Table 1.
Baseline Characteristics by Median Arsenic Exposure During Follow-Up
| At or Below Median (n=962) | Above Median (n=961) | Total (n=1,923) | P-value | |
|---|---|---|---|---|
| Mean age, yrs (SD) | 38.2 (16.1) | 34.7 (14.8) | 36.5 (15.6) | <0.01 |
| No. female (%) | 591 (61.4) | 566 (58.9) | 1,157 (60.2) | 0.26 |
| Center (%) | <0.01 | |||
| Arizona | 43 (4.5) | 155 (16.1) | 198 (10.3) | |
| Oklahoma | 466 (48.4) | 353 (36.7) | 819 (42.6) | |
| North/South Dakota | 453 (47.1) | 453 (47.1) | 906 (47.1) | |
| Median arsenic, μg/L (IQR) | 3.6 (2.4–4.7) | 10.0 (7.6–15.0) | 5.9 (3.6–10.0) | <0.01 |
| Mean BMI, kg/m2 (SD) | 29.8 (6.9) | 31.0 (7.7) | 30.4 (7.3) | <0.01 |
| Mean fasting glucose, mmol/L (SD) | 93.2 (9.8) | 93.6 (10.7) | 93.4 (10.3) | 0.39 |
| Mean fasting insulin, pmol/L (SD) | 15.6 (15.5) | 17.6 (17.2) | 16.6 (16.4) | <0.01 |
| Median HOMA-IR (IQR) | 2.6 (1.6–4.4) | 2.9 (1.8–4.8) | 2.7 (1.7–4.6) | <0.01 |
| Median HOMA-B (IQR) | 148.4 (100.4–224.2) | 165.5 (107.9–264.7) | 155.2 (104.9–246) | <0.01 |
| Median cHOMA-Ba (IQR) | 184.7 (153.3–230.1) | 187.3 (153.4–240.7) | 186.3 (153.3–236.2) | 0.35 |
Abbreviations: BMI, body mass index; HOMA-B, homeostatic model assessment-beta cell function; HOMA-IR, homeostatic model assessment-insulin resistance; yrs, years.
a
Corrected HOMA-B; Sum of residuals adjusted for HOMA-IR and mean HOMA-B.