C‐reactive protein; HDL, high‐density lipoprotein; IQR, interquartile range (25th–75th percentile); LDL, low‐density lipoprotein; and TMAO, trimethylamine N‐oxide.
For continuous variables, independent t‐test was performed; and for TMAO and CRP, Mann–Whitney U test was performed because of the distribution of data. For indicator variables, the χ 2 test was performed.
Estimated glomerular filtration rate (mL/min per 1.73 m2) is calculated on the basis of the Chronic Kidney Disease Epidemiology Collaboration creatinine–cystatin C equation. 39
Total animal source food is the sum of intakes of unprocessed red meat, processed meat, fish, chicken, and eggs.