Table 1.
Baseline characteristics by sex-specific quartiles of serum betaine levels 1.
| Sex-Specific Quartiles of Serum Betaine Levels | p | p-Trend | ||||
|---|---|---|---|---|---|---|
| Q1 (n = 391) | Q2 (n = 393) | Q3 (n = 391) | Q4 (n = 390) | |||
| Serum betaine, μmol/L | ||||||
| Females | 25.60 ± 7.74 | 41.58 ± 2.97 | 50.72 ± 2.91 | 68.90 ± 13.71 | <0.001 | <0.001 |
| Males | 31.47 ± 8.50 | 48.35 ± 3.14 | 58.73 ± 2.98 | 77.02 ± 12.32 | ||
| Age, years | 57.59 ± 4.97 | 57.47 ± 4.92 | 57.69 ± 5.09 | 57.26 ± 4.91 | 0.659 | 0.504 |
| WHR | 0.88 ± 0.07 | 0.89 ± 0.06 | 0.88 ± 0.06 | 0.87 ± 0.07 | 0.002 | 0.014 |
| Energy intake, kcal/day | 1829.86 ± 534.72 | 1814.73 ± 480.77 | 1827.31 ± 507.30 | 1819.52 ± 489.09 | 0.973 | 0.872 |
| Physical activity, MET × hours/day | 25.83 ± 6.86 | 25.50 ± 7.25 | 25.84 ± 7.85 | 25.68 ± 6.65 | 0.901 | 0.939 |
| Females | 271 (69.3) | 272 (69.2) | 270 (69.1) | 271 (69.5) | 0.999 | 0.971 |
| Education levels | 0.043 | 0.341 | ||||
| Less than high school | 122 (31.2) | 112 (28.5) | 124 (31.7) | 105 (26.9) | ||
| High school | 161 (41.2) | 181 (46.1) | 183 (46.8) | 205 (52.6) | ||
| College or above | 108 (27.6) | 100 (25.4) | 84 (21.5) | 80 (20.5) | ||
| Household income, yuan/month/person | 0.786 | 0.624 | ||||
| <1500 | 147 (37.6) | 127 (32.3) | 136 (34.8) | 139 (35.6) | ||
| 1500–3000 | 176 (45.0) | 183 (46.6) | 179 (45.8) | 175 (44.9) | ||
| ≥3000 | 68 (17.4) | 83 (21.1) | 76 (19.4) | 76 (19.5) | ||
| Smoking status | 0.985 | 0.702 | ||||
| Non-smoker | 329 (84.1) | 332 (84.5) | 331 (84.7) | 332 (85.1) | ||
| Smoker | 62 (15.9) | 61 (15.5) | 60 (15.3) | 58 (14.9) | ||
| Alcohol drinking | 0.247 | 0.196 | ||||
| Non-alcohol drinker | 364 (93.1) | 362 (92.1) | 373 (95.4) | 368 (94.4) | ||
| Alcohol drinker | 27 (6.9) | 31 (7.9) | 18 (4.6) | 22 (5.6) | ||
1 Data are mean ± SD or n (%). Abbreviations: MET, metabolic equivalent tasks; Q1, first quartile; Q2, second quartile; Q3, third quartile; Q4, fourth quartile; WHR, ratio of waist to hip circumference.