Table 1.
Baseline characteristics of study participants according to constipation status.
| Variable | Overall (N = 11,014) |
No constipation (n = 9939) |
Constipation (n = 1075) |
P |
|---|---|---|---|---|
| Age (%) | .004 | |||
| 20–39 | 3880 (38.8) | 3434 (38.2) | 446 (44.7) | |
| 40–59 | 3853 (40.9) | 3487 (41.2) | 366 (38.2) | |
| ≥60 | 3281 (20.3) | 3018 (20.6) | 263 (17.1) | |
| Gender (%) | <.001 | |||
| Female | 5355 (49.5) | 4613 (47.1) | 742 (73.5) | |
| Male | 5659 (50.5) | 5326 (52.9) | 333 (26.5) | |
| Race (%) | <.001 | |||
| Mexican American | 2073 (8.3) | 1883 (8.3) | 190 (8.7) | |
| NH Black | 2179 (10.7) | 1895 (10.1) | 284 (16.5) | |
| NH White | 5406 (71.4) | 4941 (72.0) | 465 (65.5) | |
| Other Hispanic | 901 (4.2) | 801 (4.2) | 100 (4.9) | |
| Other race | 455 (5.3) | 419 (5.4) | 36 (4.4) | |
| Education (%) | <.001 | |||
| Less than ninth grade | 1230 (5.6) | 1098 (5.4) | 132 (6.7) | |
| 9–11th grade | 1792 (12.3) | 1581 (12.0) | 211 (15.3) | |
| High school graduate/GED or equivalent | 2627 (24.1) | 2321 (23.5) | 306 (29.9) | |
| Some college or AA degree | 3120 (30.9) | 2846 (31.2) | 274 (28.5) | |
| College graduate or above | 2245 (27.1) | 2093 (27.8) | 152 (19.4) | |
| Marital status (%) | <.001 | |||
| Married | 6780 (65.3) | 6183 (65.9) | 597 (59.2) | |
| Sep/div/wid | 2371 (17.5) | 2111 (17.1) | 260 (21.6) | |
| Unmarried | 1863 (17.1) | 1645 (16.9) | 218 (19.3) | |
| PIR (%) | <.001 | |||
| ≤1.30 | 3279 (19.1) | 2860 (18.2) | 419 (28.0) | |
| 1.31–3.49 | 3559 (45.2) | 3310 (35.5) | 249 (38.1) | |
| ≥3.50 | 4176 (35.7) | 3769 (46.3) | 407 (34.0) | |
| BMI (%) | <.001 | |||
| <25 | 3137 (31.1) | 2761 (30.4) | 376 (38.4) | |
| 25–29.9 | 4097 (35.2) | 3746 (33.9) | 351 (32.4) | |
| ≥30 | 3780 (33.7) | 3432 (35.7) | 348 (29.2) | |
| Smoking (%) | <.001 | |||
| Current | 2538 (22.9) | 2287 (22.8) | 251 (24.3) | |
| Former | 2699 (24.1) | 2503 (24.7) | 196 (17.1) | |
| Never | 5777 (53.0) | 5149 (52.5) | 628 (58.5) | |
| Alcohol (%) | <.001 | |||
| Excessive | 1652 (17.6) | 1542 (18.1) | 110 (11.9) | |
| Mild | 1927 (19.3) | 1791 (19.9) | 136 (13.5) | |
| Nondrinker | 7435 (63.2) | 6606 (62.0) | 829 (74.7) | |
| Moderate activity (%) | <.001 | |||
| No | 3068 (22.5) | 2707 (22.0) | 361 (28.0) | |
| Yes | 7946 (77.5) | 7232 (78.0) | 714 (72.0) | |
| Vigorous activity (%) | .01 | |||
| No | 7158 (60.1) | 6416 (59.6) | 742 (65.4) | |
| Yes | 3856 (39.9) | 3523 (40.4) | 333 (34.6) | |
| Hypertension (%) | .06 | |||
| No | 7396 (71.2) | 6624 (71.0) | 772 (74.0) | |
| Yes | 3618 (28.8) | 3315 (29.0) | 303 (26.0) | |
| Diabetes (%) | .64 | |||
| No | 9837 (92.5) | 8881 (92.5) | 956 (92.1) | |
| Yes | 1177 (7.5) | 1058 (7.5) | 119 (7.9) | |
| eGFR stage (%) | .08 | |||
| <60 | 766 (4.7) | 681 (4.6) | 85 (5.6) | |
| 60–89 | 3436 (30.6) | 3145 (30.9) | 291 (27.5) | |
| ≥90 | 6812 (64.7) | 6113 (64.5) | 699 (66.9) | |
| Energy (%) | <.001 | |||
| T1 | 3674 (29.4) | 3217 (28.4) | 457 (39.8) | |
| T2 | 3671 (33.7) | 3326 (33.8) | 345 (32.7) | |
| T3 | 3669 (36.9) | 3396 (37.9) | 273 (27.5) | |
| Fiber density (%) | <.001 | |||
| T1 | 3672 (35.0) | 3243 (34.3) | 429 (42.7) | |
| T2 | 3671 (34.1) | 3334 (34.3) | 337 (32.0) | |
| T3 | 3671 (30.8) | 3362 (31.4) | 309 (25.3) | |
| Water intake (%) | <.001 | |||
| T1 | 3672 (26.5) | 3161 (24.9) | 511 (42.8) | |
| T2 | 3671 (33.9) | 3341 (34.0) | 330 (33.2) | |
| T3 | 3671 (39.5) | 3437 (41.1) | 234 (24.0) | |
| Caffeine (%) | <.001 | |||
| T1 | 3679 (28.1) | 3240 (27.3) | 439 (36.2) | |
| T2 | 3669 (31.8) | 3311 (31.8) | 358 (31.8) | |
| T3 | 3666 (40.1) | 3388 (40.9) | 278 (32.0) | |
| Supplement (%) | <.001 | |||
| No | 5827 (49.3) | 5193 (48.5) | 634 (56.6) | |
| Yes | 5187 (50.7) | 4746 (51.5) | 441 (43.4) | |
| Lead (%) | <.001 | |||
| Q1 | 2754 (28.4) | 2380 (27.2) | 374 (41.3) | |
| Q2 | 2757 (26.7) | 2495 (26.9) | 262 (25.2) | |
| Q3 | 2767 (24.0) | 2549 (24.6) | 218 (17.5) | |
| Q4 | 2736 (20.8) | 2515 (21.3) | 221 (16.0) | |
| Cadmium (%) | .17 | |||
| Q1 | 3013 (30.3) | 2701 (30.2) | 312 (31.1) | |
| Q2 | 2643 (24.6) | 2414 (24.9) | 229 (21.5) | |
| Q3 | 2604 (21.5) | 2348 (21.5) | 256 (21.1) | |
| Q4 | 2754 (23.6) | 2476 (23.3) | 278 (26.2) | |
| Mercury (%) | <.001 | |||
| Q1 | 2816 (23.6) | 2464 (22.8) | 352 (32.4) | |
| Q2 | 2731 (23.8) | 2460 (23.8) | 271 (24.3) | |
| Q3 | 2724 (24.9) | 2469 (24.9) | 255 (24.5) | |
| Q4 | 2743 (27.6) | 2546 (28.5) | 197 (18.7) | |
| eGFR (mL/min/1.73 m2) (median [IQR]) | 98.18 [82.93, 111.15] | 97.90 [82.90, 110.67] | 100.65 [83.89, 114.96] | .003 |
| log lead (µg/L) (median [IQR]) | 1.11 [0.92, 1.30] | 1.11 [0.93, 1.30] | 1.02 [0.86,1.24] | <.001 |
| log cadmium (µg/L) (median [IQR]) | −0.51 [−0.70, −0.24] | −0.51 [−0.70, −0.24] | −0.48 [−0.70, −0.20] | .14 |
| log mercury (µg/L) (median [IQR]) | -0.01 [-0.28, 0.28] | 0.00 [−0.27, 0.29] | −0.10 [−0.39, 0.15] | <.001 |
The values are presented as unweighted counts (n) and weighted percentages (%) or weighted medians (IQRs), as appropriate. P values were calculated using survey-weighted methods accounting for the complex sampling design.
Quartiles of blood heavy metals (μg/L): Blood lead: Q1 (1.8–8.92), Q2 (8.92–13.9), Q3 (13.9–21.6), and Q4 (21.6–331); blood mercury: Q1 (0.14–0.50), Q2 (0.50–0.91), Q3 (0.91–1.73), and Q4 (1.73–85.7); blood cadmium: Q1 (0.14–0.22), Q2 (0.22–0.34), Q3 (0.34–0.608), and Q4 (0.608–10.8).
BMI = body mass index, eGFR = estimated glomerular filtration, GED = General Educational Development, NH = Non-Hispanic, PIR = poverty income ratio, IQR = interquartile range.