Table 5.
Meta-regression results: Effects of study features and participant characteristics on 12-month mean 2-hour blood glucose and HbA1c change. Dependent variable: relative mean 2-hour blood glucose (BG) and HbA1c reduction (intervention groups vs. control groups).
| Variable Name | Description | 2-BG as outcome | HbA1c as outcome | ||
|---|---|---|---|---|---|
| Data Summary Mean a (SD)b | All data Coefficient (SE) c | Data Summary Mean a (SD)b | All data Coefficient (SE) c | ||
| Length | Duration of the nutrition education intervention (months) | 17.42 (12.09) | 0.08 (0.11) | 12.28 (7.74) | −0.00 (0.00) |
| Sample size | Sample size of the study | 247.17 (136.12) | −0.00 (0.01) | 176.72 (169.66) | 0.00 (0.00) |
| Percentage women | Percentage of women | 60.92 (24.78) | 0.07 (0.05) | 52.39 (26.67) | −0.00 (0.00) |
| Setting | =1, if studies are conducted in primary care setting | 0.79 (0.41) | 5.29 (3.33) | 0.61 (0.50) | 0.02 (0.32) |
| Delivery Agent | =1, if intervention is delivered by a dietitian | 0.58 (0.50) | 2.75 (3.24) | 0.50 (0.51) | −0.14 (0.18) |
| Study type | =1, if studies are RCT | 0.67 (0.48) | −8.86 (4.52) | 0.94 (0.24) | 0.72 (0.39) |
| Location | =1, if studies are conducted in United States | 0.04 (0.20) | 2.66 (10.57) | 0.50 (0.51) | 0.08 (0.31) |
| Delivery channel | =1, if intervention employs in-person delivery | 0.88 (0.34) | −5.57 (4.23) | 0.89 (0.32) | −0.16 (0.33) |
| Mean age | Average age of sample | 54.45 (5.42) | −0.17 (0.35) | 52.92 (6.52) | −0.00 (0.01) |
| Group-based | =1, if intervention is delivered in groups | 0.67 (0.48) | 4.47 (4.15) | 0.78 (0.43) | 0.18 (0.13) |
| Baseline BMI | Average BMI at baseline | 29.77 (3.09) | 0.80 (0.65) | 29.92 (3.41) | 0.01 (0.02) |
| Constant | - | −24.29 (26.12) | −1.07 (0.79) | ||
| Adjusted R-squared | 93.49% | 100.00% | |||
a
Mean=Mean value
b
SD=Standard deviation of included variables.
c
SE= Standard errors
*
Statistical significance at 10% level.
**
Statistical significance at 5% level.
***
Statistical significance at 1% level.