Table 1.
Baseline characteristics of women who developed type 2 diabetes and their matched controls.
| Covariates | Control (N=370) | Case (N=370) | p-value* | |
|---|---|---|---|---|
| Median (5 - 95% range) | ||||
| Urine aMT6s/creatinine (ng/mg)# | 36.3 (6.9 – 110.8) | 28.2 (5.5 – 84.2) | <0.001 | |
| Urine aMT6s (ng/dL) # | 2410 (430 – 9920) | 1910 (340 – 7980) | 0.002 | |
| Urine creatinine (mg/dL) # | 65.3 (33.7 – 160.4) | 69.6 (35.2 – 162.0) | 0.20 | |
| Age (years) | 64.2 (55.8 – 75.2) | 64.4 (55.5 – 75.7) | 0.56† | |
| BMI (kg/m2) | 25.3 (19.9 – 35.5) | 29.3 (21.7 – 40.4) | <0.001 | |
| Physical activity, (METs/week)‡ | 13.3 (0.7 – 63.3) | 10.2 (0.2 – 49.1) | 0.003 | |
| AHEI scorei | 46.4 (26.7 – 65.4) | 41.4 (24.9 – 61.2) | <0.001 | |
| Glycemic index | 53.4 (48.0 – 58.2) | 53.4 (47.4 – 58.9) | 0.15 | |
| Polyunsaturated/saturated fat | 0.59 (0.35 – 1.10) | 0.59 (0.35 – 0.98) | 0.46 | |
| %energy trans fat | 1.47 (0.69 – 2.62) | 1.61 (0.86 – 2.66) | <0.001 | |
| Cereal fiber in diet (gm) | 6.2 (3.0 – 12.1) | 5.4 (2.6 – 10.4) | <0.001 | |
| Alcohol consumption (gm/day) | 1.5 (0.0 – 19.7) | 0.9 (0.0 – 27.4) | 0.007 | |
| E-selectin (ng/mL) | 33.4 (15.8 – 56.8) | 41.3 (18.0 – 74.4) | <0.001 | |
| hsCRP (mg/L) | 2.0 (0.31 – 9.9) | 3.7 (0.7 – 22.5) | <0.001 | |
| ICAM-1 (ng/mL) | 258.1 (175.1 – 367.9) | 281.4 (188.2 – 466.0) | <0.001 | |
| IL-6 (pg/mL) | 1.2 (0.50 – 4.05) | 1.8 (0.7 – 7.1) | <0.001 | |
| Insulin (uU/mL) | 5.2 (1.8 – 13.3) | 8.9 (2.6 – 31.1) | <0.001 | |
| Triglyceride(mg/dL) | 116 (55 – 238) | 164.0 (71.0 – 348.0) | <0.001 | |
| Insulin sensitivity (McAuley index) | 8.1 (5.5 – 12.4) | 6.2 (4.1 – 9.6) | <0.001 | |
| N (%) | ||||
| White race | 355 (96) | 353 (95) | 0.72 | |
| Smoking history | Current | 20 (5.4) | 26 (7.0) | 0.36 |
| Past | 166 (44.9) | 172 (46.5) | 0.66 | |
| Family history of diabetes | 69 (18.7) | 131 (35.4) | <0.001 | |
| History of HTN | 146 (39.5) | 230 (62.2) | <0.001 | |
| Treatment for HTN | 116 (31.4) | 210 (56.8) | <0.001 | |
| Snoring | Most nights | 74 (20.0) | 103 (27.8) | 0.01 |
| Occasionally | 24 (6.5) | 27 (7.3) | 0.66 | |
| Almost never | 260 (70.3) | 232 (62.7) | 0.03 | |
| Sleep duration (hours per night) | ≤ 5 | 9 (2.4) | 24 (6.5) | 0.008 |
| 6 | 69 (18.7) | 78 (21.1) | 0.41 | |
| 7-8 | 263 (71.1) | 237 (64.1) | 0.04 | |
| 9 | 17 (4.6) | 23 (6.2) | 0.33 | |
| ≥10 | 6 (1.6) | 4 (1.1) | 0.52 | |
| Region of the US!! | North | 175 (47) | 204 (55) | 0.03 |
| South | 62 (17) | 57 (15) | 0.62 | |
| Mid-west | 80 (22) | 97 (26) | 0.14 | |
| West | 53 (14) | 12 (3) | < 0.001 | |
| NSAID use | 137(37) | 156(42) | 0.15 | |
| Beta-blocker use | 57 (15) | 80 (22) | 0.03 | |
| Post-menopausal | 362 (98) | 366 (99) | 0.24 | |
P-values for continuous variables calculated using Wilcoxon signed rank test and categorical variables using Chi-Square test.
Urinary melatonin levels were assessed by measuring the urinary appearance of its primary metabolite (6-sulfatoxymelatonin [aMT6s]). aMT6s, aMT6s/creatinine and creatinine are displayed without log-transformation. In later analyses, aMT6s/creatinine is log-transformed when used as a continuous variable.
Matching criteria in case-control selection.
Physical activity (METs/week), sum of the average time/week spent in each activity × MET value of each activity. METs measure the ratio of the work metabolic rate to the resting metabolic rate.
AHEI is a diet-quality score that reflects a common dietary pattern associated with a lower risk of type 2 diabetes.
North region includes PA, NY, NJ, CT, RI, MA, NH, VT, and ME. South region includes OK, TX, LA, AR, MS, AL, FL, GA, SC, NC, VA, TN, KY, WV, DC, MD, and DE. Midwest region includes ND, SD, NE, KS, MN, IA, MO, WI, IL, MI, IN and OH. West region includes WA, OR MT, ID, WY, CA, NV, UT, CO, AZ, and NM.
Abbreviations: AHEI, alternative healthy eating index; hsCRP, high sensitivity c-reactive protein; ICAM-1, intercellular adhesion molecule-1; IL-6, interleukin 6; HTN, hypertension; METs, metabolic equivalent of task.