Table 1.
Demographics and clinical characteristics by sex in D2d
| Overall (n = 2,423) | Men (n = 1,337) | Women (n = 1,086) | P for men vs. women | |
|---|---|---|---|---|
| Diabetes risk factors | ||||
| Age, years, mean (SD) | 60.0 (9.9) | 60.4 (10.3) | 59.4 (9.5) | 0.01 |
| Age range, years, n (%) | <0.01 | |||
| 25–44 | 209 (8.6) | 122 (9.1) | 87 (8.0) | |
| 45–59 | 907 (37.4) | 457 (34.2) | 450 (41.4) | |
| ≥60 | 1,307 (53.9) | 758 (56.7) | 549 (50.6) | |
| BMI, kg/m2, mean (SD) | 32.1 (4.5) | 31.5 (4.3) | 32.7 (4.6) | <0.01 |
| Waist circumference, cm, mean (SD) | 105.0 (11.7) | 107.1 (11.6) | 102.5 (11.4) | <0.01 |
| Self-reported family history of diabetes, n (%) | 1,514 (62.5) | 774 (57.9) | 740 (68.1) | <0.01 |
| Self-reported gestational diabetes mellitus, n (%) women | NA | NA | 83 (7.6) | NA |
| Demographics, n (%) | ||||
| Race | 0.04 | |||
| Asian | 130 (5.4) | 84 (6.3) | 46 (4.2) | |
| Black or African American | 616 (25.4) | 318 (23.8) | 298 (27.4) | |
| White | 1,616 (66.7) | 902 (67.5) | 714 (65.7) | |
| Other1 | 61 (2.5) | 33 (2.5) | 28 (2.6) | |
| Hispanic or Latino ethnicity | 225 (9.3) | 89 (6.7) | 136 (12.5) | <0.01 |
| Residence above 37° N latitude | 1,790 (73.9) | 1,021 (76.4) | 769 (70.8) | <0.01 |
| Socioeconomic, n (%) | ||||
| Current employment | <0.01 | |||
| Homemaker | 81 (3.3) | 5 (0.4) | 76 (7.0) | |
| Employed at least part-time | 1,421 (58.6) | 779 (58.3) | 642 (59.1) | |
| Retired | 781 (32.2) | 479 (35.8) | 302 (27.8) | |
| Not employed | 63 (2.6) | 29 (2.2) | 34 (3.1) | |
| Other | 63 (2.6) | 40 (3.0) | 23 (2.1) | |
| Unknown or not reported | 14 (0.6) | 5 (0.4) | 9 (0.8) | |
| Education | <0.01 | |||
| No schooling or less than high school (no diploma or GED) | 126 (5.2) | 48 (3.6) | 78 (7.2) | |
| Completed high school | 268 (11.1) | 145 (10.8) | 123 (11.3) | |
| Some post–high school education, no certificate or degree | 420 (17.3) | 236 (17.7) | 184 (16.9) | |
| Some post–high school education, Associate’s degree | 379 (15.6) | 201 (15.0) | 178 (16.4) | |
| Bachelor’s degree | 644 (26.6) | 377 (28.2) | 267 (24.6) | |
| Graduate or professional degree | 574 (23.7) | 324 (24.2) | 250 (23.0) | |
| Unknown or not reported | 12 (0.5) | 6 (0.4) | 6 (0.6) | |
| Annual household income ($) | <0.01 | |||
| <35,000 | 373 (15.4) | 183 (13.7) | 190 (17.5) | |
| 36,000–50,000 | 353 (14.6) | 176 (13.2) | 177 (16.3) | |
| 51,000–75,000 | 405 (16.7) | 199 (14.9) | 206 (19.0) | |
| 75,000 or more | 909 (37.5) | 586 (43.8) | 323 (29.7) | |
| Unknown or not reported | 383 (15.8) | 193 (14.4) | 190 (17.5) | |
| Health history, n (%) | ||||
| Smoking | <0.01 | |||
| Never | 1,410 (58.7) | 711 (53.6) | 699 (64.9) | |
| Former | 838 (34.9) | 513 (38.7) | 325 (30.2) | |
| Current | 155 (6.5) | 102 (7.7) | 53 (4.9) | |
| Unknown or not reported | 20 (0.8) | 11 (0.8) | 9 (0.8) | |
| Medical conditions, n (%) | ||||
| Hypercholesterolemia | 1,344 (55.5) | 821 (61.4) | 523 (48.2) | <0.01 |
| Cancer2 | 262 (10.8) | 145 (10.8) | 117 (10.8) | 0.95 |
| Cardiovascular disease3 | 299 (12.3) | 198 (14.8) | 101 (9.3) | <0.01 |
| Hypertension | 1,296 (53.5) | 758 (56.7) | 538 (49.5) | <0.01 |
| Asthma | 204 (8.4) | 72 (5.4) | 132 (12.2) | <0.01 |
| Chronic obstructive pulmonary disease | 35 (1.4) | 18 (1.3) | 17 (1.6) | 0.65 |
| Sleep apnea | 299 (12.3) | 203 (15.2) | 96 (8.8) | <0.01 |
| Osteoarthritis or degenerative joint disease | 534 (22.0) | 242 (18.1) | 292 (26.9) | <0.01 |
| Osteoporosis or osteopenia | 78 (3.2) | 7 (0.5) | 71 (6.5) | <0.01 |
| Medication use, n (%) | ||||
| Hypercholesterolemia | 1,065 (44.0) | 681 (50.9) | 384 (35.4) | <0.01 |
| Hypertension | 1,263 (52.1) | 738 (55.2) | 525 (48.3) | <0.01 |
| Osteoporosis | 13 (0.5) | 0 (0.0) | 13 (1.2) | <0.01 |
| Dietary supplements4 | ||||
| Vitamin D | ||||
| Participants taking vitamin D, n (%) | 1,037 (42.8) | 506 (37.8) | 531 (48.9) | <0.01 |
| Vitamin D intake among all participants, IU/day, mean (SD) | 313 (399) | 265 (371) | 372 (423) | <0.01 |
| Vitamin D intake among participants using supplements, IU/day, mean (SD) | 732 (255) | 701 (242) | 761 (264) | <0.01 |
| Calcium | ||||
| Participants taking calcium, n (%) | 804 (33.2) | 393 (29.4) | 411 (37.8) | <0.01 |
| Calcium intake among all participants, mg/day, mean (SD) | 103 (176) | 70 (126) | 145 (215) | <0.01 |
| Calcium intake among participants using supplements, mg/day, mean (SD) | 312 (167) | 238 (117) | 382 (177) | <0.01 |
| Clinical testing, mean (SD) | ||||
| Systolic blood pressure, mmHg | 128.4 (13.4) | 129.9 (12.8) | 126.5 (13.9) | <0.01 |
| Diastolic blood pressure, mmHg | 77.0 (9.3) | 78.7 (8.9) | 74.9 (9.3) | <0.01 |
| Serum creatinine, mg/dL | 0.89 (0.19) | 0.99 (0.17) | 0.77 (0.14) | <0.01 |
| eGFR5, mL/min/1.73 m2 | 87.1 (15.7) | 85.8 (15.2) | 88.6 (16.2) | <0.01 |
| Serum calcium, mg/dL | 9.41 (0.37) | 9.38 (0.36) | 9.44 (0.38) | <0.01 |
| Urine calcium-to-creatinine ratio | 0.09 (0.06) | 0.08 (0.05) | 0.09 (0.06) | <0.01 |
| Glycemic testing, mean (SD) | ||||
| FPG, mg/dL | 107.9 (7.4) | 108.8 (7.4) | 106.9 (7.3) | <0.01 |
| 2hPG, mg/dL | 137.2 (34.3) | 135.3 (35.9) | 139.7 (32.1) | <0.01 |
| HbA1c, % | 5.9 (0.2) | 5.9 (0.2) | 5.9 (0.2) | 0.23 |
| Prediabetes categories, n (%) | <0.01 | |||
| iA1c + IFG | 1,184 (48.9) | 687 (51.4) | 497 (45.8) | |
| IFG + IGT | 152 (6.3) | 83 (6.2) | 69 (6.4) | |
| IGT + iA1c | 231 (9.5) | 103 (7.7) | 128 (11.8) | |
| iA1c + IFG + IGT | 856 (35.3) | 464 (34.7) | 392 (36.1) |
Health history and medication use were assessed by self-report. Self-reported gestational diabetes mellitus is among all women participants whether they were pregnant or not. Racial and ethnic categories follow NIH guidelines. “Hispanic” refers to ethnicity and includes any race. IFG defined as FPG 100–125 mg/dL (5.6–6.9 mmol/L). IGT defined as 2hPG glucose after a 75-g glucose load 140–199 mg/dL (7.8–11.0 mmol/L). iA1c defined as HbA1c 5.7–6.4% (39–47 mmol/mol).
1“Other” includes American Indian or Alaska Native, Native Hawaiian or other Pacific Islander, or other race.
2Cancer (except for basal cell skin cancer) within 5 years of randomization was an exclusion criterion. Prostate cancer or well-differentiated thyroid cancer not expected to require treatment over the next 4 years were not exclusions. Volunteers with history of squamous cell cancer of the skin, which was completely excised and with no evidence of metastases, were eligible.
3Cardiovascular disease included arrhythmias, chest pain, congestive heart failure, aortic or coronary artery disease, coronary artery bypass graft/percutaneous coronary intervention, myocardial infarction, palpitations, peripheral vascular disease.
4Data are derived from a direct question about medications and supplements—not from a food-frequency questionnaire.
5eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation.