Table 5.
Crude and adjusted odds ratios of upper respiratory infections (URIs) for Alzheimer’s disease (AD) when participants had been diagnosed with URI ≥ 1 within 2 years 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 | 10,056/26,920 (37.4%) | 35,412/107,680 (32.9%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 16,864/26,920 (62.6%) | 72,268/107,680 (67.1%) | 0.82 (0.80–0.84) | <0.001 * | 0.82 (0.80–0.85) | <0.001 * | 0.83 (0.81–0.85) | <0.001 * |
| Age < 65 years old (n = 12,050) | ||||||||
| No URI | 967/2410 (40.1%) | 3587/9640 (37.2%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 1443/2410 (59.9%) | 6053/9640 (62.8%) | 0.88 (0.81–0.97) | 0.008 * | 0.88 (0.81–0.97) | 0.009 * | 0.90 (0.82–0.99) | 0.030 * |
| Age ≥ 65 years old (n = 122,550) | ||||||||
| No URI | 9089/24,510 (37.1%) | 31,825/98,040 (32.5%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 15,421/24,510 (62.9%) | 66,215/98,040 (67.5%) | 0.82 (0.79–0.84) | <0.001 * | 0.82 (0.80–0.85) | <0.001 * | 0.82 (0.80–0.85) | <0.001 * |
| Men (n = 59,335) | ||||||||
| No URI | 4898/11,867 (41.3%) | 17,129/47,468 (36.1%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 6969/11,867 (58.7%) | 30,339/47,468 (63.9%) | 0.80 (0.77–0.84) | <0.001 * | 0.81 (0.78–0.85) | <0.001 * | 0.81 (0.78–0.85) | <0.001 * |
| Women (n = 75,265) | ||||||||
| No URI | 5158/15,053 (34.3%) | 18,283/60,212 (30.4%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 9895/15,053 (65.7%) | 41,929/60,212 (69.6%) | 0.84 (0.81–0.87) | <0.001 * | 0.84 (0.81–0.88) | <0.001 * | 0.85 (0.81–0.88) | <0.001 * |
| Low income (n = 58,810) | ||||||||
| No URI | 4595/11,762 (39.1%) | 15,778/47,048 (33.5%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 7167/11,762 (60.9%) | 31,270/47,048 (66.5%) | 0.79 (0.75–0.82) | <0.001 * | 0.80 (0.76–0.83) | <0.001 * | 0.79 (0.76–0.83) | <0.001 * |
| High income (n = 75,790) | ||||||||
| No URI | 5461/15,158 (36.0%) | 19,634/60,632 (32.4%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 9697/15,158 (64.0%) | 40,998/60,632 (67.6%) | 0.85 (0.82–0.88) | <0.001 * | 0.86 (0.83–0.89) | <0.001 * | 0.86 (0.83–0.89) | <0.001 * |
| Urban residents (n = 48,415) | ||||||||
| No URI | 3858/9683 (39.8%) | 13,689/38,732 (35.3%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 5825/9683 (60.2%) | 25,043/38,732 (64.7%) | 0.83 (0.79–0.86) | <0.001 * | 0.83 (0.80–0.87) | <0.001 * | 0.84 (0.80–0.88) | <0.001 * |
| Rural residents (n = 86,185) | ||||||||
| No URI | 6198/17,237 (36.0%) | 21,723/68,948 (31.5%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 11,039/17,237 (64.0%) | 47,225/68,948 (68.5%) | 0.82 (0.79–0.85) | <0.001 * | 0.83 (0.80–0.86) | <0.001 * | 0.82 (0.80–0.85) | <0.001 * |
| Underweight (n = 5086) | ||||||||
| No URI | 595/1303 (45.7%) | 1305/3783 (34.5%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 708/1303 (54.3%) | 2478/3783 (65.5%) | 0.63 (0.55–0.71) | <0.001 * | 0.64 (0.56–0.73) | <0.001 * | 0.64 (0.56–0.73) | <0.001 * |
| Normal weight (n = 47,986) | ||||||||
| No URI | 4016/10,462 (38.4%) | 12,444/37,524 (33.2%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 6446/10,462 (61.6%) | 25,080/37,524 (66.8%) | 0.80 (0.76–0.83) | <0.001 * | 0.81 (0.77–0.84) | <0.001 * | 0.80 (0.77–0.84) | <0.001 * |
| Overweight (n = 34,776) | ||||||||
| No URI | 2347/6511 (36.1%) | 9233/28,265 (32.7%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 4164/6511 (64.0%) | 19,032/28,265 (67.3%) | 0.86 (0.81–0.91) | <0.001 * | 0.87 (0.82–0.92) | <0.001 * | 0.87 (0.82–0.92) | <0.001 * |
| Obese (n = 46,752) | ||||||||
| No URI | 3098/8644 (35.8%) | 12,430/38,108 (32.6%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 5546/8644 (64.2%) | 25,678/38,108 (67.4%) | 0.87 (0.83–0.91) | <0.001 * | 0.88 (0.83–0.92) | <0.001 * | 0.87 (0.83–0.92) | <0.001 * |
| Non-smoker (n = 101,581) | ||||||||
| No URI | 7304/20,404 (35.8%) | 25,691/81,177 (31.7%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 13,100/20,404 (64.2%) | 55,486/81,177 (68.4%) | 0.83 (0.80–0.86) | <0.001 * | 0.84 (0.81–0.87) | <0.001 * | 0.84 (0.81–0.87) | <0.001 * |
| Past smoker and current smoker (n = 33,019) | ||||||||
| No URI | 2752/6516 (42.2%) | 9721/26,503 (36.7%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 3764/6516 (57.8%) | 16,782/26,503 (63.3%) | 0.79 (0.75–0.84) | <0.001 * | 0.80 (0.75–0.84) | <0.001 * | 0.80 (0.75–0.84) | <0.001 * |
| Alcohol consumption < 1 time a week (n = 90,139) | ||||||||
| No URI | 6842/18,701 (36.6%) | 22,768/71,438 (31.9%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 11,859/18,701 (63.4%) | 48,670/71,438 (68.1%) | 0.81 (0.78–0.84) | <0.001 * | 0.82 (0.79–0.85) | <0.001 * | 0.82 (0.79–0.85) | <0.001 * |
| Alcohol consumption ≥ 1 time a week (n = 44,461) | ||||||||
| No URI | 3214/8219 (39.1%) | 12,644/36,242 (34.9%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 5005/8219 (60.9%) | 23,598/36,242 (65.1%) | 0.83 (0.79–0.88) | <0.001 * | 0.84 (0.80–0.88) | <0.001 * | 0.85 (0.81–0.89) | <0.001 * |
| SBP < 140 mmHg and DBP < 90 mmHg (n = 93,888) | ||||||||
| No URI | 6632/18,540 (35.8%) | 24,110/75,348 (32.0%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 11,908/18,540 (64.2%) | 51,238/75,348 (68.0%) | 0.84 (0.82-0.87) | <0.001 * | 0.85 (0.82-0.88) | <0.001 * | 0.85 (0.82–0.88) | <0.001 * |
| SBP ≥ 140 mmHg or DBP ≥ 90 mmHg (n = 40,712) | ||||||||
| No URI | 3424/8380 (40.9%) | 11,302/32,332 (35.0%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 4956/8380 (59.1%) | 21,030/32,332 (65.0%) | 0.78 (0.74–0.82) | <0.001 * | 0.79 (0.75–0.83) | <0.001 * | 0.79 (0.75–0.83) | <0.001 * |
| Fasting blood glucose < 100 mg/dL (n = 73,946) | ||||||||
| No URI | 11,302/32,332 (35.0%) | 18,960/59,845 (31.7%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 21,030/32,332 (65.0%) | 40,885/59,845 (68.3%) | 0.84 (0.81–0.87) | <0.001 * | 0.84 (0.81–0.87) | <0.001 * | 0.84 (0.81–0.87) | <0.001 * |
| Fasting blood glucose ≥ 100 mg/dL (n = 60,654) | ||||||||
| No URI | 5033/12,819 (39.3%) | 16,452/47,835 (34.4%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 7786/12,819 (60.7%) | 31,383/47,835 (65.6%) | 0.81 (0.78–0.84) | <0.001 * | 0.82 (0.79–0.85) | <0.001 * | 0.82 (0.79–0.85) | <0.001 * |
| Total cholesterol < 200 mg/dL (n = 77,487) | ||||||||
| No URI | 5765/15,407 (37.4%) | 20,479/62,080 (33.0%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 9642/15,407 (62.6%) | 41,601/62,080 (67.0%) | 0.82 (0.79–0.85) | <0.001 * | 0.83 (0.80–0.86) | <0.001 * | 0.83 (0.80–0.86) | <0.001 * |
| Total cholesterol ≥ 200 mg/dL (n = 57,113) | ||||||||
| No URI | 4291/11,513 (37.3%) | 14,933/45,600 (32.8%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 7222/11,513 (62.7%) | 30,667/45,600 (67.3%) | 0.82 (0.79–0.86) | <0.001 * | 0.83 (0.79–0.86) | <0.001 * | 0.83 (0.80–0.87) | <0.001 * |
| CCI score = 0 (n = 63,571) | ||||||||
| No URI | 3096/8540 (36.3%) | 18,625/55,031 (33.8%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 5444/8540 (63.8%) | 36,406/55,031 (66.2%) | 0.90 (0.86–0.94) | <0.001 * | 0.89 (0.85–0.93) | <0.001 * | 0.89 (0.85–0.94) | <0.001 * |
| CCI score = 1 (n = 27,148) | ||||||||
| No URI | 2248/6260 (35.9%) | 6457/20,888 (30.9%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 4012/6260 (64.1%) | 14,431/20,888 (69.1%) | 0.80 (0.75–0.85) | <0.001 * | 0.80 (0.75–0.85) | <0.001 * | 0.80 (0.76–0.85) | <0.001 * |
| CCI score ≥ 2 (n = 43,881) | ||||||||
| No URI | 4712/12,120 (38.9%) | 10,330/31,761 (32.5%) | 1 | 1 | 1 | |||
| URI ≥ 1 | 7408/12,120 (61.1%) | 21,431/31,761 (67.5%) | 0.76 (0.73–0.79) | <0.001 * | 0.77 (0.73–0.80) | <0.001 * | 0.77 (0.74–0.80) | <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.