Table 4.
Crude and adjusted odds ratios of upper respiratory infections (URIs) for Alzheimer’s disease (AD) when participants had been diagnosed with URI ≥ 3 within 1 year before the index date.
| n of AD | n of Control | Odd Ratios for AD (95% Confidence Interval) | ||||||
|---|---|---|---|---|---|---|---|---|
| (Exposure/Total, %) | (Exposure/Total, %) | Crude † | p | Model 1 †‡ | p | Model 2 †§ | p | |
| Total (n = 134,600) | ||||||||
| No URI | 21,334/26,920 (79.3%) | 82,928/107,680 (77.0%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 5586/26,920 (20.8%) | 24,752/107,680 (23.0%) | 0.88 (0.85–0.91) | <0.001 * | 0.88 (0.85–0.91) | <0.001 * | 0.88 (0.85–0.91) | <0.001 * |
| Age < 65 years old (n = 12,050) | ||||||||
| No URI | 1972/2410 (81.8%) | 7812/9640 (81.0%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 438/2410 (18.2%) | 1828/9640 (19.0%) | 0.95 (0.85–1.07) | 0.376 | 0.95 (0.85–1.07) | 0.417 | 0.98 (0.87–1.11) | 0.801 |
| Age ≥ 65 years old (n = 122,550) | ||||||||
| No URI | 19,362/24,510 (79.0%) | 75,116/98,040 (76.6%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 5148/24,510 (21.0%) | 22,924/98,040 (23.4%) | 0.87 (0.84–0.90) | <0.001 * | 0.88 (0.85–0.91) | <0.001 * | 0.88 (0.85–0.91) | <0.001 * |
| Men (n = 59,335) | ||||||||
| No URI | 9637/11,867 (81.2%) | 37,365/47,468 (78.7%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 2230/11,867 (18.8%) | 10,103/47,468 (21.3%) | 0.86 (0.81–0.90) | <0.001 * | 0.86 (0.82–0.91) | <0.001 * | 0.86 (0.82–0.91) | <0.001 * |
| Women (n = 75,265) | ||||||||
| No URI | 11,697/15,053 (77.7%) | 45,563/60,212 (75.7%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 3356/15,053 (22.3%) | 14,649/60,212 (24.3%) | 0.89 (0.86–0.93) | <0.001 * | 0.90 (0.86–0.94) | <0.001 * | 0.90 (0.86–0.94) | <0.001 * |
| Low income (n = 58,810) | ||||||||
| No URI | 9378/11,762 (79.7%) | 36,340/47,048 (77.2%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 2384/11,762 (20.3%) | 10,708/47,048 (22.8%) | 0.86 (0.82–0.91) | <0.001 * | 0.87 (0.83–0.91) | <0.001 * | 0.86 (0.82–0.91) | <0.001 * |
| High income (n = 75,790) | ||||||||
| No URI | 11,956/15,158 (78.9%) | 46,588/60,632 (76.8%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 3202/15,158 (21.1%) | 14,044/60,632 (23.2%) | 0.89 (0.85–0.93) | <0.001 * | 0.89 (0.86–0.93) | <0.001 * | 0.90 (0.86–0.94) | <0.001 * |
| Urban residents (n = 48,415) | ||||||||
| No URI | 7737/9683 (79.9%) | 30,125/38,732 (77.8%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1,946/9683 (20.1%) | 8607/38,732 (22.2%) | 0.88 (0.83–0.93) | <0.001 * | 0.89 (0.84–0.94) | <0.001 * | 0.89 (0.85–0.95) | <0.001 * |
| Rural residents (n = 86,185) | ||||||||
| No URI | 13,597/17,237 (78.9%) | 52,803/68,948 (76.6%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 3640/17,237 (21.1%) | 16,145/68,948 (23.4%) | 0.88 (0.84–0.91) | <0.001 * | 0.88 (0.85–0.92) | <0.001 * | 0.88 (0.84–0.91) | <0.001 * |
| Underweight (n = 5086) | ||||||||
| No URI | 1081/1303 (83.0%) | 2941/3783 (77.7%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 222/1303 (17.0%) | 842/3783 (22.3%) | 0.72 (0.61–0.84) | <0.001 * | 0.73 (0.62–0.86) | <0.001 * | 0.74 (0.63–0.87) | 0.000 * |
| Normal weight (n = 47,986) | ||||||||
| No URI | 8371/10,462 (80.0%) | 28,940/37,524 (77.1%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 2091/10,462 (20.0%) | 8584/37,524 (22.9%) | 0.84 (0.80–0.89) | <0.001 * | 0.85 (0.81–0.90) | <0.001 * | 0.85 (0.81–0.9) | <0.001 * |
| Overweight (n = 34,776) | ||||||||
| No URI | 5064/6511 (77.8%) | 21,698/28,265 (76.8%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1447/6511 (22.2%) | 6567/28,265 (23.2%) | 0.94 (0.89–1.01) | 0.081 | 0.95 (0.89–1.01) | 0.109 | 0.95 (0.89–1.01) | 0.095 |
| Obese (n = 46,752) | ||||||||
| No URI | 6818/8644 (78.9%) | 29,349/38,108 (77.0%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1826/8644 (21.1%) | 8759/38,108 (23.0%) | 0.90 (0.85–0.95) | 0.000 * | 0.90 (0.85–0.96) | <0.001 * | 0.90 (0.85–0.95) | 0.000 * |
| Non-smoker (n = 101,581) | ||||||||
| No URI | 16,021/20,404 (78.5%) | 62,034/81,177 (76.4%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 4383/20,404 (21.5%) | 19,143/81,177 (23.6%) | 0.89 (0.85–0.92) | <0.001 * | 0.89 (0.86–0.93) | <0.001 * | 0.90 (0.86–0.93) | <0.001 * |
| Past smoker and current smoker (n = 33,019) | ||||||||
| No URI | 5313/6516 (81.5%) | 20,894/26,503 (78.8%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1203/6516 (18.5%) | 5609/26,503 (21.2%) | 0.84 (0.79–0.90) | <0.001 * | 0.85 (0.79–0.91) | <0.001 * | 0.84 (0.78–0.90) | <0.001 * |
| Alcohol consumption < 1 time a week (n = 90,139) | ||||||||
| No URI | 14,755/18,701 (78.9%) | 54,605/71,438 (76.4%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 3946/18,701 (21.1%) | 16,833/71,438 (23.6%) | 0.87 (0.83–0.90) | <0.001 * | 0.88 (0.84–0.91) | <0.001 * | 0.87 (0.84–0.91) | <0.001 * |
| Alcohol consumption ≥ 1 time a week (n = 44,461) | ||||||||
| No URI | 6579/8219 (80.1%) | 28,323/36,242 (78.2%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1640/8219 (20.0%) | 7919/36,242 (21.9%) | 0.89 (0.84–0.95) | <0.001 * | 0.90 (0.84–0.95) | <0.001 * | 0.90 (0.85–0.96) | <0.001 * |
| SBP < 140 mmHg and DBP < 90 mmHg (n = 93,888) | ||||||||
| No URI | 14,528/18,540 (78.4%) | 57,651/75,348 (76.5%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 4012/18,540 (21.6%) | 17,697/75,348 (23.5%) | 0.90 (0.87–0.94) | <0.001 * | 0.91 (0.87–0.94) | <0.001 * | 0.90 (0.87–0.94) | <0.001 * |
| SBP ≥ 140 mmHg or DBP ≥ 90 mmHg (n = 40,712) | ||||||||
| No URI | 6806/8380 (81.2%) | 25,277/32,332 (78.2%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1574/8380 (18.8%) | 7055/32,332 (21.8%) | 0.83 (0.78–0.88) | <0.001 * | 0.84 (0.79–0.89) | <0.001 * | 0.84 (0.79–0.90) | <0.001 * |
| Fasting blood glucose < 100 mg/dL (n = 73,946) | ||||||||
| No URI | 10,988/14,101 (77.9%) | 45,569/59,845 (76.2%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 3113/14,101 (22.1%) | 14,276/59,845 (23.9%) | 0.90 (0.87–0.95) | <0.001 * | 0.91 (0.87–0.95) | <0.001 * | 0.90 (0.87–0.95) | <0.001 * |
| Fasting blood glucose ≥ 100 mg/dL (n = 60,654) | ||||||||
| No URI | 10,346/12,819 (80.7%) | 37,359/47,835 (78.1%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 2473/12,819 (19.3%) | 10,476/47,835 (21.9%) | 0.85 (0.81–0.90) | <0.001 * | 0.86 (0.82–0.90) | <0.001 * | 0.86 (0.82–0.90) | <0.001 * |
| Total cholesterol < 200 mg/dL (n = 77,487) | ||||||||
| No URI | 12,262/15,407 (79.6%) | 48,018/62,080 (77.4%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 3145/15,407 (20.4%) | 14,062/62,080 (22.7%) | 0.88 (0.84–0.91) | <0.001 * | 0.88 (0.85–0.92) | <0.001 * | 0.88 (0.84–0.92) | <0.001 * |
| Total cholesterol ≥ 200 mg/dL (n = 57,113) | ||||||||
| No URI | 9072/11,513 (78.8%) | 34,910/45,600 (76.6%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 2441/11,513 (21.2%) | 10,690/45,600 (23.4%) | 0.88 (0.84–0.92) | <0.001 * | 0.89 (0.84–0.93) | <0.001 * | 0.89 (0.84–0.93) | <0.001 * |
| CCI score = 0 (n = 63,571) | ||||||||
| No URI | 6648/8540 (77.9%) | 42,930/55,031 (78%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1892/8540 (22.2%) | 12,101/55,031 (22%) | 1.01 (0.96–1.07) | 0.731 | 1.00 (0.94–1.05) | 0.932 | 1.00 (0.95–1.06) | 0.969 |
| CCI score = 1 (n = 27,148) | ||||||||
| No URI | 4968/6260 (79.4%) | 15,755/20,888 (75.4%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 1292/6260 (20.6%) | 5133/20,888 (24.6%) | 0.80 (0.75–0.86) | <0.001 * | 0.80 (0.74–0.85) | <0.001 * | 0.80 (0.75–0.86) | <0.001 * |
| CCI score ≥ 2 (n = 43,881) | ||||||||
| No URI | 9718/12,120 (80.2%) | 24,243/31,761 (76.3%) | 1 | 1 | 1 | |||
| URI ≥ 3 | 2402/12,120 (19.8%) | 7518/31,761 (23.7%) | 0.80 (0.76–0.84) | <0.001 * | 0.81 (0.77–0.85) | <0.001 * | 0.81 (0.77–0.86) | <0.001 * |
Abbreviations: AD, Alzheimer’s disease; URI, upper respiratory infection; SBP, systolic blood pressure; DBP, diastolic blood pressure; CCI, Charlson Comorbidity Index. * Conditional or unconditional logistic regression analysis, significance at p < 0.05. † Stratified model for age, sex, income, and region of residence. ‡ Model 1 was adjusted for smoking, alcohol consumption, obesity, and CCI scores. § Model 2 was adjusted for model 1 plus total cholesterol, systolic blood pressure, diastolic blood pressure, and fasting blood glucose.