Table 4.
Univariate Regression Analysis of Clinical Parameters and the Serum-Free T3:Free T4 Ratio
| LT4-Treated (n = 469) | Matched Controls (n = 469) | |||
|---|---|---|---|---|
| Regression Coefficient | P Value | Regression Coefficient | P Value | |
| Demographics variables | ||||
| Age (5-y increase) | −0.12 | <.0001 | −0.07 | <.0001 |
| Female | −0.27 | <.01 | −0.08 | .35 |
| Hispanic | 0.17 | .08 | 0.27 | <.01 |
| Non-Hispanic white | −0.16 | .05 | −0.12 | .12 |
| Non-Hispanic black | 0.16 | .25 | −0.07 | .59 |
| Other race/ethnicity | −0.05 | .80 | −0.16 | .35 |
| Objective measures | ||||
| BMI (5 kg/m2 increase) | 0.08 | <.01 | 0.09 | <.01 |
| Systolic blood pressure (mm Hg) | −0.01 | .02 | −0.01 | .41 |
| Diastolic blood pressure (mm Hg) | 0.01 | <.0001 | 0.01 | <.0001 |
| Heart rate (beats per minute) | 0.01 | .03 | 0.01 | .64 |
| HgbA1C (%) | 0.01 | .92 | 0.01 | .88 |
| Fasting glucose (50 mg/dl increase) | −0.03 | .55 | 0.02 | .74 |
| Total cholesterol (50 mg/dl increase) | 0.067 | .12 | 0.05 | .28 |
| LDL (50 mg/dl increase) | 0.04 | .64 | 0.05 | .52 |
| HDL (50 mg/dl increase) | −0.23 | .04 | −0.30 | <.01 |
| Triglyceride (50 mg/dl increase) | 0.14 | <.0001 | 0.16 | <.0001 |
| C-reactive protein (mg/dl) | −0.03 | .61 | −0.06 | .10 |
| Ferritin (50 ng/dl increase) | 0.01 | .85 | 0.07 | .12 |
| Creatinine (0.5 mg/dl increase) | −0.11 | <.01 | −0.25 | <.0001 |
| Creatinine phosphokinase (50 IU/liter increase) | 0.07 | .18 | 0.07 | .20 |
| Medication use | ||||
| Beta-blocker | −0.10 | .21 | −0.21 | <.0001 |
| Statin | 0.03 | .76 | 0.16 | .10 |
| Insulin | 0.17 | .35 | −0.06 | .78 |
| Oral hypoglycemic | 0.28 | .06 | 0.16 | .25 |
| Antidepressant | 0.23 | .01 | 0.04 | .71 |
| Antianxiety | −0.13 | .41 | −0.17 | .25 |
| Antipsychotic | −0.23 | .52 | −0.24 | .45 |
| Metabolic equivalents (METs)/physical parameters | ||||
| 1000 MET activity (work and recreational activity) | 0.01 | .46 | 0.01 | .31 |
| Work/job requires vigorous activity (%) | −0.01 | .96 | 0.06 | .71 |
| 1000 Vigorous work MET | −0.03 | .39 | 0.03 | .21 |
| Work/job requires moderate activity (%) | 0.04 | .66 | −0.06 | .43 |
| 1000 Moderate work MET | 0.07 | .03 | 0.03 | .15 |
| Walks/bikes for transportation (%) | −0.10 | .34 | −0.04 | .67 |
| 1000 Transportation MET | 0.06 | .57 | 0.01 | .80 |
| Participates in vigorous recreational activity (%) | −0.28 | .03 | −0.07 | .58 |
| 1000 Vigorous recreational MET | −0.02 | .38 | 0.02 | .15 |
| Participates in moderate recreational activity (%) | −0.05 | .54 | −0.08 | .29 |
| 1000 Moderate recreational MET | −0.09 | .33 | 0.06 | .40 |
| Cognitive/well-being parameters | ||||
| Excellent/good stated health condition | −0.03 | .70 | −0.04 | .61 |
| Poor stated health condition | 0.34 | .03 | −0.10 | .56 |
| Number of days in the past month physical health was not good | 0.01 | .04 | −0.01 | .76 |
| Number of days in the past month mental health was not good | 0.01 | .16 | 0.01 | .85 |
| Number of days in the past month inactive because of physical or mental health | 0.01 | .08 | 0.01 | .67 |
| Physical, mental, or emotional limitation kept from working | −0.06 | .55 | −0.03 | .79 |
| Experience confusion/memory problem | −0.01 | .98 | 0.26 | .03 |
| Limited in activity due to physical, mental, or emotional problem | 0.36 | .08 | −0.04 | .85 |
| Social factors | ||||
| Smoked at least 100 cigarettes | −0.02 | .82 | 0.02 | .79 |
| Currently smoking daily | 0.27 | .04 | 0.09 | .50 |
| Consumed at least 12 drinks per year | −0.20 | .04 | 0.06 | .51 |
| Number of alcoholic drinks consumed per day | 0.16 | <.0001 | 0.11 | .01 |
| Nutrient intake | ||||
| 1000 calories consumed in 24-h recall | 0.21 | <.0001 | 0.09 | .20 |
| Calories consumed, adjusted by body weight (kcal/day/kg) | 0.01 | .24 | 0.01 | .68 |
| % calorie intake compared to DRI for energy | 0.01 | .24 | 0.01 | .68 |
| 100 g carbohydrate consumed | 0.11 | <.01 | 0.05 | .09 |
| Carbohydrate consumed (%) | −0.01 | .21 | 0.01 | .35 |
| 50 g protein consumed | 0.25 | <.0001 | 0.07 | .15 |
| Protein consumed (%) | 0.01 | .87 | −0.02 | .02 |
| 50 grams fat consumed | 0.16 | <.01 | 0.08 | .06 |
| Fat consumed (%) | 0.01 | .68 | −0.01 | .38 |
| Selenium intake (mcg) | 0.01 | .98 | −0.01 | .35 |
Abbreviations: DRI, dietary reference intake; HbA1C, hemoglobin A1C.