Table 3.
Multivariate analyses of MSSA/MRSA cases versus controls.
| Variable | Control vs MSSA | Control vs MRSA | ||||||
|---|---|---|---|---|---|---|---|---|
| Unadjusted model† | Final adjusted model‡ | Unadjusted model† | Final adjusted model§ | |||||
| OR (95% CI) | P value | OR (95% CI) | P value | OR (95% CI) | P value | OR (95% CI) | P value | |
| Gender | ||||||||
| Female | 0.69 (0.62–0.77) | <.01* | 0.69 (0.62–0.77) | <.01* | 1.31 (0.94–1.84) | .13 | ||
| Age | ||||||||
| 0–20 | Reference | Reference | Reference | |||||
| 21–40 | 0.78 (0.66–0.93) | .01* | 0.82 (0.72–0.93) | .01* | 0.95 (0.48–1.87) | .89 | ||
| 41–60 | 0.71 (0.62–0.83) | <.01* | 0.74 (0.65–0.85) | <.01* | 0.71 (0.32–1.55) | .40 | ||
| >60 | 0.54 (0.45–0.64) | <.01* | 0.55 (0.47–0.63) | <.01* | 1.35 (0.64–2.86) | .44 | ||
| Race (%) | ||||||||
| Mexican American | Reference | Reference | Reference | |||||
| Other Hispanic | 1.50 (1.25–1.80) | <.01* | 1.51 (1.27–1.80) | <.01* | 0.25 (0.04–1.40) | .12 | ||
| White | 1.27 (1.11–1.45) | <.01* | 1.29 (1.14–1.46) | <.01* | 1.91 (0.77–4.71) | .17 | ||
| Black¶ | 0.82 (0.74–0.91) | <.01* | 0.84 (0.77–0.93) | <.01* | 1.79 (0.82–3.89) | .15 | ||
| Other Race# | 0.92 (0.71–1.19) | .53 | 0.95 (0.73–1.22) | .67 | 1.37 (0.45–4.18) | .59 | ||
| Education (%) | ||||||||
| <High School Diploma | Reference | |||||||
| High School Diploma | 1.00 (0.86–1.17) | .99 | ||||||
| >High School Diploma | 1.09 (0.92–1.28) | .32 | ||||||
| Number of Household # | ||||||||
| 1–3 | Reference | Reference | Reference | |||||
| ≥4 | 1.18 (1.05–1.32) | .01 | 1.19 (1.06–1.33) | .01 | 0.90 (0.44–1.85) | .78 | ||
| Household income (USD) | ||||||||
| <45,000 | Reference | Reference | ||||||
| ≥45,000 | 1.01 (0.91–1.12) | .89 | 0.50 (0.32–0.78) | <.01* | 0.42 (0.27–0.67) | <.01* | ||
| Prescription medicine (%) | ||||||||
| No medicine | Reference | Reference | Reference | |||||
| Cephalosporins | 0.90 (0.58–1.39) | .63 | 0 | - | ||||
| Macrolides | 0.56 (0.31–0.99) | .05 | 0 | - | ||||
| Penicillins | 1.02 (0.73–1.41) | .92 | 1.50 (0.43–5.21) | .53 | ||||
| Fluoroquinolones | 0.26 (0.09–0.76) | .02* | 0.25 (0.09–0.72) | .02* | 5.28 (1.22–22.82) | .03 | 5.90 (1.37–25.33) | .02 |
| Sulfonamides | 0.02 (0.01–0.13) | <.01* | 0.02 (0.01–0.13) | <.01* | 0 | - | ||
| Tetracyclines | 0.19 (0.08–0.46) | <.01* | 0.19 (0.08–0.46) | <.01* | 0 | - | ||
| Aminoglycosides | 0.50 (0.03–9.77) | .65 | 2.65 (0.17–42.17) | .50 | ||||
| Lincomycin derivatives | 0.19 (0.03–1.31) | .10 | 0 | - | ||||
| Antibiotic combination therapy | 0.24 (0.12–0.48) | <.01* | 0.24 (0.12–0.47) | <.01* | 1.68 (0.25–11.11) | .59 | ||
| Antibiotics unspecified | 0.81 (0.38–1.70) | .58 | 0 | - | ||||
| Non-antibiotics drugs | 1.16 (1.04–1.29) | .01* | 1.16 (1.03–1.29) | .02* | 2.28 (1.49–3.49) | <.01* | 2.51 (1.75–3.60) | <.01* |
| Coughing # | ||||||||
| Yes | 0.85 (0.67–1.07) | .17 | 1.27 (0.66–2.44) | .49 | ||||
| Long-term care (%) | ||||||||
| Yes | 0.61 (0.33–1.12) | .12 | 2.54 (1.21–5.33) | .02 | 2.86 (1.37–5.95) | .01 | ||
| Insurance | ||||||||
| Yes | 2.15 (0.99–4.65) | .06 | ||||||
| Smoking status | ||||||||
| Never-smokers | Reference | Reference | ||||||
| Former smokers | 0.93 (0.81–1.08) | .34 | 2.07 (1.18–3.66) | .02 | 2.11 (1.26–3.55) | .01 | ||
| Current smokers | 0.75 (0.68–0.84) | <.01* | 0.73 (0.65–0.81) | <.01* | 1.04 (0.55–1.98) | .90 | ||
| Diabetes mellitus (%) | ||||||||
| No | Reference | |||||||
| Borderline | 1.48 (0.45–4.85) | .52 | ||||||
| Yes | 1.11 (0.64–1.94) | .71 | ||||||
CI = confidence interval, OR = odds ratio.
Unadjusted model, multivariable full models correspond to models including all the variables with P value < 0.20 in univariate analyses.
Final adjusted models for gender, age, race, the total number of people in the household, prescription medicine and smoking status, which correspond to models including all the remaining variables showing significant OR estimates after manual backward-stepwise selections.
Final adjusted models for race, household income, fluoroquinolones, long-term care and former smokers, which correspond to models including all the remaining variables showing significant OR estimates after manual backward-stepwise selections.
Non-Hispanic White.
Non-Hispanic Black.
Other Race - Including Multi-Racial.
The total number of people in the household.
*P < .05.