Table 2.
Results of linear regression analysis.
| Univariate | Multivariate | |||||
|---|---|---|---|---|---|---|
| Variable | Estimate (95% CI) (transformed from log) | P | Direction of relationship | Estimate (95% CI) (transformed from log)a | P | Direction of relationship |
| % Population over 65 years old | 1.184 ± 0.064 | P < 0.001 | Positive | 1.1 ± 0.07 | 0.009 | Positive |
| Total 2020 population | 0.99 ± 0.006 | P < 0.001 | Negative | 0.99 ± 0.0047 | 0.03 | Negative |
| BCG vaccination in the preceding 15 years | 0.1 ± 0.054 | P < 0.001 | Negative | 0.29 ± 0.18 | 0.011 | Negative |
| Population density | 1 ± 0.003 | Not significant | Not significant | Not significant | Not significant | |
| Average temperature | 0.913 ± 0.04 | P < 0.001 | Negative | Not significant | Not significant | |
| GDP per capita | 1 ± 0 | P < 0.001 | Positive | Not significant | Not significant | |
| Stringency Index | 0.97 ± 0.022 | 0.012 | Negative | Not significant | Not significant | |
| BCG vaccination in the preceding 40 years | 0.235 ± 0.136 | 0.001 | Negative | Not significant | Not significant | |
| BCG coverage in last 40 years | 0.988 ± 0.008 | 0.007 | Negative | Not significant | Not significant | |
| Polio vaccine coverage | 1.009 ± 0.012 | Not significant | Not significant | Not significant | Not significant | |
| Polio vaccine duration | 1.009 ± 0.013 | Not significant | Not significant | Not significant | Not significant | |
| Measles vaccine coverage | 0.005 ± 0.008 | Not significant | Not significant | Not significant | Not significant | |
| Measles vaccine duration | 0.0004 ± 0.0006 | Not significant | Not significant | Not significant | Not significant |
The percentage of the population over 65 years of age was associated with higher rates of CRM such that for every percent increase in population over 65 years old, CRM increased by 10% (95% confidence interval 2–18%). The total population of a country was associated with improved CRM (for every unit increase there was a 1% decrease in CRM (95% CI 0.53–1.47%). An active BCG vaccination program for the preceding 15 years was shown to reduce CRM significantly by 71% (95% CI 53–89%). A negative relationship suggests that the variable results in a decrease in CRM and vice versa.
aThe antilog of all estimates. For example, when % population above 65 yrs. increases by 1%, the deaths/mn on an average increase by 1.10 times, i.e., 10% (with a 95% CI of 1.02–1.18 or 2–18%). Likewise, when a country has BCG coverage in the last 15 years, the deaths/mn decreases by 0.29 times, i.e., 71% (with a 95% CI of 0.11–0.47 or 89–53%).