Table 4

HRs for incident Alzheimer’s disease, vascular and non-specific dementia during 2005–2013 by air and noise pollutants

ExposureCategory (or IQR change)Alzheimer’s diseaseVascular dementiaNon-specific
HR2* (95% CI)HR2* (95% CI)HR2* (95% CI)
NO(µg/m3)0–31.91 (reference)1 (reference)1 (reference)
>31.9–35.20.98 (0.74 to 1.28)0.94 (0.69 to 1.29)1.09 (0.84 to 1.40)
>35.2–37.50.99 (0.73 to 1.35)0.83 (0.57 to 1.20)1.08 (0.82 to 1.43)
>37.5–41.51.15 (0.84 to 1.58)0.98 (0.66 to 1.44)1.01 (0.75 to 1.35)
>41.51.50 (1.08 to 2.08)1.01 (0.66 to 1.55)1.55 (1.16 to 2.07)
+7.5 (IQR change)1.23 (1.07 to 1.43)1.15 (0.96 to 1.39)1.13 (0.99 to 1.28)
PM2.5 (µg/m3)0–15.11 (reference)1 (reference)1 (reference)
>15.1–15.41.01 (0.77 to 1.32)0.89 (0.66 to 1.20)1.00 (0.77 to 1.28)
>15.4–15.71.13 (0.84 to 1.52)0.72 (0.50 to 1.02)1.13 (0.86 to 1.47)
>15.7–16.31.24 (0.92 to 1.68)0.91 (0.63 to 1.32)1.00 (0.76 to 1.33)
>16.31.42 (1.03 to 1.96)0.86 (0.57 to 1.30)1.33 (0.99 to 1.77)
+0.9 (IQR change)1.10 (1.02 to 1.18)1.06 (0.97 to 1.16)1.06 (0.99 to 1.13)
PM2.5traffic 
(µg/m3)
0–1.041 (reference)1 (reference)1 (reference)
>1.04–1.221.00 (0.76 to 1.30)1.14 (0.86 to 1.52)1.07 (0.84 to 1.38)
>1.22–1.421.09 (0.82 to 1.45)0.92 (0.66 to 1.27)1.06 (0.81 to 1.38)
>1.42–1.751.23 (0.93 to 1.64)0.90 (0.63 to 1.28)0.97 (0.73 to 1.27)
>1.751.46 (1.08 to 1.98)0.99 (0.68 to 1.44)1.33 (1.00 to 1.75)
+0.58 (IQR change)1.13 (1.02 to 1.26)1.08 (0.95 to 1.23)1.08 (0.97 to 1.19)
O(µg/m3)0–34.71 (reference)1 (reference)1 (reference)
>34.7–37.30.83 (0.65 to 1.07)0.88 (0.63 to 1.24)0.68 (0.52 to 0.89)
>37.3–39.10.64 (0.48 to 0.86)0.81 (0.55 to 1.17)0.76 (0.58 to 1.00)
>39.1–41.80.62 (0.46 to 0.85)0.82 (0.55 to 1.23)0.73 (0.55 to 0.96)
>41.80.67 (0.48 to 0.94)0.92 (0.59 to 1.43)0.67 (0.50 to 0.90)
+5.6 (IQR change)0.78 (0.66 to 0.92)0.88 (0.71 to 1.09)0.87 (0.76 to 1.01)
Lnight (dB)0–49.41 (reference)1 (reference)1 (reference)
>49.4–49.60.95 (0.76 to 1.18)1.22 (0.94 to 1.58)1.07 (0.85 to 1.34)
>49.6–50.30.96 (0.77 to 1.20)1.23 (0.94 to 1.59)0.97 (0.77 to 1.23)
>50.3–53.80.94 (0.75 to 1.18)1.17 (0.90 to 1.52)0.93 (0.73 to 1.19)
>53.81.05 (0.84 to 1.31)1.09 (0.83 to 1.42)1.14 (0.91 to 1.43)
+2.7 (IQR change) 1.03 (0.99 to 1.07)1.00 (0.96 to 1.05)1.03 (0.99 to 1.07)
  • *HR2: Cox model with practice fitted as shared frailty. Adjusted for age, sex, ethnicity, smoking, alcohol consumption, body mass index and Index of Multiple Deprivation. For each exposure, models fit either quintiles with reference category, or IQR change.

  • Lnight, night-time noise levels; NO2, nitrogen dioxide; O3, ozone; PM2.5, particulate matter ≤2.5 µm.