Table 2.
Associations of 1-Year PM2.5 a and Temperatureb Exposure With Risk of Metabolic Syndrome and Its Components, Normative Aging Study, 2000–2011
| Metabolic Syndrome or Component | No. of Participants | No. of Observations | No. of Events | PM2.5 Level | Temperature | ||||
|---|---|---|---|---|---|---|---|---|---|
| Hazard Ratio | 95% CI | P Valuec | Hazard Ratio | 95% CI | P Valuec | ||||
| Abdominal obesityd | 396 | 857 | 107 | 1.00 | 0.86, 1.16 | 1.00 | 1.06 | 0.86, 1.31 | 0.58 |
| High fasting blood glucosed | 293 | 562 | 118 | 1.20 | 1.03, 1.39 | 0.02 | 1.33 | 1.14, 1.56 | <0.001 |
| Low HDL cholesterold | 326 | 625 | 165 | 0.98 | 0.85, 1.13 | 0.76 | 1.01 | 0.85, 1.20 | 0.90 |
| Hypertensiond | 116 | 207 | 82 | 1.20 | 0.97, 1.49 | 0.09 | 1.14 | 0.86, 1.50 | 0.37 |
| Hypertriglyceridemiad | 316 | 598 | 154 | 1.14 | 1.00, 1.30 | 0.05 | 1.07 | 0.92, 1.24 | 0.36 |
| Metabolic syndromed , e | 271 | 517 | 140 | 1.27 | 1.06, 1.52 | 0.01 | 0.99 | 0.82, 1.21 | 0.95 |
Abbreviations: HDL, high-density lipoprotein; CI, confidence interval; PM2.5, particulate matter with an aerodynamic diameter less than or equal to 2.5 μm.
a PM2.5 concentration (for each 1 µg/m3) was a 1-year average from daily estimates including aerosol-optical-depth data from the 1-km × 1-km model and 10-km × 10-km model.
b Temperature (for each 1°C) was a 1-year average from daily estimates including aerosol-optical-depth data from the 1-km × 1-km model.
c Two-sided P value.
d The model included both time-dependent variables and variables measured at baseline. Time-dependent variables: age at the visit (years; continuous), dark fish consumption (less than once a week, at least once a week), alcohol consumption (<2 drinks/day, ≥2 drinks/day), smoking status (current, former, never), and physical activity level (metabolic equivalent hours per week, <12, 12–29.9, ≥30). Variables measured at baseline: education (years, ≤12, 12.1–16, >16), whether the participant was a permanent resident of the Greater Boston area (yes/no), and percentage of the participant's census tract that was nonwhite (continuous).
e Category included medications varying over time: diabetes medication (no/yes), statins (no/yes), and antihypertensive medication (no/yes).