Table 4.
Overall and age strata-specific incidence rate ratios
| Stratum/sample* |
n
events / total |
Age (years) | Incidence rate ratio | ||
|---|---|---|---|---|---|
| Median (IQR) | p | Estimate [95% CI] | p | ||
| 55 to 65 years | |||||
|
SCDWinblad SCDJak/Bondi |
1 / 30 4 / 43 |
59.5 (57.6 to 61.8) 61.5 (59.2 to 63.3) |
0.09 | 2.7 [0.3 to 134.5] | 0.64 |
| 65 to 75 years | |||||
|
SCDWinblad SCDJak/Bondi |
1 / 36 10 / 54 |
71.4 (68.0 to 73.6) 71.6 (68.7 to 73.6) |
0.76 | 6.4 [0.9 to 277.9] | 0.09 |
| 75 years and above | |||||
|
SCDWinblad SCDJak/Bondi |
3 / 20 38 / 88 |
78.4 (76.7 to 83.3) 80.2 (77.2 to 83.1) |
0.64 | 3.2 [1.0 to 16.4] | 0.07 |
| Overall (unadjusted): | 5.1 [2.0 to 16.2] | < 0.01 | |||
| Overall (age-adjusted): | 3.7 [1.5 to 9.3] | < 0.01 | |||
Inferential statistics are from Mann-Whitney U tests (for comparing age between samples/strata) or chi-squared tests (for assessing the significance of incidence rate ratios; bold p-values are < 0.05). The total person-years at risk for each SCDWinblad stratum were: 55–65 yrs = 116; 65–75 yrs = 143; and ≥ 75 yrs = 76. The total person-years at risk for each SCDJak/Bondi stratum were: 55–65 yrs = 170; 65–75 yrs = 223; and ≥ 75 yrs = 296. Abbreviations: SCD = subjective cognitive decline; IQR = interquartile range; CI = confidence interval. *Lower bounds for age strata are inclusive, upper bounds (where applicable) are exclusive.