Table 2.
Negative binomial regression models of the relationship between the percentage of the population that is Black and the COVID-19 cases in Oakland County, MI (n = 70)
| Bivariate analysis | Full model | Reduced model | PCA model | |||||
|---|---|---|---|---|---|---|---|---|
| IRR (95% CI) | p value | IRR (95% CI) | p value | IRR (95% CI) | p value | IRR (95% CI) | p value | |
| Black (%) |
1.03 (1.02 to 1.04) |
< 0.0001 |
1.02 (1.01 to 1.03) |
0.0001 |
1.03 (1.02 to 1.04) |
< 0.0001 |
1.03 (1.02 to 1.04) |
< 0.0001 |
| Median age (years) |
1.00 (0.95 to 1.04) |
0.8415 |
1.03 (0.99 to 1.08) |
0.1005 |
1.02 (0.98 to 1.06) |
0.3141 |
1.02 (0.98 to 1.06) |
0.3258 |
| Persons per household (n) |
0.26 (0.13 to 0.5) |
0.0001 |
0.73 (0.35 to 1.52) |
0.402 |
0.48 (0.27 to 0.85) |
0.0114 |
0.45 (0.25 to 0.81) |
0.0073 |
| Drove alone to work (%) |
0.95 (0.91 to 1.01) |
0.0806 |
1.03 (0.96 to 1.11) |
0.4279 |
0.99 (0.94 to 1.04) |
0.5915 |
0.98 (0.93 to 1.04) |
0.5366 |
| Have a bachelor’s degree or higher (%) |
0.99 (0.98 to 1.01) |
0.3536 |
1.03 (1 to 1.05) |
0.0213 |
1.01 (1 to 1.02) |
0.0804 | n.i. | |
| Median family income (US$) |
0.78 (0.65 to 0.93) |
0.0069 |
0.76 (0.5 to 1.17) |
0.2131 | n.i. | n.i. | ||
| Population below poverty line (%) |
1.05 (1.02 to 1.08) |
0.0006 |
1.04 (0.99 to 1.11) |
0.1381 | n.i. | n.i. | ||
| Wealth (PCA) score |
1.15 (1.02 to 1.28) |
0.0193 | n.i. | n.i. |
0.92 (0.82 to 1.04) |
0.2072 | ||
| Fit statistics | ||||||||
| LR test p value | N/A | Reference | 0.0955 | 0.0955 | ||||
| AIC | N/A | 736.90 | 736.23 | 737.60 | ||||
Case counts include those that ended in deaths. Population size was used as offset in the model. AIC Akaike information criterion, CI confidence interval, IRR incidence rate ratio, LR likelihood ratio, n.i. not included, PCA principal component analysis