Table 3. Regression models for CD4+ naive and memory cell subpopulations.
| Variable (increment) | %Naive | %Memory | ||
| β Coef. | P value | β Coef. | P value | |
| Age (10 yr. increase) | −1.25 | <0.05 | −0.47 | ns |
| Gender (male vs. female) | −4.2 | <0.0001 | 2.81 | <0.05 |
| Race/Ethnicity(vs. European-American) | ||||
| Chinese-American | 1.91 | ns | 1.11 | ns |
| African-American | −1.97 | ns | 2.61 | ns |
| Hispanic-American | −1.69 | ns | 4.33 | <0.005 |
| Season (vs. Winter) | ||||
| Spring | 2.11 | ns | 0.01 | ns |
| Summer | 4.07 | <0.05 | 3.26 | ns |
| Fall | 7.21 | <0.0001 | 0.76 | ns |
| BMI (5.6 kg/m2) | −1.26 | <0.05 | 0.54 | ns |
| IL-6 (1.2 pg/ml) | −1.49 | <0.05 | 2.26 | <0.0001 |
| CMV (vs. 0.0 EU/ml) | ||||
| 0.1 – 99.9 EU/ml | −2.91 | <0.05 | 4.71 | <0.005 |
| 100 – 199.9 EU/ml | −6.15 | <0.0001 | 8.11 | <0.0001 |
| 200 – 299.9 EU/ml | −7.05 | <0.005 | 7.29 | <0.005 |
| H. pylori (vs. <0.9) | ||||
| 0.9–6.9 | −3.44 | <0.005 | 2.68 | <0.05 |
| 6.9–13.9 | −6.60 | <0.05 | 3.99 | <0.05 |
| Model R2 | 0.15 | 0.12 | ||
Backward elimination regression was used to develop multivariate models for CD4+ T cell subpopulations. Independent variables were divided by their standard deviations (shown in parentheses). Age, gender, race/ethnicity, seasonality, BMI, IL-6, and CMV and H. pylori titers were included as the candidate starting variables. Only significant variables (p<0.05) were retained in the final models. BMI: Body mass index; CMV: Cytomegalovirus; IL-6: Interleukin-6; ns: non-significant.