Table 3.

Negative binomial regression models of the relationship between the percentage of the population that is Black and the COVID-19 deaths in Oakland County, MI (n = 68)

	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 (%)	1.00 (1.00 to 1.01)	0.2185	1.00 (0.99 to 1.01)	0.9109	1.00 (1.00 to 1.01)	0.352	1.00 (1.00 to 1.01)	0.3104
Median age (years)	1.01 (0.99 to 1.04)	0.2772	1.03 (1.00 to 1.06)	0.0824	1.02 (0.99 to 1.05)	0.2247	1.02 (0.99 to 1.05)	0.2477
Persons per household	0.54 (0.35 to 0.83)	0.0057	0.64 (0.35 to 1.17)	0.1498	0.49 (0.3 to 0.79)	0.0033	0.46 (0.28 to 0.75)	0.0019
Drove alone to work (%)	1.01 (0.98 to 1.04)	0.4535	1.00 (0.94 to 1.06)	0.9604	0.99 (0.95 to 1.03)	0.6002	0.99 (0.95 to 1.03)	0.4987
Have a bachelor’s degree or higher (%)	1.01 (1.00 to 1.01)	0.1221	1.02 (1.00 to 1.04)	0.0383	1.01 (1.00 to 1.02)	0.0771	n.i.
Median family income	1.00 (0.90 to 1.12)	0.9423	0.77 (0.54 to 1.09)	0.1374	n.i.		n.i.
Population below poverty line (%)	1.00 (0.98 to 1.01)	0.5799	1.01 (0.97 to 1.06)	0.5863	n.i.		n.i.
Wealth (PCA) score	0.98 (0.91 to 1.04)	0.4493	n.i.		n.i.		0.93 (0.84 to 1.03)	0.1572
Fit statistics
LR test p value	N/A		Reference		0.0955		0.0955
AIC	N/A		736.90		736.23		737.60

Two zip codes (48430 and 48439) that had no confirmed COVID-19 cases were excluded. Cases were 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